kcl_lib/execution/

mod.rs

//! The executor for the AST.

use std::collections::BTreeMap;
use std::sync::Arc;

use anyhow::Result;
pub use artifact::ArtifactCommand;
pub(crate) use artifact::EntityCloneInfo;
pub(crate) use artifact::named_view_artifact;
pub(crate) use artifact::sketch_block_constraint_type;
use cache::GlobalState;
pub use cache::bust_cache;
pub use cache::clear_mem_cache;
pub use geometry::*;
pub use id_generator::IdGenerator;
pub(crate) use import::PreImportedGeometry;
use indexmap::IndexMap;
pub use kcl_api::Operation;
pub use kcl_api::artifact::Artifact;
pub use kcl_api::artifact::ArtifactGraph;
pub use kcl_api::artifact::CapSubType;
pub use kcl_api::artifact::CodeRef;
pub use kcl_api::artifact::GdtAnnotationArtifact;
pub use kcl_api::artifact::SketchBlock;
pub use kcl_api::artifact::SketchBlockConstraint;
#[allow(unused_imports)]
pub use kcl_api::artifact::SketchBlockConstraintType;
pub use kcl_api::artifact::StartSketchOnFace;
pub use kcl_api::artifact::StartSketchOnPlane;
use kcl_api::ast::node_path::NodePath;
pub use kcl_value::KclObjectFields;
pub use kcl_value::KclObjectKind;
pub use kcl_value::KclValue;
pub use kcl_value_view::EdgeCutViewExt;
pub use kcl_value_view::ExtrudeSurfaceViewExt;
pub use kcl_value_view::KclValueView;
pub use kcl_value_view::PathViewExt;
pub use kcl_value_view::SolidViewExt;
use kcmc::ImageFormat;
use kcmc::ModelingCmd;
use kcmc::each_cmd as mcmd;
use kcmc::ok_response::OkModelingCmdResponse;
use kcmc::ok_response::output::TakeSnapshot;
use kcmc::websocket::ModelingSessionData;
use kcmc::websocket::OkWebSocketResponseData;
use kittycad_modeling_cmds::id::ModelingCmdId;
use kittycad_modeling_cmds::{self as kcmc};
pub use memory::EnvironmentRef;
#[cfg(test)]
pub(crate) use memory::MemoryBackendKind;
pub(crate) use modeling::ModelingCmdMeta;
pub use named_views::*;
use serde::Deserialize;
use serde::Serialize;
pub(crate) use sketch_solve::normalize_to_solver_distance_unit;
pub(crate) use sketch_solve::solver_numeric_type;
pub(crate) use solver_arc::SolverArc;
pub(crate) use state::ConstraintKey;
pub(crate) use state::ConstraintState;
pub(crate) use state::ConsumedRegionInfo;
pub(crate) use state::ConsumedRegionOperation;
pub(crate) use state::ConsumedSolidInfo;
pub(crate) use state::ConsumedSolidKey;
pub(crate) use state::ConsumedSolidOperation;
pub use state::DirectTagFilletMeta;
pub use state::DirectTagFilletTagEntry;
pub use state::EdgeRefactorMeta;
pub use state::EdgeRefactorStdlibFn;
pub use state::ExecState;
pub use state::KclVersion;
pub use state::LegacyAngleRefactorMeta;
pub use state::MetaSettings;
pub(crate) use state::ModuleArtifactState;
pub(crate) use state::PendingEdgeRefactorMeta;
pub(crate) use state::PendingLegacyAngleRefactorMeta;
pub use state::RefactorMetadata;
pub(crate) use state::TangencyMode;

use crate::CompilationIssue;
use crate::ExecError;
use crate::KclErrorWithOutputs;
use crate::NodePathExt;
use crate::SourceRange;
use crate::collections::AhashIndexSet;
use crate::engine::EngineBatchContext;
use crate::engine::GridScaleBehavior;
use crate::engine::engine_manager::EngineManager;
use crate::errors::KclError;
use crate::errors::KclErrorDetails;
use crate::execution::cache::CacheInformation;
use crate::execution::cache::CacheResult;
use crate::execution::cad_op::OperationExt;
use crate::execution::import_graph::Universe;
use crate::execution::import_graph::UniverseMap;
use crate::execution::typed_path::TypedPath;
use crate::front::Number;
use crate::front::Object;
use crate::front::ObjectId;
use crate::fs::FileManager;
use crate::fs::FileSystemHandle;
use crate::modules::ModuleExecutionOutcome;
use crate::modules::ModuleId;
use crate::modules::ModulePath;
use crate::modules::ModuleRepr;
use crate::modules::ModuleSource;
use crate::parsing::ast::types::Expr;
use crate::parsing::ast::types::ImportPath;
use crate::parsing::ast::types::NodeRef;

#[derive(Debug, Clone, Serialize, ts_rs::TS, PartialEq, Default)]
#[ts(export)]
pub struct OperationsByModule {
    pub map: IndexMap<ModuleId, Vec<Operation>>,
}

#[derive(Clone, Serialize, ts_rs::TS)]
#[ts(export)]
#[serde(rename_all = "camelCase")]
pub struct OperationCallbackArgs {
    pub module_id: ModuleId,
    pub operation: Operation,
    pub index: usize,
}

pub trait ExecutionCallbacks: std::fmt::Debug + Send + Sync + 'static {
    fn on_operation(&self, _args: OperationCallbackArgs) {}
}

impl OperationsByModule {
    pub fn count(&self) -> usize {
        self.map.values().map(Vec::len).sum()
    }

    pub fn is_empty(&self) -> bool {
        self.map.values().all(Vec::is_empty)
    }

    pub fn get(&self, module_id: &ModuleId) -> Option<&Vec<Operation>> {
        self.map.get(module_id)
    }

    pub fn values(&self) -> indexmap::map::Values<'_, ModuleId, Vec<Operation>> {
        self.map.values()
    }

    pub fn insert(&mut self, module_id: ModuleId, operations: Vec<Operation>) {
        self.map.insert(module_id, operations);
    }
}

pub(crate) mod annotations;
mod artifact;
#[cfg(test)]
pub(crate) use artifact::mermaid_tests::ArtifactGraphMermaidExt;
pub(crate) mod cache;
mod cad_op;
pub(crate) mod exec_ast;
pub mod fn_call;
#[cfg(test)]
mod freedom_analysis_tests;
mod geometry;
#[cfg(test)]
mod hide_id_contract_kcl_test_pins;
mod id_generator;
mod import;
mod import_graph;
pub(crate) mod kcl_value;
pub(crate) mod kcl_value_view;
pub(crate) mod machine;
mod memory;
mod modeling;
mod named_views;
mod sketch_solve;
mod solver_arc;
mod state;
pub mod typed_path;
pub(crate) mod types;

pub(crate) const SKETCH_BLOCK_PARAM_ON: &str = "on";
pub(crate) const SKETCH_OBJECT_META: &str = "meta";
pub(crate) const SKETCH_OBJECT_META_SKETCH: &str = "sketch";

/// Convenience macro for handling [`KclValueControlFlow`] in execution by
/// returning early if it is some kind of early return or stripping off the
/// control flow otherwise. If it's an early return, it's returned as a
/// `Result::Ok`.
macro_rules! control_continue {
    ($control_flow:expr) => {{
        let cf = $control_flow;
        if cf.is_some_return() {
            return Ok(cf);
        } else {
            cf.into_value()
        }
    }};
}
// Expose the macro to other modules.
pub(crate) use control_continue;

/// Convenience macro for handling [`KclValueControlFlow`] in execution by
/// returning early if it is some kind of early return or stripping off the
/// control flow otherwise. If it's an early return, [`EarlyReturn`] is
/// used to return it as a `Result::Err`.
macro_rules! early_return {
    ($control_flow:expr) => {{
        let cf = $control_flow;
        if cf.is_some_return() {
            return Err(EarlyReturn::from(cf));
        } else {
            cf.into_value()
        }
    }};
}
// Expose the macro to other modules.
pub(crate) use early_return;

#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, Serialize)]
pub enum ControlFlowKind {
    /// Normal control flow. Continue to the next step.
    #[default]
    Continue,
    /// A `return` statement executed under KCL 3.0: unwind to the nearest
    /// function-call boundary, which absorbs it as the function's result. Never
    /// constructed under older entry points, whose `return` uses
    /// write-and-continue semantics instead; see `bind_return_value`.
    Return,
    /// `exit()` was called: unwind all the way to the program root, bypassing
    /// function-call boundaries.
    Exit,
}

impl ControlFlowKind {
    /// Returns true if this is any kind of early return.
    pub fn is_some_return(&self) -> bool {
        match self {
            ControlFlowKind::Continue => false,
            ControlFlowKind::Return => true,
            ControlFlowKind::Exit => true,
        }
    }
}

#[must_use = "You should always handle the control flow value when it is returned"]
#[derive(Debug, Clone, PartialEq, Serialize)]
pub struct KclValueControlFlow {
    /// Use [control_continue] or [Self::into_value] to get the value.
    value: Box<KclValue>,
    pub control: ControlFlowKind,
}

impl KclValue {
    pub(crate) fn continue_(self) -> KclValueControlFlow {
        KclValueControlFlow {
            value: Box::new(self),
            control: ControlFlowKind::Continue,
        }
    }

    pub(crate) fn return_(self) -> KclValueControlFlow {
        KclValueControlFlow {
            value: Box::new(self),
            control: ControlFlowKind::Return,
        }
    }

    pub(crate) fn exit(self) -> KclValueControlFlow {
        KclValueControlFlow {
            value: Box::new(self),
            control: ControlFlowKind::Exit,
        }
    }
}

impl KclValueControlFlow {
    /// Returns true if this is any kind of early return.
    pub fn is_some_return(&self) -> bool {
        self.control.is_some_return()
    }

    pub(crate) fn is_return(&self) -> bool {
        matches!(self.control, ControlFlowKind::Return)
    }

    pub(crate) fn is_exit(&self) -> bool {
        matches!(self.control, ControlFlowKind::Exit)
    }

    /// The source ranges of the wrapped value, for error reporting.
    pub(crate) fn source_ranges(&self) -> Vec<SourceRange> {
        self.value.metadata().iter().map(|m| m.source_range).collect()
    }

    pub(crate) fn into_value(self) -> KclValue {
        *self.value
    }
}

/// A [`KclValueControlFlow`] or an error that needs to be returned early. This
/// is useful for when functions might encounter either control flow or errors
/// that need to bubble up early, but these aren't the primary return values of
/// the function. We can use `EarlyReturn` as the error type in a `Result`.
///
/// Normally, you don't construct this directly. Use the `early_return!` macro.
#[must_use = "You should always handle the control flow value when it is returned"]
#[allow(clippy::large_enum_variant)]
#[derive(Debug, Clone)]
pub(crate) enum EarlyReturn {
    /// A normal value with control flow.
    Value(KclValueControlFlow),
    /// An error that occurred during execution.
    Error(KclError),
}

impl From<KclValueControlFlow> for EarlyReturn {
    fn from(cf: KclValueControlFlow) -> Self {
        EarlyReturn::Value(cf)
    }
}

impl From<KclError> for EarlyReturn {
    fn from(err: KclError) -> Self {
        EarlyReturn::Error(err)
    }
}

pub(crate) enum StatementKind<'a> {
    Declaration { name: &'a str },
    Expression,
}

#[derive(Debug, Clone, Copy)]
pub enum PreserveMem {
    Normal,
    Always,
}

impl PreserveMem {
    fn normal(self) -> bool {
        match self {
            PreserveMem::Normal => true,
            PreserveMem::Always => false,
        }
    }
}

/// Outcome of executing a program.  This is used in TS.
#[derive(Debug, Clone, Serialize, ts_rs::TS, PartialEq)]
#[ts(export)]
#[serde(rename_all = "camelCase")]
pub struct ExecOutcome {
    /// Variables in the top-level of the root module. Note that functions will have an invalid env ref.
    pub variables: IndexMap<String, KclValueView>,
    /// Runtime memory retained only for tests that need to verify internal behavior.
    #[cfg(test)]
    #[serde(skip)]
    #[ts(skip)]
    pub(crate) test_program_memory: IndexMap<String, KclValue>,
    /// Operations that have been performed in execution order, grouped by
    /// owning module id, for display in the Feature Tree.
    pub operations: OperationsByModule,
    /// Output artifact graph.
    pub artifact_graph: ArtifactGraph,
    /// Objects in the scene, created from execution.
    #[serde(skip)]
    pub scene_objects: Vec<Object>,
    /// Map from source range to object ID for lookup of objects by their source
    /// range.
    #[serde(skip)]
    pub source_range_to_object: BTreeMap<SourceRange, ObjectId>,
    #[serde(skip)]
    pub var_solutions: Vec<(SourceRange, Option<NodePath>, Number)>,
    /// Execution-backed metadata used by Z0006 and future auto-refactors.
    pub refactor_metadata: Vec<RefactorMetadata>,
    /// Non-fatal errors and warnings.
    pub issues: Vec<CompilationIssue>,
    /// File Names in module Id array index order
    pub filenames: IndexMap<ModuleId, ModulePath>,
    /// Source code of each module, for rendering issues against the module
    /// their source range points into. Not serialized to keep the WASM
    /// payload small; native callers (e.g. the Python bindings) read it
    /// directly.
    #[serde(skip)]
    pub source_files: IndexMap<ModuleId, ModuleSource>,
    /// The default planes.
    pub default_planes: Option<DefaultPlanes>,
}

/// Per-segment freedom used by the constraint report. Mirrors
/// [`crate::front::Freedom`] but adds an `Error` variant for when
/// a point lookup fails.
#[derive(Debug, Clone, Copy, PartialEq)]
enum SegmentFreedom {
    Free,
    Fixed,
    Conflict,
    /// A required point could not be found in the scene graph.
    Error,
}

impl From<crate::front::Freedom> for SegmentFreedom {
    fn from(f: crate::front::Freedom) -> Self {
        match f {
            crate::front::Freedom::Free => Self::Free,
            crate::front::Freedom::Fixed => Self::Fixed,
            crate::front::Freedom::Conflict => Self::Conflict,
        }
    }
}

/// Overall constraint status of a sketch.
#[derive(Debug, Clone, Copy, PartialEq, Serialize, Deserialize)]
pub enum ConstraintKind {
    FullyConstrained,
    UnderConstrained,
    OverConstrained,
    /// Analysis could not determine constraint status (e.g., a point lookup
    /// failed due to an inconsistent scene graph). Callers decide how to treat
    /// this — as under-constrained, over-constrained, or something else.
    Error,
}

/// Per-sketch summary of constraint freedom analysis.
///
/// A sketch with no countable segments (`total_count == 0`) is reported as
/// [`ConstraintKind::FullyConstrained`]. This is vacuously true — there are
/// no free or conflicting segments. Callers can check `total_count == 0` to
/// distinguish this from a genuinely constrained sketch.
#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
pub struct SketchConstraintStatus {
    /// Name of the variable the sketch was assigned to, for example
    /// "sketch001". This is the nearest enclosing declaration at the point the
    /// sketch was created, which is not always the sketch's own name:
    /// - Empty for a sketch written as an expression statement, because there
    ///   is no enclosing declaration.
    /// - The outer variable's name for a sketch passed straight into another
    ///   call, as in `part = extrude(sketch(on = XY) { ... }, length = 10)`.
    /// - The same name for two sketches, when a function body declares the
    ///   sketch and is called more than once.
    ///
    /// This name is accepted by [`ExecOutcome::render_sketch_png`]. Because
    /// the report carries no other sketch identifier, rendering returns an
    /// ambiguity error when multiple sketches share a name.
    pub name: String,
    /// Overall constraint status derived from per-segment freedom.
    pub status: ConstraintKind,
    /// Number of segments that are under-constrained (free to move).
    pub free_count: usize,
    /// Number of segments that are over-constrained (conflicting constraints).
    pub conflict_count: usize,
    /// Total number of segments analyzed.
    pub total_count: usize,
}

/// Grouped report of all sketches by constraint status.
#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
pub struct SketchConstraintReport {
    pub fully_constrained: Vec<SketchConstraintStatus>,
    pub under_constrained: Vec<SketchConstraintStatus>,
    pub over_constrained: Vec<SketchConstraintStatus>,
    /// Sketches where analysis encountered an error (e.g., a point lookup
    /// failed). Callers decide how to treat these.
    pub errors: Vec<SketchConstraintStatus>,
}

/// Compute the constraint status for a single sketch object.
///
/// Returns `None` if `sketch_obj` is not a sketch.
///
/// Note: a sketch with no countable segments (`total_count == 0`) is reported
/// as [`ConstraintKind::FullyConstrained`]. This is vacuously true — there are
/// no free or conflicting segments. Callers can check `total_count == 0` to
/// distinguish this from a genuinely constrained sketch.
pub(crate) fn sketch_constraint_status_for_sketch(
    scene_objects: &[Object],
    sketch_obj: &Object,
) -> Option<SketchConstraintStatus> {
    use crate::front::ObjectKind;
    use crate::front::Segment;

    let ObjectKind::Sketch(sketch) = &sketch_obj.kind else {
        return None;
    };

    // Closure to look up a point's freedom by ObjectId.
    let lookup = |id: ObjectId| -> Option<crate::front::Freedom> {
        let obj = scene_objects.get(id.0)?;
        if let ObjectKind::Segment {
            segment: Segment::Point(p),
        } = &obj.kind
        {
            Some(p.freedom())
        } else {
            None
        }
    };

    let mut free_count: usize = 0;
    let mut conflict_count: usize = 0;
    let mut error_count: usize = 0;
    let mut total_count: usize = 0;

    for &seg_id in &sketch.segments {
        let Some(seg_obj) = scene_objects.get(seg_id.0) else {
            continue;
        };
        let ObjectKind::Segment { segment } = &seg_obj.kind else {
            continue;
        };
        // Skip owned points — their freedom is already captured by
        // the parent geometry (Line/Arc/Circle) that looks them up.
        if let Segment::Point(p) = segment
            && p.owner.is_some()
        {
            continue;
        }
        let freedom = segment
            .freedom(lookup)
            .map(SegmentFreedom::from)
            .unwrap_or(SegmentFreedom::Error);
        total_count += 1;
        match freedom {
            SegmentFreedom::Free => free_count += 1,
            SegmentFreedom::Conflict => conflict_count += 1,
            SegmentFreedom::Error => error_count += 1,
            SegmentFreedom::Fixed => {}
        }
    }

    let status = if error_count > 0 {
        ConstraintKind::Error
    } else if conflict_count > 0 {
        ConstraintKind::OverConstrained
    } else if free_count > 0 {
        ConstraintKind::UnderConstrained
    } else {
        ConstraintKind::FullyConstrained
    };

    Some(SketchConstraintStatus {
        name: sketch_obj.label.clone(),
        status,
        free_count,
        conflict_count,
        total_count,
    })
}

pub(crate) fn sketch_constraint_report_from_scene_objects(scene_objects: &[Object]) -> SketchConstraintReport {
    let mut fully_constrained = Vec::new();
    let mut under_constrained = Vec::new();
    let mut over_constrained = Vec::new();
    let mut errors = Vec::new();
    for obj in scene_objects {
        let Some(entry) = sketch_constraint_status_for_sketch(scene_objects, obj) else {
            continue;
        };
        match entry.status {
            ConstraintKind::FullyConstrained => fully_constrained.push(entry),
            ConstraintKind::UnderConstrained => under_constrained.push(entry),
            ConstraintKind::OverConstrained => over_constrained.push(entry),
            ConstraintKind::Error => errors.push(entry),
        }
    }

    SketchConstraintReport {
        fully_constrained,
        under_constrained,
        over_constrained,
        errors,
    }
}

impl ExecOutcome {
    pub fn scene_object_by_id(&self, id: ObjectId) -> Option<&Object> {
        debug_assert!(
            id.0 < self.scene_objects.len(),
            "Requested object ID {} but only have {} objects",
            id.0,
            self.scene_objects.len()
        );
        self.scene_objects.get(id.0)
    }

    /// Returns non-fatal errors. Warnings are not included.
    pub fn errors(&self) -> impl Iterator<Item = &CompilationIssue> {
        self.issues.iter().filter(|error| error.is_err())
    }

    /// Analyze all sketches in the execution result and group them by
    /// constraint status (fully, under, or over constrained).
    ///
    /// Each segment in a sketch computes its own freedom by looking up the
    /// freedom of its constituent points. Owned points (belonging to a
    /// Line/Arc/Circle) are skipped to avoid double-counting.
    pub fn sketch_constraint_report(&self) -> SketchConstraintReport {
        sketch_constraint_report_from_scene_objects(&self.scene_objects)
    }

    /// Render one sketch from this execution result as a PNG, colored by
    /// solver freedom.
    pub fn render_sketch_png(
        &self,
        sketch_name: &str,
    ) -> std::result::Result<Vec<u8>, crate::tooling::sketch_visualizer::SketchVisualizationError> {
        use crate::front::ObjectKind;
        use crate::tooling::sketch_visualizer::SketchVisualizationError;

        let sketches = self
            .scene_objects
            .iter()
            .filter_map(|object| match &object.kind {
                ObjectKind::Sketch(sketch) if object.label == sketch_name => Some(sketch),
                _ => None,
            })
            .collect::<Vec<_>>();
        let sketch = match sketches.as_slice() {
            [] => {
                return Err(SketchVisualizationError::SketchNotFound {
                    name: sketch_name.to_owned(),
                });
            }
            [sketch] => *sketch,
            _ => {
                return Err(SketchVisualizationError::AmbiguousSketchName {
                    name: sketch_name.to_owned(),
                    count: sketches.len(),
                });
            }
        };

        crate::tooling::sketch_visualizer::render_sketch_png(&self.scene_objects, sketch)
    }
}

/// Configuration for mock execution.
#[derive(Debug, Clone, PartialEq)]
pub struct MockConfig {
    pub use_prev_memory: bool,
    /// The `ObjectId` of the sketch block to execute for sketch mode. Only the
    /// specified sketch block will be executed. All other code is ignored.
    pub sketch_block_id: Option<ObjectId>,
    /// True to do more costly analysis of whether the sketch block segments are
    /// under-constrained.
    pub freedom_analysis: bool,
    /// The segments that were edited that triggered this execution.
    pub segment_ids_edited: AhashIndexSet<ObjectId>,
    /// Segment-body drag anchors that temporarily pull a point on a segment toward the cursor.
    pub drag_anchors: Vec<SegmentDragAnchor>,
}

#[derive(Debug, Clone, PartialEq, Deserialize, Serialize, ts_rs::TS)]
#[ts(export, export_to = "FrontendApi.ts")]
#[serde(rename_all = "camelCase")]
pub struct SegmentDragAnchor {
    pub segment_id: ObjectId,
    pub target: crate::front::Point2d<Number>,
}

impl Default for MockConfig {
    fn default() -> Self {
        Self {
            // By default, use previous memory. This is usually what you want.
            use_prev_memory: true,
            sketch_block_id: None,
            freedom_analysis: true,
            segment_ids_edited: AhashIndexSet::default(),
            drag_anchors: Vec::new(),
        }
    }
}

impl MockConfig {
    /// Create a new mock config for sketch mode.
    pub fn new_sketch_mode(sketch_block_id: ObjectId) -> Self {
        Self {
            sketch_block_id: Some(sketch_block_id),
            ..Default::default()
        }
    }

    #[must_use]
    pub(crate) fn no_freedom_analysis(mut self) -> Self {
        self.freedom_analysis = false;
        self
    }
}

#[derive(Debug, Default, Clone, Deserialize, Serialize, PartialEq, ts_rs::TS)]
#[ts(export)]
#[serde(rename_all = "camelCase")]
pub struct DefaultPlanes {
    pub xy: uuid::Uuid,
    pub xz: uuid::Uuid,
    pub yz: uuid::Uuid,
    pub neg_xy: uuid::Uuid,
    pub neg_xz: uuid::Uuid,
    pub neg_yz: uuid::Uuid,
}

#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, ts_rs::TS)]
#[ts(export)]
#[serde(tag = "type", rename_all = "camelCase")]
pub struct TagIdentifier {
    pub value: String,
    // Multi-version representation of info about the tag. Kept ordered. The usize is the epoch at which the info
    // was written.
    #[serde(skip)]
    pub info: Vec<(usize, TagEngineInfo)>,
    #[serde(skip)]
    pub meta: Vec<Metadata>,
}

impl TagIdentifier {
    /// Get the tag info for this tag at a specified epoch.
    pub fn get_info(&self, at_epoch: usize) -> Option<&TagEngineInfo> {
        for (e, info) in self.info.iter().rev() {
            if *e <= at_epoch {
                return Some(info);
            }
        }

        None
    }

    /// Get the most recent tag info for this tag.
    pub fn get_cur_info(&self) -> Option<&TagEngineInfo> {
        self.info.last().map(|i| &i.1)
    }

    /// Get all tag info entries at the most recent epoch.
    /// For region-mapped tags, this returns multiple entries (one per region segment).
    pub fn get_all_cur_info(&self) -> Vec<&TagEngineInfo> {
        let Some(cur_epoch) = self.info.last().map(|(e, _)| *e) else {
            return vec![];
        };
        self.info
            .iter()
            .rev()
            .take_while(|(e, _)| *e == cur_epoch)
            .map(|(_, info)| info)
            .collect()
    }

    /// Add info from a different instance of this tag.
    pub fn merge_info(&mut self, other: &TagIdentifier) {
        assert_eq!(&self.value, &other.value);
        for (oe, ot) in &other.info {
            if let Some((e, t)) = self.info.last_mut() {
                // If there is newer info, then skip this iteration.
                if *e > *oe {
                    continue;
                }
                // If we're in the same epoch, then overwrite.
                if e == oe {
                    *t = ot.clone();
                    continue;
                }
            }
            self.info.push((*oe, ot.clone()));
        }
    }

    pub fn geometry(&self) -> Option<Geometry> {
        self.get_cur_info().map(|info| info.geometry.clone())
    }

    pub(crate) fn is_body_created_tag(&self) -> bool {
        self.get_cur_info().is_some_and(|info| {
            matches!(&info.geometry, Geometry::Solid(_)) && info.path.is_none() && info.surface.is_some()
        })
    }
}

impl Eq for TagIdentifier {}

impl std::fmt::Display for TagIdentifier {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "{}", self.value)
    }
}

impl std::str::FromStr for TagIdentifier {
    type Err = KclError;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        Ok(Self {
            value: s.to_string(),
            info: Vec::new(),
            meta: Default::default(),
        })
    }
}

impl Ord for TagIdentifier {
    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
        self.value.cmp(&other.value)
    }
}

impl PartialOrd for TagIdentifier {
    fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
        Some(self.cmp(other))
    }
}

impl std::hash::Hash for TagIdentifier {
    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
        self.value.hash(state);
    }
}

/// Engine information for a tag.
#[derive(Debug, Clone, Serialize, PartialEq, ts_rs::TS)]
#[ts(export)]
#[serde(tag = "type", rename_all = "camelCase")]
pub struct TagEngineInfo {
    /// The id of the tagged object.
    pub id: uuid::Uuid,
    /// The geometry the tag is on.
    pub geometry: Geometry,
    /// The path the tag is on.
    pub path: Option<Path>,
    /// The surface information for the tag.
    pub surface: Option<ExtrudeSurface>,
}

#[derive(Debug, Copy, Clone, Deserialize, Serialize, PartialEq)]
pub enum BodyType {
    Root,
    Block,
}

/// Metadata.
#[derive(Debug, Clone, Deserialize, Serialize, PartialEq, ts_rs::TS, Eq, Copy)]
#[ts(export)]
#[serde(rename_all = "camelCase")]
pub struct Metadata {
    /// The source range.
    pub source_range: SourceRange,
}

impl From<Metadata> for Vec<SourceRange> {
    fn from(meta: Metadata) -> Self {
        vec![meta.source_range]
    }
}

impl From<&Metadata> for SourceRange {
    fn from(meta: &Metadata) -> Self {
        meta.source_range
    }
}

impl From<SourceRange> for Metadata {
    fn from(source_range: SourceRange) -> Self {
        Self { source_range }
    }
}

impl<T> From<NodeRef<'_, T>> for Metadata {
    fn from(node: NodeRef<'_, T>) -> Self {
        Self {
            source_range: SourceRange::new(node.start, node.end, node.module_id),
        }
    }
}

impl From<&Expr> for Metadata {
    fn from(expr: &Expr) -> Self {
        Self {
            source_range: SourceRange::from(expr),
        }
    }
}

impl Metadata {
    pub fn to_source_ref(meta: &[Metadata], node_path: Option<NodePath>) -> crate::front::SourceRef {
        if meta.len() == 1 {
            let meta = &meta[0];
            return crate::front::SourceRef::Simple {
                range: meta.source_range,
                node_path,
            };
        }
        crate::front::SourceRef::BackTrace {
            ranges: meta.iter().map(|m| (m.source_range, node_path.clone())).collect(),
        }
    }
}

/// The type of ExecutorContext being used
#[derive(PartialEq, Debug, Default, Clone)]
pub enum ContextType {
    /// Live engine connection
    #[default]
    Live,

    /// Completely mocked connection
    /// Mock mode is only for the Design Studio when they just want to mock engine calls and not
    /// actually make them.
    Mock,

    /// Handled by some other interpreter/conversion system
    MockCustomForwarded,
}

/// The executor context.
/// Cloning will return another handle to the same engine connection/session,
/// as this uses `Arc` under the hood.
#[derive(Clone)]
pub struct ExecutorContext {
    pub engine: Arc<EngineManager>,
    pub engine_batch: EngineBatchContext,
    pub fs: FileSystemHandle,
    pub settings: ExecutorSettings,
    pub context_type: ContextType,
    pub execution_callbacks: Option<Arc<dyn ExecutionCallbacks>>,
    /// Which executor evaluates KCL. Crate-internal: set before the first
    /// run and immutable during execution (run methods take &self). Cloned
    /// contexts (fresh roots, Args) inherit the same executor.
    pub(crate) executor_kind: machine::ExecutorKind,
    /// Call-depth limit for the machine executor's runaway-recursion guard.
    /// Crate-internal policy, not user configuration.
    pub(crate) machine_call_depth_limit: usize,
}

impl std::fmt::Debug for ExecutorContext {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.debug_struct("ExecutorContext")
            .field("engine", &self.engine)
            .field("engine_batch", &self.engine_batch)
            .field("settings", &self.settings)
            .field("context_type", &self.context_type)
            .field("execution_callbacks", &self.execution_callbacks)
            .field("executor_kind", &self.executor_kind)
            .field("machine_call_depth_limit", &self.machine_call_depth_limit)
            .finish()
    }
}

/// The executor settings.
#[derive(Debug, Clone, Deserialize, Serialize, PartialEq, ts_rs::TS)]
#[ts(export)]
pub struct ExecutorSettings {
    /// Highlight edges of 3D objects?
    pub highlight_edges: bool,
    /// Whether or not Screen Space Ambient Occlusion (SSAO) is enabled.
    pub enable_ssao: bool,
    /// Show grid?
    pub show_grid: bool,
    /// Should engine store this for replay?
    /// If so, under what name?
    pub replay: Option<String>,
    /// The directory of the current project.  This is used for resolving import
    /// paths.  If None is given, the current working directory is used.
    pub project_directory: Option<TypedPath>,
    /// This is the path to the current file being executed.
    /// We use this for preventing cyclic imports.
    pub current_file: Option<TypedPath>,
    /// Whether or not to automatically scale the grid when user zooms.
    pub fixed_size_grid: bool,
    /// Skip sending the engine messages that are only needed to build the
    /// artifact graph. When this is true, the artifact graph will be
    /// incomplete. So you should only use this option if you know you don't
    /// need the artifact graph or anything that depends on it. In that case,
    /// skipping these commands can make execution slightly faster.
    #[serde(default, skip_serializing_if = "is_false")]
    pub skip_artifact_graph: bool,
    /// If Some(N), sends a heartbeat to keep the WebSocket active, every N seconds.
    /// If None, no heartbeats will be sent.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub heartbeats: Option<u64>,
    /// If given, sets the default backface colour.
    /// If not, defaults to whatever the engine's default is.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub default_backface_color: Option<String>,
    /// asks the engine for geometry only mode - no video stream
    pub geometry_only: bool,
}

fn is_false(b: &bool) -> bool {
    !*b
}

impl Default for ExecutorSettings {
    fn default() -> Self {
        Self {
            highlight_edges: true,
            enable_ssao: false,
            show_grid: false,
            replay: None,
            project_directory: None,
            current_file: None,
            fixed_size_grid: true,
            skip_artifact_graph: false,
            heartbeats: None,
            default_backface_color: None,
            geometry_only: false,
        }
    }
}

impl From<crate::settings::types::Configuration> for ExecutorSettings {
    fn from(config: crate::settings::types::Configuration) -> Self {
        Self::from(config.settings)
    }
}

impl From<crate::settings::types::Settings> for ExecutorSettings {
    fn from(settings: crate::settings::types::Settings) -> Self {
        let modeling_settings = settings.modeling.unwrap_or_default();
        Self {
            highlight_edges: modeling_settings.highlight_edges.unwrap_or_default().into(),
            enable_ssao: modeling_settings.enable_ssao.unwrap_or_default().into(),
            show_grid: modeling_settings.show_scale_grid.unwrap_or_default(),
            replay: None,
            project_directory: None,
            current_file: None,
            fixed_size_grid: modeling_settings.fixed_size_grid.unwrap_or_default().0,
            skip_artifact_graph: false,
            heartbeats: None,
            default_backface_color: modeling_settings.backface_color.map(|color| color.0),
            geometry_only: false,
        }
    }
}

impl From<crate::settings::types::project::ProjectConfiguration> for ExecutorSettings {
    fn from(config: crate::settings::types::project::ProjectConfiguration) -> Self {
        Self::from(config.settings.modeling)
    }
}

impl From<crate::settings::types::ModelingSettings> for ExecutorSettings {
    fn from(modeling: crate::settings::types::ModelingSettings) -> Self {
        Self {
            highlight_edges: modeling.highlight_edges.unwrap_or_default().into(),
            enable_ssao: modeling.enable_ssao.unwrap_or_default().into(),
            show_grid: modeling.show_scale_grid.unwrap_or_default(),
            replay: None,
            project_directory: None,
            current_file: None,
            fixed_size_grid: true,
            skip_artifact_graph: false,
            heartbeats: None,
            default_backface_color: modeling.backface_color.map(|color| color.0),
            geometry_only: false,
        }
    }
}

impl From<crate::settings::types::project::ProjectModelingSettings> for ExecutorSettings {
    fn from(modeling: crate::settings::types::project::ProjectModelingSettings) -> Self {
        Self {
            highlight_edges: modeling.highlight_edges.into(),
            enable_ssao: modeling.enable_ssao.into(),
            show_grid: Default::default(),
            replay: None,
            project_directory: None,
            current_file: None,
            fixed_size_grid: true,
            skip_artifact_graph: false,
            heartbeats: None,
            default_backface_color: None,
            geometry_only: false,
        }
    }
}

impl ExecutorSettings {
    /// Add the current file path to the executor settings.
    pub fn with_current_file(&mut self, current_file: TypedPath) {
        // We want the parent directory of the file.
        if current_file.extension() == Some("kcl") {
            self.current_file = Some(current_file.clone());
            // Get the parent directory.
            if let Some(parent) = current_file.parent() {
                self.project_directory = Some(parent);
            } else {
                self.project_directory = Some(TypedPath::from(""));
            }
        } else {
            self.project_directory = Some(current_file);
        }
    }
}

impl ExecutorContext {
    /// Create a new live executor context from an engine and file manager.
    pub fn new_with_engine_and_fs(
        engine: Arc<EngineManager>,
        fs: FileSystemHandle,
        settings: ExecutorSettings,
    ) -> Self {
        ExecutorContext {
            engine,
            engine_batch: EngineBatchContext::default(),
            fs,
            settings,
            context_type: ContextType::Live,
            execution_callbacks: Default::default(),
            executor_kind: machine::ExecutorKind::resolve(),
            machine_call_depth_limit: machine::DEFAULT_MACHINE_CALL_DEPTH_LIMIT,
        }
    }

    fn clone_with_fresh_execution_batch(&self) -> Self {
        Self {
            engine: self.engine.clone(),
            engine_batch: EngineBatchContext::new(),
            fs: self.fs.clone(),
            settings: self.settings.clone(),
            context_type: self.context_type.clone(),
            execution_callbacks: self.execution_callbacks.clone(),
            // Imported modules execute on this cloned context; keep them on
            // the executor selected for the run instead of the default.
            executor_kind: self.executor_kind,
            machine_call_depth_limit: self.machine_call_depth_limit,
        }
    }

    /// Create a new live executor context from an engine using the local file manager.
    #[cfg(not(target_arch = "wasm32"))]
    pub fn new_with_engine(engine: Arc<EngineManager>, settings: ExecutorSettings) -> Self {
        Self::new_with_engine_and_fs(engine, crate::fs::new_file_system_handle(FileManager::new()), settings)
    }

    /// Create a new default executor context.
    #[cfg(not(target_arch = "wasm32"))]
    pub async fn new(client: &kittycad::Client, settings: ExecutorSettings) -> Result<Self> {
        let pr = std::env::var("ZOO_ENGINE_PR").ok().and_then(|s| s.parse().ok());
        let (ws, _headers) = client
            .modeling()
            .commands_ws(kittycad::modeling::CommandsWsParams {
                api_call_id: None,
                fps: None,
                order_independent_transparency: None,
                post_effect: if settings.enable_ssao {
                    Some(kittycad::types::PostEffectType::Ssao)
                } else {
                    None
                },
                replay: settings.replay.clone(),
                show_grid: if settings.show_grid { Some(true) } else { None },
                pool: settings.geometry_only.then_some("cpu".to_string()),
                geometry_only: Some(settings.geometry_only),
                kcl_version: None,
                pr,
                unlocked_framerate: None,
                webrtc: Some(false),
                video_res_width: None,
                video_res_height: None,
            })
            .await?;

        let engine_conn = EngineManager::new_websocket_transport(ws, settings.heartbeats).await;
        let engine = Arc::new(engine_conn);

        Ok(Self::new_with_engine(engine, settings))
    }

    #[cfg(target_arch = "wasm32")]
    pub fn new(engine: Arc<EngineManager>, fs: FileSystemHandle, settings: ExecutorSettings) -> Self {
        Self::new_with_engine_and_fs(engine, fs, settings)
    }

    #[cfg(not(target_arch = "wasm32"))]
    pub async fn new_mock(settings: Option<ExecutorSettings>) -> Self {
        ExecutorContext {
            engine: Arc::new(EngineManager::new_mock()),
            engine_batch: EngineBatchContext::default(),
            fs: crate::fs::new_file_system_handle(FileManager::new()),
            settings: settings.unwrap_or_default(),
            context_type: ContextType::Mock,
            execution_callbacks: Default::default(),
            executor_kind: machine::ExecutorKind::resolve(),
            machine_call_depth_limit: machine::DEFAULT_MACHINE_CALL_DEPTH_LIMIT,
        }
    }

    #[cfg(target_arch = "wasm32")]
    pub fn new_mock(engine: Arc<EngineManager>, fs: FileSystemHandle, settings: ExecutorSettings) -> Self {
        ExecutorContext {
            engine,
            engine_batch: EngineBatchContext::default(),
            fs,
            settings,
            context_type: ContextType::Mock,
            execution_callbacks: Default::default(),
            executor_kind: machine::ExecutorKind::resolve(),
            machine_call_depth_limit: machine::DEFAULT_MACHINE_CALL_DEPTH_LIMIT,
        }
    }

    /// Create a new mock executor context for WASM LSP servers.
    /// This is a convenience function that creates a mock engine and FileManager from a FileSystemManager.
    #[cfg(target_arch = "wasm32")]
    pub fn new_mock_for_lsp(
        fs_manager: crate::fs::wasm::FileSystemManager,
        settings: ExecutorSettings,
    ) -> Result<Self, String> {
        let fs = crate::fs::new_file_system_handle(FileManager::new(fs_manager));

        Ok(ExecutorContext {
            engine: Arc::new(EngineManager::new_mock()),
            engine_batch: EngineBatchContext::default(),
            fs,
            settings,
            context_type: ContextType::Mock,
            execution_callbacks: Default::default(),
            executor_kind: machine::ExecutorKind::resolve(),
            machine_call_depth_limit: machine::DEFAULT_MACHINE_CALL_DEPTH_LIMIT,
        })
    }

    #[cfg(not(target_arch = "wasm32"))]
    pub fn new_forwarded_mock(engine: Arc<EngineManager>) -> Self {
        ExecutorContext {
            engine,
            engine_batch: EngineBatchContext::default(),
            fs: crate::fs::new_file_system_handle(FileManager::new()),
            settings: Default::default(),
            context_type: ContextType::MockCustomForwarded,
            execution_callbacks: Default::default(),
            executor_kind: machine::ExecutorKind::resolve(),
            machine_call_depth_limit: machine::DEFAULT_MACHINE_CALL_DEPTH_LIMIT,
        }
    }

    /// Create a new default executor context.
    /// With a kittycad client.
    /// This allows for passing in `ZOO_API_TOKEN` and `ZOO_HOST` as environment
    /// variables.
    /// But also allows for passing in a token and engine address directly.
    #[cfg(not(target_arch = "wasm32"))]
    pub async fn new_with_client(
        settings: ExecutorSettings,
        token: Option<String>,
        engine_addr: Option<String>,
    ) -> Result<Self> {
        // Create the client.
        let client = crate::engine::new_zoo_client(token, engine_addr)?;

        let ctx = Self::new(&client, settings).await?;
        Ok(ctx)
    }

    /// Create a new default executor context.
    /// With the default kittycad client.
    /// This allows for passing in `ZOO_API_TOKEN` and `ZOO_HOST` as environment
    /// variables.
    #[cfg(not(target_arch = "wasm32"))]
    pub async fn new_with_default_client() -> Result<Self> {
        // Create the client.
        let ctx = Self::new_with_client(Default::default(), None, None).await?;
        Ok(ctx)
    }

    /// For executing unit tests.
    #[cfg(not(target_arch = "wasm32"))]
    pub async fn new_for_unit_test(engine_addr: Option<String>) -> Result<Self> {
        let ctx = ExecutorContext::new_with_client(
            ExecutorSettings {
                highlight_edges: true,
                enable_ssao: false,
                show_grid: false,
                replay: None,
                project_directory: None,
                current_file: None,
                fixed_size_grid: false,
                skip_artifact_graph: false,
                heartbeats: None,
                default_backface_color: None,
                geometry_only: false,
            },
            None,
            engine_addr,
        )
        .await?;
        Ok(ctx)
    }

    pub fn is_mock(&self) -> bool {
        self.context_type == ContextType::Mock || self.context_type == ContextType::MockCustomForwarded
    }

    /// Returns true if we should not send engine commands for any reason.
    pub async fn no_engine_commands(&self) -> bool {
        self.is_mock()
    }

    pub async fn send_clear_scene(
        &self,
        exec_state: &mut ExecState,
        source_range: crate::execution::SourceRange,
    ) -> Result<(), KclError> {
        // Ensure artifacts are cleared so that we don't accumulate them across
        // runs.
        exec_state.mod_local.artifacts.clear();
        exec_state.global.root_module_artifacts.clear();
        exec_state.global.artifacts.clear();

        self.engine
            .clear_scene(&self.engine_batch, &mut exec_state.mod_local.id_generator, source_range)
            .await?;
        // The engine errors out if you toggle OIT with SSAO off.
        // So ignore OIT settings if SSAO is off.
        if self.settings.enable_ssao {
            let cmd_id = exec_state.next_uuid();
            exec_state
                .batch_modeling_cmd(
                    ModelingCmdMeta::with_id(exec_state, self, source_range, cmd_id),
                    ModelingCmd::from(mcmd::SetOrderIndependentTransparency::builder().enabled(false).build()),
                )
                .await?;
        }
        Ok(())
    }

    pub async fn bust_cache_and_reset_scene(&self) -> Result<ExecOutcome, KclErrorWithOutputs> {
        cache::bust_cache().await;

        // Execute an empty program to clear and reset the scene.
        // We specifically want to be returned the objects after the scene is reset.
        // Like the default planes so it is easier to just execute an empty program
        // after the cache is busted.
        let outcome = self.run_with_caching(crate::Program::empty()).await?;

        Ok(outcome)
    }

    async fn prepare_mem(&self, exec_state: &mut ExecState) -> Result<(), KclErrorWithOutputs> {
        self.eval_prelude(exec_state, SourceRange::synthetic())
            .await
            .map_err(KclErrorWithOutputs::no_outputs)?;
        exec_state
            .mut_stack()
            .push_new_root_env(true)
            .map_err(KclErrorWithOutputs::no_outputs)?;
        Ok(())
    }

    fn restore_mock_memory(
        exec_state: &mut ExecState,
        mem: cache::SketchModeState,
        _mock_config: &MockConfig,
    ) -> Result<(), KclErrorWithOutputs> {
        *exec_state.mut_stack() = mem.stack;
        exec_state.global.module_infos = mem.module_infos;
        exec_state.global.path_to_source_id = mem.path_to_source_id;
        exec_state.global.id_to_source = mem.id_to_source;
        exec_state.mod_local.constraint_state = mem.constraint_state;
        let len = _mock_config
            .sketch_block_id
            .map(|sketch_block_id| sketch_block_id.0)
            .unwrap_or(0);
        if let Some(scene_objects) = mem.scene_objects.get(0..len) {
            exec_state
                .global
                .root_module_artifacts
                .restore_scene_objects(scene_objects);
        } else {
            let message = format!(
                "Cached scene objects length {} is less than expected length from cached object ID generator {}",
                mem.scene_objects.len(),
                len
            );
            debug_assert!(false, "{message}");
            return Err(KclErrorWithOutputs::no_outputs(KclError::new_internal(
                KclErrorDetails::new(message, vec![SourceRange::synthetic()]),
            )));
        }

        Ok(())
    }

    pub async fn run_mock(
        &self,
        program: &crate::Program,
        mock_config: &MockConfig,
    ) -> Result<ExecOutcome, KclErrorWithOutputs> {
        let (exec_state, main_ref) = self.run_mock_returning_state(program, mock_config).await?;

        // Restore any temporary variables, then save any newly created variables back to
        // memory in case another run wants to use them. Note this is just saved to the preserved
        // memory, not to the exec_state which is not cached for mock execution.

        let mut stack = exec_state.stack().clone();
        let module_infos = exec_state.global.module_infos.clone();
        let path_to_source_id = exec_state.global.path_to_source_id.clone();
        let id_to_source = exec_state.global.id_to_source.clone();
        let constraint_state = exec_state.mod_local.constraint_state.clone();
        let scene_objects = exec_state.global.root_module_artifacts.scene_objects.clone();
        let outcome = exec_state
            .into_exec_outcome(main_ref, self)
            .await
            .map_err(KclErrorWithOutputs::no_outputs)?;

        stack.squash_env(main_ref).map_err(KclErrorWithOutputs::no_outputs)?;
        let state = cache::SketchModeState {
            stack,
            module_infos,
            path_to_source_id,
            id_to_source,
            constraint_state,
            scene_objects,
        };
        cache::write_old_memory(state).await;

        Ok(outcome)
    }

    /// The mock-execution pipeline through interpretation: set up mock state,
    /// restore or prepare memory, and execute. Split from [`Self::run_mock`],
    /// which converts the state to an [`ExecOutcome`], so that tests can
    /// inspect the [`ExecState`] after a mock run.
    async fn run_mock_returning_state(
        &self,
        program: &crate::Program,
        mock_config: &MockConfig,
    ) -> Result<(ExecState, EnvironmentRef), KclErrorWithOutputs> {
        assert!(
            self.is_mock(),
            "To use mock execution, instantiate via ExecutorContext::new_mock, not ::new"
        );

        let use_prev_memory = mock_config.use_prev_memory;
        let mut exec_state = ExecState::new_mock(self, mock_config);
        if use_prev_memory {
            match cache::read_old_memory().await {
                Some(mem) => Self::restore_mock_memory(&mut exec_state, mem, mock_config)?,
                None => self.prepare_mem(&mut exec_state).await?,
            }
        } else {
            self.prepare_mem(&mut exec_state).await?
        };

        // Push a scope so that old variables can be overwritten (since we might be re-executing some
        // part of the scene).
        exec_state
            .mut_stack()
            .push_new_env_for_scope()
            .map_err(KclErrorWithOutputs::no_outputs)?;

        let (main_ref, _) = self.inner_run(program, &mut exec_state, PreserveMem::Always).await?;

        Ok((exec_state, main_ref))
    }

    pub async fn run_with_caching(&self, program: crate::Program) -> Result<ExecOutcome, KclErrorWithOutputs> {
        assert!(!self.is_mock());
        let grid_scale = if self.settings.fixed_size_grid {
            GridScaleBehavior::Fixed(program.meta_settings().ok().flatten().map(|s| s.default_length_units))
        } else {
            GridScaleBehavior::ScaleWithZoom
        };

        let original_program = program.clone();

        let (_program, exec_state, result) = match cache::read_old_ast().await {
            Some(mut cached_state) => {
                let old = CacheInformation {
                    ast: &cached_state.main.ast,
                    settings: &cached_state.settings,
                };
                let new = CacheInformation {
                    ast: &program.ast,
                    settings: &self.settings,
                };

                // Get the program that actually changed from the old and new information.
                let (clear_scene, program, import_check_info) = match cache::get_changed_program(old, new).await {
                    CacheResult::ReExecute {
                        clear_scene,
                        reapply_settings,
                        program: changed_program,
                    } => {
                        if reapply_settings
                            && self
                                .engine
                                .reapply_settings(
                                    &self.engine_batch,
                                    &self.settings,
                                    Default::default(),
                                    &mut cached_state.main.exec_state.id_generator,
                                    grid_scale,
                                )
                                .await
                                .is_err()
                        {
                            (true, program, None)
                        } else {
                            (
                                clear_scene,
                                crate::Program {
                                    ast: changed_program,
                                    original_file_contents: program.original_file_contents,
                                },
                                None,
                            )
                        }
                    }
                    CacheResult::CheckImportsOnly {
                        reapply_settings,
                        ast: changed_program,
                    } => {
                        let mut reapply_failed = false;
                        if reapply_settings {
                            if self
                                .engine
                                .reapply_settings(
                                    &self.engine_batch,
                                    &self.settings,
                                    Default::default(),
                                    &mut cached_state.main.exec_state.id_generator,
                                    grid_scale,
                                )
                                .await
                                .is_ok()
                            {
                                cache::write_old_ast(GlobalState::with_settings(
                                    cached_state.clone(),
                                    self.settings.clone(),
                                ))
                                .await;
                            } else {
                                reapply_failed = true;
                            }
                        }

                        if reapply_failed {
                            (true, program, None)
                        } else {
                            // We need to check our imports to see if they changed.
                            let mut new_exec_state = ExecState::new(self);
                            let (new_universe, new_universe_map) =
                                self.get_universe(&program, &mut new_exec_state).await?;

                            let clear_scene = new_universe.values().any(|value| {
                                let id = value.1;
                                match (
                                    cached_state.exec_state.get_source(id),
                                    new_exec_state.global.get_source(id),
                                ) {
                                    (Some(s0), Some(s1)) => s0.source != s1.source,
                                    _ => false,
                                }
                            });

                            if !clear_scene {
                                // Return early we don't need to clear the scene.
                                cache::write_old_memory(
                                    cached_state
                                        .mock_memory_state()
                                        .map_err(KclErrorWithOutputs::no_outputs)?,
                                )
                                .await;
                                return cached_state
                                    .into_exec_outcome(self)
                                    .await
                                    .map_err(KclErrorWithOutputs::no_outputs);
                            }

                            (
                                true,
                                crate::Program {
                                    ast: changed_program,
                                    original_file_contents: program.original_file_contents,
                                },
                                Some((new_universe, new_universe_map, new_exec_state)),
                            )
                        }
                    }
                    CacheResult::NoAction(true) => {
                        if self
                            .engine
                            .reapply_settings(
                                &self.engine_batch,
                                &self.settings,
                                Default::default(),
                                &mut cached_state.main.exec_state.id_generator,
                                grid_scale,
                            )
                            .await
                            .is_ok()
                        {
                            // We need to update the old ast state with the new settings!!
                            cache::write_old_ast(GlobalState::with_settings(
                                cached_state.clone(),
                                self.settings.clone(),
                            ))
                            .await;

                            cache::write_old_memory(
                                cached_state
                                    .mock_memory_state()
                                    .map_err(KclErrorWithOutputs::no_outputs)?,
                            )
                            .await;
                            return cached_state
                                .into_exec_outcome(self)
                                .await
                                .map_err(KclErrorWithOutputs::no_outputs);
                        }
                        (true, program, None)
                    }
                    CacheResult::NoAction(false) => {
                        cache::write_old_memory(
                            cached_state
                                .mock_memory_state()
                                .map_err(KclErrorWithOutputs::no_outputs)?,
                        )
                        .await;
                        return cached_state
                            .into_exec_outcome(self)
                            .await
                            .map_err(KclErrorWithOutputs::no_outputs);
                    }
                };

                let (exec_state, result) = match import_check_info {
                    Some((new_universe, new_universe_map, mut new_exec_state)) => {
                        // Clear the scene if the imports changed.
                        self.send_clear_scene(&mut new_exec_state, Default::default())
                            .await
                            .map_err(KclErrorWithOutputs::no_outputs)?;

                        let result = self
                            .run_concurrent(
                                &program,
                                &mut new_exec_state,
                                Some((new_universe, new_universe_map)),
                                PreserveMem::Normal,
                            )
                            .await;

                        (new_exec_state, result)
                    }
                    None if clear_scene => {
                        // Pop the execution state, since we are starting fresh.
                        let mut exec_state = cached_state.reconstitute_exec_state(self);
                        exec_state.reset(self);

                        self.send_clear_scene(&mut exec_state, Default::default())
                            .await
                            .map_err(KclErrorWithOutputs::no_outputs)?;

                        let result = self
                            .run_concurrent(&program, &mut exec_state, None, PreserveMem::Normal)
                            .await;

                        (exec_state, result)
                    }
                    None => {
                        let mut exec_state = cached_state.reconstitute_exec_state(self);
                        exec_state
                            .mut_stack()
                            .restore_env(cached_state.main.result_env)
                            .map_err(KclErrorWithOutputs::no_outputs)?;

                        let result = self
                            .run_concurrent(&program, &mut exec_state, None, PreserveMem::Always)
                            .await;

                        (exec_state, result)
                    }
                };

                (program, exec_state, result)
            }
            None => {
                let mut exec_state = ExecState::new(self);
                self.send_clear_scene(&mut exec_state, Default::default())
                    .await
                    .map_err(KclErrorWithOutputs::no_outputs)?;

                let result = self
                    .run_concurrent(&program, &mut exec_state, None, PreserveMem::Normal)
                    .await;

                (program, exec_state, result)
            }
        };

        if result.is_err() {
            cache::bust_cache().await;
        }

        // Throw the error.
        let result = result?;

        // Save this as the last successful execution to the cache.
        // Gotcha: `CacheResult::ReExecute.program` may be diff-based, do not save that AST
        // the last-successful AST. Instead, save in the full AST passed in.
        cache::write_old_ast(GlobalState::new(
            exec_state.clone(),
            self.settings.clone(),
            original_program.ast,
            result.0,
        ))
        .await;

        let outcome = exec_state
            .into_exec_outcome(result.0, self)
            .await
            .map_err(KclErrorWithOutputs::no_outputs)?;
        Ok(outcome)
    }

    /// Perform the execution of a program.
    ///
    /// To access non-fatal errors and warnings, extract them from the `ExecState`.
    pub async fn run(
        &self,
        program: &crate::Program,
        exec_state: &mut ExecState,
    ) -> Result<(EnvironmentRef, Option<ModelingSessionData>), KclErrorWithOutputs> {
        self.run_concurrent(program, exec_state, None, PreserveMem::Normal)
            .await
    }

    /// Perform the execution of a program using a concurrent
    /// execution model.
    ///
    /// To access non-fatal errors and warnings, extract them from the `ExecState`.
    pub async fn run_concurrent(
        &self,
        program: &crate::Program,
        exec_state: &mut ExecState,
        universe_info: Option<(Universe, UniverseMap)>,
        preserve_mem: PreserveMem,
    ) -> Result<(EnvironmentRef, Option<ModelingSessionData>), KclErrorWithOutputs> {
        // Record the entry point's kclVersion before anything executes;
        // imported modules pre-execute on clones of this state below and must
        // inherit it.
        exec_state.set_entry_point_kcl_version(program);

        // Reuse our cached universe if we have one.

        let (universe, universe_map) = if let Some((universe, universe_map)) = universe_info {
            (universe, universe_map)
        } else {
            self.get_universe(program, exec_state).await?
        };

        // Push ModuleInstance ops for the root module's direct imports before
        // child modules execute. This lets the live feature tree show module
        // names immediately rather than waiting for the root module body to run.
        // Sort by source position so they appear in source-code order (the
        // universe_map is a HashMap with non-deterministic iteration order).
        let mut sorted_imports: Vec<_> = universe_map.iter().collect();
        sorted_imports.sort_by_key(|(_, import_stmt)| SourceRange::from(*import_stmt));
        for (_path, import_stmt) in sorted_imports {
            // Look up by the raw import filename (e.g. "car-wheel.kcl") which
            // is the key format used by Universe, NOT the resolved absolute
            // TypedPath that UniverseMap uses as its key.
            let filename = match &import_stmt.path {
                ImportPath::Kcl { filename } => filename.to_string(),
                ImportPath::Foreign { path } => path.to_string(),
                ImportPath::Std { .. } => continue,
            };
            if let Some((_, module_id, module_path, _)) = universe.get(&filename)
                && let ModulePath::Local { value, .. } = module_path
            {
                let name = import_stmt
                    .module_name()
                    .unwrap_or_else(|| value.file_name().unwrap_or_default());
                let source_range = SourceRange::from(import_stmt);
                exec_state.push_op(crate::execution::cad_op::Operation::ModuleInstance {
                    name,
                    module_id: *module_id,
                    glob: matches!(
                        import_stmt.selector,
                        crate::parsing::ast::types::ImportSelector::Glob(_)
                    ),
                    node_path: crate::NodePath::placeholder(),
                    source_range,
                });
            }
        }

        let default_planes = self.engine.get_default_planes().read().await.clone();

        // Run the prelude to set up the engine.
        self.eval_prelude(exec_state, SourceRange::synthetic())
            .await
            .map_err(KclErrorWithOutputs::no_outputs)?;

        for modules in import_graph::import_graph(&universe, self)
            .map_err(|err| exec_state.error_with_outputs(err, None, default_planes.clone()))?
            .into_iter()
        {
            #[cfg(not(target_arch = "wasm32"))]
            let mut set = tokio::task::JoinSet::new();

            #[allow(clippy::type_complexity)]
            let (results_tx, mut results_rx): (
                tokio::sync::mpsc::Sender<(ModuleId, ModulePath, Result<ModuleRepr, KclError>)>,
                tokio::sync::mpsc::Receiver<_>,
            ) = tokio::sync::mpsc::channel(1);

            for module in modules {
                let Some((import_stmt, module_id, module_path, repr)) = universe.get(&module) else {
                    return Err(KclErrorWithOutputs::no_outputs(KclError::new_internal(
                        KclErrorDetails::new(format!("Module {module} not found in universe"), Default::default()),
                    )));
                };
                let module_id = *module_id;
                let module_path = module_path.clone();
                let source_range = SourceRange::from(import_stmt);
                // Clone before mutating.
                let module_exec_state = exec_state.clone();

                let repr = repr.clone();
                let exec_ctxt = self.clone_with_fresh_execution_batch();
                let results_tx = results_tx.clone();

                let exec_module = async |exec_ctxt: &ExecutorContext,
                                         repr: &ModuleRepr,
                                         module_id: ModuleId,
                                         module_path: &ModulePath,
                                         exec_state: &mut ExecState,
                                         source_range: SourceRange|
                       -> Result<ModuleRepr, KclError> {
                    match repr {
                        ModuleRepr::Kcl(program, _) => {
                            let result = exec_ctxt
                                .exec_module_from_ast(
                                    program,
                                    module_id,
                                    module_path,
                                    exec_state,
                                    source_range,
                                    PreserveMem::Normal,
                                )
                                .await;

                            result.map(|val| ModuleRepr::Kcl(program.clone(), Some(val)))
                        }
                        ModuleRepr::Foreign(geom, _) => {
                            // The concurrent executor starts from a clone of the root module state.
                            // Use a fresh artifact state so the import command belongs only to the
                            // foreign module that issued it.
                            exec_state.mod_local.artifacts = Default::default();
                            let result = crate::execution::import::send_to_engine(geom.clone(), exec_state, exec_ctxt)
                                .await
                                .map(|geom| Some(KclValue::ImportedGeometry(geom)))
                                // Label the failure with the import so the
                                // backtrace names the foreign file (and so
                                // add_import_backtrace's assumption that the
                                // immediate frame is present holds).
                                .map_err(|err| err.add_import_location(&module_path.import_name(), source_range));
                            let module_artifacts = std::mem::take(&mut exec_state.mod_local.artifacts);

                            result.map(|val| ModuleRepr::Foreign(geom.clone(), Some((val, module_artifacts))))
                        }
                        ModuleRepr::Dummy | ModuleRepr::Root => Err(KclError::new_internal(KclErrorDetails::new(
                            format!("Module {module_path} not found in universe"),
                            vec![source_range],
                        ))),
                    }
                };

                #[cfg(target_arch = "wasm32")]
                {
                    wasm_bindgen_futures::spawn_local(async move {
                        let mut exec_state = module_exec_state;
                        let exec_ctxt = exec_ctxt;

                        let result = exec_module(
                            &exec_ctxt,
                            &repr,
                            module_id,
                            &module_path,
                            &mut exec_state,
                            source_range,
                        )
                        .await;

                        results_tx
                            .send((module_id, module_path, result))
                            .await
                            .unwrap_or_default();
                    });
                }
                #[cfg(not(target_arch = "wasm32"))]
                {
                    set.spawn(async move {
                        let mut exec_state = module_exec_state;
                        let exec_ctxt = exec_ctxt;

                        let result = exec_module(
                            &exec_ctxt,
                            &repr,
                            module_id,
                            &module_path,
                            &mut exec_state,
                            source_range,
                        )
                        .await;

                        results_tx
                            .send((module_id, module_path, result))
                            .await
                            .unwrap_or_default();
                    });
                }
            }

            drop(results_tx);

            while let Some((module_id, _, result)) = results_rx.recv().await {
                match result {
                    Ok(new_repr) => {
                        let mut repr = exec_state.global.module_infos[&module_id].take_repr();

                        match &mut repr {
                            ModuleRepr::Kcl(_, cache) => {
                                let ModuleRepr::Kcl(_, session_data) = new_repr else {
                                    unreachable!();
                                };
                                *cache = session_data;
                            }
                            ModuleRepr::Foreign(_, cache) => {
                                let ModuleRepr::Foreign(_, session_data) = new_repr else {
                                    unreachable!();
                                };
                                *cache = session_data;
                            }
                            ModuleRepr::Dummy | ModuleRepr::Root => unreachable!(),
                        }

                        exec_state.global.module_infos[&module_id].restore_repr(repr);
                    }
                    Err(e) => {
                        let e = import_graph::add_import_backtrace(e, module_id, &universe);
                        return Err(exec_state.error_with_outputs(e, None, default_planes));
                    }
                }
            }
        }

        // The early-pushed ModuleInstance operations have already served their
        // purpose (firing onOperation callbacks for the live feature tree).
        // Clear them so they don't duplicate the operations the root module
        // body will produce when it actually executes its import statements.
        exec_state.mod_local.artifacts.operations.clear();

        // Move any remaining setup artifacts (non-operation data from the
        // prelude, etc.) into the root state.
        exec_state
            .global
            .root_module_artifacts
            .extend(std::mem::take(&mut exec_state.mod_local.artifacts));

        self.inner_run(program, exec_state, preserve_mem)
            .await
            .map_err(|mut error| {
                // Engine rejections of async commands (e.g. foreign imports)
                // surface after module execution, so they miss the import
                // frames the eager loop attaches. Without a top-level range
                // the frontend cannot anchor the error in the root file;
                // rebuild the ancestry from the outermost range's module.
                let source_ranges = error.error.source_ranges();
                if !source_ranges.is_empty()
                    && !source_ranges.iter().any(|range| range.module_id().is_top_level())
                    && let Some(outermost) = source_ranges.last()
                {
                    error.error =
                        import_graph::add_import_backtrace_from(error.error.clone(), outermost.module_id(), &universe);
                }
                error
            })
    }

    /// Get the universe & universe map of the program.
    /// And see if any of the imports changed.
    async fn get_universe(
        &self,
        program: &crate::Program,
        exec_state: &mut ExecState,
    ) -> Result<(Universe, UniverseMap), KclErrorWithOutputs> {
        exec_state.add_root_module_contents(program);

        let mut universe = std::collections::HashMap::new();

        let default_planes = self.engine.get_default_planes().read().await.clone();

        let root_imports = import_graph::import_universe(
            self,
            &ModulePath::Main,
            &ModuleRepr::Kcl(program.ast.clone(), None),
            &mut universe,
            exec_state,
        )
        .await
        .map_err(|err| exec_state.error_with_outputs(err, None, default_planes))?;

        Ok((universe, root_imports))
    }

    /// Perform the execution of a program.  Accept all possible parameters and
    /// output everything.
    async fn inner_run(
        &self,
        program: &crate::Program,
        exec_state: &mut ExecState,
        preserve_mem: PreserveMem,
    ) -> Result<(EnvironmentRef, Option<ModelingSessionData>), KclErrorWithOutputs> {
        let _stats = crate::log::LogPerfStats::new("Interpretation");

        // Record the entry point's kclVersion. Mock execution reaches here
        // without going through run_concurrent; on the engine path this
        // re-assigns the same value, which is harmless.
        exec_state.set_entry_point_kcl_version(program);

        // Re-apply the settings, in case the cache was busted.
        let grid_scale = if self.settings.fixed_size_grid {
            GridScaleBehavior::Fixed(program.meta_settings().ok().flatten().map(|s| s.default_length_units))
        } else {
            GridScaleBehavior::ScaleWithZoom
        };
        self.engine
            .reapply_settings(
                &self.engine_batch,
                &self.settings,
                Default::default(),
                exec_state.id_generator(),
                grid_scale,
            )
            .await
            .map_err(KclErrorWithOutputs::no_outputs)?;

        let default_planes = self.engine.get_default_planes().read().await.clone();
        let result = self
            .execute_and_build_graph(&program.ast, exec_state, preserve_mem)
            .await;

        crate::log::log(format!(
            "Post interpretation KCL memory stats: {:#?}",
            exec_state.stack().memory.stats()
        ));
        crate::log::log(format!("Engine stats: {:?}", self.engine.stats()));

        /// Write the memory of an execution to the cache for reuse in mock
        /// execution.
        async fn write_old_memory(
            ctx: &ExecutorContext,
            exec_state: &ExecState,
            env_ref: EnvironmentRef,
        ) -> Result<(), KclError> {
            if ctx.is_mock() {
                return Ok(());
            }
            let mut stack = exec_state.stack().deep_clone()?;
            stack.restore_env(env_ref)?;
            let state = cache::SketchModeState {
                stack,
                module_infos: exec_state.global.module_infos.clone(),
                path_to_source_id: exec_state.global.path_to_source_id.clone(),
                id_to_source: exec_state.global.id_to_source.clone(),
                constraint_state: exec_state.mod_local.constraint_state.clone(),
                scene_objects: exec_state.global.root_module_artifacts.scene_objects.clone(),
            };
            cache::write_old_memory(state).await;
            Ok(())
        }

        let env_ref = match result {
            Ok(env_ref) => env_ref,
            Err((err, env_ref)) => {
                // Preserve memory on execution failures so follow-up mock
                // execution can still reuse stable IDs before the error.
                if let Some(env_ref) = env_ref {
                    write_old_memory(self, exec_state, env_ref)
                        .await
                        .map_err(|err| exec_state.error_with_outputs(err, Some(env_ref), default_planes.clone()))?;
                }
                return Err(exec_state.error_with_outputs(err, env_ref, default_planes));
            }
        };

        write_old_memory(self, exec_state, env_ref)
            .await
            .map_err(|err| exec_state.error_with_outputs(err, Some(env_ref), default_planes.clone()))?;

        let session_data = self.engine.get_session_data().await;

        Ok((env_ref, session_data))
    }

    /// Execute an AST's program and build auxiliary outputs like the artifact
    /// graph.
    async fn execute_and_build_graph(
        &self,
        program: NodeRef<'_, crate::parsing::ast::types::Program>,
        exec_state: &mut ExecState,
        preserve_mem: PreserveMem,
    ) -> Result<EnvironmentRef, (KclError, Option<EnvironmentRef>)> {
        // Don't early return!  We need to build other outputs regardless of
        // whether execution failed.

        // Because of execution caching, we may start with operations from a
        // previous run.
        let start_op = exec_state.global.root_module_artifacts.operations.len();

        self.eval_prelude(exec_state, SourceRange::from(program).start_as_range())
            .await
            .map_err(|e| (e, None))?;

        let exec_result = self
            .exec_module_body(
                program,
                exec_state,
                preserve_mem,
                ModuleId::default(),
                &ModulePath::Main,
            )
            .await
            .map(
                |ModuleExecutionOutcome {
                     environment: env_ref,
                     artifacts: module_artifacts,
                     ..
                 }| {
                    // We need to extend because it may already have operations from
                    // imports.
                    exec_state.global.root_module_artifacts.extend(module_artifacts);
                    env_ref
                },
            )
            .map_err(|(err, env_ref, module_artifacts)| {
                if let Some(module_artifacts) = module_artifacts {
                    // We need to extend because it may already have operations
                    // from imports.
                    exec_state.global.root_module_artifacts.extend(module_artifacts);
                }
                (err, env_ref)
            });

        // Fill in NodePath for operations.
        let programs = &exec_state.build_program_lookup(program.clone());
        let cached_body_items = exec_state.global.artifacts.cached_body_items();
        for op in exec_state
            .global
            .root_module_artifacts
            .operations
            .iter_mut()
            .skip(start_op)
        {
            op.fill_node_paths(programs, cached_body_items);
        }
        for module in exec_state.global.module_infos.values_mut() {
            if let ModuleRepr::Kcl(_, Some(outcome)) = &mut module.repr {
                for op in &mut outcome.artifacts.operations {
                    op.fill_node_paths(programs, cached_body_items);
                }
            }
        }

        // Ensure all the async commands completed.
        self.engine
            .ensure_async_commands_completed(&self.engine_batch)
            .await
            .map_err(|e| {
                match &exec_result {
                    Ok(env_ref) => (e, Some(*env_ref)),
                    // Prefer the execution error.
                    Err((exec_err, env_ref)) => (exec_err.clone(), *env_ref),
                }
            })?;

        // If we errored out and early-returned, there might be commands which haven't been executed
        // and should be dropped.
        self.engine.clear_queues(&self.engine_batch).await;

        match exec_state.build_artifact_graph(&self.engine, program).await {
            Ok(_) => exec_result,
            Err(err) => exec_result.and_then(|env_ref| Err((err, Some(env_ref)))),
        }
    }

    /// 'Import' std::prelude as the outermost scope.
    ///
    /// SAFETY: the current thread must have sole access to the memory referenced in exec_state.
    async fn eval_prelude(&self, exec_state: &mut ExecState, source_range: SourceRange) -> Result<(), KclError> {
        if exec_state.stack().memory.requires_std() {
            let initial_ops = exec_state.mod_local.artifacts.operations.len();

            let path = vec!["std".to_owned(), "prelude".to_owned()];
            let resolved_path = ModulePath::from_std_import_path(&path)?;
            let id = self
                .open_module(&ImportPath::Std { path }, &[], &resolved_path, exec_state, source_range)
                .await?;
            let (module_memory, _) = self.exec_module_for_items(id, exec_state, source_range).await?;

            exec_state.mut_stack().memory.set_std(module_memory)?;

            // Operations generated by the prelude are not useful, so clear them
            // out.
            //
            // TODO: Should we also clear them out of each module so that they
            // don't appear in test output?
            exec_state.mod_local.artifacts.operations.truncate(initial_ops);
        }

        Ok(())
    }

    /// Get a snapshot of the current scene.
    pub async fn prepare_snapshot(&self) -> std::result::Result<TakeSnapshot, ExecError> {
        // Zoom to fit.
        self.engine
            .send_modeling_cmd(
                &self.engine_batch,
                uuid::Uuid::new_v4(),
                crate::execution::SourceRange::default(),
                &ModelingCmd::from(
                    mcmd::ZoomToFit::builder()
                        .object_ids(Default::default())
                        .animated(false)
                        .padding(0.1)
                        .build(),
                ),
            )
            .await
            .map_err(KclErrorWithOutputs::no_outputs)?;

        // Send a snapshot request to the engine.
        let resp = self
            .engine
            .send_modeling_cmd(
                &self.engine_batch,
                uuid::Uuid::new_v4(),
                crate::execution::SourceRange::default(),
                &ModelingCmd::from(mcmd::TakeSnapshot::builder().format(ImageFormat::Png).build()),
            )
            .await
            .map_err(KclErrorWithOutputs::no_outputs)?;

        let OkWebSocketResponseData::Modeling {
            modeling_response: OkModelingCmdResponse::TakeSnapshot(contents),
        } = resp
        else {
            return Err(ExecError::BadPng(format!(
                "Instead of a TakeSnapshot response, the engine returned {resp:?}"
            )));
        };
        Ok(contents)
    }

    /// Export the current scene as a CAD file.
    pub async fn export(
        &self,
        format: kittycad_modeling_cmds::format::OutputFormat3d,
    ) -> Result<Vec<kittycad_modeling_cmds::websocket::RawFile>, KclError> {
        let resp = self
            .engine
            .send_modeling_cmd(
                &self.engine_batch,
                uuid::Uuid::new_v4(),
                crate::SourceRange::default(),
                &kittycad_modeling_cmds::ModelingCmd::Export(
                    kittycad_modeling_cmds::Export::builder()
                        .entity_ids(vec![])
                        .format(format)
                        .build(),
                ),
            )
            .await?;

        let kittycad_modeling_cmds::websocket::OkWebSocketResponseData::Export { files } = resp else {
            return Err(KclError::new_internal(crate::errors::KclErrorDetails::new(
                format!("Expected Export response, got {resp:?}",),
                vec![SourceRange::default()],
            )));
        };

        Ok(files)
    }

    /// Export the current scene as a STEP file.
    pub async fn export_step(
        &self,
        deterministic_time: bool,
    ) -> Result<Vec<kittycad_modeling_cmds::websocket::RawFile>, KclError> {
        let files = self
            .export(kittycad_modeling_cmds::format::OutputFormat3d::Step(
                kittycad_modeling_cmds::format::step::export::Options::builder()
                    .coords(*kittycad_modeling_cmds::coord::KITTYCAD)
                    .maybe_created(if deterministic_time {
                        Some("2021-01-01T00:00:00Z".parse().map_err(|e| {
                            KclError::new_internal(crate::errors::KclErrorDetails::new(
                                format!("Failed to parse date: {e}"),
                                vec![SourceRange::default()],
                            ))
                        })?)
                    } else {
                        None
                    })
                    .build(),
            ))
            .await?;

        Ok(files)
    }

    pub async fn close(&self) {
        self.engine.close().await;
    }
}

pub use kcl_api::ArtifactId;

pub fn cmd_id_ref_to_artifact_id(id: &ModelingCmdId) -> ArtifactId {
    ArtifactId::new(*id.as_ref())
}

#[cfg(test)]
pub(crate) async fn parse_execute(code: &str) -> Result<ExecTestResults, KclError> {
    parse_execute_with_project_dir(code, None).await
}

#[cfg(test)]
pub(crate) async fn parse_execute_with_project_dir(
    code: &str,
    project_directory: Option<TypedPath>,
) -> Result<ExecTestResults, KclError> {
    // Differential testing: unit tests run under both executors.
    parse_execute_with_executor_kind(code, project_directory, machine::ExecutorKind::resolve()).await
}

/// A mock-engine executor context for tests that need to inspect the context
/// (e.g. the engine's batch queue) even when execution fails.
#[cfg(test)]
pub(crate) fn new_mock_executor_context(
    project_directory: Option<TypedPath>,
    executor_kind: machine::ExecutorKind,
) -> ExecutorContext {
    ExecutorContext {
        engine: Arc::new(EngineManager::new_mock()),
        engine_batch: EngineBatchContext::default(),
        fs: crate::fs::new_file_system_handle(crate::fs::FileManager::new()),
        settings: ExecutorSettings {
            project_directory,
            ..Default::default()
        },
        context_type: ContextType::Mock,
        execution_callbacks: Default::default(),
        executor_kind,
        machine_call_depth_limit: crate::execution::machine::DEFAULT_MACHINE_CALL_DEPTH_LIMIT,
    }
}

#[cfg(test)]
pub(crate) async fn parse_execute_with_executor_kind(
    code: &str,
    project_directory: Option<TypedPath>,
    executor_kind: machine::ExecutorKind,
) -> Result<ExecTestResults, KclError> {
    let program = crate::Program::parse_no_errs(code)?;

    let exec_ctxt = new_mock_executor_context(project_directory, executor_kind);
    let mut exec_state = ExecState::new(&exec_ctxt);
    let result = exec_ctxt.run(&program, &mut exec_state).await?;

    Ok(ExecTestResults {
        program,
        mem_env: result.0,
        exec_ctxt,
        exec_state,
    })
}

#[cfg(test)]
#[derive(Debug)]
pub(crate) struct ExecTestResults {
    program: crate::Program,
    mem_env: EnvironmentRef,
    exec_ctxt: ExecutorContext,
    exec_state: ExecState,
}

#[cfg(test)]
impl ExecTestResults {
    pub(crate) fn root_module_artifact_commands(&self) -> &[ArtifactCommand] {
        &self.exec_state.global.root_module_artifacts.commands
    }

    /// The diagnostics the run reported. Non-fatal issues, such as use of an
    /// experimental feature without the opt-in, are recorded here rather than
    /// returned as an error, so this is the only place a test can see them.
    pub(crate) fn issues(&self) -> &[CompilationIssue] {
        self.exec_state.issues()
    }

    /// The value bound to `name` after the run. Panics when the variable is
    /// absent, because a test that names a variable the program does not
    /// declare is broken rather than failing.
    #[track_caller]
    pub(crate) fn variable(&self, name: &str) -> KclValue {
        self.exec_state
            .stack()
            .memory
            .get_from_unchecked(name, self.mem_env)
            .unwrap()
    }
}

/// There are several places where we want to traverse a KCL program or find a symbol in it,
/// but because KCL modules can import each other, we need to traverse multiple programs.
/// This stores multiple programs, keyed by their module ID for quick access.
pub struct ProgramLookup {
    programs: IndexMap<ModuleId, crate::parsing::ast::types::Node<crate::parsing::ast::types::Program>>,
}

impl ProgramLookup {
    // TODO: Could this store a reference to KCL programs instead of owning them?
    // i.e. take &state::ModuleInfoMap instead?
    pub fn new(
        current: crate::parsing::ast::types::Node<crate::parsing::ast::types::Program>,
        module_infos: state::ModuleInfoMap,
    ) -> Self {
        let mut programs = IndexMap::with_capacity(module_infos.len());
        for (id, info) in module_infos {
            if let ModuleRepr::Kcl(program, _) = info.repr {
                programs.insert(id, program);
            }
        }
        programs.insert(ModuleId::default(), current);
        Self { programs }
    }

    pub fn program_for_module(
        &self,
        module_id: ModuleId,
    ) -> Option<&crate::parsing::ast::types::Node<crate::parsing::ast::types::Program>> {
        self.programs.get(&module_id)
    }
}

#[cfg(test)]
mod tests {
    use kcl_api::NumericType;
    use pretty_assertions::assert_eq;

    use super::*;
    use crate::ModuleId;
    use crate::errors::KclErrorDetails;
    use crate::errors::Severity;
    use crate::execution::memory::Stack;
    use crate::execution::types::RuntimeType;

    macro_rules! kcl_input {
        ($file:literal) => {
            include_str!(concat!("../../e2e/executor/inputs/", $file, ".kcl"))
        };
    }

    #[test]
    fn clone_with_fresh_execution_batch_keeps_executor_selection() {
        // Imported modules execute on a context created by
        // clone_with_fresh_execution_batch. They must stay on the executor
        // selected for the run instead of silently reverting to the default.
        let mut ctx = new_mock_executor_context(None, machine::ExecutorKind::Machine);
        ctx.machine_call_depth_limit = 123;
        let cloned = ctx.clone_with_fresh_execution_batch();
        assert_eq!(cloned.executor_kind, machine::ExecutorKind::Machine);
        assert_eq!(cloned.machine_call_depth_limit, 123);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn concurrent_foreign_import_preserves_artifact_command() {
        let tmpdir = tempfile::TempDir::with_prefix("zma_foreign_import_artifact").unwrap();
        tokio::fs::write(tmpdir.path().join("cube.obj"), "o cube\n")
            .await
            .unwrap();

        let program = crate::Program::parse_no_errs("import \"cube.obj\" as cube\n\nmodel = cube\n").unwrap();
        let ctx = new_mock_executor_context(
            Some(crate::TypedPath(tmpdir.path().into())),
            machine::ExecutorKind::resolve(),
        );
        let mut exec_state = ExecState::new(&ctx);
        let (main_ref, _) = ctx.run(&program, &mut exec_state).await.unwrap();
        let outcome = exec_state
            .into_exec_outcome(main_ref, &ctx)
            .await
            .expect("foreign import execution should produce an outcome");
        ctx.close().await;

        let KclValueView::ImportedGeometry(imported) = &outcome.variables["model"] else {
            panic!("model should be imported geometry");
        };
        let artifact_id = ArtifactId::new(imported.id);
        let Some(Artifact::ImportedGeometry(artifact)) = outcome.artifact_graph.get(&artifact_id) else {
            panic!("foreign import should produce an imported geometry artifact");
        };
        assert_eq!(artifact.id, artifact_id);
        assert!(!artifact.code_ref.node_path.is_empty());
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn nested_import_preserves_inner_error_and_backtrace() {
        // The imported modules live in an in-memory file system under a
        // synthetic project directory, so parallel tests share no on-disk
        // state and there is nothing to clean up even if the process is
        // killed.
        let project_dir = crate::TypedPath::new("/zma-kcl-import-error");
        let main_path = project_dir.join("main.kcl");
        let assembly_path = project_dir.join("assembly.kcl");
        let main_code = "import assemblyValue from \"assembly.kcl\"\n\nassemblyValue\n";
        // Key each module by the same join that import resolution performs, so
        // the lookup matches on every platform.
        let files = [
            (
                project_dir.join("broken.kcl").to_string(),
                b"export brokenValue = missingName + 1\n".to_vec(),
            ),
            (
                assembly_path.to_string(),
                b"import brokenValue from \"broken.kcl\"\n\nexport assemblyValue = brokenValue\n".to_vec(),
            ),
        ]
        .into_iter()
        .collect();
        let fs = crate::fs::new_file_system_handle(crate::InMemoryFiles::new(files));
        let settings = ExecutorSettings {
            project_directory: Some(project_dir),
            current_file: Some(main_path.clone()),
            ..Default::default()
        };
        let program = crate::Program::parse_no_errs(main_code).unwrap();

        let assert_error = |error: &KclErrorWithOutputs| {
            let KclError::UndefinedValue { details, name } = &error.error else {
                panic!("expected UndefinedValue, got {:#?}", error.error);
            };
            assert_eq!(name.as_deref(), Some("missingName"));
            assert_eq!(details.message, "`missingName` is not defined");
            assert_eq!(
                error
                    .error
                    .backtrace()
                    .iter()
                    .map(|frame| frame.fn_name.as_deref())
                    .collect::<Vec<_>>(),
                [Some("import broken.kcl"), Some("import assembly.kcl"), None]
            );
            assert_eq!(
                error
                    .error
                    .backtrace()
                    .iter()
                    .map(|frame| frame.kind)
                    .collect::<Vec<_>>(),
                [
                    kcl_error::BacktraceItemKind::Import,
                    kcl_error::BacktraceItemKind::Import,
                    kcl_error::BacktraceItemKind::Call
                ]
            );

            let report = error.clone().into_miette_report_with_outputs(main_code).unwrap();
            assert!(report.filename.ends_with("broken.kcl"));
            assert_eq!(
                report
                    .related
                    .iter()
                    .map(|related| related.filename.as_str())
                    .collect::<Vec<_>>(),
                [assembly_path.to_string(), main_path.to_string()]
            );

            let rendered = format!("{:?}", miette::Report::new(report));
            assert!(rendered.contains("broken.kcl"));
            assert!(rendered.contains("assembly.kcl"));
            assert!(rendered.contains("main.kcl"));
            assert!(rendered.contains("export brokenValue = missingName + 1"));
            assert!(!rendered.contains("Failed to read contents"));
        };

        let mut mock_ctx = ExecutorContext::new_mock(Some(settings.clone())).await;
        mock_ctx.fs = fs.clone();
        let mock_error = mock_ctx
            .run_mock(
                &program,
                &MockConfig {
                    use_prev_memory: false,
                    ..Default::default()
                },
            )
            .await
            .unwrap_err();
        mock_ctx.close().await;
        assert_error(&mock_error);

        let mut concurrent_ctx = ExecutorContext::new_mock(Some(settings)).await;
        concurrent_ctx.fs = fs;
        let mut exec_state = ExecState::new(&concurrent_ctx);
        let concurrent_error = concurrent_ctx.run(&program, &mut exec_state).await.unwrap_err();
        concurrent_ctx.close().await;
        assert_error(&concurrent_error);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn function_error_across_import_keeps_backtrace_innermost_first() {
        // A function defined in an imported module fails when the importing
        // module calls it: function frames and the import frame must stay in
        // one innermost-first chain.
        let project_dir = crate::TypedPath::new("/zma-kcl-import-fn-error");
        let main_path = project_dir.join("main.kcl");
        let main_code = "import assemblyValue from \"assembly.kcl\"\n\nassemblyValue\n";
        let files = [
            (
                project_dir.join("helper.kcl").to_string(),
                b"export fn inner() { return missingName }\nexport fn outer() { return inner() }\n".to_vec(),
            ),
            (
                project_dir.join("assembly.kcl").to_string(),
                b"import outer from \"helper.kcl\"\n\nexport assemblyValue = outer()\n".to_vec(),
            ),
        ]
        .into_iter()
        .collect();
        let fs = crate::fs::new_file_system_handle(crate::InMemoryFiles::new(files));
        let settings = ExecutorSettings {
            project_directory: Some(project_dir.clone()),
            current_file: Some(main_path),
            ..Default::default()
        };
        let program = crate::Program::parse_no_errs(main_code).unwrap();

        let assert_error = |error: &KclErrorWithOutputs| {
            assert!(
                matches!(&error.error, KclError::UndefinedValue { .. }),
                "expected UndefinedValue, got {:#?}",
                error.error
            );
            assert_eq!(
                error
                    .error
                    .backtrace()
                    .iter()
                    .map(|frame| frame.fn_name.as_deref())
                    .collect::<Vec<_>>(),
                [Some("inner"), Some("outer"), Some("import assembly.kcl"), None]
            );
            assert_eq!(
                error
                    .error
                    .backtrace()
                    .iter()
                    .map(|frame| frame.kind)
                    .collect::<Vec<_>>(),
                [
                    kcl_error::BacktraceItemKind::Call,
                    kcl_error::BacktraceItemKind::Call,
                    kcl_error::BacktraceItemKind::Import,
                    kcl_error::BacktraceItemKind::Call
                ]
            );

            let report = error.clone().into_miette_report_with_outputs(main_code).unwrap();
            assert!(report.filename.ends_with("helper.kcl"));
            assert_eq!(
                report
                    .related
                    .iter()
                    .map(|related| related.filename.as_str())
                    .collect::<Vec<_>>(),
                [
                    project_dir.join("assembly.kcl").to_string(),
                    project_dir.join("main.kcl").to_string()
                ]
            );
            let rendered = format!("{:?}", miette::Report::new(report));
            assert!(rendered.contains("return missingName"));
            assert!(!rendered.contains("Failed to read contents"));
        };

        let mut mock_ctx = ExecutorContext::new_mock(Some(settings.clone())).await;
        mock_ctx.fs = fs.clone();
        let mock_error = mock_ctx
            .run_mock(
                &program,
                &MockConfig {
                    use_prev_memory: false,
                    ..Default::default()
                },
            )
            .await
            .unwrap_err();
        mock_ctx.close().await;
        assert_error(&mock_error);

        let mut concurrent_ctx = ExecutorContext::new_mock(Some(settings)).await;
        concurrent_ctx.fs = fs;
        let mut exec_state = ExecState::new(&concurrent_ctx);
        let concurrent_error = concurrent_ctx.run(&program, &mut exec_state).await.unwrap_err();
        concurrent_ctx.close().await;
        assert_error(&concurrent_error);
    }

    /// Convenience function to get a JSON value from memory and unwrap.
    #[track_caller]
    fn mem_get_json(memory: &Stack, env: EnvironmentRef, name: &str) -> KclValue {
        memory.memory.get_from_unchecked(name, env).unwrap()
    }

    async fn execute_variables_with_backend(
        code: &str,
        backend: memory::MemoryBackendKind,
    ) -> IndexMap<String, KclValueView> {
        execute_outcome_with_backend(code, backend).await.variables
    }

    async fn execute_outcome_with_backend(code: &str, backend: memory::MemoryBackendKind) -> ExecOutcome {
        let program = crate::Program::parse_no_errs(code).unwrap();
        let ctx = ExecutorContext::new_mock(None).await;
        let mut exec_state = ExecState::new_with_memory_backend(&ctx, backend);
        let (env_ref, _) = ctx.run(&program, &mut exec_state).await.unwrap();
        let outcome = exec_state
            .into_exec_outcome(env_ref, &ctx)
            .await
            .expect("test execution outcome should collect variables");
        ctx.close().await;
        outcome
    }

    async fn execute_error_variables_with_backend(
        code: &str,
        backend: memory::MemoryBackendKind,
    ) -> IndexMap<String, KclValueView> {
        let program = crate::Program::parse_no_errs(code).unwrap();
        let ctx = ExecutorContext::new_mock(None).await;
        let mut exec_state = ExecState::new_with_memory_backend(&ctx, backend);
        let error = ctx.run(&program, &mut exec_state).await.unwrap_err();
        ctx.close().await;
        error.variables
    }

    async fn execute_project_variables_with_backend(
        main_code: &str,
        files: &[(&str, &str)],
        backend: memory::MemoryBackendKind,
    ) -> IndexMap<String, KclValueView> {
        let tmpdir = tempfile::TempDir::with_prefix("zma_kcl_memory_backend_project").unwrap();
        for (name, contents) in files {
            tokio::fs::write(tmpdir.path().join(name), contents).await.unwrap();
        }

        let program = crate::Program::parse_no_errs(main_code).unwrap();
        let ctx = ExecutorContext {
            engine: Arc::new(EngineManager::new_mock()),
            engine_batch: EngineBatchContext::default(),
            fs: crate::fs::new_file_system_handle(crate::fs::FileManager::new()),
            settings: ExecutorSettings {
                project_directory: Some(crate::TypedPath(tmpdir.path().into())),
                ..Default::default()
            },
            context_type: ContextType::Mock,
            execution_callbacks: Default::default(),
            executor_kind: machine::ExecutorKind::resolve(),
            machine_call_depth_limit: crate::execution::machine::DEFAULT_MACHINE_CALL_DEPTH_LIMIT,
        };
        let mut exec_state = ExecState::new_with_memory_backend(&ctx, backend);
        let (env_ref, _) = ctx.run(&program, &mut exec_state).await.unwrap();
        let outcome = exec_state
            .into_exec_outcome(env_ref, &ctx)
            .await
            .expect("test execution outcome should collect variables");
        ctx.close().await;
        outcome.variables
    }

    async fn run_with_caching_variables_with_backend(
        code: &str,
        backend: memory::MemoryBackendKind,
    ) -> IndexMap<String, KclValueView> {
        let _backend = memory::MemoryBackendKind::override_for_test(backend);
        cache::bust_cache().await;
        clear_mem_cache().await;

        let ctx = ExecutorContext::new_with_engine(Arc::new(EngineManager::new_mock()), Default::default());
        let program = crate::Program::parse_no_errs(code).unwrap();
        ctx.run_with_caching(program.clone()).await.unwrap();
        let cached = ctx.run_with_caching(program).await.unwrap();

        cache::bust_cache().await;
        clear_mem_cache().await;
        ctx.close().await;
        cached.variables
    }

    async fn run_mock_variables_with_backend(
        code: &str,
        backend: memory::MemoryBackendKind,
    ) -> IndexMap<String, KclValueView> {
        let _backend = memory::MemoryBackendKind::override_for_test(backend);
        clear_mem_cache().await;

        let ctx = ExecutorContext::new_mock(None).await;
        let first = crate::Program::parse_no_errs("x = 2").unwrap();
        ctx.run_mock(
            &first,
            &MockConfig {
                use_prev_memory: false,
                ..Default::default()
            },
        )
        .await
        .unwrap();

        let program = crate::Program::parse_no_errs(code).unwrap();
        let outcome = ctx.run_mock(&program, &MockConfig::default()).await.unwrap();

        clear_mem_cache().await;
        ctx.close().await;
        outcome.variables
    }

    fn sorted_variable_keys(variables: &IndexMap<String, KclValueView>) -> Vec<String> {
        let mut keys = variables.keys().cloned().collect::<Vec<_>>();
        keys.sort();
        keys
    }

    async fn collect_backend_results<T, Fut>(
        mut run: impl FnMut(memory::MemoryBackendKind) -> Fut,
    ) -> Vec<(memory::MemoryBackendKind, T)>
    where
        Fut: std::future::Future<Output = T>,
    {
        let all = memory::MemoryBackendKind::all();
        let mut results = Vec::with_capacity(all.len());
        for &kind in all {
            results.push((kind, run(kind).await));
        }
        results
    }

    fn assert_backend_results_match<T>(results: &[(memory::MemoryBackendKind, T)])
    where
        T: std::fmt::Debug + PartialEq,
    {
        let (first, rest) = results.split_first().expect("expected at least one memory backend");
        let (first_kind, first_result) = first;
        for (kind, result) in rest {
            assert_eq!(
                result, first_result,
                "memory kind {kind:?} doesn't match {first_kind:?}"
            );
        }
    }

    fn assert_backend_variable_results_match_expected_keys(
        results: &[(memory::MemoryBackendKind, IndexMap<String, KclValueView>)],
        expected_keys: &[&str],
    ) {
        let (first_kind, first_variables) = results.first().expect("expected at least one memory backend");
        let expected_keys = expected_keys.iter().map(|key| (*key).to_owned()).collect::<Vec<_>>();
        assert_eq!(
            sorted_variable_keys(first_variables),
            expected_keys,
            "memory kind {first_kind:?} doesn't match expected variables"
        );
        assert_backend_results_match(results);
    }

    fn assert_number_variable(variables: &IndexMap<String, KclValueView>, key: &str, expected: f64) {
        let value = variables.get(key).unwrap_or_else(|| panic!("missing variable `{key}`"));
        let KclValueView::Number { value, .. } = value else {
            panic!("expected `{key}` to be a number, got {value:?}");
        };
        assert_eq!(*value, expected, "{key}: {value:?}");
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn exec_outcome_variables_match_between_memory_backends() {
        let code = "x = 2\ny = x + 1\narr = [x, y]";

        let results = collect_backend_results(|kind| execute_variables_with_backend(code, kind)).await;

        assert_backend_variable_results_match_expected_keys(&results, &["arr", "x", "y"]);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn error_output_variables_match_between_memory_backends() {
        let code = "x = 2\ny = missing + 1";

        let results = collect_backend_results(|kind| execute_error_variables_with_backend(code, kind)).await;

        assert_backend_variable_results_match_expected_keys(&results, &["x"]);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn cached_execution_variables_match_between_memory_backends() {
        let code = "x = 2\ny = x + 1";

        let results = collect_backend_results(|kind| run_with_caching_variables_with_backend(code, kind)).await;

        assert_backend_variable_results_match_expected_keys(&results, &["x", "y"]);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn mock_execution_variables_match_between_memory_backends() {
        let code = "y = x + 1";

        let results = collect_backend_results(|kind| run_mock_variables_with_backend(code, kind)).await;

        assert_backend_variable_results_match_expected_keys(&results, &["y"]);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn module_imports_and_exported_closures_match_between_memory_backends() {
        let module_code = r#"
export base = 40

export fn addBase(n) {
  return n + base
}
"#;
        let main_code = r#"
import base, addBase from 'math.kcl'
import 'math.kcl'

named = addBase(n = 2)
qualified = math::addBase(n = 1)
direct = math::base
"#;

        let files = [("math.kcl", module_code)];
        let results =
            collect_backend_results(|kind| execute_project_variables_with_backend(main_code, &files, kind)).await;

        let (_, first_variables) = results.first().expect("expected at least one memory backend");
        assert_number_variable(first_variables, "named", 42.0);
        assert_number_variable(first_variables, "qualified", 41.0);
        assert_number_variable(first_variables, "direct", 40.0);
        assert_backend_results_match(&results);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn sketch_block_variables_match_between_memory_backends() {
        let code = r#"
sketch001 = sketch(on = XY) {
  line1 = line(start = [0, 0], end = [1, 0])
  line2 = line(start = [1, 0], end = [0, 1])
}
lineCount = 2
"#;

        let results = collect_backend_results(|kind| execute_variables_with_backend(code, kind)).await;

        let (_, first_variables) = results.first().expect("expected at least one memory backend");
        assert!(first_variables.contains_key("sketch001"), "actual: {first_variables:?}");
        assert_number_variable(first_variables, "lineCount", 2.0);
        assert_backend_results_match(&results);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn tag_call_stack_lookup_matches_between_memory_backends() {
        let code = r#"
sketch001 = startSketchOn(XY)
  |> startProfile(at = [0, 0])
  |> xLine(length = 10, tag = $seg01)

segLength = segLen(seg01)
"#;

        let results = collect_backend_results(|kind| execute_variables_with_backend(code, kind)).await;

        let (_, first_variables) = results.first().expect("expected at least one memory backend");
        assert_number_variable(first_variables, "segLength", 10.0);
        assert_backend_results_match(&results);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_execute_warn() {
        let text = "@blah";
        let result = parse_execute(text).await.unwrap();
        let errs = result.exec_state.issues();
        assert_eq!(errs.len(), 1);
        assert_eq!(errs[0].severity, crate::errors::Severity::Warning);
        assert!(
            errs[0].message.contains("Unknown annotation"),
            "unexpected warning message: {}",
            errs[0].message
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_execute_fn_definitions() {
        let ast = r#"fn def(@x) {
  return x
}
fn ghi(@x) {
  return x
}
fn jkl(@x) {
  return x
}
fn hmm(@x) {
  return x
}

yo = 5 + 6

abc = 3
identifierGuy = 5
part001 = startSketchOn(XY)
|> startProfile(at = [-1.2, 4.83])
|> line(end = [2.8, 0])
|> angledLine(angle = 100 + 100, length = 3.01)
|> angledLine(angle = abc, length = 3.02)
|> angledLine(angle = def(yo), length = 3.03)
|> angledLine(angle = ghi(2), length = 3.04)
|> angledLine(angle = jkl(yo) + 2, length = 3.05)
|> close()
yo2 = hmm([identifierGuy + 5])"#;

        parse_execute(ast).await.unwrap();
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn multiple_sketch_blocks_do_not_reuse_on_cache_name() {
        let code = r#"
firstProfile = sketch(on = XY) {
  edge1 = line(start = [var 0mm, var 0mm], end = [var 4mm, var 0mm])
  edge2 = line(start = [var 4mm, var 0mm], end = [var 4mm, var 3mm])
  edge3 = line(start = [var 4mm, var 3mm], end = [var 0mm, var 3mm])
  edge4 = line(start = [var 0mm, var 3mm], end = [var 0mm, var 0mm])
  coincident([edge1.end, edge2.start])
  coincident([edge2.end, edge3.start])
  coincident([edge3.end, edge4.start])
  coincident([edge4.end, edge1.start])
}

secondProfile = sketch(on = offsetPlane(XY, offset = 6mm)) {
  edge5 = line(start = [var 1mm, var 1mm], end = [var 5mm, var 1mm])
  edge6 = line(start = [var 5mm, var 1mm], end = [var 5mm, var 4mm])
  edge7 = line(start = [var 5mm, var 4mm], end = [var 1mm, var 4mm])
  edge8 = line(start = [var 1mm, var 4mm], end = [var 1mm, var 1mm])
  coincident([edge5.end, edge6.start])
  coincident([edge6.end, edge7.start])
  coincident([edge7.end, edge8.start])
  coincident([edge8.end, edge5.start])
}

firstSolid = extrude(region(point = [2mm, 1mm], sketch = firstProfile), length = 2mm)
secondSolid = extrude(region(point = [2mm, 2mm], sketch = secondProfile), length = 2mm)
"#;

        let result = parse_execute(code).await.unwrap();
        assert!(result.exec_state.issues().is_empty());
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn sketch_block_artifact_preserves_standard_plane_name() {
        let code = r#"
sketch001 = sketch(on = -YZ) {
  line1 = line(start = [var 0mm, var 0mm], end = [var 1mm, var 1mm])
}
"#;

        let result = parse_execute(code).await.unwrap();
        let sketch_blocks = result
            .exec_state
            .global
            .artifacts
            .graph
            .values()
            .filter_map(|artifact| match artifact {
                Artifact::SketchBlock(block) => Some(block),
                _ => None,
            })
            .collect::<Vec<_>>();

        assert_eq!(sketch_blocks.len(), 1);
        assert_eq!(sketch_blocks[0].standard_plane, Some(crate::engine::PlaneName::NegYz));
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn issue_10639_blend_example_with_two_sketch_blocks_executes() {
        let code = r#"
sketch001 = sketch(on = YZ) {
  line1 = line(start = [var 4.1mm, var -0.1mm], end = [var 5.5mm, var 0mm])
  line2 = line(start = [var 5.5mm, var 0mm], end = [var 5.5mm, var 3mm])
  line3 = line(start = [var 5.5mm, var 3mm], end = [var 3.9mm, var 2.8mm])
  line4 = line(start = [var 4.1mm, var 3mm], end = [var 4.5mm, var -0.2mm])
  coincident([line1.end, line2.start])
  coincident([line2.end, line3.start])
  coincident([line3.end, line4.start])
  coincident([line4.end, line1.start])
}

sketch002 = sketch(on = -XZ) {
  line5 = line(start = [var -5.3mm, var -0.1mm], end = [var -3.5mm, var -0.1mm])
  line6 = line(start = [var -3.5mm, var -0.1mm], end = [var -3.5mm, var 3.1mm])
  line7 = line(start = [var -3.5mm, var 4.5mm], end = [var -5.4mm, var 4.5mm])
  line8 = line(start = [var -5.3mm, var 3.1mm], end = [var -5.3mm, var -0.1mm])
  coincident([line5.end, line6.start])
  coincident([line6.end, line7.start])
  coincident([line7.end, line8.start])
  coincident([line8.end, line5.start])
}

region001 = region(point = [-4.4mm, 2mm], sketch = sketch002)
extrude001 = extrude(region001, length = -2mm, bodyType = SURFACE)
region002 = region(point = [4.8mm, 1.5mm], sketch = sketch001)
extrude002 = extrude(region002, length = -2mm, bodyType = SURFACE)

myBlend = blend([extrude001.sketch.tags.line7, extrude002.sketch.tags.line3])
"#;

        let result = parse_execute(code).await.unwrap();
        assert!(result.exec_state.issues().is_empty());
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn issue_10741_point_circle_coincident_executes() {
        let code = r#"
sketch001 = sketch(on = YZ) {
  circle1 = circle(start = [var -2.67mm, var 1.8mm], center = [var -1.53mm, var 0.78mm])
  line1 = line(start = [var -1.05mm, var 2.22mm], end = [var -3.58mm, var -0.78mm])
  coincident([line1.start, circle1])
}
"#;

        let result = parse_execute(code).await.unwrap();
        assert!(
            result
                .exec_state
                .issues()
                .iter()
                .all(|issue| issue.severity != Severity::Error),
            "unexpected execution issues: {:#?}",
            result.exec_state.issues()
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_execute_with_pipe_substitutions_unary() {
        let ast = r#"myVar = 3
part001 = startSketchOn(XY)
  |> startProfile(at = [0, 0])
  |> line(end = [3, 4], tag = $seg01)
  |> line(end = [
  min([segLen(seg01), myVar]),
  -legLen(hypotenuse = segLen(seg01), leg = myVar)
])
"#;

        parse_execute(ast).await.unwrap();
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_execute_with_pipe_substitutions() {
        let ast = r#"myVar = 3
part001 = startSketchOn(XY)
  |> startProfile(at = [0, 0])
  |> line(end = [3, 4], tag = $seg01)
  |> line(end = [
  min([segLen(seg01), myVar]),
  legLen(hypotenuse = segLen(seg01), leg = myVar)
])
"#;

        parse_execute(ast).await.unwrap();
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_execute_with_inline_comment() {
        let ast = r#"baseThick = 1
armAngle = 60

baseThickHalf = baseThick / 2
halfArmAngle = armAngle / 2

arrExpShouldNotBeIncluded = [1, 2, 3]
objExpShouldNotBeIncluded = { a = 1, b = 2, c = 3 }

part001 = startSketchOn(XY)
  |> startProfile(at = [0, 0])
  |> yLine(endAbsolute = 1)
  |> xLine(length = 3.84) // selection-range-7ish-before-this

variableBelowShouldNotBeIncluded = 3
"#;

        parse_execute(ast).await.unwrap();
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_execute_with_function_literal_in_pipe() {
        let ast = r#"w = 20
l = 8
h = 10

fn thing() {
  return -8
}

firstExtrude = startSketchOn(XY)
  |> startProfile(at = [0,0])
  |> line(end = [0, l])
  |> line(end = [w, 0])
  |> line(end = [0, thing()])
  |> close()
  |> extrude(length = h)"#;

        parse_execute(ast).await.unwrap();
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_execute_with_function_unary_in_pipe() {
        let ast = r#"w = 20
l = 8
h = 10

fn thing(@x) {
  return -x
}

firstExtrude = startSketchOn(XY)
  |> startProfile(at = [0,0])
  |> line(end = [0, l])
  |> line(end = [w, 0])
  |> line(end = [0, thing(8)])
  |> close()
  |> extrude(length = h)"#;

        parse_execute(ast).await.unwrap();
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_execute_with_function_array_in_pipe() {
        let ast = r#"w = 20
l = 8
h = 10

fn thing(@x) {
  return [0, -x]
}

firstExtrude = startSketchOn(XY)
  |> startProfile(at = [0,0])
  |> line(end = [0, l])
  |> line(end = [w, 0])
  |> line(end = thing(8))
  |> close()
  |> extrude(length = h)"#;

        parse_execute(ast).await.unwrap();
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_execute_with_function_call_in_pipe() {
        let ast = r#"w = 20
l = 8
h = 10

fn other_thing(@y) {
  return -y
}

fn thing(@x) {
  return other_thing(x)
}

firstExtrude = startSketchOn(XY)
  |> startProfile(at = [0,0])
  |> line(end = [0, l])
  |> line(end = [w, 0])
  |> line(end = [0, thing(8)])
  |> close()
  |> extrude(length = h)"#;

        parse_execute(ast).await.unwrap();
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_execute_with_function_sketch() {
        let ast = r#"fn box(h, l, w) {
 myBox = startSketchOn(XY)
    |> startProfile(at = [0,0])
    |> line(end = [0, l])
    |> line(end = [w, 0])
    |> line(end = [0, -l])
    |> close()
    |> extrude(length = h)

  return myBox
}

fnBox = box(h = 3, l = 6, w = 10)"#;

        parse_execute(ast).await.unwrap();
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_get_member_of_object_with_function_period() {
        let ast = r#"fn box(@obj) {
 myBox = startSketchOn(XY)
    |> startProfile(at = obj.start)
    |> line(end = [0, obj.l])
    |> line(end = [obj.w, 0])
    |> line(end = [0, -obj.l])
    |> close()
    |> extrude(length = obj.h)

  return myBox
}

thisBox = box({start = [0,0], l = 6, w = 10, h = 3})
"#;
        parse_execute(ast).await.unwrap();
    }

    #[tokio::test(flavor = "multi_thread")]
    #[ignore] // https://github.com/KittyCAD/modeling-app/issues/3338
    async fn test_object_member_starting_pipeline() {
        let ast = r#"
fn test2() {
  return {
    thing: startSketchOn(XY)
      |> startProfile(at = [0, 0])
      |> line(end = [0, 1])
      |> line(end = [1, 0])
      |> line(end = [0, -1])
      |> close()
  }
}

x2 = test2()

x2.thing
  |> extrude(length = 10)
"#;
        parse_execute(ast).await.unwrap();
    }

    #[tokio::test(flavor = "multi_thread")]
    #[ignore] // ignore til we get loops
    async fn test_execute_with_function_sketch_loop_objects() {
        let ast = r#"fn box(obj) {
let myBox = startSketchOn(XY)
    |> startProfile(at = obj.start)
    |> line(end = [0, obj.l])
    |> line(end = [obj.w, 0])
    |> line(end = [0, -obj.l])
    |> close()
    |> extrude(length = obj.h)

  return myBox
}

for var in [{start: [0,0], l: 6, w: 10, h: 3}, {start: [-10,-10], l: 3, w: 5, h: 1.5}] {
  thisBox = box(var)
}"#;

        parse_execute(ast).await.unwrap();
    }

    #[tokio::test(flavor = "multi_thread")]
    #[ignore] // ignore til we get loops
    async fn test_execute_with_function_sketch_loop_array() {
        let ast = r#"fn box(h, l, w, start) {
 myBox = startSketchOn(XY)
    |> startProfile(at = [0,0])
    |> line(end = [0, l])
    |> line(end = [w, 0])
    |> line(end = [0, -l])
    |> close()
    |> extrude(length = h)

  return myBox
}


for var in [[3, 6, 10, [0,0]], [1.5, 3, 5, [-10,-10]]] {
  const thisBox = box(var[0], var[1], var[2], var[3])
}"#;

        parse_execute(ast).await.unwrap();
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_get_member_of_array_with_function() {
        let ast = r#"fn box(@arr) {
 myBox =startSketchOn(XY)
    |> startProfile(at = arr[0])
    |> line(end = [0, arr[1]])
    |> line(end = [arr[2], 0])
    |> line(end = [0, -arr[1]])
    |> close()
    |> extrude(length = arr[3])

  return myBox
}

thisBox = box([[0,0], 6, 10, 3])

"#;
        parse_execute(ast).await.unwrap();
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_function_cannot_access_future_definitions() {
        let ast = r#"
fn returnX() {
  // x shouldn't be defined yet.
  return x
}

x = 5

answer = returnX()"#;

        let result = parse_execute(ast).await;
        let err = result.unwrap_err();
        assert_eq!(err.message(), "`x` is not defined");
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_override_prelude() {
        let text = "PI = 3.0";
        let result = parse_execute(text).await.unwrap();
        let issues = result.exec_state.issues();
        assert!(issues.is_empty(), "issues={issues:#?}");
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn type_aliases() {
        let text = r#"@settings(experimentalFeatures = allow)
type MyTy = [number; 2]
fn foo(@x: MyTy) {
    return x[0]
}

foo([0, 1])

type Other = MyTy | Helix
"#;
        let result = parse_execute(text).await.unwrap();
        let issues = result.exec_state.issues();
        assert!(issues.is_empty(), "issues={issues:#?}");
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_cannot_shebang_in_fn() {
        let ast = r#"
fn foo() {
  #!hello
  return true
}

foo
"#;

        let result = parse_execute(ast).await;
        let err = result.unwrap_err();
        assert_eq!(
            err,
            KclError::new_syntax(KclErrorDetails::new(
                "Unexpected token: #".to_owned(),
                vec![SourceRange::new(14, 15, ModuleId::default())],
            )),
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_pattern_transform_function_cannot_access_future_definitions() {
        let ast = r#"
fn transform(@replicaId) {
  // x shouldn't be defined yet.
  scale = x
  return {
    translate = [0, 0, replicaId * 10],
    scale = [scale, 1, 0],
  }
}

fn layer() {
  return startSketchOn(XY)
    |> circle( center= [0, 0], radius= 1, tag = $tag1)
    |> extrude(length = 10)
}

x = 5

// The 10 layers are replicas of each other, with a transform applied to each.
shape = layer() |> patternTransform(instances = 10, transform = transform)
"#;

        let result = parse_execute(ast).await;
        let err = result.unwrap_err();
        assert_eq!(err.message(), "`x` is not defined",);
    }

    // ADAM: Move some of these into simulation tests.

    #[tokio::test(flavor = "multi_thread")]
    async fn test_math_execute_with_functions() {
        let ast = r#"myVar = 2 + min([100, -1 + legLen(hypotenuse = 5, leg = 3)])"#;
        let result = parse_execute(ast).await.unwrap();
        assert_eq!(
            5.0,
            mem_get_json(result.exec_state.stack(), result.mem_env, "myVar")
                .as_f64()
                .unwrap()
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_math_execute() {
        let ast = r#"myVar = 1 + 2 * (3 - 4) / -5 + 6"#;
        let result = parse_execute(ast).await.unwrap();
        assert_eq!(
            7.4,
            mem_get_json(result.exec_state.stack(), result.mem_env, "myVar")
                .as_f64()
                .unwrap()
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_string_uppercase() {
        let composed = "\u{e9}";
        let uppercase_composed = "\u{c9}";
        let decomposed = "e\u{301}";
        let uppercase_decomposed = "E\u{301}";
        let code = format!(
            r#"
ascii = string::uppercase("Kcl")
unicode_expansion = string::uppercase("Straße")
uncased = string::uppercase("東京")
empty = string::uppercase("")
composed = string::uppercase("{composed}")
decomposed = string::uppercase("{decomposed}")
piped = "ready" |> string::uppercase()
"#
        );

        let result = parse_execute(&code).await.unwrap();
        for (name, expected) in [
            ("ascii", "KCL"),
            ("unicode_expansion", "STRASSE"),
            ("uncased", "東京"),
            ("empty", ""),
            ("composed", uppercase_composed),
            ("decomposed", uppercase_decomposed),
            ("piped", "READY"),
        ] {
            assert_eq!(
                mem_get_json(result.exec_state.stack(), result.mem_env, name)
                    .as_str()
                    .unwrap(),
                expected,
                "{name}"
            );
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_string_lowercase() {
        let composed = "\u{c9}";
        let lowercase_composed = "\u{e9}";
        let decomposed = "E\u{301}";
        let lowercase_decomposed = "e\u{301}";
        let expanded = "i\u{307}";
        let code = format!(
            r#"
ascii = string::lowercase("KCL")
final_sigma = string::lowercase("ΟΣ")
medial_sigma = string::lowercase("ΟΣΑ")
unicode_expansion = string::lowercase("İ")
uncased = string::lowercase("東京")
empty = string::lowercase("")
composed = string::lowercase("{composed}")
decomposed = string::lowercase("{decomposed}")
piped = "READY" |> string::lowercase()
"#
        );

        let result = parse_execute(&code).await.unwrap();
        for (name, expected) in [
            ("ascii", "kcl"),
            ("final_sigma", "ος"),
            ("medial_sigma", "οσα"),
            ("unicode_expansion", expanded),
            ("uncased", "東京"),
            ("empty", ""),
            ("composed", lowercase_composed),
            ("decomposed", lowercase_decomposed),
            ("piped", "ready"),
        ] {
            assert_eq!(
                mem_get_json(result.exec_state.stack(), result.mem_env, name)
                    .as_str()
                    .unwrap(),
                expected,
                "{name}"
            );
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_string_is_equal() {
        let composed = "\u{e9}";
        let decomposed = "e\u{301}";
        let code = format!(
            r#"
exact_same = string::isEqual("KCL", to = "KCL")
exact_different_case = string::isEqual("KCL", to = "kcl")
explicit_case_sensitive = string::isEqual("KCL", to = "kcl", caseInsensitive = false)
case_insensitive_ascii = string::isEqual("KCL", to = "kcl", caseInsensitive = true)
case_fold_expansion = string::isEqual("Straße", to = "STRASSE", caseInsensitive = true)
case_fold_expansion_reversed = string::isEqual("STRASSE", to = "Straße", caseInsensitive = true)
case_fold_sigma = string::isEqual("ος", to = "οσ", caseInsensitive = true)
case_fold_non_turkic = string::isEqual("I", to = "i", caseInsensitive = true)
case_fold_not_turkic = string::isEqual("I", to = "ı", caseInsensitive = true)
empty_same = string::isEqual("", to = "")
empty_different = string::isEqual("", to = "KCL")
exact_without_normalization = string::isEqual("{composed}", to = "{decomposed}")
case_fold_without_normalization = string::isEqual("{composed}", to = "{decomposed}", caseInsensitive = true)
piped = "ready" |> string::isEqual(to = "READY", caseInsensitive = true)
"#
        );

        let result = parse_execute(&code).await.unwrap();
        for (name, expected) in [
            ("exact_same", true),
            ("exact_different_case", false),
            ("explicit_case_sensitive", false),
            ("case_insensitive_ascii", true),
            ("case_fold_expansion", true),
            ("case_fold_expansion_reversed", true),
            ("case_fold_sigma", true),
            ("case_fold_non_turkic", true),
            ("case_fold_not_turkic", false),
            ("empty_same", true),
            ("empty_different", false),
            ("exact_without_normalization", false),
            ("case_fold_without_normalization", false),
            ("piped", true),
        ] {
            assert_eq!(
                mem_get_json(result.exec_state.stack(), result.mem_env, name)
                    .as_bool()
                    .unwrap(),
                expected,
                "{name}"
            );
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_string_is_equal_inside_sketch_block_is_predicate() {
        let code = r#"
@settings(experimentalFeatures = allow)

sketch(on = XY) {
  stringsAreEqual = string::isEqual("KCL", to = "kcl", caseInsensitive = true)
}
"#;

        parse_execute(code).await.unwrap();
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_string_trim() {
        let ascii_whitespace = " \t\n";
        let tab = "\t";
        let non_breaking_space = "\u{a0}";
        let em_space = "\u{2003}";
        let ideographic_space = "\u{3000}";
        let zero_width_space = "\u{200b}";
        let decomposed = "e\u{301}";
        let code = format!(
            r#"
ascii = string::trim("{ascii_whitespace}KCL{ascii_whitespace}")
internal = string::trim("  KCL{tab}strings  ")
unicode = string::trim("{non_breaking_space}{em_space}KCL{ideographic_space}")
all_whitespace = string::trim("{ascii_whitespace}{non_breaking_space}")
empty = string::trim("")
unchanged = string::trim("KCL")
without_normalization = string::trim(" {decomposed} ")
non_whitespace = string::trim("{zero_width_space}KCL{zero_width_space}")
piped = "  ready  " |> string::trim()
"#
        );

        let result = parse_execute(&code).await.unwrap();
        let non_whitespace = format!("{zero_width_space}KCL{zero_width_space}");
        for (name, expected) in [
            ("ascii", "KCL"),
            ("internal", "KCL\tstrings"),
            ("unicode", "KCL"),
            ("all_whitespace", ""),
            ("empty", ""),
            ("unchanged", "KCL"),
            ("without_normalization", decomposed),
            ("non_whitespace", non_whitespace.as_str()),
            ("piped", "ready"),
        ] {
            assert_eq!(
                mem_get_json(result.exec_state.stack(), result.mem_env, name)
                    .as_str()
                    .unwrap(),
                expected,
                "{name}"
            );
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_string_trim_start() {
        let ascii_whitespace = " \t\n";
        let tab = "\t";
        let non_breaking_space = "\u{a0}";
        let em_space = "\u{2003}";
        let ideographic_space = "\u{3000}";
        let zero_width_space = "\u{200b}";
        let decomposed = "e\u{301}";
        let code = format!(
            r#"
ascii = string::trimStart("{ascii_whitespace}KCL{ascii_whitespace}")
internal = string::trimStart("  KCL{tab}strings")
unicode = string::trimStart("{non_breaking_space}{em_space}KCL{ideographic_space}")
all_whitespace = string::trimStart("{ascii_whitespace}{non_breaking_space}")
empty = string::trimStart("")
unchanged = string::trimStart("KCL")
without_normalization = string::trimStart(" {decomposed}")
non_whitespace_prefix = string::trimStart("{zero_width_space}{ascii_whitespace}KCL")
piped = "  ready  " |> string::trimStart()
"#
        );

        let result = parse_execute(&code).await.unwrap();
        let ascii = format!("KCL{ascii_whitespace}");
        let unicode = format!("KCL{ideographic_space}");
        let non_whitespace_prefix = format!("{zero_width_space}{ascii_whitespace}KCL");
        for (name, expected) in [
            ("ascii", ascii.as_str()),
            ("internal", "KCL\tstrings"),
            ("unicode", unicode.as_str()),
            ("all_whitespace", ""),
            ("empty", ""),
            ("unchanged", "KCL"),
            ("without_normalization", decomposed),
            ("non_whitespace_prefix", non_whitespace_prefix.as_str()),
            ("piped", "ready  "),
        ] {
            assert_eq!(
                mem_get_json(result.exec_state.stack(), result.mem_env, name)
                    .as_str()
                    .unwrap(),
                expected,
                "{name}"
            );
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_string_trim_end() {
        let ascii_whitespace = " \t\n";
        let tab = "\t";
        let non_breaking_space = "\u{a0}";
        let em_space = "\u{2003}";
        let ideographic_space = "\u{3000}";
        let zero_width_space = "\u{200b}";
        let decomposed = "e\u{301}";
        let code = format!(
            r#"
ascii = string::trimEnd("{ascii_whitespace}KCL{ascii_whitespace}")
internal = string::trimEnd("KCL{tab}strings  ")
unicode = string::trimEnd("{non_breaking_space}KCL{em_space}{ideographic_space}")
all_whitespace = string::trimEnd("{ascii_whitespace}{non_breaking_space}")
empty = string::trimEnd("")
unchanged = string::trimEnd("KCL")
without_normalization = string::trimEnd("{decomposed} ")
non_whitespace_suffix = string::trimEnd("KCL{ascii_whitespace}{zero_width_space}")
piped = "  ready  " |> string::trimEnd()
"#
        );

        let result = parse_execute(&code).await.unwrap();
        let ascii = format!("{ascii_whitespace}KCL");
        let unicode = format!("{non_breaking_space}KCL");
        let non_whitespace_suffix = format!("KCL{ascii_whitespace}{zero_width_space}");
        for (name, expected) in [
            ("ascii", ascii.as_str()),
            ("internal", "KCL\tstrings"),
            ("unicode", unicode.as_str()),
            ("all_whitespace", ""),
            ("empty", ""),
            ("unchanged", "KCL"),
            ("without_normalization", decomposed),
            ("non_whitespace_suffix", non_whitespace_suffix.as_str()),
            ("piped", "  ready"),
        ] {
            assert_eq!(
                mem_get_json(result.exec_state.stack(), result.mem_env, name)
                    .as_str()
                    .unwrap(),
                expected,
                "{name}"
            );
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_string_to_string() {
        // Each case runs on its own so a failure names the expression that
        // produced it rather than collapsing the whole table.
        for (name, expr, expected) in [
            // Every row of the table in the `toString` doc comment appears
            // here, so the documentation cannot drift from the behaviour.
            ("unitless integer", "12", "12"),
            ("unitless fractional", "1.5", "1.5"),
            ("no digits dropped", "0.1 + 0.2", "0.30000000000000004"),
            ("unitless negative", "-7", "-7"),
            ("unitless zero", "0", "0"),
            ("negative zero", "-0", "0"),
            ("count", "3_", "3_"),
            ("millimeters", "12mm", "12mm"),
            ("centimeters", "12cm", "12cm"),
            ("meters", "12m", "12m"),
            ("inches", "1.5in", "1.5in"),
            ("feet", "2ft", "2ft"),
            ("yards", "3yd", "3yd"),
            ("degrees", "90deg", "90deg"),
            ("radians", "1.5rad", "1.5rad"),
            // Arithmetic keeps the unit it started with.
            ("length arithmetic", "2mm + 10mm", "12mm"),
            // Multiplying two lengths exceeds what the type system tracks, so
            // only the numeric component survives.
            ("units the type system loses", "2mm * 10mm", "20"),
            ("unitless arithmetic", "1 + 2", "3"),
        ] {
            let code = format!("actual = string::toString({expr})");
            let result = parse_execute(&code).await.unwrap();

            assert_eq!(
                mem_get_json(result.exec_state.stack(), result.mem_env, "actual")
                    .as_str()
                    .unwrap(),
                expected,
                "case: {name}"
            );
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_string_to_string_ignores_the_files_default_unit() {
        // A value with no suffix has the file's default unit attached, but that
        // unit was never written down, so neither is it in the output. Reading
        // the result back in a file with a different default gives a different
        // quantity; the guarantee is about the number, not the measurement.
        let code = "@settings(defaultLengthUnit = inch)\nactual = string::toString(12)";
        let result = parse_execute(code).await.unwrap();

        assert_eq!(
            mem_get_json(result.exec_state.stack(), result.mem_env, "actual")
                .as_str()
                .unwrap(),
            "12"
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_string_to_string_rejects_a_non_number() {
        let error = parse_execute(r#"actual = string::toString("already text")"#)
            .await
            .unwrap_err();

        // The declared signature rejects this before the implementation runs,
        // so the diagnostic names the function and both types.
        assert_eq!(
            error.message(),
            "The input argument of `string::toString` requires a value with type `number`, but found a value with type `string`."
        );
        assert!(
            matches!(error, KclError::Argument { .. }),
            "expected an Argument error, found {error:?}"
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_string_to_string_accepts_a_piped_argument() {
        let result = parse_execute("actual = 12mm |> string::toString()").await.unwrap();

        assert_eq!(
            mem_get_json(result.exec_state.stack(), result.mem_env, "actual")
                .as_str()
                .unwrap(),
            "12mm"
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_string_to_string_echoes_how_the_literal_was_written() {
        // Reading the output back is not a supported operation, but for a
        // literal that carries its own units the text still comes out looking
        // like what the author typed, which is what makes it readable.
        for literal in [
            "12",
            "1.5",
            "0.30000000000000004",
            "3_",
            // A fractional count and a negative both have to survive the trip,
            // since the formatter emits them.
            "2.5_",
            "-4_",
            "12mm",
            "-5mm",
            "1.5in",
            "90deg",
            "1.5rad",
        ] {
            let code = format!("actual = string::toString({literal})");
            let result = parse_execute(&code).await.unwrap();

            assert_eq!(
                mem_get_json(result.exec_state.stack(), result.mem_env, "actual")
                    .as_str()
                    .unwrap(),
                literal,
                "literal: {literal}"
            );
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_string_to_string_spells_out_non_finite_numbers() {
        // Division is unguarded, so these are reachable from ordinary KCL. They
        // convert like any other number: the point of the function is to build
        // a message, and a message about a NaN is exactly when you need one.
        for (name, expr, expected) in [
            ("positive infinity", "1 / 0", "Infinity"),
            ("negative infinity", "-1 / 0", "-Infinity"),
            ("nan", "0 / 0", "NaN"),
            // The unit is dropped: no length is described by "Infinitymm".
            ("infinity from a length", "1mm / 0", "Infinity"),
            ("nan from a length", "0mm / 0", "NaN"),
            ("infinity from an angle", "1deg / 0", "Infinity"),
        ] {
            let code = format!("actual = string::toString({expr})");
            let result = parse_execute(&code).await.unwrap();

            assert_eq!(
                mem_get_json(result.exec_state.stack(), result.mem_env, "actual")
                    .as_str()
                    .unwrap(),
                expected,
                "case: {name}"
            );
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_string_equality_operators() {
        let composed = "\u{e9}";
        let decomposed = "e\u{301}";
        let code = format!(
            r#"
equal_same_ascii = "KCL" == "KCL"
equal_different_case = "KCL" == "kcl"
not_equal_same_ascii = "KCL" != "KCL"
not_equal_different_case = "KCL" != "kcl"
equal_same_unicode = "{composed}" == "{composed}"
not_equal_same_unicode = "{composed}" != "{composed}"
equal_without_normalization = "{composed}" == "{decomposed}"
not_equal_without_normalization = "{composed}" != "{decomposed}"
"#
        );

        let result = parse_execute(&code).await.unwrap();
        for (name, expected) in [
            ("equal_same_ascii", true),
            ("equal_different_case", false),
            ("not_equal_same_ascii", false),
            ("not_equal_different_case", true),
            ("equal_same_unicode", true),
            ("not_equal_same_unicode", false),
            ("equal_without_normalization", false),
            ("not_equal_without_normalization", true),
        ] {
            assert_eq!(
                mem_get_json(result.exec_state.stack(), result.mem_env, name)
                    .as_bool()
                    .unwrap(),
                expected,
                "{name}"
            );
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_string_equality_inside_sketch_block_fails_like_number_equality() {
        let string_code = r#"
@settings(experimentalFeatures = allow)

sketch(on = XY) {
  stringsAreEqual = "KCL" == "KCL"
}
"#;
        let number_code = r#"
@settings(experimentalFeatures = allow)

sketch(on = XY) {
  numbersAreEqual = 1 == 1
}
"#;

        assert_eq!(
            parse_execute(string_code).await.unwrap_err().message(),
            "Cannot create an equivalence constraint between values of these types: a string and a string"
        );
        assert_eq!(
            parse_execute(number_code).await.unwrap_err().message(),
            "Cannot create an equivalence constraint between values of these types: a number and a number"
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_math_execute_start_negative() {
        let ast = r#"myVar = -5 + 6"#;
        let result = parse_execute(ast).await.unwrap();
        assert_eq!(
            1.0,
            mem_get_json(result.exec_state.stack(), result.mem_env, "myVar")
                .as_f64()
                .unwrap()
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_math_execute_with_pi() {
        let ast = r#"myVar = PI * 2"#;
        let result = parse_execute(ast).await.unwrap();
        assert_eq!(
            std::f64::consts::TAU,
            mem_get_json(result.exec_state.stack(), result.mem_env, "myVar")
                .as_f64()
                .unwrap()
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_math_define_decimal_without_leading_zero() {
        let ast = r#"thing = .4 + 7"#;
        let result = parse_execute(ast).await.unwrap();
        assert_eq!(
            7.4,
            mem_get_json(result.exec_state.stack(), result.mem_env, "thing")
                .as_f64()
                .unwrap()
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn pass_std_to_std() {
        let ast = r#"sketch001 = startSketchOn(XY)
profile001 = circle(sketch001, center = [0, 0], radius = 2)
extrude001 = extrude(profile001, length = 5)
extrudes = patternLinear3d(
  extrude001,
  instances = 3,
  distance = 5,
  axis = [1, 1, 0],
)
clone001 = map(extrudes, f = clone)
"#;
        parse_execute(ast).await.unwrap();
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_array_reduce_nested_array() {
        let code = r#"
fn id(@el, accum)  { return accum }

answer = reduce([], initial=[[[0,0]]], f=id)
"#;
        let result = parse_execute(code).await.unwrap();
        assert_eq!(
            mem_get_json(result.exec_state.stack(), result.mem_env, "answer"),
            KclValue::HomArray {
                value: vec![KclValue::HomArray {
                    value: vec![KclValue::HomArray {
                        value: vec![
                            KclValue::Number {
                                value: 0.0,
                                ty: NumericType::default(),
                                meta: vec![SourceRange::new(69, 70, Default::default()).into()],
                            },
                            KclValue::Number {
                                value: 0.0,
                                ty: NumericType::default(),
                                meta: vec![SourceRange::new(71, 72, Default::default()).into()],
                            }
                        ],
                        ty: RuntimeType::any(),
                    }],
                    ty: RuntimeType::any(),
                }],
                ty: RuntimeType::any(),
            }
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_zero_param_fn() {
        let ast = r#"sigmaAllow = 35000 // psi
leg1 = 5 // inches
leg2 = 8 // inches
fn thickness() { return 0.56 }

bracket = startSketchOn(XY)
  |> startProfile(at = [0,0])
  |> line(end = [0, leg1])
  |> line(end = [leg2, 0])
  |> line(end = [0, -thickness()])
  |> line(end = [-leg2 + thickness(), 0])
"#;
        parse_execute(ast).await.unwrap();
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_unary_operator_not_succeeds() {
        let ast = r#"
fn returnTrue() { return !false }
t = true
f = false
notTrue = !t
notFalse = !f
c = !!true
d = !returnTrue()

assertIs(!false, error = "expected to pass")

fn check(x) {
  assertIs(!x, error = "expected argument to be false")
  return true
}
check(x = false)
"#;
        let result = parse_execute(ast).await.unwrap();
        assert_eq!(
            false,
            mem_get_json(result.exec_state.stack(), result.mem_env, "notTrue")
                .as_bool()
                .unwrap()
        );
        assert_eq!(
            true,
            mem_get_json(result.exec_state.stack(), result.mem_env, "notFalse")
                .as_bool()
                .unwrap()
        );
        assert_eq!(
            true,
            mem_get_json(result.exec_state.stack(), result.mem_env, "c")
                .as_bool()
                .unwrap()
        );
        assert_eq!(
            false,
            mem_get_json(result.exec_state.stack(), result.mem_env, "d")
                .as_bool()
                .unwrap()
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_unary_operator_not_on_non_bool_fails() {
        let code1 = r#"
// Yup, this is null.
myNull = 0 / 0
notNull = !myNull
"#;
        assert_eq!(
            parse_execute(code1).await.unwrap_err().message(),
            "Cannot apply unary operator ! to non-boolean value: a number",
        );

        let code2 = "notZero = !0";
        assert_eq!(
            parse_execute(code2).await.unwrap_err().message(),
            "Cannot apply unary operator ! to non-boolean value: a number",
        );

        let code3 = r#"
notEmptyString = !""
"#;
        assert_eq!(
            parse_execute(code3).await.unwrap_err().message(),
            "Cannot apply unary operator ! to non-boolean value: a string",
        );

        let code4 = r#"
obj = { a = 1 }
notMember = !obj.a
"#;
        assert_eq!(
            parse_execute(code4).await.unwrap_err().message(),
            "Cannot apply unary operator ! to non-boolean value: a number",
        );

        let code5 = "
a = []
notArray = !a";
        assert_eq!(
            parse_execute(code5).await.unwrap_err().message(),
            "Cannot apply unary operator ! to non-boolean value: an empty array",
        );

        let code6 = "
x = {}
notObject = !x";
        assert_eq!(
            parse_execute(code6).await.unwrap_err().message(),
            "Cannot apply unary operator ! to non-boolean value: an object",
        );

        let code7 = "
fn x() { return 1 }
notFunction = !x";
        let fn_err = parse_execute(code7).await.unwrap_err();
        // These are currently printed out as JSON objects, so we don't want to
        // check the full error.
        assert!(
            fn_err
                .message()
                .starts_with("Cannot apply unary operator ! to non-boolean value: "),
            "Actual error: {fn_err:?}"
        );

        let code8 = "
myTagDeclarator = $myTag
notTagDeclarator = !myTagDeclarator";
        let tag_declarator_err = parse_execute(code8).await.unwrap_err();
        // These are currently printed out as JSON objects, so we don't want to
        // check the full error.
        assert!(
            tag_declarator_err
                .message()
                .starts_with("Cannot apply unary operator ! to non-boolean value: a tag declarator"),
            "Actual error: {tag_declarator_err:?}"
        );

        let code9 = "
myTagDeclarator = $myTag
notTagIdentifier = !myTag";
        let tag_identifier_err = parse_execute(code9).await.unwrap_err();
        // These are currently printed out as JSON objects, so we don't want to
        // check the full error.
        assert!(
            tag_identifier_err
                .message()
                .starts_with("Cannot apply unary operator ! to non-boolean value: a tag identifier"),
            "Actual error: {tag_identifier_err:?}"
        );

        let code10 = "notPipe = !(1 |> 2)";
        assert_eq!(
            // TODO: We don't currently parse this, but we should.  It should be
            // a runtime error instead.
            parse_execute(code10).await.unwrap_err(),
            KclError::new_syntax(KclErrorDetails::new(
                "Unexpected token: !".to_owned(),
                vec![SourceRange::new(10, 11, ModuleId::default())],
            ))
        );

        let code11 = "
fn identity(x) { return x }
notPipeSub = 1 |> identity(!%))";
        assert_eq!(
            // TODO: We don't currently parse this, but we should.  It should be
            // a runtime error instead.
            parse_execute(code11).await.unwrap_err(),
            KclError::new_syntax(KclErrorDetails::new(
                "There was an unexpected `!`. Try removing it.".to_owned(),
                vec![SourceRange::new(56, 57, ModuleId::default())],
            ))
        );

        // TODO: Add these tests when we support these types.
        // let notNan = !NaN
        // let notInfinity = !Infinity
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_start_sketch_on_invalid_kwargs() {
        let current_dir = std::env::current_dir().unwrap();
        let mut path = current_dir.join("tests/inputs/startSketchOn_0.kcl");
        let mut code = std::fs::read_to_string(&path).unwrap();
        assert_eq!(
            parse_execute(&code).await.unwrap_err().message(),
            "You cannot give both `face` and `normalToFace` params, you have to choose one or the other.".to_owned(),
        );

        path = current_dir.join("tests/inputs/startSketchOn_1.kcl");
        code = std::fs::read_to_string(&path).unwrap();

        assert_eq!(
            parse_execute(&code).await.unwrap_err().message(),
            "`alignAxis` is required if `normalToFace` is specified.".to_owned(),
        );

        path = current_dir.join("tests/inputs/startSketchOn_2.kcl");
        code = std::fs::read_to_string(&path).unwrap();

        assert_eq!(
            parse_execute(&code).await.unwrap_err().message(),
            "`normalToFace` is required if `alignAxis` is specified.".to_owned(),
        );

        path = current_dir.join("tests/inputs/startSketchOn_3.kcl");
        code = std::fs::read_to_string(&path).unwrap();

        assert_eq!(
            parse_execute(&code).await.unwrap_err().message(),
            "`normalToFace` is required if `alignAxis` is specified.".to_owned(),
        );

        path = current_dir.join("tests/inputs/startSketchOn_4.kcl");
        code = std::fs::read_to_string(&path).unwrap();

        assert_eq!(
            parse_execute(&code).await.unwrap_err().message(),
            "`normalToFace` is required if `normalOffset` is specified.".to_owned(),
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_math_negative_variable_in_binary_expression() {
        let ast = r#"sigmaAllow = 35000 // psi
width = 1 // inch

p = 150 // lbs
distance = 6 // inches
FOS = 2

leg1 = 5 // inches
leg2 = 8 // inches

thickness_squared = distance * p * FOS * 6 / sigmaAllow
thickness = 0.56 // inches. App does not support square root function yet

bracket = startSketchOn(XY)
  |> startProfile(at = [0,0])
  |> line(end = [0, leg1])
  |> line(end = [leg2, 0])
  |> line(end = [0, -thickness])
  |> line(end = [-leg2 + thickness, 0])
"#;
        parse_execute(ast).await.unwrap();
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_execute_function_no_return() {
        let ast = r#"fn test(@origin) {
  origin
}

test([0, 0])
"#;
        let result = parse_execute(ast).await;
        assert!(result.is_err());
        assert!(result.unwrap_err().to_string().contains("undefined"));
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_max_stack_size_exceeded_error() {
        let ast = r#"
fn forever(@n) {
  return 1 + forever(n)
}

forever(1)
"#;
        let result = parse_execute(ast).await;
        let err = result.unwrap_err();
        // The recursive executor's native-stack cap and the machine
        // executor's call-depth guard report differently.
        let msg = err.to_string();
        assert!(
            msg.contains("stack size exceeded") || msg.contains("Call depth limit"),
            "actual: {err:?}"
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_math_doubly_nested_parens() {
        let ast = r#"sigmaAllow = 35000 // psi
width = 4 // inch
p = 150 // Force on shelf - lbs
distance = 6 // inches
FOS = 2
leg1 = 5 // inches
leg2 = 8 // inches
thickness_squared = (distance * p * FOS * 6 / (sigmaAllow - width))
thickness = 0.32 // inches. App does not support square root function yet
bracket = startSketchOn(XY)
  |> startProfile(at = [0,0])
    |> line(end = [0, leg1])
  |> line(end = [leg2, 0])
  |> line(end = [0, -thickness])
  |> line(end = [-1 * leg2 + thickness, 0])
  |> line(end = [0, -1 * leg1 + thickness])
  |> close()
  |> extrude(length = width)
"#;
        parse_execute(ast).await.unwrap();
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_math_nested_parens_one_less() {
        let ast = r#" sigmaAllow = 35000 // psi
width = 4 // inch
p = 150 // Force on shelf - lbs
distance = 6 // inches
FOS = 2
leg1 = 5 // inches
leg2 = 8 // inches
thickness_squared = distance * p * FOS * 6 / (sigmaAllow - width)
thickness = 0.32 // inches. App does not support square root function yet
bracket = startSketchOn(XY)
  |> startProfile(at = [0,0])
    |> line(end = [0, leg1])
  |> line(end = [leg2, 0])
  |> line(end = [0, -thickness])
  |> line(end = [-1 * leg2 + thickness, 0])
  |> line(end = [0, -1 * leg1 + thickness])
  |> close()
  |> extrude(length = width)
"#;
        parse_execute(ast).await.unwrap();
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_fn_as_operand() {
        let ast = r#"fn f() { return 1 }
x = f()
y = x + 1
z = f() + 1
w = f() + f()
"#;
        parse_execute(ast).await.unwrap();
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn kcl_test_ids_stable_between_executions() {
        let code = r#"sketch001 = startSketchOn(XZ)
|> startProfile(at = [61.74, 206.13])
|> xLine(length = 305.11, tag = $seg01)
|> yLine(length = -291.85)
|> xLine(length = -segLen(seg01))
|> line(endAbsolute = [profileStartX(%), profileStartY(%)])
|> close()
|> extrude(length = 40.14)
|> shell(
    thickness = 3.14,
    faces = [seg01]
)
"#;

        let ctx = crate::test_server::new_context_engine_graphics(true, None)
            .await
            .unwrap();
        let old_program = crate::Program::parse_no_errs(code).unwrap();

        // Execute the program.
        if let Err(err) = ctx.run_with_caching(old_program).await {
            let report = err.into_miette_report_with_outputs(code).unwrap();
            let report = miette::Report::new(report);
            panic!("Error executing program: {report:?}");
        }

        // Get the id_generator from the first execution.
        let id_generator = cache::read_old_ast().await.unwrap().main.exec_state.id_generator;

        let code = r#"sketch001 = startSketchOn(XZ)
|> startProfile(at = [62.74, 206.13])
|> xLine(length = 305.11, tag = $seg01)
|> yLine(length = -291.85)
|> xLine(length = -segLen(seg01))
|> line(endAbsolute = [profileStartX(%), profileStartY(%)])
|> close()
|> extrude(length = 40.14)
|> shell(
    faces = [seg01],
    thickness = 3.14,
)
"#;

        // Execute a slightly different program again.
        let program = crate::Program::parse_no_errs(code).unwrap();
        // Execute the program.
        ctx.run_with_caching(program).await.unwrap();

        let new_id_generator = cache::read_old_ast().await.unwrap().main.exec_state.id_generator;

        assert_eq!(id_generator, new_id_generator);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn kcl_test_changing_a_setting_updates_the_cached_state() {
        let code = r#"sketch001 = startSketchOn(XZ)
|> startProfile(at = [61.74, 206.13])
|> xLine(length = 305.11, tag = $seg01)
|> yLine(length = -291.85)
|> xLine(length = -segLen(seg01))
|> line(endAbsolute = [profileStartX(%), profileStartY(%)])
|> close()
|> extrude(length = 40.14)
|> shell(
    thickness = 3.14,
    faces = [seg01]
)
"#;

        let mut ctx = crate::test_server::new_context_engine_graphics(true, None)
            .await
            .unwrap();
        let old_program = crate::Program::parse_no_errs(code).unwrap();

        // Execute the program.
        ctx.run_with_caching(old_program.clone()).await.unwrap();

        let settings_state = cache::read_old_ast().await.unwrap().settings;

        // Ensure the settings are as expected.
        assert_eq!(settings_state, ctx.settings);

        // Change a setting.
        ctx.settings.highlight_edges = !ctx.settings.highlight_edges;

        // Execute the program.
        ctx.run_with_caching(old_program.clone()).await.unwrap();

        let settings_state = cache::read_old_ast().await.unwrap().settings;

        // Ensure the settings are as expected.
        assert_eq!(settings_state, ctx.settings);

        // Change a setting.
        ctx.settings.highlight_edges = !ctx.settings.highlight_edges;

        // Execute the program.
        ctx.run_with_caching(old_program).await.unwrap();

        let settings_state = cache::read_old_ast().await.unwrap().settings;

        // Ensure the settings are as expected.
        assert_eq!(settings_state, ctx.settings);

        ctx.close().await;
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn mock_after_not_mock() {
        let ctx = ExecutorContext::new_with_default_client().await.unwrap();
        let program = crate::Program::parse_no_errs("x = 2").unwrap();
        let result = ctx.run_with_caching(program).await.unwrap();
        assert_number_variable(&result.variables, "x", 2.0);

        let ctx2 = ExecutorContext::new_mock(None).await;
        let program2 = crate::Program::parse_no_errs("z = x + 1").unwrap();
        let result = ctx2.run_mock(&program2, &MockConfig::default()).await.unwrap();
        assert_number_variable(&result.variables, "z", 3.0);

        ctx.close().await;
        ctx2.close().await;
    }

    /// Regression test for https://github.com/KittyCAD/modeling-app/issues/12498
    #[tokio::test(flavor = "multi_thread")]
    async fn mock_execution_succeeds_after_split() {
        let code = kcl_input!("repro_mock_extrude");
        let ctx = ExecutorContext::new_mock(None).await;
        let program = crate::Program::parse_no_errs(code).unwrap();
        let _result = match ctx.run_mock(&program, &MockConfig::default()).await {
            Ok(res) => res,
            Err(e) => panic!("{}", e.error),
        };
    }

    /// Regression test for https://github.com/KittyCAD/modeling-app/issues/13319
    #[tokio::test(flavor = "multi_thread")]
    async fn mock_execution_rejects_oob_on_frontend_array() {
        let code = r#"
values = [10, 20]
third = values[2]
"#;
        let ctx = ExecutorContext::new_mock(None).await;
        let program = crate::Program::parse_no_errs(code).unwrap();
        let err = ctx.run_mock(&program, &MockConfig::default()).await.unwrap_err();
        ctx.close().await;

        assert!(
            err.error.message().contains("array doesn't have any item at index 2"),
            "{err:?}"
        );
    }

    /// Regression test for https://github.com/KittyCAD/modeling-app/issues/13103
    /// i.e.
    /// If you do a pattern circular 3d in mock execution mode,
    /// and you ask for 10 instances, you should get 10 instances.
    #[tokio::test(flavor = "multi_thread")]
    async fn mock_execution_pattern_circular_number() {
        let code = kcl_input!("repro_mock_pattern_circular");
        let ctx = ExecutorContext::new_mock(None).await;
        let program = crate::Program::parse_no_errs(code).unwrap();
        let result = ctx.run_mock(&program, &MockConfig::default()).await.unwrap();
        let copies = result
            .variables
            .get("copies")
            .expect("no variable called 'copies' found");
        let value = match copies {
            KclValueView::Solid { .. } => {
                panic!("One solid?");
            }
            KclValueView::HomArray { value } => value,
            other => panic!("{other:#?}"),
        };
        let actual_instances = value.len();
        let expected_instances = 10; // from the KCL `instances = `
        assert_eq!(actual_instances, expected_instances);
    }

    /// Regression test for https://github.com/KittyCAD/modeling-app/issues/13103
    /// i.e.
    /// If you do a pattern circular 3d in mock execution mode,
    /// and you ask for 10 instances, you should get 10 instances.
    #[tokio::test(flavor = "multi_thread")]
    async fn mock_execution_subtract() {
        // Run this KCL file, in mock execution.
        let code = kcl_input!("repro_mock_subtract");
        let ctx = ExecutorContext::new_mock(None).await;
        let program = crate::Program::parse_no_errs(code).unwrap();
        let result = ctx.run_mock(&program, &MockConfig::default()).await;
        ctx.close().await;
        let result = match result {
            Ok(x) => x,
            Err(e) => {
                let error = e.error;
                panic!("{error}");
            }
        };

        // Get the variable we're interested in, from KCL program memory.
        let subtracted_parts = result
            .variables
            .get("subtractedParts")
            .expect("no variable called 'subtracted_parts' found");
        let subtracted_parts = match subtracted_parts {
            KclValueView::Solid { .. } => {
                panic!("One solid?");
            }
            KclValueView::HomArray { value } => value,
            other => panic!("{other:#?}"),
        };

        // Validate the variable.
        // from the KCL, there's 2 parts being subtracted from.
        let expected_number_of_parts = 2;
        let actual_number_of_parts = subtracted_parts.len();
        assert_eq!(actual_number_of_parts, expected_number_of_parts);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn mock_then_add_extrude_then_mock_again() {
        let code = "s = sketch(on = XY) {
    line1 = line(start = [0.05, 0.05], end = [3.88, 0.81])
    line2 = line(start = [3.88, 0.81], end = [0.92, 4.67])
    coincident([line1.end, line2.start])
    line3 = line(start = [0.92, 4.67], end = [0.05, 0.05])
    coincident([line2.end, line3.start])
    coincident([line1.start, line3.end])
}
    ";
        let ctx = ExecutorContext::new_mock(None).await;
        let program = crate::Program::parse_no_errs(code).unwrap();
        let result = ctx.run_mock(&program, &MockConfig::default()).await.unwrap();
        assert!(result.variables.contains_key("s"), "actual: {:?}", result.variables);

        let code2 = code.to_owned()
            + "
region001 = region(point = [1mm, 1mm], sketch = s)
extrude001 = extrude(region001, length = 1)
    ";
        let program2 = crate::Program::parse_no_errs(&code2).unwrap();
        let result = ctx.run_mock(&program2, &MockConfig::default()).await.unwrap();
        assert!(
            result.variables.contains_key("region001"),
            "actual: {:?}",
            result.variables
        );

        ctx.close().await;
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn face_parent_solid_stays_compact_for_repeated_sketch_on_face() {
        let code = format!(
            r#"{}

face7 = faceOf(solid6, face = r6.tags.line1)
r7 = squareRegion(onSurface = face7)
solid7 = extrude(r7, length = width)
"#,
            include_str!("../../tests/endless_impeller/input.kcl")
        );

        let result = parse_execute(&code).await.unwrap();
        let solid7 = mem_get_json(result.exec_state.stack(), result.mem_env, "solid7");
        assert!(matches!(solid7, KclValue::Solid { .. }), "actual: {solid7:?}");

        let face7 = match mem_get_json(result.exec_state.stack(), result.mem_env, "face7") {
            KclValue::Face { value } => value,
            value => panic!("expected face7 to be a Face, got {value:?}"),
        };
        assert!(face7.parent_solid.creator_sketch_id.is_some());
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn mock_has_stable_ids() {
        let ctx = ExecutorContext::new_mock(None).await;
        let mock_config = MockConfig {
            use_prev_memory: false,
            ..Default::default()
        };
        let code = "sk = startSketchOn(XY)
        |> startProfile(at = [0, 0])";
        let program = crate::Program::parse_no_errs(code).unwrap();
        let result = ctx.run_mock(&program, &mock_config).await.unwrap();
        let ids = result.artifact_graph.iter().map(|(k, _)| *k).collect::<Vec<_>>();
        assert!(!ids.is_empty(), "IDs should not be empty");

        let ctx2 = ExecutorContext::new_mock(None).await;
        let program2 = crate::Program::parse_no_errs(code).unwrap();
        let result = ctx2.run_mock(&program2, &mock_config).await.unwrap();
        let ids2 = result.artifact_graph.iter().map(|(k, _)| *k).collect::<Vec<_>>();

        assert_eq!(ids, ids2, "Generated IDs should match");
        ctx.close().await;
        ctx2.close().await;
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn mock_memory_restore_preserves_module_maps() {
        clear_mem_cache().await;

        let ctx = ExecutorContext::new_mock(None).await;
        let cold_start = MockConfig {
            use_prev_memory: false,
            ..Default::default()
        };
        ctx.run_mock(&crate::Program::empty(), &cold_start).await.unwrap();

        let mut mem = cache::read_old_memory().await.unwrap();
        assert!(
            mem.path_to_source_id.len() > 3,
            "expected prelude imports to populate multiple modules, got {:?}",
            mem.path_to_source_id
        );
        mem.constraint_state.insert(
            crate::front::ObjectId(1),
            indexmap::indexmap! {
                crate::execution::ConstraintKey::LineCircle([0, 1, 2, 3, 4, 5, 6, 7, 8, 9]) =>
                    crate::execution::ConstraintState::Tangency(crate::execution::TangencyMode::LineCircle(ezpz::LineSide::Left))
            },
        );

        let mut exec_state = ExecState::new_mock(&ctx, &MockConfig::default());
        ExecutorContext::restore_mock_memory(&mut exec_state, mem.clone(), &MockConfig::default()).unwrap();

        assert_eq!(exec_state.global.path_to_source_id, mem.path_to_source_id);
        assert_eq!(exec_state.global.id_to_source, mem.id_to_source);
        assert_eq!(exec_state.global.module_infos, mem.module_infos);
        assert_eq!(exec_state.mod_local.constraint_state, mem.constraint_state);

        clear_mem_cache().await;
        ctx.close().await;
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn run_with_caching_no_action_refreshes_mock_memory() {
        cache::bust_cache().await;
        clear_mem_cache().await;

        let ctx = ExecutorContext::new_with_engine(Arc::new(EngineManager::new_mock()), Default::default());
        let program = crate::Program::parse_no_errs(
            r#"sketch001 = sketch(on = XY) {
  line1 = line(start = [var 0mm, var 0mm], end = [var 1mm, var 0mm])
}
"#,
        )
        .unwrap();

        ctx.run_with_caching(program.clone()).await.unwrap();
        let baseline_memory = cache::read_old_memory().await.unwrap();
        assert!(
            !baseline_memory.scene_objects.is_empty(),
            "expected engine execution to persist full-scene mock memory"
        );

        cache::write_old_memory(cache::SketchModeState::new_for_tests()).await;
        assert_eq!(cache::read_old_memory().await.unwrap().scene_objects.len(), 0);

        ctx.run_with_caching(program).await.unwrap();
        let refreshed_memory = cache::read_old_memory().await.unwrap();
        assert_eq!(refreshed_memory.scene_objects, baseline_memory.scene_objects);
        assert_eq!(refreshed_memory.path_to_source_id, baseline_memory.path_to_source_id);
        assert_eq!(refreshed_memory.id_to_source, baseline_memory.id_to_source);

        cache::bust_cache().await;
        clear_mem_cache().await;
        ctx.close().await;
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn sim_sketch_mode_real_mock_real() {
        let ctx = ExecutorContext::new_with_default_client().await.unwrap();
        let code = r#"sketch001 = startSketchOn(XY)
profile001 = startProfile(sketch001, at = [0, 0])
  |> line(end = [10, 0])
  |> line(end = [0, 10])
  |> line(end = [-10, 0])
  |> line(end = [0, -10])
  |> close()
"#;
        let program = crate::Program::parse_no_errs(code).unwrap();
        let result = ctx.run_with_caching(program).await.unwrap();
        assert_eq!(result.operations.get(&ModuleId::default()).unwrap().len(), 1);

        let mock_ctx = ExecutorContext::new_mock(None).await;
        let mock_program = crate::Program::parse_no_errs(code).unwrap();
        let mock_result = mock_ctx.run_mock(&mock_program, &MockConfig::default()).await.unwrap();
        assert_eq!(mock_result.operations.get(&ModuleId::default()).unwrap().len(), 1);

        let code2 = code.to_owned()
            + r#"
extrude001 = extrude(profile001, length = 10)
"#;
        let program2 = crate::Program::parse_no_errs(&code2).unwrap();
        let result = ctx.run_with_caching(program2).await.unwrap();
        assert_eq!(result.operations.get(&ModuleId::default()).unwrap().len(), 2);

        ctx.close().await;
        mock_ctx.close().await;
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn read_tag_version() {
        let ast = r#"fn bar(@t) {
  return startSketchOn(XY)
    |> startProfile(at = [0,0])
    |> angledLine(
        angle = -60,
        length = segLen(t),
    )
    |> line(end = [0, 0])
    |> close()
}

sketch = startSketchOn(XY)
  |> startProfile(at = [0,0])
  |> line(end = [0, 10])
  |> line(end = [10, 0], tag = $tag0)
  |> line(endAbsolute = [0, 0])

fn foo() {
  // tag0 tags an edge
  return bar(tag0)
}

solid = sketch |> extrude(length = 10)
// tag0 tags a face
sketch2 = startSketchOn(solid, face = tag0)
  |> startProfile(at = [0,0])
  |> line(end = [0, 1])
  |> line(end = [1, 0])
  |> line(end = [0, 0])

foo() |> extrude(length = 1)
"#;
        parse_execute(ast).await.unwrap();
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn experimental() {
        let code = r#"
startSketchOn(XY)
  |> startProfile(at = [0, 0], tag = $start)
  |> elliptic(center = [0, 0], angleStart = segAng(start), angleEnd = 160deg, majorRadius = 2, minorRadius = 3)
"#;
        let result = parse_execute(code).await.unwrap();
        let issues = result.exec_state.issues();
        assert_eq!(issues.len(), 1);
        assert_eq!(issues[0].severity, Severity::Error);
        let msg = &issues[0].message;
        assert!(msg.contains("experimental"), "found {msg}");

        let code = r#"@settings(experimentalFeatures = allow)
startSketchOn(XY)
  |> startProfile(at = [0, 0], tag = $start)
  |> elliptic(center = [0, 0], angleStart = segAng(start), angleEnd = 160deg, majorRadius = 2, minorRadius = 3)
"#;
        let result = parse_execute(code).await.unwrap();
        let issues = result.exec_state.issues();
        assert!(issues.is_empty(), "issues={issues:#?}");

        let code = r#"@settings(experimentalFeatures = warn)
startSketchOn(XY)
  |> startProfile(at = [0, 0], tag = $start)
  |> elliptic(center = [0, 0], angleStart = segAng(start), angleEnd = 160deg, majorRadius = 2, minorRadius = 3)
"#;
        let result = parse_execute(code).await.unwrap();
        let issues = result.exec_state.issues();
        assert_eq!(issues.len(), 1);
        assert_eq!(issues[0].severity, Severity::Warning);
        let msg = &issues[0].message;
        assert!(msg.contains("experimental"), "found {msg}");

        let code = r#"@settings(experimentalFeatures = deny)
startSketchOn(XY)
  |> startProfile(at = [0, 0], tag = $start)
  |> elliptic(center = [0, 0], angleStart = segAng(start), angleEnd = 160deg, majorRadius = 2, minorRadius = 3)
"#;
        let result = parse_execute(code).await.unwrap();
        let issues = result.exec_state.issues();
        assert_eq!(issues.len(), 1);
        assert_eq!(issues[0].severity, Severity::Error);
        let msg = &issues[0].message;
        assert!(msg.contains("experimental"), "found {msg}");

        let code = r#"@settings(experimentalFeatures = foo)
startSketchOn(XY)
  |> startProfile(at = [0, 0], tag = $start)
  |> elliptic(center = [0, 0], angleStart = segAng(start), angleEnd = 160deg, majorRadius = 2, minorRadius = 3)
"#;
        parse_execute(code).await.unwrap_err();
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn default_angle_unit_warns_in_legacy_kcl() {
        for version in ["", "kclVersion = 1.0, ", "kclVersion = 2.0, "] {
            for unit in ["deg", "rad"] {
                let code = format!("@settings({version}defaultAngleUnit = {unit})\nx = 1\n");
                let result = parse_execute(&code).await.unwrap();
                let issues = result.issues();
                assert_eq!(issues.len(), 1, "code={code}");
                assert_eq!(issues[0].severity, Severity::Warning, "code={code}");
                assert_eq!(
                    issues[0].message,
                    "The `defaultAngleUnit` setting is deprecated; use explicit units for angles"
                );
                assert_eq!(variable_f64(&result, "x"), 1.0);
            }
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn default_angle_unit_errors_in_kcl_v3() {
        for settings in [
            "@settings(kclVersion = \"3.0-preview\", defaultAngleUnit = deg)",
            "@settings(defaultAngleUnit = rad, kclVersion = \"3.0-preview\")",
            "@settings(defaultAngleUnit = deg)\n@settings(kclVersion = \"3.0-preview\")",
            "@settings(kclVersion = \"3.0-preview\")\n@settings(defaultAngleUnit = rad)",
        ] {
            let code = format!("{settings}\nx = 1\n");
            let Err(error) = parse_execute(&code).await else {
                panic!("defaultAngleUnit must fail in KCL 3.0: {code}");
            };
            assert_eq!(
                error.message(),
                "The `defaultAngleUnit` setting was removed in KCL 3.0; use explicit units for angles",
                "code={code}"
            );
            let ranges = error.source_ranges();
            assert_eq!(ranges.len(), 1);
            assert!(code[ranges[0].start()..ranges[0].end()].contains("defaultAngleUnit"));
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn default_angle_unit_error_cannot_be_suppressed() {
        for version in ["1.0", "2.0", "\"3.0-preview\""] {
            let code = format!(
                "@warnings(allow = angleUnits)\n@settings(kclVersion = {version}, defaultAngleUnit = deg)\nx = 1\n"
            );
            let result = parse_execute(&code).await;
            if version == "\"3.0-preview\"" {
                assert_eq!(
                    result.unwrap_err().message(),
                    "The `defaultAngleUnit` setting was removed in KCL 3.0; use explicit units for angles"
                );
            } else {
                assert!(result.unwrap().issues().is_empty(), "code={code}");
            }
        }
    }

    /// The `defaultAngleUnit` gate in an imported module follows the effective
    /// kclVersion: the entry point's when it declares KCL 3.0, otherwise the
    /// module's own (undeclared here, so 1.0). The module declares no
    /// kclVersion because a KCL 3.0 entry point rejects an import declaring a
    /// different one before this gate is reached.
    #[tokio::test(flavor = "multi_thread")]
    async fn default_angle_unit_in_import_uses_effective_kcl_version() {
        let dep = "@settings(defaultAngleUnit = deg)\nexport x = 1\n";
        for version in ["1.0", "2.0", "\"3.0-preview\""] {
            let main = format!("@settings(kclVersion = {version})\nimport x from \"dep.kcl\"\n");
            let result = execute_with_modules(&main, &[("dep.kcl", dep)]).await;
            if version == "\"3.0-preview\"" {
                assert_eq!(
                    result.unwrap_err().message(),
                    "The `defaultAngleUnit` setting was removed in KCL 3.0; use explicit units for angles"
                );
            } else {
                assert_eq!(variable_f64(&result.unwrap(), "x"), 1.0);
            }
        }
    }

    /// The entry point's declared kclVersion is recorded whatever it is, so
    /// that errors can name it. Only KCL 3.0 or later pins the version for the
    /// whole execution; see [`ExecState::kcl_version`].
    #[tokio::test(flavor = "multi_thread")]
    async fn entry_point_kcl_version_records_declared_version() {
        for (code, expected) in [
            ("x = 1\n", None),
            ("@settings(defaultLengthUnit = in)\nx = 1\n", None),
            ("@settings(kclVersion = 1.0)\nx = 1\n", Some(KclVersion::V1)),
            ("@settings(kclVersion = 2.0)\nx = 1\n", Some(KclVersion::V2)),
            (
                "@settings(kclVersion = \"3.0-preview\")\nx = 1\n",
                Some(KclVersion::V3Preview),
            ),
        ] {
            let result = parse_execute(code).await.unwrap();
            assert_eq!(
                result.exec_state.global.entry_point_kcl_version, expected,
                "code={code}"
            );
            assert_eq!(
                result.exec_state.entry_point_version_is_v3_or_higher(),
                expected == Some(KclVersion::V3Preview),
                "code={code}"
            );
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn kcl_version_lookup_prefers_entry_point_over_module_local() {
        let mut exec_state = parse_execute("x = 1\n").await.unwrap().exec_state;

        // Legacy fallback: the module-local settings.
        exec_state.global.entry_point_kcl_version = None;
        exec_state.mod_local.settings.kcl_version = KclVersion::V2;
        assert_eq!(exec_state.kcl_version(), KclVersion::V2);
        assert_eq!(exec_state.legacy_caller_kcl_version(), KclVersion::V2);

        // A pre-3.0 entry-point declaration does not pin the version: the
        // module-local settings still apply.
        exec_state.global.entry_point_kcl_version = Some(KclVersion::V1);
        assert_eq!(exec_state.kcl_version(), KclVersion::V2);

        // An entry-point KCL 3.0 declaration overrides the module-local
        // settings for the unified lookup, but not for the legacy one.
        exec_state.global.entry_point_kcl_version = Some(KclVersion::V3Preview);
        assert_eq!(exec_state.kcl_version(), KclVersion::V3Preview);
        assert_eq!(exec_state.legacy_caller_kcl_version(), KclVersion::V2);
    }

    /// Mock execution skips `run_concurrent`, so it relies on `inner_run` to
    /// record the entry point's kclVersion -- including re-recording it on
    /// every run when restoring memory preserved from a previous mock run,
    /// since the preserved memory must not pin the previous program's version.
    #[tokio::test(flavor = "multi_thread")]
    async fn mock_execution_records_entry_point_kcl_version() {
        use futures::FutureExt;

        clear_mem_cache().await;

        let ctx = ExecutorContext::new_mock(None).await;
        let fresh_memory = MockConfig {
            use_prev_memory: false,
            ..Default::default()
        };
        let prev_memory = MockConfig::default();

        let v3_program = crate::Program::parse_no_errs("@settings(kclVersion = \"3.0-preview\")\nx = 1\n").unwrap();
        let v2_program = crate::Program::parse_no_errs("@settings(kclVersion = 2.0)\nx = 1\n").unwrap();

        // Close the context and clear the cache even if an assertion panics,
        // then let the panic continue.
        let test_result = std::panic::AssertUnwindSafe(async {
            let (exec_state, _) = ctx.run_mock_returning_state(&v3_program, &fresh_memory).await.unwrap();
            assert_eq!(
                exec_state.global.entry_point_kcl_version,
                Some(KclVersion::V3Preview),
                "mock execution should record a 3.0-preview entry point"
            );
            assert!(exec_state.entry_point_version_is_v3_or_higher());

            // Populate the preserved mock memory with a 3.0-preview run, then
            // check that a 2.0 run restoring that memory isn't pinned to
            // 3.0-preview...
            ctx.run_mock(&v3_program, &fresh_memory).await.unwrap();
            let (exec_state, _) = ctx.run_mock_returning_state(&v2_program, &prev_memory).await.unwrap();
            assert_eq!(exec_state.global.entry_point_kcl_version, Some(KclVersion::V2));
            assert!(!exec_state.entry_point_version_is_v3_or_higher());

            // ...and that a 3.0-preview run restoring a 2.0 run's memory
            // records 3.0-preview.
            ctx.run_mock(&v2_program, &fresh_memory).await.unwrap();
            let (exec_state, _) = ctx.run_mock_returning_state(&v3_program, &prev_memory).await.unwrap();
            assert_eq!(exec_state.global.entry_point_kcl_version, Some(KclVersion::V3Preview));
        })
        .catch_unwind()
        .await;

        clear_mem_cache().await;
        ctx.close().await;
        if let Err(panic) = test_result {
            std::panic::resume_unwind(panic);
        }
    }

    /// Mock execution applies the KCL 3.0 semantics -- early return and
    /// if-arm scoping -- since it records the entry point's kclVersion via
    /// `inner_run` rather than `run_concurrent`.
    #[tokio::test(flavor = "multi_thread")]
    async fn mock_execution_applies_v3_semantics() {
        use futures::FutureExt;

        clear_mem_cache().await;

        let ctx = ExecutorContext::new_mock(None).await;
        let fresh_memory = MockConfig {
            use_prev_memory: false,
            ..Default::default()
        };
        let program = crate::Program::parse_no_errs(
            r#"@settings(kclVersion = "3.0-preview")
fn f() {
  return 1
  assert(1, isEqualTo = 2, error = "code after return ran")
}
x = f()
outer = 1
y = if true {
  outer = 2
  outer + 10
} else {
  0
}
"#,
        )
        .unwrap();

        // Close the context and clear the cache even if an assertion panics,
        // then let the panic continue.
        let test_result = std::panic::AssertUnwindSafe(async {
            let (exec_state, env) = ctx.run_mock_returning_state(&program, &fresh_memory).await.unwrap();
            let var = |name: &str| mem_get_json(exec_state.stack(), env, name).as_f64().unwrap();
            assert_eq!(var("x"), 1.0, "early return produces the function's value");
            assert_eq!(var("y"), 12.0, "the branch sees its own shadowing binding");
            assert_eq!(var("outer"), 1.0, "the outer binding is unchanged after the if");
        })
        .catch_unwind()
        .await;

        clear_mem_cache().await;
        ctx.close().await;
        if let Err(panic) = test_result {
            std::panic::resume_unwind(panic);
        }
    }

    /// The modeling commands sent to the engine during the run, across the
    /// root module and every imported module.
    fn commands_everywhere(result: &ExecTestResults) -> impl Iterator<Item = &kittycad_modeling_cmds::ModelingCmd> {
        let module_commands = result
            .exec_state
            .global
            .module_infos
            .values()
            .filter_map(|info| match &info.repr {
                ModuleRepr::Kcl(_, Some(outcome)) => Some(outcome.artifacts.commands.iter()),
                _ => None,
            })
            .flatten();
        result
            .root_module_artifact_commands()
            .iter()
            .chain(module_commands)
            .map(|artifact_command| &artifact_command.command)
    }

    /// All fillet algorithm versions sent to the engine during the run. The
    /// version emitted is the observable for which kclVersion governed the
    /// filleting code; see `default_edge_cut_version`.
    fn emitted_fillet_versions_everywhere(
        result: &ExecTestResults,
    ) -> Vec<kittycad_modeling_cmds::shared::EdgeCutVersion> {
        commands_everywhere(result)
            .filter_map(|command| match command {
                kittycad_modeling_cmds::ModelingCmd::Solid3dCutEdges(command) => Some(command.version),
                _ => None,
            })
            .collect()
    }

    /// All region algorithm versions sent to the engine during the run. The
    /// version emitted is the observable for whether KCL 1.0 or 2.0 governed
    /// the region code, their only runtime difference; see `region_version`
    /// in `std::sketch`.
    fn emitted_region_versions_everywhere(
        result: &ExecTestResults,
    ) -> Vec<kittycad_modeling_cmds::shared::RegionVersion> {
        commands_everywhere(result)
            .filter_map(|command| match command {
                kittycad_modeling_cmds::ModelingCmd::CreateRegion(command) => Some(command.version.clone()),
                _ => None,
            })
            .collect()
    }

    const FILLET_AT_MODULE_TOP_LEVEL: &str = r#"
profile = startSketchOn(XY)
  |> startProfile(at = [0, 0])
  |> line(end = [10, 0], tag = $edge)
  |> line(end = [0, 10])
  |> line(end = [-10, 0])
  |> close()
solid = extrude(profile, length = 10)
fillet(solid, tags = [edge], radius = 1)
"#;

    const FILLET_IN_EXPORTED_FN: &str = r#"
export fn filletedBox() {
  profile = startSketchOn(XY)
    |> startProfile(at = [0, 0])
    |> line(end = [10, 0], tag = $edge)
    |> line(end = [0, 10])
    |> line(end = [-10, 0])
    |> close()
  solid = extrude(profile, length = 10)
  return fillet(solid, tags = [edge], radius = 1)
}
"#;

    /// A KCL 3.0 entry point pins the kclVersion for the whole execution: an
    /// imported module that declares no kclVersion (1.0 under the legacy
    /// lookup) observes KCL 3.0 both in its module-level code and in its
    /// functions, wherever they are called from. An import declaring a
    /// different version is rejected instead; see
    /// [`imported_module_kcl_version_must_match_v3_entry_point`].
    #[tokio::test(flavor = "multi_thread")]
    async fn entry_point_v3_pins_kcl_version_for_imported_modules() {
        use kittycad_modeling_cmds::shared::EdgeCutVersion;

        let dep = FILLET_AT_MODULE_TOP_LEVEL;
        let main = r#"@settings(kclVersion = "3.0-preview")
import "dep.kcl" as dep
"#;
        let result = execute_with_modules(main, &[("dep.kcl", dep)]).await.unwrap();
        assert_eq!(emitted_fillet_versions_everywhere(&result), vec![EdgeCutVersion::V2]);

        let dep = FILLET_IN_EXPORTED_FN;
        let main = r#"@settings(kclVersion = "3.0-preview")
import filletedBox from "dep.kcl"
box = filletedBox()
"#;
        let result = execute_with_modules(main, &[("dep.kcl", dep)]).await.unwrap();
        assert_eq!(emitted_fillet_versions_everywhere(&result), vec![EdgeCutVersion::V2]);
    }

    const REGION_AT_MODULE_TOP_LEVEL: &str = r#"
profile = sketch(on = XY) {
  outline = circle(start = [var 5mm, var 0mm], center = [var 0mm, var 0mm])
}
disc = region(segments = [profile.outline])
"#;

    const REGION_IN_EXPORTED_FN: &str = r#"
export fn disc() {
  profile = sketch(on = XY) {
    outline = circle(start = [var 5mm, var 0mm], center = [var 0mm, var 0mm])
  }
  return region(segments = [profile.outline])
}
"#;

    /// Without a KCL 3.0 entry point, the legacy lookup applies unchanged,
    /// including its quirk: an imported module's module-level code observes the
    /// module's own declared version, but its functions observe the CALLING
    /// module's version. Pinned with KCL 1.0 and 2.0, so that the pin does not
    /// depend on importing a KCL 3.0 file.
    #[tokio::test(flavor = "multi_thread")]
    async fn legacy_kcl_version_quirk_applies_without_v3_entry_point() {
        use kittycad_modeling_cmds::shared::RegionVersion;

        let dep = format!("@settings(kclVersion = 1.0)\n{REGION_AT_MODULE_TOP_LEVEL}");
        let main = r#"@settings(kclVersion = 2.0)
import "dep.kcl" as dep
"#;
        let result = execute_with_modules(main, &[("dep.kcl", &dep)]).await.unwrap();
        assert_eq!(emitted_region_versions_everywhere(&result), vec![RegionVersion::V0]);

        let dep = format!("@settings(kclVersion = 1.0)\n{REGION_IN_EXPORTED_FN}");
        let main = r#"@settings(kclVersion = 2.0)
import disc from "dep.kcl"
face = disc()
"#;
        let result = execute_with_modules(main, &[("dep.kcl", &dep)]).await.unwrap();
        assert_eq!(emitted_region_versions_everywhere(&result), vec![RegionVersion::V1]);
    }

    /// Builds a mock-engine context whose project directory holds `modules`
    /// in an in-memory file system, with `main.kcl` as the current file so
    /// that errors can name the entry point's path. Nothing touches disk, so
    /// parallel tests share no state.
    fn versioned_modules_context(modules: &[(&str, &str)]) -> ExecutorContext {
        let project_dir = crate::TypedPath::new("/zma-kcl-version-mismatch");
        // Key each module by the same join that import resolution performs,
        // so the lookup matches on every platform.
        let files = modules
            .iter()
            .map(|(name, source)| (project_dir.join(name).to_string(), source.as_bytes().to_vec()))
            .collect();
        ExecutorContext {
            engine: Arc::new(EngineManager::new_mock()),
            engine_batch: EngineBatchContext::default(),
            fs: crate::fs::new_file_system_handle(crate::InMemoryFiles::new(files)),
            settings: ExecutorSettings {
                current_file: Some(project_dir.join("main.kcl")),
                project_directory: Some(project_dir),
                ..Default::default()
            },
            context_type: ContextType::Mock,
            execution_callbacks: Default::default(),
            executor_kind: machine::ExecutorKind::resolve(),
            machine_call_depth_limit: crate::execution::machine::DEFAULT_MACHINE_CALL_DEPTH_LIMIT,
        }
    }

    /// Runs `main` with `modules` (see [`versioned_modules_context`]) the way
    /// engine execution does, which runs every imported module eagerly.
    async fn run_versioned_modules(main: &str, modules: &[(&str, &str)]) -> Result<(), KclError> {
        let ctx = versioned_modules_context(modules);
        let program = crate::Program::parse_no_errs(main).unwrap();
        let mut exec_state = ExecState::new(&ctx);
        let result = ctx.run(&program, &mut exec_state).await;
        ctx.close().await;
        result.map(|_| ()).map_err(|err| err.error)
    }

    /// Runs `main` with `modules` (see [`versioned_modules_context`]) through
    /// mock execution, which runs imported modules lazily.
    async fn run_versioned_modules_mock(main: &str, modules: &[(&str, &str)]) -> Result<(), KclError> {
        let ctx = versioned_modules_context(modules);
        let program = crate::Program::parse_no_errs(main).unwrap();
        let mock_config = MockConfig {
            use_prev_memory: false,
            ..Default::default()
        };
        let result = ctx.run_mock_returning_state(&program, &mock_config).await;
        ctx.close().await;
        result.map(|_| ()).map_err(|err| err.error)
    }

    const V3_MAIN_IMPORTING_DEP: &str =
        "@settings(kclVersion = \"3.0-preview\")\nimport width from \"dep.kcl\"\nx = width\n";

    fn dep_declaring(version: &str) -> String {
        format!("@settings(kclVersion = {version})\nexport width = 10\n")
    }

    /// The error a mismatch between `main.kcl` and `dep.kcl` must produce,
    /// with `expected_dep_version` as the imported file's version.
    #[track_caller]
    fn assert_kcl_version_mismatch(error: &KclError, expected_dep_version: &str) {
        assert!(matches!(error, KclError::Semantic { .. }), "{error:#?}");
        assert_eq!(
            error.message(),
            format!(
                "Mixing KCL versions in a single program is not allowed. The entry point `/zma-kcl-version-mismatch/main.kcl` declares kclVersion 3.0-preview, but the imported file `/zma-kcl-version-mismatch/dep.kcl` declares kclVersion {expected_dep_version}. Update the kclVersion setting in one of these files to match the other."
            )
        );
    }

    /// A KCL 3.0 entry point rejects an imported file that declares a
    /// different kclVersion. The error names both files and both versions,
    /// points at the declaration in the imported file, and carries the import
    /// site in the entry point as its outer frame.
    #[tokio::test(flavor = "multi_thread")]
    async fn imported_module_kcl_version_must_match_v3_entry_point() {
        for dep_version in ["2.0", "1.0"] {
            let dep = dep_declaring(dep_version);
            let error = run_versioned_modules(V3_MAIN_IMPORTING_DEP, &[("dep.kcl", &dep)])
                .await
                .expect_err("mismatched kclVersion should be rejected");
            assert_kcl_version_mismatch(&error, dep_version);

            let ranges = error.source_ranges();
            assert_eq!(ranges.len(), 2, "{ranges:#?}");
            // The `kclVersion = ...` setting in dep.kcl.
            assert!(!ranges[0].module_id().is_top_level());
            let declaration = format!("kclVersion = {dep_version}");
            let start = dep.find(&declaration).unwrap();
            assert_eq!((ranges[0].start(), ranges[0].end()), (start, start + declaration.len()));
            // The import statement in main.kcl.
            assert!(ranges[1].module_id().is_top_level());
            let import_stmt = "import width from \"dep.kcl\"";
            let start = V3_MAIN_IMPORTING_DEP.find(import_stmt).unwrap();
            assert_eq!((ranges[1].start(), ranges[1].end()), (start, start + import_stmt.len()));
            assert_eq!(
                error
                    .backtrace()
                    .iter()
                    .map(|frame| frame.fn_name.as_deref())
                    .collect::<Vec<_>>(),
                [Some("import dep.kcl"), None]
            );
        }
    }

    /// Imported files that declare no kclVersion are unaffected: they run
    /// under the entry point's version, as before.
    #[tokio::test(flavor = "multi_thread")]
    async fn imported_module_without_kcl_version_is_allowed_under_v3_entry_point() {
        for dep in [
            "export width = 10\n",
            "@settings(defaultLengthUnit = in)\nexport width = 10\n",
        ] {
            run_versioned_modules(V3_MAIN_IMPORTING_DEP, &[("dep.kcl", dep)])
                .await
                .unwrap_or_else(|err| panic!("dep={dep:?}: {err:#?}"));
        }
    }

    /// Declaring the entry point's own version, in any accepted spelling, is
    /// a match.
    #[tokio::test(flavor = "multi_thread")]
    async fn imported_module_matching_v3_kcl_version_is_allowed() {
        for dep_version in ["\"3.0-preview\"", "\"3-preview\"", "\"3.0.0-preview\""] {
            let dep = dep_declaring(dep_version);
            run_versioned_modules(V3_MAIN_IMPORTING_DEP, &[("dep.kcl", &dep)])
                .await
                .unwrap_or_else(|err| panic!("dep={dep_version}: {err:#?}"));
        }
    }

    /// Without a KCL 3.0 entry point, KCL 1.0 and 2.0 may still be mixed, as
    /// before.
    #[tokio::test(flavor = "multi_thread")]
    async fn pre_v3_kcl_versions_may_be_mixed_without_v3_entry_point() {
        for main_header in ["", "@settings(kclVersion = 1.0)\n", "@settings(kclVersion = 2.0)\n"] {
            for dep_version in ["1.0", "2.0"] {
                let main = format!("{main_header}import width from \"dep.kcl\"\nx = width\n");
                let dep = dep_declaring(dep_version);
                run_versioned_modules(&main, &[("dep.kcl", &dep)])
                    .await
                    .unwrap_or_else(|err| panic!("main={main_header:?} dep={dep_version}: {err:#?}"));
            }
        }
    }

    /// The error an entry point `main.kcl` that declares no kclVersion must
    /// produce when it imports a 3.0-preview `dep.kcl`.
    const V3_DEP_UNDER_UNDECLARED_ENTRY_POINT: &str = "Mixing KCL versions in a single program is not allowed. The entry point `/zma-kcl-version-mismatch/main.kcl` does not declare a kclVersion, but the imported file `/zma-kcl-version-mismatch/dep.kcl` declares kclVersion 3.0-preview. Declare the same kclVersion in the entry point, or update the setting in the imported file.";

    /// Without a KCL 3.0 entry point, an imported file may not declare KCL
    /// 3.0: the legacy per-module lookup would otherwise apply KCL 3.0
    /// semantics to that file alone. The error names both files, says what
    /// the entry point declares (if anything), points at the declaration in
    /// the imported file, and carries the import site in the entry point as
    /// its outer frame.
    #[tokio::test(flavor = "multi_thread")]
    async fn v3_import_requires_v3_entry_point() {
        for (main_header, entry_point_declares, fix) in [
            (
                "",
                "does not declare a kclVersion",
                "Declare the same kclVersion in the entry point, or update the setting in the imported file.",
            ),
            (
                "@settings(kclVersion = 1.0)\n",
                "declares kclVersion 1.0",
                "Update the kclVersion setting in one of these files to match the other.",
            ),
            (
                "@settings(kclVersion = 2.0)\n",
                "declares kclVersion 2.0",
                "Update the kclVersion setting in one of these files to match the other.",
            ),
        ] {
            let main = format!("{main_header}import width from \"dep.kcl\"\nx = width\n");
            let dep = dep_declaring("\"3.0-preview\"");
            let error = run_versioned_modules(&main, &[("dep.kcl", &dep)])
                .await
                .expect_err("a KCL 3.0 import without a KCL 3.0 entry point should be rejected");
            assert!(matches!(error, KclError::Semantic { .. }), "{error:#?}");
            assert_eq!(
                error.message(),
                format!(
                    "Mixing KCL versions in a single program is not allowed. The entry point `/zma-kcl-version-mismatch/main.kcl` {entry_point_declares}, but the imported file `/zma-kcl-version-mismatch/dep.kcl` declares kclVersion 3.0-preview. {fix}"
                ),
                "main={main_header:?}"
            );

            let ranges = error.source_ranges();
            assert_eq!(ranges.len(), 2, "{ranges:#?}");
            // The `kclVersion = ...` setting in dep.kcl.
            assert!(!ranges[0].module_id().is_top_level());
            let declaration = "kclVersion = \"3.0-preview\"";
            let start = dep.find(declaration).unwrap();
            assert_eq!((ranges[0].start(), ranges[0].end()), (start, start + declaration.len()));
            // The import statement in main.kcl.
            assert!(ranges[1].module_id().is_top_level());
            let import_stmt = "import width from \"dep.kcl\"";
            let start = main.find(import_stmt).unwrap();
            assert_eq!((ranges[1].start(), ranges[1].end()), (start, start + import_stmt.len()));
            assert_eq!(
                error
                    .backtrace()
                    .iter()
                    .map(|frame| frame.fn_name.as_deref())
                    .collect::<Vec<_>>(),
                [Some("import dep.kcl"), None]
            );
        }
    }

    /// Every accepted spelling of 3.0-preview is rejected, and the message
    /// uses the canonical spelling.
    #[tokio::test(flavor = "multi_thread")]
    async fn v3_import_spellings_are_all_rejected_without_v3_entry_point() {
        let main = "import width from \"dep.kcl\"\nx = width\n";
        for dep_version in ["\"3-preview\"", "\"3.0.0-preview\""] {
            let dep = dep_declaring(dep_version);
            let error = run_versioned_modules(main, &[("dep.kcl", &dep)])
                .await
                .expect_err("a KCL 3.0 import without a KCL 3.0 entry point should be rejected");
            assert_eq!(
                error.message(),
                V3_DEP_UNDER_UNDECLARED_ENTRY_POINT,
                "dep={dep_version}"
            );
        }
    }

    /// Mock execution runs a whole-module import's body only when the module
    /// is referenced, so the check also runs at the import site.
    #[tokio::test(flavor = "multi_thread")]
    async fn unreferenced_v3_whole_module_import_is_checked_in_mock_execution() {
        let main = "import \"dep.kcl\" as dep\nx = 1\n";
        let dep = dep_declaring("\"3.0-preview\"");
        let error = run_versioned_modules_mock(main, &[("dep.kcl", &dep)])
            .await
            .expect_err("a KCL 3.0 import without a KCL 3.0 entry point should be rejected in mock execution");
        assert_eq!(error.message(), V3_DEP_UNDER_UNDECLARED_ENTRY_POINT);
        let ranges = error.source_ranges();
        assert_eq!(ranges.len(), 2, "{ranges:#?}");
        assert!(!ranges[0].module_id().is_top_level());
        assert!(ranges[1].module_id().is_top_level());
        let import_stmt = "import \"dep.kcl\" as dep";
        let start = main.find(import_stmt).unwrap();
        assert_eq!((ranges[1].start(), ranges[1].end()), (start, start + import_stmt.len()));

        // Engine execution runs the module eagerly and rejects it too.
        let error = run_versioned_modules(main, &[("dep.kcl", &dep)])
            .await
            .expect_err("a KCL 3.0 import without a KCL 3.0 entry point should be rejected in engine execution");
        assert_eq!(error.message(), V3_DEP_UNDER_UNDECLARED_ENTRY_POINT);
    }

    /// The check covers transitive imports. The message names the entry point
    /// and the mismatched file; the file in between appears in the import
    /// backtrace.
    #[tokio::test(flavor = "multi_thread")]
    async fn transitive_v3_import_requires_v3_entry_point() {
        let main = "import doubled from \"a.kcl\"\nx = doubled\n";
        let a = "import width from \"b.kcl\"\nexport doubled = width * 2\n";
        let b = dep_declaring("\"3.0-preview\"");
        let error = run_versioned_modules(main, &[("a.kcl", a), ("b.kcl", &b)])
            .await
            .expect_err("a transitive KCL 3.0 import without a KCL 3.0 entry point should be rejected");
        assert_eq!(
            error.message(),
            "Mixing KCL versions in a single program is not allowed. The entry point `/zma-kcl-version-mismatch/main.kcl` does not declare a kclVersion, but the imported file `/zma-kcl-version-mismatch/b.kcl` declares kclVersion 3.0-preview. Declare the same kclVersion in the entry point, or update the setting in the imported file."
        );
        assert_eq!(
            error
                .backtrace()
                .iter()
                .map(|frame| frame.fn_name.as_deref())
                .collect::<Vec<_>>(),
            [Some("import b.kcl"), Some("import a.kcl"), None]
        );
    }

    /// When execution was started without a file path, the message still
    /// describes the entry point, just without a path.
    #[tokio::test(flavor = "multi_thread")]
    async fn v3_import_without_v3_entry_point_or_entry_point_path() {
        let main = "import width from \"dep.kcl\"\nx = width\n";
        let dep = dep_declaring("\"3.0-preview\"");
        let error = execute_with_modules(main, &[("dep.kcl", &dep)])
            .await
            .expect_err("a KCL 3.0 import without a KCL 3.0 entry point should be rejected");
        let message = error.message();
        assert!(
            message.starts_with(
                "Mixing KCL versions in a single program is not allowed. The entry point does not declare a kclVersion, but the imported file `"
            ),
            "{message}"
        );
        assert!(
            message.ends_with(
                "dep.kcl` declares kclVersion 3.0-preview. Declare the same kclVersion in the entry point, or update the setting in the imported file."
            ),
            "{message}"
        );
    }

    /// The check covers transitive imports. The message names the entry point
    /// and the mismatched file; the file in between appears in the import
    /// backtrace.
    #[tokio::test(flavor = "multi_thread")]
    async fn transitive_import_kcl_version_mismatch_names_entry_point_and_mismatched_file() {
        let main = "@settings(kclVersion = \"3.0-preview\")\nimport doubled from \"a.kcl\"\nx = doubled\n";
        let a = "import width from \"b.kcl\"\nexport doubled = width * 2\n";
        let b = dep_declaring("2.0");
        let error = run_versioned_modules(main, &[("a.kcl", a), ("b.kcl", &b)])
            .await
            .expect_err("mismatched kclVersion in a transitive import should be rejected");
        assert_eq!(
            error.message(),
            "Mixing KCL versions in a single program is not allowed. The entry point `/zma-kcl-version-mismatch/main.kcl` declares kclVersion 3.0-preview, but the imported file `/zma-kcl-version-mismatch/b.kcl` declares kclVersion 2.0. Update the kclVersion setting in one of these files to match the other."
        );
        assert_eq!(
            error
                .backtrace()
                .iter()
                .map(|frame| frame.fn_name.as_deref())
                .collect::<Vec<_>>(),
            [Some("import b.kcl"), Some("import a.kcl"), None]
        );
        let ranges = error.source_ranges();
        assert_eq!(ranges.len(), 3, "{ranges:#?}");
        assert!(!ranges[0].module_id().is_top_level());
        assert!(!ranges[1].module_id().is_top_level());
        assert!(ranges[2].module_id().is_top_level());
    }

    /// Mock execution runs a whole-module import's body only when the module
    /// is referenced, so the check also runs at the import site.
    #[tokio::test(flavor = "multi_thread")]
    async fn unreferenced_whole_module_import_kcl_version_is_checked_in_mock_execution() {
        let main = "@settings(kclVersion = \"3.0-preview\")\nimport \"dep.kcl\" as dep\nx = 1\n";
        let dep = dep_declaring("2.0");
        let error = run_versioned_modules_mock(main, &[("dep.kcl", &dep)])
            .await
            .expect_err("mismatched kclVersion should be rejected in mock execution");
        assert_kcl_version_mismatch(&error, "2.0");
        let ranges = error.source_ranges();
        assert_eq!(ranges.len(), 2, "{ranges:#?}");
        assert!(!ranges[0].module_id().is_top_level());
        assert!(ranges[1].module_id().is_top_level());
        let import_stmt = "import \"dep.kcl\" as dep";
        let start = main.find(import_stmt).unwrap();
        assert_eq!((ranges[1].start(), ranges[1].end()), (start, start + import_stmt.len()));

        // Engine execution runs the module eagerly and rejects it too.
        let error = run_versioned_modules(main, &[("dep.kcl", &dep)])
            .await
            .expect_err("mismatched kclVersion should be rejected in engine execution");
        assert_kcl_version_mismatch(&error, "2.0");

        // An undeclared version is fine in mock execution as well.
        run_versioned_modules_mock(main, &[("dep.kcl", "export width = 10\n")])
            .await
            .unwrap();
    }

    /// Standard library modules declare kclVersion 1.0 but are exempt: they
    /// always run under the entry point's version, and the user cannot edit
    /// them. The prelude is imported implicitly; `std::turns` is imported
    /// explicitly here.
    #[tokio::test(flavor = "multi_thread")]
    async fn std_modules_are_exempt_from_kcl_version_matching() {
        let main = "@settings(kclVersion = \"3.0-preview\", experimentalFeatures = allow)\nimport QUARTER_TURN from \"std::turns\"\nx = QUARTER_TURN\n";
        run_versioned_modules(main, &[]).await.unwrap();
        run_versioned_modules_mock(main, &[]).await.unwrap();
    }

    /// When execution was started without a file path, the message still
    /// describes the entry point, just without a path.
    #[tokio::test(flavor = "multi_thread")]
    async fn kcl_version_mismatch_without_entry_point_path() {
        let dep = dep_declaring("2.0");
        let error = execute_with_modules(V3_MAIN_IMPORTING_DEP, &[("dep.kcl", &dep)])
            .await
            .expect_err("mismatched kclVersion should be rejected");
        let message = error.message();
        assert!(
            message.starts_with(
                "Mixing KCL versions in a single program is not allowed. The entry point declares kclVersion 3.0-preview, but the imported file `"
            ),
            "{message}"
        );
        assert!(
            message.ends_with(
                "dep.kcl` declares kclVersion 2.0. Update the kclVersion setting in one of these files to match the other."
            ),
            "{message}"
        );
    }

    #[track_caller]
    fn variable_f64(result: &ExecTestResults, name: &str) -> f64 {
        mem_get_json(result.exec_state.stack(), result.mem_env, name)
            .as_f64()
            .unwrap()
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn return_terminates_function_early_in_v3() {
        let code = r#"@settings(kclVersion = "3.0-preview")
fn f() {
  return 1
  assert(1, isEqualTo = 2, error = "code after return ran")
}
x = f()
"#;
        let result = parse_execute(code).await.unwrap();
        assert_eq!(variable_f64(&result, "x"), 1.0);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn second_return_is_unreachable_in_v3() {
        let code = r#"@settings(kclVersion = "3.0-preview")
fn f() {
  return 1
  return 2
}
x = f()
"#;
        let result = parse_execute(code).await.unwrap();
        assert_eq!(variable_f64(&result, "x"), 1.0);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn return_inside_if_arm_returns_from_function_in_v3() {
        let code = r#"@settings(kclVersion = "3.0-preview")
fn f(@b) {
  dummy = if b {
    return 1
    0
  } else {
    0
  }
  return 2
}
x = f(true)
y = f(false)
"#;
        let result = parse_execute(code).await.unwrap();
        assert_eq!(variable_f64(&result, "x"), 1.0);
        assert_eq!(variable_f64(&result, "y"), 2.0);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn return_inside_nested_if_returns_from_function_in_v3() {
        let code = r#"@settings(kclVersion = "3.0-preview")
fn f(@a, b) {
  dummy = if a {
    inner = if b {
      return 10
      0
    } else {
      1
    }
    inner + 1
  } else {
    2
  }
  return dummy * 100
}
x = f(true, b = true)
y = f(true, b = false)
z = f(false, b = false)
"#;
        let result = parse_execute(code).await.unwrap();
        assert_eq!(variable_f64(&result, "x"), 10.0);
        assert_eq!(variable_f64(&result, "y"), 200.0);
        assert_eq!(variable_f64(&result, "z"), 200.0);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn return_inside_closure_returns_only_from_closure_in_v3() {
        let code = r#"@settings(kclVersion = "3.0-preview")
fn outer() {
  inner = fn() {
    return 5
    assert(1, isEqualTo = 2, error = "code after inner return ran")
  }
  v = inner()
  return v + 1
}
x = outer()
"#;
        let result = parse_execute(code).await.unwrap();
        assert_eq!(variable_f64(&result, "x"), 6.0);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn return_type_coercion_applies_to_early_return_in_v3() {
        let code = r#"@settings(kclVersion = "3.0-preview")
fn f(): number(mm) {
  return 1
  assert(1, isEqualTo = 2, error = "code after return ran")
}
x = f()
"#;
        let result = parse_execute(code).await.unwrap();
        assert_eq!(variable_f64(&result, "x"), 1.0);

        // A coercion failure surfaces as an error (on the machine, this
        // exercises unwind_return's error path).
        let code = r#"@settings(kclVersion = "3.0-preview")
fn f(): number(mm) {
  return "nope"
}
x = f()
"#;
        let err = parse_execute(code).await.expect_err("coercion failure should error");
        assert!(err.message().contains("type"), "unexpected message: {}", err.message());
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn return_at_top_level_errors() {
        // A return statement at the top level is rejected in all versions.
        for header in ["", "@settings(kclVersion = \"3.0-preview\")\n"] {
            let code = format!("{header}return 1\n");
            assert_eq!(
                parse_execute(&code).await.expect_err("should error").message(),
                "Cannot return from outside a function."
            );
        }

        // Under KCL 3.0, a return escaping a top-level if-arm is also rejected
        // (without the setting it is silently ignored; see
        // top_level_if_arm_return_ignored_without_v3).
        let code = r#"@settings(kclVersion = "3.0-preview")
x = if true {
  return 1
  0
} else {
  0
}
"#;
        assert_eq!(
            parse_execute(code).await.expect_err("should error").message(),
            "Cannot return from outside a function."
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn exit_inside_function_still_exits_program_in_v3() {
        let code = r#"@settings(kclVersion = "3.0-preview")
fn f() {
  exit()
  return 1
}
x = f()
assert(1, isEqualTo = 2, error = "code after exit ran")
"#;
        parse_execute(code).await.unwrap();
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn return_inside_sketch_block_terminates_function_in_v3() {
        let code = r#"@settings(kclVersion = "3.0-preview", experimentalFeatures = allow)
fn f() {
  sketch(on = XY) {
    l1 = line(start = [var 0mm, var 0mm], end = [var 10mm, var 0mm])
    return 42
  }
  return 0
}
x = f()
"#;
        let result = parse_execute(code).await.unwrap();
        assert_eq!(variable_f64(&result, "x"), 42.0);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn return_inside_sketch_block_ignored_without_v3() {
        // Pins the pre-KCL-3.0 behavior: `__return` binds in the sketch block's
        // child environment and is lost when it pops.
        let code = r#"@settings(experimentalFeatures = allow)
fn f() {
  sketch(on = XY) {
    l1 = line(start = [var 0mm, var 0mm], end = [var 10mm, var 0mm])
    return 42
  }
  return 0
}
x = f()
"#;
        let result = parse_execute(code).await.unwrap();
        assert_eq!(variable_f64(&result, "x"), 0.0);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn code_after_return_still_runs_without_v3() {
        let code = r#"fn f() {
  return 1
  assert(1, isEqualTo = 2, error = "ran past return")
}
x = f()
"#;
        let err = parse_execute(code).await.expect_err("should error");
        assert!(
            err.message().contains("ran past return"),
            "unexpected message: {}",
            err.message()
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn multiple_returns_error_without_v3() {
        let code = r#"fn f() {
  return 1
  return 2
}
x = f()
"#;
        assert_eq!(
            parse_execute(code).await.expect_err("should error").message(),
            "Multiple returns from a single function."
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn if_arm_return_plus_function_return_errors_without_v3() {
        // Pins the pre-KCL-3.0 behavior: the if-arm's `return` writes
        // `__return` into the function's environment, so the function-level
        // `return` is a second return.
        let code = r#"fn f() {
  dummy = if true {
    return 1
    0
  } else {
    0
  }
  return 2
}
x = f()
"#;
        assert_eq!(
            parse_execute(code).await.expect_err("should error").message(),
            "Multiple returns from a single function."
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn top_level_if_arm_return_ignored_without_v3() {
        // Pins the pre-KCL-3.0 behavior: the return silently binds
        // `__return` in the root environment and the arm yields its trailing
        // expression.
        let code = r#"x = if true {
  return 1
  0
} else {
  0
}
"#;
        let result = parse_execute(code).await.unwrap();
        assert_eq!(variable_f64(&result, "x"), 0.0);
        assert_eq!(variable_f64(&result, memory::RETURN_NAME), 1.0);
    }

    /// Early return is gated on the entry point's kclVersion, not the
    /// defining module's. A module cannot opt into KCL 3.0 on its own.
    #[tokio::test(flavor = "multi_thread")]
    async fn return_semantics_gated_on_entry_point_not_module() {
        // A 2.0 entry point importing a module that declares KCL 3.0 is
        // rejected as a version mismatch before the module runs, so its
        // function never gets to observe either return semantics.
        let dep = r#"@settings(kclVersion = "3.0-preview")
export fn f() {
  return 1
  assert(1, isEqualTo = 2, error = "ran past return")
}
"#;
        let main = r#"@settings(kclVersion = 2.0)
import f from "dep.kcl"
x = f()
"#;
        let err = execute_with_modules(main, &[("dep.kcl", dep)]).await.unwrap_err();
        assert!(
            err.message()
                .starts_with("Mixing KCL versions in a single program is not allowed."),
            "unexpected message: {}",
            err.message()
        );

        // A KCL 3.0 entry point applies early return everywhere, including
        // inside an imported module that declares no kclVersion (1.0 under the
        // legacy lookup). Declaring 2.0 there is rejected as a version mismatch
        // instead.
        let dep = r#"export fn f() {
  return 1
  assert(1, isEqualTo = 2, error = "ran past return")
}
"#;
        let main = r#"@settings(kclVersion = "3.0-preview")
import f from "dep.kcl"
x = f()
"#;
        let result = execute_with_modules(main, &[("dep.kcl", dep)]).await.unwrap();
        assert_eq!(variable_f64(&result, "x"), 1.0);
    }

    /// Early return inside a callback driven by a builtin terminates only
    /// that callback invocation; the builtin keeps iterating. On the machine
    /// executor, map/reduce callbacks run behind a Callback-completion call
    /// boundary, so this exercises unwind_return's resume-the-builtin path,
    /// unlike a directly called function.
    #[tokio::test(flavor = "multi_thread")]
    async fn return_inside_map_and_reduce_callbacks_in_v3() {
        let code = r#"@settings(kclVersion = "3.0-preview")
doubled = map([1, 2, 3], f = fn(@i) {
  return i * 2
  assert(1, isEqualTo = 2, error = "code after return ran in the map callback")
})
assert(doubled[0], isEqualTo = 2, error = "map result 0")
assert(doubled[1], isEqualTo = 4, error = "map result 1")
assert(doubled[2], isEqualTo = 6, error = "map result 2")

total = reduce([1, 2, 3], initial = 0, f = fn(@i, accum) {
  return accum + i
  assert(1, isEqualTo = 2, error = "code after return ran in the reduce callback")
})
assert(total, isEqualTo = 6, error = "reduce total")
"#;
        let result = parse_execute(code).await.unwrap();
        assert_eq!(variable_f64(&result, "total"), 6.0);
    }

    /// unwind_return must decrement the machine call depth like a normal
    /// call completion; otherwise sequential early-return calls would
    /// accumulate depth until the runaway guard trips. The recursive
    /// executor doesn't use the counter, so the bound is trivially true
    /// there.
    #[tokio::test(flavor = "multi_thread")]
    async fn early_returns_do_not_leak_machine_call_depth() {
        let code = r#"@settings(kclVersion = "3.0-preview")
fn one() {
  return 1
  assert(1, isEqualTo = 2, error = "code after return ran")
}
total = reduce([1..100], initial = 0, f = fn(@i, accum) {
  return accum + one()
})
assert(total, isEqualTo = 100, error = "each call returns 1")
"#;
        let result = parse_execute(code).await.unwrap();
        // Real nesting here is a few levels (reduce callback then one()).
        // If early returns leaked a level per call, the 100 sequential
        // calls would push the high water toward 100.
        let high_water = result.exec_state.global.machine_depth_high_water;
        assert!(high_water < 10, "high water: {high_water}");
    }

    /// A return escaping to the top level of an imported module is rejected
    /// under a KCL 3.0 entry point. The entry module's version governs, so
    /// the imported module, which declares no kclVersion (1.0 under the
    /// legacy lookup), doesn't opt back out. Declaring 2.0 there would be
    /// rejected as a version mismatch instead. (Without a KCL 3.0 entry point
    /// the return is silently ignored; see
    /// top_level_if_arm_return_ignored_without_v3.)
    #[tokio::test(flavor = "multi_thread")]
    async fn top_level_if_arm_return_in_imported_module_errors_in_v3() {
        let dep = r#"x = if true {
  return 1
  0
} else {
  0
}
export y = x
"#;
        let main = r#"@settings(kclVersion = "3.0-preview")
import y from "dep.kcl"
z = y
"#;
        let err = execute_with_modules(main, &[("dep.kcl", dep)]).await.unwrap_err();
        assert!(
            err.message().contains("Cannot return from outside a function."),
            "unexpected message: {}",
            err.message()
        );
    }

    /// exit() in a return's argument still exits the whole program: the
    /// Exit control flow from evaluating the argument takes precedence over
    /// turning the statement into an early return. If it were mistakenly
    /// treated as the function's return value, execution would continue
    /// after the call and hit the failing assert.
    #[tokio::test(flavor = "multi_thread")]
    async fn return_of_exit_still_exits_program_in_v3() {
        let code = r#"@settings(kclVersion = "3.0-preview")
fn f() {
  return exit()
}
x = f()
assert(1, isEqualTo = 2, error = "code after exit ran")
"#;
        parse_execute(code).await.unwrap();
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn if_arm_bindings_do_not_leak_in_v3() {
        let code = r#"@settings(kclVersion = "3.0-preview")
x = if true {
  y = 1
  y
} else {
  0
}
z = y
"#;
        let err = parse_execute(code).await.expect_err("should error");
        assert!(
            err.message().contains("`y` is not defined"),
            "unexpected message: {}",
            err.message()
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn if_arm_bindings_leak_without_v3() {
        // Pins the pre-KCL-3.0 behavior: arm bodies share the enclosing
        // environment, so arm bindings are visible after the if.
        for header in ["", "@settings(kclVersion = 2.0)\n"] {
            let code = format!(
                r#"{header}x = if true {{
  y = 1
  y
}} else {{
  0
}}
z = y
"#
            );
            let result = parse_execute(&code).await.unwrap();
            assert_eq!(variable_f64(&result, "z"), 1.0);
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn if_arm_shadowing_allowed_in_v3() {
        let code = r#"@settings(kclVersion = "3.0-preview")
y = 1
x = if true {
  y = 2
  y + 10
} else {
  0
}
"#;
        let result = parse_execute(code).await.unwrap();
        assert_eq!(variable_f64(&result, "x"), 12.0);
        assert_eq!(variable_f64(&result, "y"), 1.0);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn if_arm_shadowing_still_errors_without_v3() {
        // Pins the pre-KCL-3.0 behavior: the arm shares the enclosing
        // environment, so redeclaring an outer name is an error.
        for header in ["", "@settings(kclVersion = 2.0)\n"] {
            let code = format!(
                r#"{header}y = 1
x = if true {{
  y = 2
  y
}} else {{
  0
}}
"#
            );
            let err = parse_execute(&code).await.expect_err("should error");
            assert!(
                err.message().contains("Cannot redefine `y`"),
                "unexpected message: {}",
                err.message()
            );
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn if_arm_closure_escape_in_v3() {
        // A closure declared in an arm captures arm-locals and stays valid
        // after the arm's scope is popped.
        let code = r#"@settings(kclVersion = "3.0-preview")
n = 1
f = if true {
  m = 41
  g = fn() {
    return m + n
  }
  g
} else {
  g = fn() {
    return 0
  }
  g
}
x = f()
"#;
        let result = parse_execute(code).await.unwrap();
        assert_eq!(variable_f64(&result, "x"), 42.0);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn recursive_if_arm_closure_keeps_enclosing_function_frame_alive_in_v3() {
        // A named recursive closure takes a different snapshot path from an
        // anonymous closure. Escaping through an arm must retain both the arm
        // and its enclosing call frame.
        let code = r#"@settings(kclVersion = "3.0-preview")
fn makeCounter() {
  outer = 40
  selected = if true {
    inner = 2
    fn count(@n) {
      return if n == 0 {
        outer + inner
      } else {
        count(n - 1) + 1
      }
    }
    count
  } else {
    fn fallback(@n) {
      return n
    }
    fallback
  }
  return selected
}
counter = makeCounter()
x = counter(3)
"#;
        let result = parse_execute(code).await.unwrap();
        assert_eq!(variable_f64(&result, "x"), 45.0);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn return_inside_scoped_if_arm_in_v3() {
        // Early return from inside a scoped arm pops the arm environment on
        // the way out.
        let code = r#"@settings(kclVersion = "3.0-preview")
fn f(@b) {
  local = if b {
    w = 1
    return w + 9
    0
  } else {
    0
  }
  return local
}
x = f(true)
y = f(false)
"#;
        let result = parse_execute(code).await.unwrap();
        assert_eq!(variable_f64(&result, "x"), 10.0);
        assert_eq!(variable_f64(&result, "y"), 0.0);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn else_if_and_nested_if_scoping_in_v3() {
        let code = r#"@settings(kclVersion = "3.0-preview")
x = if false {
  0
} else if true {
  a = 1
  b = if true {
    c = 2
    a + c
  } else {
    0
  }
  a + b
} else {
  0
}
"#;
        let result = parse_execute(code).await.unwrap();
        assert_eq!(variable_f64(&result, "x"), 4.0);

        // A nested arm's binding is not visible in the enclosing arm.
        let code = r#"@settings(kclVersion = "3.0-preview")
x = if true {
  b = if true {
    c = 2
    c
  } else {
    0
  }
  b + c
} else {
  0
}
"#;
        let err = parse_execute(code).await.expect_err("should error");
        assert!(
            err.message().contains("`c` is not defined"),
            "unexpected message: {}",
            err.message()
        );
    }

    /// Else-if and final-else arms are isolated exactly like then-arms:
    /// their bindings are invisible after the if, and they may shadow outer
    /// bindings without changing them. Pinned per arm kind so a refactor of
    /// the shared arm dispatch can't silently drop one.
    #[tokio::test(flavor = "multi_thread")]
    async fn else_if_and_final_else_arms_are_isolated_in_v3() {
        // A taken else-if arm's binding doesn't leak.
        let code = r#"@settings(kclVersion = "3.0-preview")
x = if false {
  0
} else if true {
  y = 1
  y
} else {
  0
}
z = y
"#;
        let err = parse_execute(code).await.expect_err("should error");
        assert!(
            err.message().contains("`y` is not defined"),
            "unexpected message: {}",
            err.message()
        );

        // A taken final-else arm's binding doesn't leak.
        let code = r#"@settings(kclVersion = "3.0-preview")
x = if false {
  0
} else if false {
  0
} else {
  y = 1
  y
}
z = y
"#;
        let err = parse_execute(code).await.expect_err("should error");
        assert!(
            err.message().contains("`y` is not defined"),
            "unexpected message: {}",
            err.message()
        );

        // A taken else-if arm can shadow an outer binding without changing it.
        let code = r#"@settings(kclVersion = "3.0-preview")
outer = 1
x = if false {
  0
} else if true {
  outer = 2
  outer + 10
} else {
  0
}
"#;
        let result = parse_execute(code).await.unwrap();
        assert_eq!(variable_f64(&result, "x"), 12.0);
        assert_eq!(variable_f64(&result, "outer"), 1.0);

        // Same from the final-else arm.
        let code = r#"@settings(kclVersion = "3.0-preview")
outer = 1
x = if false {
  0
} else if false {
  0
} else {
  outer = 2
  outer + 10
}
"#;
        let result = parse_execute(code).await.unwrap();
        assert_eq!(variable_f64(&result, "x"), 12.0);
        assert_eq!(variable_f64(&result, "outer"), 1.0);
    }

    /// Pins the pre-KCL-3.0 behavior for else-if and final-else arms: their
    /// bindings leak into the enclosing environment, and shadowing an outer
    /// name is a redefinition error, matching then-arms.
    #[tokio::test(flavor = "multi_thread")]
    async fn else_if_and_final_else_arm_bindings_leak_without_v3() {
        for header in ["", "@settings(kclVersion = 2.0)\n"] {
            let code = format!(
                r#"{header}x = if false {{
  0
}} else if true {{
  y = 1
  y
}} else {{
  0
}}
z = y
"#
            );
            let result = parse_execute(&code).await.unwrap();
            assert_eq!(variable_f64(&result, "z"), 1.0, "code={code}");

            let code = format!(
                r#"{header}x = if false {{
  0
}} else if false {{
  0
}} else {{
  y = 1
  y
}}
z = y
"#
            );
            let result = parse_execute(&code).await.unwrap();
            assert_eq!(variable_f64(&result, "z"), 1.0, "code={code}");

            let code = format!(
                r#"{header}outer = 1
x = if false {{
  0
}} else if true {{
  outer = 2
  outer
}} else {{
  0
}}
"#
            );
            let err = parse_execute(&code).await.expect_err("should error");
            assert!(
                err.message().contains("Cannot redefine `outer`"),
                "unexpected message: {}",
                err.message()
            );
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn error_inside_if_arm_unwinds_balanced_in_v3() {
        // The user's error surfaces (not an internal environment-imbalance
        // error), on both executors.
        let code = r#"@settings(kclVersion = "3.0-preview")
fn f() {
  dummy = if true {
    assert(1, isEqualTo = 2, error = "boom")
    0
  } else {
    0
  }
  return dummy
}
x = f()
"#;
        let err = parse_execute(code).await.expect_err("should error");
        assert!(err.message().contains("boom"), "unexpected message: {}", err.message());
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn exit_inside_scoped_if_arm_in_v3() {
        let code = r#"@settings(kclVersion = "3.0-preview")
fn f() {
  dummy = if true {
    exit()
    0
  } else {
    0
  }
  return dummy
}
x = f()
assert(1, isEqualTo = 2, error = "code after exit ran")
"#;
        parse_execute(code).await.unwrap();
    }

    /// If-arm scoping is gated on the entry point's kclVersion, not the
    /// defining module's. A module cannot opt into KCL 3.0 on its own.
    #[tokio::test(flavor = "multi_thread")]
    async fn if_arm_scoping_gated_on_entry_point_not_module() {
        // A 2.0 entry point importing a module that declares KCL 3.0 is
        // rejected as a version mismatch before the module runs, so its arms
        // never get to leak or not leak.
        let dep = r#"@settings(kclVersion = "3.0-preview")
ignored = if true {
  leaked = 1
  leaked
} else {
  0
}
export leakCheck = leaked
"#;
        let main = r#"@settings(kclVersion = 2.0)
import leakCheck from "dep.kcl"
x = leakCheck
"#;
        let err = execute_with_modules(main, &[("dep.kcl", dep)]).await.unwrap_err();
        assert!(
            err.message()
                .starts_with("Mixing KCL versions in a single program is not allowed."),
            "unexpected message: {}",
            err.message()
        );

        // A KCL 3.0 entry point applies arm scoping everywhere, including
        // inside an imported module that declares no kclVersion (1.0 under the
        // legacy lookup). Declaring 2.0 there is rejected as a version mismatch
        // instead.
        let dep = r#"ignored = if true {
  arm = 1
  arm
} else {
  0
}
export fn leakCheck() {
  return arm
}
"#;
        let main = r#"@settings(kclVersion = "3.0-preview")
import leakCheck from "dep.kcl"
x = leakCheck()
"#;
        let err = execute_with_modules(main, &[("dep.kcl", dep)]).await.unwrap_err();
        assert!(
            err.message().contains("`arm` is not defined"),
            "unexpected message: {}",
            err.message()
        );
    }

    /// Unwinding out of a sketch block nested inside a scoped if-arm must
    /// run the sketch cleanup and then pop the arm's scope environment, in
    /// that order, on all three unwind paths: error, exit(), and early
    /// return.
    #[tokio::test(flavor = "multi_thread")]
    async fn unwind_through_sketch_block_inside_scoped_if_arm_in_v3() {
        // Error: the user's error surfaces, not an internal
        // environment-imbalance error.
        let code = r#"@settings(kclVersion = "3.0-preview", experimentalFeatures = allow)
fn f() {
  dummy = if true {
    s = sketch(on = XY) {
      l1 = line(start = [var 0mm, var 0mm], end = [var 10mm, var 0mm])
      q = notDefinedAnywhere
    }
    0
  } else {
    0
  }
  return dummy
}
x = f()
"#;
        let err = parse_execute(code).await.unwrap_err();
        assert!(
            err.message().contains("`notDefinedAnywhere` is not defined"),
            "unexpected message: {}",
            err.message()
        );

        // exit() terminates the program; nothing after it runs.
        let code = r#"@settings(kclVersion = "3.0-preview", experimentalFeatures = allow)
fn f() {
  dummy = if true {
    s = sketch(on = XY) {
      l1 = line(start = [var 0mm, var 0mm], end = [var 10mm, var 0mm])
      e = exit()
    }
    0
  } else {
    0
  }
  return dummy
}
x = f()
assert(1, isEqualTo = 2, error = "code after exit ran")
"#;
        parse_execute(code).await.unwrap();

        // Early return terminates the enclosing function with its value.
        let code = r#"@settings(kclVersion = "3.0-preview", experimentalFeatures = allow)
fn g() {
  dummy = if true {
    s = sketch(on = XY) {
      l1 = line(start = [var 0mm, var 0mm], end = [var 10mm, var 0mm])
      return 42
    }
    0
  } else {
    0
  }
  return 0
}
y = g()
"#;
        let result = parse_execute(code).await.unwrap();
        assert_eq!(variable_f64(&result, "y"), 42.0);
    }

    /// A tag declared inside an if-arm is bound like any arm-local: usable
    /// within its arm, and under KCL 3.0 not visible after the if. Without
    /// KCL 3.0 it leaks like other arm bindings.
    #[tokio::test(flavor = "multi_thread")]
    async fn tag_declared_inside_if_arm_is_arm_local_in_v3() {
        let arm_body = r#"p = if true {
  profile = startSketchOn(XY)
    |> startProfile(at = [0, 0])
    |> line(end = [10, 0], tag = $edge)
    |> line(end = [0, 10])
    |> line(end = [-10, 0])
    |> close()
  inArmLen = segLen(edge)
  assert(inArmLen, isEqualTo = 10, error = "tag is usable within its arm")
  profile
} else {
  startSketchOn(XY)
    |> startProfile(at = [0, 0])
    |> line(end = [5, 0])
    |> line(end = [0, 5])
    |> line(end = [-5, 0])
    |> close()
}
len = segLen(edge)
"#;

        let code = format!("@settings(kclVersion = \"3.0-preview\")\n{arm_body}");
        let err = parse_execute(&code).await.unwrap_err();
        assert!(
            err.message().contains("`edge` is not defined"),
            "unexpected message: {}",
            err.message()
        );

        // Pins the pre-KCL-3.0 behavior: the tag leaks out of the arm.
        let result = parse_execute(arm_body).await.unwrap();
        assert_eq!(variable_f64(&result, "len"), 10.0);
    }

    /// Repeated calls to a function whose body evaluates an if-expression must
    /// not accumulate retained call frames when nothing escapes the arms: the
    /// arm's scope environment defers pinning its parent until it is itself
    /// referenced. Before deferred pinning, each of the 100 calls below
    /// permanently retained its frame.
    #[tokio::test(flavor = "multi_thread")]
    async fn if_arm_scopes_do_not_retain_function_frames_in_v3() {
        let code = r#"@settings(kclVersion = "3.0-preview")
fn pick(@i) {
  r = if i > 50 {
    a = i * 2
    a
  } else {
    b = i + 1
    b
  }
  return r
}
results = map([1..100], f = fn(@i) { return pick(i) })
assert(results[0], isEqualTo = 2, error = "pick(1) = 2")
assert(results[99], isEqualTo = 200, error = "pick(100) = 200")
"#;
        let result = parse_execute(code).await.unwrap();
        // Long-lived environments (std prelude modules, the root env, ...) are
        // a small constant independent of the call count.
        let retained = result.exec_state.stack().memory.envs_with_bindings();
        assert!(retained < 20, "retained environments: {retained}");
    }

    /// An if-expression used as a pipe element gets arm scoping without
    /// disturbing the ambient pipe value: the arm's result feeds the next
    /// element's `%` (the parser doesn't accept `%` anywhere inside the if
    /// element itself), and arm-locals don't leak.
    #[tokio::test(flavor = "multi_thread")]
    async fn if_arm_scoping_inside_pipe_in_v3() {
        let code = r#"@settings(kclVersion = "3.0-preview")
cond = true
result = 5
  |> if cond {
    a = 20
    a
  } else {
    0
  }
  |> max([%, 1])
"#;
        let result = parse_execute(code).await.unwrap();
        // The then-arm's 20 must flow through the pipe into max's `%`. If
        // the arm's scope push/pop corrupted the ambient pipe value, this
        // would not be 20.
        assert_eq!(variable_f64(&result, "result"), 20.0);

        // Arm-locals of a pipe element are invisible after the pipe.
        let code = r#"@settings(kclVersion = "3.0-preview")
cond = true
result = 5
  |> if cond {
    a = 20
    a
  } else {
    0
  }
leaked = a
"#;
        let err = parse_execute(code).await.unwrap_err();
        assert!(
            err.message().contains("`a` is not defined"),
            "unexpected message: {}",
            err.message()
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn member_expression_evaluates_object_before_property_in_v3() {
        // Both operands are undefined, so the error names whichever one is
        // evaluated first. KCL 3.0 evaluates in source order: `a` before `b`.
        let code = r#"@settings(kclVersion = "3.0-preview")
x = a[b]
"#;
        let err = parse_execute(code).await.expect_err("should error");
        assert_eq!(err.message(), "`a` is not defined");
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn member_expression_evaluates_property_before_object_without_v3() {
        // Pre-KCL-3.0 order, preserved for compatibility: the computed
        // property is evaluated before the object.
        let code = r#"@settings(kclVersion = 2.0)
x = a[b]
"#;
        let err = parse_execute(code).await.expect_err("should error");
        assert_eq!(err.message(), "`b` is not defined");
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn member_expression_undefined_object_with_static_property_in_v3() {
        let code = r#"@settings(kclVersion = "3.0-preview")
x = a.b
"#;
        let err = parse_execute(code).await.expect_err("should error");
        assert_eq!(err.message(), "`a` is not defined");
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn member_expression_values_in_v3() {
        // The source-order path handles computed, non-computed, chained, and
        // call-result access.
        let code = r#"@settings(kclVersion = "3.0-preview")
fn xs() {
  return [10, 20, 30]
}
fn one() {
  return 1
}
obj = { inner = { xs = xs() } }
objs = [obj, obj]
a = obj.inner.xs[one()]
b = xs()[one() + 1]
c = objs[0].inner.xs[0]
"#;
        let result = parse_execute(code).await.unwrap();
        assert_eq!(variable_f64(&result, "a"), 20.0);
        assert_eq!(variable_f64(&result, "b"), 30.0);
        assert_eq!(variable_f64(&result, "c"), 10.0);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn exit_inside_member_expression_in_v3() {
        // exit() propagates out of either half of a member expression and
        // terminates the program before the assert runs.
        for code in [
            r#"@settings(kclVersion = "3.0-preview")
x = exit()[0]
assert(1, isEqualTo = 2, error = "code after exit ran")
"#,
            r#"@settings(kclVersion = "3.0-preview")
arr = [1]
x = arr[exit()]
assert(1, isEqualTo = 2, error = "code after exit ran")
"#,
        ] {
            parse_execute(code).await.unwrap();
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn experimental_parameter() {
        let code = r#"
fn inc(@x, @(experimental = true) amount? = 1) {
  return x + amount
}

answer = inc(5, amount = 2)
"#;
        let result = parse_execute(code).await.unwrap();
        let issues = result.exec_state.issues();
        assert_eq!(issues.len(), 1);
        assert_eq!(issues[0].severity, Severity::Error);
        let msg = &issues[0].message;
        assert!(msg.contains("experimental"), "found {msg}");

        // If the parameter isn't used, there's no warning.
        let code = r#"
fn inc(@x, @(experimental = true) amount? = 1) {
  return x + amount
}

answer = inc(5)
"#;
        let result = parse_execute(code).await.unwrap();
        let issues = result.exec_state.issues();
        assert!(issues.is_empty(), "issues={issues:#?}");
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn experimental_scalar_fixed_constraint() {
        let code_left = r#"@settings(experimentalFeatures = warn)
sketch(on = XY) {
  point1 = point(at = [var 0mm, var 0mm])
  point1.at[0] == 1mm
}
"#;
        // It's symmetric. Flipping the binary operator has the same behavior.
        let code_right = r#"@settings(experimentalFeatures = warn)
sketch(on = XY) {
  point1 = point(at = [var 0mm, var 0mm])
  1mm == point1.at[0]
}
"#;

        for code in [code_left, code_right] {
            let result = parse_execute(code).await.unwrap();
            let issues = result.exec_state.issues();
            let Some(error) = issues
                .iter()
                .find(|issue| issue.message.contains("scalar fixed constraint is experimental"))
            else {
                panic!("found {issues:#?}");
            };
            assert_eq!(error.severity, Severity::Warning);
        }
    }

    // START Mock Execution tests
    // Ideally, we would do this as part of all sim tests and delete these one-off tests.

    #[tokio::test(flavor = "multi_thread")]
    async fn test_tangent_line_arc_executes_with_mock_engine() {
        let code = std::fs::read_to_string("tests/tangent_line_arc/input.kcl").unwrap();
        parse_execute(&code).await.unwrap();
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_tangent_arc_arc_math_only_executes_with_mock_engine() {
        let code = std::fs::read_to_string("tests/tangent_arc_arc_math_only/input.kcl").unwrap();
        parse_execute(&code).await.unwrap();
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_tangent_line_circle_executes_with_mock_engine() {
        let code = std::fs::read_to_string("tests/tangent_line_circle/input.kcl").unwrap();
        parse_execute(&code).await.unwrap();
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_tangent_circle_circle_native_executes_with_mock_engine() {
        let code = std::fs::read_to_string("tests/tangent_circle_circle_native/input.kcl").unwrap();
        parse_execute(&code).await.unwrap();
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_shadowed_get_opposite_edge_binding_does_not_panic() {
        let code = r#"startX = 2

baseSketch = sketch(on = XY) {
  yoyo = line(start = [startX, 0], end = [7, 6])
  line2 = line(start = [7, 6], end = [7, 12])
  hi = line(start = [7, 12], end = [startX, 0])
}

baseRegion = region(point = [5.5, 6], sketch = baseSketch)
myExtrude = extrude(
  baseRegion,
  length = 5,
  tagEnd = $endCap,
  tagStart = $startCap,
)
yodawg = getCommonEdge(faces = [
  baseRegion.tags.hi,
  baseRegion.tags.yoyo
])

cutSketch = sketch(on = YZ) {
  myDisambigutator = line(start = [-3.29, 4.75], end = [2.03, 2.44])
  myDisambigutator2 = line(start = [2.03, 2.44], end = [-3.49, 0.31])
  line3 = line(start = [-3.49, 0.31], end = [-3.29, 4.75])
}

cutRegion = region(point = [-1.5833333333, 2.5], sketch = cutSketch)
extrude001 = extrude(cutRegion, length = 5)
solid001 = subtract(myExtrude, tools = extrude001)

yoyo = getOppositeEdge(baseRegion.tags.hi)
fillet(solid001, radius = 0.1, tags = yoyo)
"#;

        parse_execute(code).await.unwrap();
    }

    // END Mock Execution tests

    // Sketch constraint report tests

    async fn run_constraint_report(kcl: &str) -> SketchConstraintReport {
        let program = crate::Program::parse_no_errs(kcl).unwrap();
        let ctx = ExecutorContext::new_with_default_client().await.unwrap();
        let mut exec_state = ExecState::new(&ctx);
        let (env_ref, _) = ctx.run(&program, &mut exec_state).await.unwrap();
        let outcome = exec_state
            .into_exec_outcome(env_ref, &ctx)
            .await
            .expect("constraint report test outcome should collect variables");
        let report = outcome.sketch_constraint_report();
        ctx.close().await;
        report
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn warn_when_sketch_is_over_constrained() {
        let code = r#"
sketch001 = sketch(on = XY) {
  line1 = line(start = [var -10.64mm, var 26.44mm], end = [var 13.05mm, var 5.52mm])
  fixed([line1.start, ORIGIN])
  fixed([line1.start, [20, 20]])
}
"#;
        let result = parse_execute(code).await.unwrap();
        let issues = result.exec_state.issues();
        let Some(warning) = issues.iter().find(|issue| issue.message.contains("over-constrained")) else {
            panic!("expected over-constrained warning; found {issues:#?}");
        };
        assert_eq!(warning.severity, Severity::Warning);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn over_constrained_warning_identifies_signed_vertical_distance_direction() {
        let code = r#"
sketch001 = sketch(on = XY) {
  line1 = line(start = [var 0mm, var 10mm], end = [var 0mm, var 0mm])
  fixed([line1.start, [0mm, 10mm]])
  fixed([line1.end, ORIGIN])
  verticalDistance([line1.start, line1.end]) == 10mm
}
"#;
        let result = parse_execute(code).await.unwrap();
        let issues = result.exec_state.issues();
        let Some(warning) = issues.iter().find(|issue| issue.message.contains("over-constrained")) else {
            panic!("expected over-constrained warning; found {issues:#?}");
        };
        assert!(
            warning.message.contains(
                "Unsatisfied signed verticalDistance constraint: a positive right-hand side requires the second point to be above the first"
            ),
            "expected signed-direction diagnostic; found {warning:#?}"
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn no_warning_when_sketch_is_not_over_constrained() {
        // Under-constrained sketch should not emit the over-constrained warning.
        let code = r#"
sketch001 = sketch(on = XY) {
  line1 = line(start = [var 1mm, var 2mm], end = [var 3mm, var 4mm])
}
"#;
        let result = parse_execute(code).await.unwrap();
        let issues = result.exec_state.issues();
        assert!(
            !issues.iter().any(|issue| issue.message.contains("over-constrained")),
            "did not expect over-constrained warning; found {issues:#?}"
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_constraint_report_fully_constrained() {
        // All points are fully constrained via equality constraints.
        let kcl = r#"
@settings(experimentalFeatures = allow)

sketch(on = YZ) {
  line1 = line(start = [var 2mm, var 8mm], end = [var 5mm, var 7mm])
  line1.start.at[0] == 2
  line1.start.at[1] == 8
  line1.end.at[0] == 5
  line1.end.at[1] == 7
}
"#;
        let report = run_constraint_report(kcl).await;
        assert_eq!(report.fully_constrained.len(), 1);
        assert_eq!(report.under_constrained.len(), 0);
        assert_eq!(report.over_constrained.len(), 0);
        assert_eq!(report.errors.len(), 0);
        assert_eq!(report.fully_constrained[0].status, ConstraintKind::FullyConstrained);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_constraint_report_under_constrained() {
        // No constraints at all — all points are free.
        let kcl = r#"
sketch(on = YZ) {
  line1 = line(start = [var 1.32mm, var -1.93mm], end = [var 6.08mm, var 2.51mm])
}
"#;
        let report = run_constraint_report(kcl).await;
        assert_eq!(report.fully_constrained.len(), 0);
        assert_eq!(report.under_constrained.len(), 1);
        assert_eq!(report.over_constrained.len(), 0);
        assert_eq!(report.errors.len(), 0);
        assert_eq!(report.under_constrained[0].status, ConstraintKind::UnderConstrained);
        assert!(report.under_constrained[0].free_count > 0);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_constraint_report_over_constrained() {
        // Conflicting distance constraints on the same pair of points.
        let kcl = r#"
@settings(experimentalFeatures = allow)

sketch(on = YZ) {
  line1 = line(start = [var 2mm, var 8mm], end = [var 5mm, var 7mm])
  line1.start.at[0] == 2
  line1.start.at[1] == 8
  line1.end.at[0] == 5
  line1.end.at[1] == 7
  distance([line1.start, line1.end]) == 100mm
}
"#;
        let report = run_constraint_report(kcl).await;
        assert_eq!(report.over_constrained.len(), 1);
        assert_eq!(report.errors.len(), 0);
        assert_eq!(report.over_constrained[0].status, ConstraintKind::OverConstrained);
        assert!(report.over_constrained[0].conflict_count > 0);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_constraint_report_multiple_sketches() {
        // Two sketches: one fully constrained, one under-constrained.
        let kcl = r#"
@settings(experimentalFeatures = allow)

s1 = sketch(on = YZ) {
  line1 = line(start = [var 2mm, var 8mm], end = [var 5mm, var 7mm])
  line1.start.at[0] == 2
  line1.start.at[1] == 8
  line1.end.at[0] == 5
  line1.end.at[1] == 7
}

s2 = sketch(on = XZ) {
  line1 = line(start = [var 1mm, var 2mm], end = [var 3mm, var 4mm])
}
"#;
        let report = run_constraint_report(kcl).await;
        assert_eq!(
            report.fully_constrained.len()
                + report.under_constrained.len()
                + report.over_constrained.len()
                + report.errors.len(),
            2,
            "Expected 2 sketches total"
        );
        assert_eq!(report.fully_constrained.len(), 1);
        assert_eq!(report.under_constrained.len(), 1);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_constraint_report_reports_sketch_names() {
        // One file holding a fully constrained, an under-constrained, and an
        // over-constrained sketch. Every entry carries the name of the
        // variable its sketch was assigned to, so a caller can say which
        // sketch needs correcting.
        let kcl = r#"
@settings(experimentalFeatures = allow)

fixedSketch = sketch(on = YZ) {
  line1 = line(start = [var 2mm, var 8mm], end = [var 5mm, var 7mm])
  line1.start.at[0] == 2
  line1.start.at[1] == 8
  line1.end.at[0] == 5
  line1.end.at[1] == 7
}

looseSketch = sketch(on = XZ) {
  line1 = line(start = [var 1mm, var 2mm], end = [var 3mm, var 4mm])
}

conflictSketch = sketch(on = XY) {
  line1 = line(start = [var 2mm, var 8mm], end = [var 5mm, var 7mm])
  line1.start.at[0] == 2
  line1.start.at[1] == 8
  line1.end.at[0] == 5
  line1.end.at[1] == 7
  distance([line1.start, line1.end]) == 100mm
}
"#;
        let report = run_constraint_report(kcl).await;
        assert_eq!(report.errors.len(), 0);
        assert_eq!(report.fully_constrained.len(), 1);
        assert_eq!(report.under_constrained.len(), 1);
        assert_eq!(report.over_constrained.len(), 1);
        assert_eq!(report.fully_constrained[0].name, "fixedSketch");
        assert_eq!(report.under_constrained[0].name, "looseSketch");
        assert_eq!(report.over_constrained[0].name, "conflictSketch");
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_constraint_report_name_empty_without_declaration() {
        // A sketch written as an expression statement has no enclosing
        // variable declaration, so there is no name to report. This pins the
        // documented limitation of SketchConstraintStatus::name.
        let kcl = r#"
sketch(on = YZ) {
  line1 = line(start = [var 1.32mm, var -1.93mm], end = [var 6.08mm, var 2.51mm])
}
"#;
        let report = run_constraint_report(kcl).await;
        assert_eq!(report.under_constrained.len(), 1);
        assert_eq!(report.under_constrained[0].name, "");
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_constraint_report_names_repeat_across_calls() {
        // Both sketches come from the same declaration inside the function
        // body, so both entries carry that declaration's name and the report
        // cannot tell them apart. This pins the documented limitation of
        // SketchConstraintStatus::name.
        let kcl = r#"
fn makeSketch() {
  inner = sketch(on = XY) {
    line1 = line(start = [var 1mm, var 2mm], end = [var 3mm, var 4mm])
  }
  return inner
}

first = makeSketch()
second = makeSketch()
"#;
        let report = run_constraint_report(kcl).await;
        assert_eq!(report.under_constrained.len(), 2);
        assert_eq!(report.under_constrained[0].name, "inner");
        assert_eq!(report.under_constrained[1].name, "inner");
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_enum_declaration_is_experimental() {
        // Without opting in, executing a program with an enum declaration
        // fails at the parsing stage with the experimental diagnostic.
        let code = "type Color { | Red }";
        assert_eq!(
            parse_execute(code).await.unwrap_err().message(),
            "Use of enum declarations is experimental and may change or be removed."
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn enum_declaration_registers_type() {
        // Plain and exported declarations both execute. Nothing references the
        // enum yet, so this only asserts that declaring one is no longer an
        // error; constructor use is exercised separately.
        let code = r#"@settings(experimentalFeatures = allow)
type Color { | Red | Green }
"#;
        parse_execute(code).await.unwrap();

        let code = r#"@settings(experimentalFeatures = allow)
export type Color { | Red | Green }
"#;
        parse_execute(code).await.unwrap();

        // A zero-variant enum is a valid declaration.
        let code = r#"@settings(experimentalFeatures = allow)
type Empty { | }
"#;
        parse_execute(code).await.unwrap();
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn enum_declaration_rejects_nested_scope() {
        // Identity is (module, declared name), so two same-named declarations in
        // one file would collide. The parser and formatter accept this shape, so
        // execution is the only thing that can reject it.
        //
        // The rule is about nesting, not about one kind of block, so all routes
        // to `BodyType::Block` are covered here.
        let allow = "@settings(experimentalFeatures = allow)\n";
        for (case, code) in [
            (
                "function body",
                format!("{allow}fn palette() {{\n  type Color {{ | Red }}\n  return 0\n}}\npalette()\n"),
            ),
            (
                "sketch block",
                format!(
                    "{allow}sketch(on = XY) {{\n  type Color {{ | Red }}\n  l1 = line(start = [var 0mm, var 0mm], end = [var 10mm, var 0mm])\n}}\n"
                ),
            ),
            (
                "if arm",
                format!("{allow}x = if true {{\n  type Color {{ | Red }}\n  0\n}} else {{\n  0\n}}\n"),
            ),
        ] {
            assert_eq!(
                parse_execute(&code).await.unwrap_err().message(),
                "Enum declarations are only supported at the top-level of a file. Move `type Color` to the top-level.",
                "case: {case}"
            );
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn enum_alone_is_restricted_to_top_level() {
        // Pins the asymmetry the rule above creates: a type alias may be declared
        // in any block, an enum may not. The difference is required by enum
        // identity rather than chosen -- two nested aliases shadow each other
        // harmlessly, while two nested `type Color` declarations would be one type
        // with two variant sets. Tightening aliases to match, or relaxing enums,
        // has to break this test first.
        let allow = "@settings(experimentalFeatures = allow)\n";
        for (case, code) in [
            (
                "function body",
                format!("{allow}fn f() {{\n  type Temperature = number(_)\n  return 0\n}}\nx = f()\n"),
            ),
            (
                "sketch block",
                format!(
                    "{allow}sketch(on = XY) {{\n  type Temperature = number(_)\n  l1 = line(start = [var 0mm, var 0mm], end = [var 10mm, var 0mm])\n}}\n"
                ),
            ),
        ] {
            parse_execute(&code)
                .await
                .unwrap_or_else(|err| panic!("a type alias should be allowed in a {case}: {}", err.message()));
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn enum_declaration_rejects_duplicate() {
        let code = r#"@settings(experimentalFeatures = allow)
type Color { | Red | Green | Red }
"#;
        assert_eq!(
            parse_execute(code).await.unwrap_err().message(),
            "Duplicate variant `Red` in enum `Color`."
        );
    }

    /// Runs `main` with `modules` written beside it, so import paths resolve.
    async fn execute_with_modules(main: &str, modules: &[(&str, &str)]) -> Result<ExecTestResults, KclError> {
        let tmpdir = tempfile::TempDir::with_prefix("zma_kcl_enum_clash").unwrap();
        for (name, source) in modules {
            tokio::fs::write(tmpdir.path().join(name), source).await.unwrap();
        }

        parse_execute_with_project_dir(main, Some(crate::TypedPath(tmpdir.path().into()))).await
    }

    /// Runs `main` with an empty imported module named `m.kcl` in mock
    /// execution and returns the recorded compilation issues; the run may
    /// end in an error (e.g. from operating on the module's missing return
    /// value).
    ///
    /// The `m.kcl` module lives in an in-memory file system under a
    /// synthetic project directory, so parallel tests share no on-disk
    /// state and there is nothing to clean up even if the process is
    /// killed.
    async fn issues_with_empty_module(main: &str) -> Vec<crate::errors::CompilationIssue> {
        use futures::FutureExt;

        let project_dir = crate::TypedPath::new("/zma-kcl-member-ranges");
        // Key the file by the same join that import resolution performs, so
        // the lookup matches on every platform.
        let files = [(project_dir.join("m.kcl").to_string(), Vec::new())]
            .into_iter()
            .collect();

        let program = crate::Program::parse_no_errs(main).unwrap();
        let ctx = ExecutorContext {
            engine: Arc::new(EngineManager::new_mock()),
            engine_batch: EngineBatchContext::default(),
            fs: crate::fs::new_file_system_handle(crate::InMemoryFiles::new(files)),
            settings: ExecutorSettings {
                project_directory: Some(project_dir),
                ..Default::default()
            },
            context_type: ContextType::Mock,
            execution_callbacks: Default::default(),
            executor_kind: machine::ExecutorKind::resolve(),
            machine_call_depth_limit: crate::execution::machine::DEFAULT_MACHINE_CALL_DEPTH_LIMIT,
        };
        let mut exec_state = ExecState::new(&ctx);
        // Close the context even if execution panics, then let the panic
        // continue. An Err from the run itself is expected here (operating
        // on the module's missing return value) and is deliberately ignored.
        let run_result = std::panic::AssertUnwindSafe(ctx.run(&program, &mut exec_state))
            .catch_unwind()
            .await;
        ctx.close().await;
        if let Err(panic) = run_result {
            std::panic::resume_unwind(panic);
        }
        exec_state.issues().to_vec()
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn member_object_diagnostics_use_object_range() {
        // A diagnostic raised while evaluating a member expression's object
        // (here, the imported module's missing-return warning) points at the
        // object's own span, not the whole member expression.
        // Both member evaluation orders (pre-KCL-3.0 and KCL 3.0) must
        // attribute the diagnostic the same way.
        for header in ["", "@settings(kclVersion = \"3.0-preview\")\n"] {
            let main = format!("{header}import \"m.kcl\" as m\nx = m.field\n");
            let issues = issues_with_empty_module(&main).await;
            let warning = issues
                .iter()
                .find(|issue| issue.message.contains("no return value"))
                .expect("missing-return warning should be recorded");
            let object_start = main.rfind("m.field").unwrap();
            assert_eq!(
                (warning.source_range.start(), warning.source_range.end()),
                (object_start, object_start + 1),
                "warning should point at the object's span (header={header:?})"
            );
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn member_property_diagnostics_use_property_range() {
        // Same for the computed property: the warning points at the index
        // expression's span inside the brackets.
        for header in ["", "@settings(kclVersion = \"3.0-preview\")\n"] {
            let main = format!("{header}import \"m.kcl\" as m\narr = [1]\nx = arr[m]\n");
            let issues = issues_with_empty_module(&main).await;
            let warning = issues
                .iter()
                .find(|issue| issue.message.contains("no return value"))
                .expect("missing-return warning should be recorded");
            let prop_start = main.rfind("[m]").unwrap() + 1;
            assert_eq!(
                (warning.source_range.start(), warning.source_range.end()),
                (prop_start, prop_start + 1),
                "warning should point at the property's span (header={header:?})"
            );
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn backtrace_reports_fully_qualified_fn_names() {
        // An error inside a function called by a qualified name records the
        // full path (m::f), not just the final segment (f), in the
        // structured backtrace's unwind locations.
        let main = "import \"m.kcl\" as m\nx = m::f()\n";
        let modules = [("m.kcl", "export fn f() {\n  return undefinedVariable\n}\n")];
        let err = execute_with_modules(main, &modules).await.unwrap_err();
        let fn_names: Vec<_> = err.backtrace().into_iter().filter_map(|item| item.fn_name).collect();
        assert_eq!(fn_names, vec!["m::f".to_owned()]);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn whole_module_name_executes_as_operand() {
        // A whole-module import used as a binary or unary operand executes
        // the module and operates on its final-expression value, exactly like
        // using the name in expression position (x = m).
        let main = r#"import "m.kcl" as m
sum = m + m
neg = -m
"#;
        let result = execute_with_modules(main, &[("m.kcl", "42\n")]).await.unwrap();
        assert_eq!(
            mem_get_json(result.exec_state.stack(), result.mem_env, "sum").as_f64(),
            Some(84.0)
        );
        assert_eq!(
            mem_get_json(result.exec_state.stack(), result.mem_env, "neg").as_f64(),
            Some(-42.0)
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn whole_module_without_return_as_operand_errors() {
        // Matches expression-position behavior: the module still executes,
        // the missing-return fallback produces a KclNone, and the binary
        // operation then rejects it. (A trailing declaration would count as
        // the module's return value, so the module body must be empty.)
        let main = "import \"m.kcl\" as m
x = m + 1
";
        let err = execute_with_modules(main, &[("m.kcl", "")]).await.unwrap_err();
        assert!(
            err.message().contains("Expected a number, but found none"),
            "expected the operand to be the module's missing-return KclNone, got: {}",
            err.message()
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn enum_rejects_name_clash_with_module() {
        // One rule reached four ways: by declaring the enum second, by importing
        // the module second, and by importing the enum itself either by name or
        // through a glob, which arrive by different code paths because a glob
        // copies exported keys with their namespace prefix intact.
        let plain_module = ("Color.kcl", "export x = 1\n");
        let enum_module = (
            "enums.kcl",
            "@settings(experimentalFeatures = allow)\nexport type Color { | Red }\n",
        );

        for (case, main, modules) in [
            (
                "module then enum",
                "@settings(experimentalFeatures = allow)\nimport \"Color.kcl\"\ntype Color { | Red }\n",
                vec![plain_module],
            ),
            (
                "enum then module",
                "@settings(experimentalFeatures = allow)\ntype Color { | Red }\nimport \"Color.kcl\"\n",
                vec![plain_module],
            ),
            (
                "named import of an enum",
                "@settings(experimentalFeatures = allow)\nimport \"Color.kcl\"\nimport Color from 'enums.kcl'\n",
                vec![plain_module, enum_module],
            ),
            (
                "glob import of an enum",
                "@settings(experimentalFeatures = allow)\nimport \"Color.kcl\"\nimport * from 'enums.kcl'\n",
                vec![plain_module, enum_module],
            ),
        ] {
            let err = execute_with_modules(main, &modules).await.unwrap_err();
            assert_eq!(
                err.message(),
                "An enum and a module cannot share the name `Color` in the same scope, because `Color::x` would be ambiguous. Rename one of them.",
                "case: {case}"
            );
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn enum_constructs_variant() {
        let allow = "@settings(experimentalFeatures = allow)\n";
        let colors = (
            "colors.kcl",
            "@settings(experimentalFeatures = allow)\nexport type Color { | Red | Green }\n",
        );

        for (case, main, modules) in [
            (
                "declared locally",
                format!("{allow}type Color {{ | Red | Green }}\nx = Color::Red\n"),
                vec![],
            ),
            (
                // Also the regression test for the export check: a module's exports
                // record the prefixed key `__ty_Color`, not the bare name.
                "reached through a module path",
                format!("{allow}import \"colors.kcl\"\nx = colors::Color::Red\n"),
                vec![colors],
            ),
            (
                "imported by name",
                format!("{allow}import Color from 'colors.kcl'\nx = Color::Red\n"),
                vec![colors],
            ),
            (
                // An import alias renames the binding, not the type, so identity
                // and therefore the reported name stay those of the declaration.
                "imported under an alias",
                format!("{allow}import Color as Shade from 'colors.kcl'\nx = Shade::Red\n"),
                vec![colors],
            ),
        ] {
            let result = execute_with_modules(&main, &modules)
                .await
                .unwrap_or_else(|err| panic!("case: {case}: {}", err.message()));
            let KclValue::Enum { value } = mem_get_json(result.exec_state.stack(), result.mem_env, "x") else {
                panic!("case: {case}: `x` should hold an enum value");
            };
            assert_eq!(value.qualified_name(), "Color::Red", "case: {case}");
        }
    }

    // The next five tests pin lexical resolution of signature types: a type
    // name written in a function signature resolves in the scope where the
    // declaration executes, never in the caller's scope. Before
    // definition-time resolution, signature types were looked up at each call
    // in the caller's environment, so a std or user module whose exported
    // types a caller had not imported under their bare names was uncallable.

    #[tokio::test(flavor = "multi_thread")]
    async fn signature_types_resolve_in_declaring_module() {
        let colors = (
            "colors.kcl",
            "@settings(experimentalFeatures = allow)\nexport type Color { | Red | Green }\n\nexport fn paint(@c: Color) {\n  return c\n}\n",
        );
        // The caller can reach `colors::Color` but never binds the bare name
        // `Color`, so resolving the signature in the caller's scope would fail.
        let main =
            "@settings(experimentalFeatures = allow)\nimport \"colors.kcl\"\nr = colors::paint(colors::Color::Red)\n";

        let result = execute_with_modules(main, &[colors]).await.unwrap();
        let KclValue::Enum { value } = mem_get_json(result.exec_state.stack(), result.mem_env, "r") else {
            panic!("`r` should hold an enum value");
        };
        assert_eq!(value.qualified_name(), "Color::Red");
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn qualified_type_paths_resolve_in_aliases_and_ascriptions() {
        let main = r#"@settings(experimentalFeatures = allow)
type ViewOrientation = view::Orientation
front = view::Orientation::Front: view::Orientation
"#;

        parse_execute(main).await.unwrap();
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn unknown_qualified_type_reports_the_written_name() {
        let main = "fn f(@value: missing::Orientation) {}\n";

        let err = parse_execute(main).await.unwrap_err();
        assert_eq!(err.message(), "Unknown type: missing::Orientation");
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn signature_types_resolve_under_import_alias() {
        // An import alias renames the caller's binding for the module. The
        // declaring module's scope is unaffected, so the signature must
        // resolve identically under any alias.
        let colors = (
            "colors.kcl",
            "@settings(experimentalFeatures = allow)\nexport type Color { | Red | Green }\n\nexport fn paint(@c: Color) {\n  return c\n}\n",
        );
        let main = "@settings(experimentalFeatures = allow)\nimport \"colors.kcl\" as painter\nr = painter::paint(painter::Color::Red)\n";

        let result = execute_with_modules(main, &[colors]).await.unwrap();
        let KclValue::Enum { value } = mem_get_json(result.exec_state.stack(), result.mem_env, "r") else {
            panic!("`r` should hold an enum value");
        };
        assert_eq!(value.qualified_name(), "Color::Red");
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn signature_types_ignore_caller_scope() {
        // `broken.kcl` names a type it does not define. The caller defines
        // that name, which caller-scope resolution would have used. The
        // declaration must fail when the module loads, without consulting the
        // caller's binding.
        let broken = (
            "broken.kcl",
            "@settings(experimentalFeatures = allow)\nexport fn f(@x: Missing) {\n  return x\n}\n",
        );
        let main = "@settings(experimentalFeatures = allow)\ntype Missing = string\nimport \"broken.kcl\"\nr = broken::f(\"hi\")\n";

        let err = execute_with_modules(main, &[broken]).await.unwrap_err();
        assert!(
            err.message().contains("Unknown type: Missing"),
            "message: {}",
            err.message()
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn signature_types_reject_forward_reference() {
        // Resolution happens when the declaration executes, so a type declared
        // later in the file is not visible. The function is never called; the
        // error must surface at the declaration itself.
        let main = "@settings(experimentalFeatures = allow)\nfn f(@x: Later) {\n  return x\n}\ntype Later = string\n";

        let err = parse_execute(main).await.unwrap_err();
        assert!(
            err.message().contains("Unknown type: Later"),
            "message: {}",
            err.message()
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn signature_types_resolve_in_enclosing_scope() {
        // The declaring scope is the closure's scope, not merely the declaring
        // module: the anonymous function's signature must see the alias in the
        // enclosing function body. Caller-scope resolution would use the
        // module-level `Width = string` and fail to coerce `42`.
        let main = "@settings(experimentalFeatures = allow)\ntype Width = string\nfn makeMeasure() {\n  type Width = number(mm)\n  return fn(@w: Width) { return w }\n}\nmeasure = makeMeasure()\nr = measure(42)\n";

        let result = parse_execute(main).await.unwrap();
        let KclValue::Number { value, .. } = mem_get_json(result.exec_state.stack(), result.mem_env, "r") else {
            panic!("`r` should hold a number");
        };
        assert_eq!(value, 42.0);
    }

    // Pins that numeric types in signatures are settings-independent, so
    // definition-time resolution changed nothing for them: in type
    // annotations, bare `number` maps to `Any` before the settings-reading
    // path, and every explicit suffix maps to a settings-free type. A literal
    // argument therefore takes its unit from the CALLER's module defaults;
    // the declaring module's defaults (`in` here) must never leak in. If a
    // future change makes a signature's number type depend on module default
    // units, the declaring-module scope of definition-time resolution starts
    // to matter and this pin fails.
    #[tokio::test(flavor = "multi_thread")]
    async fn signature_number_types_ignore_module_default_units() {
        let units_in = (
            "units_in.kcl",
            "@settings(defaultLengthUnit = in)\nexport fn passThrough(@x: number(Length)) {\n  return x\n}\n",
        );
        // The caller's default length unit is mm (the test default), so the
        // unitless literal is 42 mm by the time it reaches the parameter.
        let main = "import \"units_in.kcl\"\na = units_in::passThrough(42)\nb = units_in::passThrough(42mm)\nc = units_in::passThrough(42in)\n";

        let result = execute_with_modules(main, &[units_in]).await.unwrap();
        for (name, expected_ty) in [
            // The unitless literal keeps its `Default` type, and that type
            // records the CALLER's module settings. Declaring-module leakage
            // would show here as `len: Inches`.
            //
            // That the coercion to `number(Length)` leaves the type as
            // `Default` rather than concretizing it to `Known(Millimeters)`
            // is pre-existing coercion behavior which this test observes but
            // does not endorse. If coercion later concretizes, update the
            // expected type; the pin here is the settings provenance.
            (
                "a",
                kcl_api::NumericType::Default {
                    len: kcl_api::UnitLength::Millimeters,
                    angle: kcl_api::UnitAngle::Degrees,
                },
            ),
            (
                "b",
                kcl_api::NumericType::Known(kcl_api::UnitType::Length(kcl_api::UnitLength::Millimeters)),
            ),
            (
                "c",
                kcl_api::NumericType::Known(kcl_api::UnitType::Length(kcl_api::UnitLength::Inches)),
            ),
        ] {
            let KclValue::Number { value, ty, .. } = mem_get_json(result.exec_state.stack(), result.mem_env, name)
            else {
                panic!("`{name}` should hold a number");
            };
            assert_eq!(value, 42.0, "`{name}` should keep its magnitude");
            assert_eq!(ty, expected_ty, "`{name}` should keep the caller-side unit context");
        }
    }

    // Pins the sharpest shadowing case, from a hand-written example during
    // review: BOTH scopes define the same type name with different meanings,
    // so the test observes which one the signature uses, not merely whether a
    // name is present. `m1.kcl`'s `A` is `string` and is NOT exported; the
    // caller's own `A` is `number(mm)`. The signature must use m1's `A`, so
    // passing `2mm` is a type error. Caller-scope resolution would have used
    // the caller's `A` and accepted the call.
    #[tokio::test(flavor = "multi_thread")]
    async fn signature_types_use_declaring_scope_when_both_scopes_define_the_name() {
        let m1 = (
            "m1.kcl",
            "@settings(experimentalFeatures = allow)\ntype A = string\n\nexport fn test(@a: A) {\n  return a\n}\n",
        );
        let main =
            "@settings(experimentalFeatures = allow)\nimport * from \"m1.kcl\"\ntype A = number(mm)\nx = test(2mm)\n";

        let err = execute_with_modules(main, &[m1]).await.unwrap_err();
        assert_eq!(
            err.message(),
            "The input argument of `test` requires a value with type `A`, but found a number (mm) (with type `number(mm)`)."
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn enum_rejects_bad_variant_paths() {
        let allow = "@settings(experimentalFeatures = allow)\n";

        for (case, main, modules, message) in [
            (
                "unknown variant",
                format!("{allow}type Color {{ | Red | Green }}\nx = Color::Blue\n"),
                vec![],
                "`Blue` is not a variant of enum `Color`. Its variants are: Red, Green.",
            ),
            (
                "enum with no variants",
                format!("{allow}type Empty {{ | }}\nx = Empty::Red\n"),
                vec![],
                "`Red` is not a variant of enum `Empty`. Enum `Empty` has no variants.",
            ),
            (
                "path continues past the enum",
                format!("{allow}type Color {{ | Red }}\nx = Color::Red::more\n"),
                vec![],
                "`Color` is an enum, so only a variant name can follow it. There is nothing to reach through `Color::Red`.",
            ),
            (
                "variant name is case sensitive",
                format!("{allow}type Color {{ | Red }}\nx = Color::red\n"),
                vec![],
                "`red` is not a variant of enum `Color`. Its variants are: Red.",
            ),
            (
                "enum not exported from its module",
                format!("{allow}import \"colors.kcl\"\nx = colors::Color::Red\n"),
                vec![(
                    "colors.kcl",
                    "@settings(experimentalFeatures = allow)\ntype Color { | Red }\n",
                )],
                "Item Color not found in module's exported items",
            ),
            (
                // The alias exemption seen from the use site: a type alias is not
                // an enum, so the segment is resolved as a module and fails.
                "a type alias cannot head a path",
                format!("{allow}type T = number(_)\nx = T::foo\n"),
                vec![],
                "`T` is not defined",
            ),
            (
                // The other half of allowing a value and an enum to share a name:
                // a value on its own can never head a path.
                "a value cannot head a path",
                "Color = 5\nx = Color::Red\n".to_owned(),
                vec![],
                "`Color` is not defined",
            ),
        ] {
            let err = execute_with_modules(&main, &modules).await.unwrap_err();
            assert_eq!(err.message(), message, "case: {case}");
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn enum_compares_by_variant() {
        let code = r#"@settings(experimentalFeatures = allow)
type Color { | Red | Green }
sameEq = Color::Red == Color::Red
sameNeq = Color::Red != Color::Red
otherEq = Color::Red == Color::Green
otherNeq = Color::Red != Color::Green
"#;
        let result = parse_execute(code).await.unwrap();

        for (name, expected) in [
            ("sameEq", true),
            ("sameNeq", false),
            ("otherEq", false),
            ("otherNeq", true),
        ] {
            let KclValue::Bool { value, .. } = mem_get_json(result.exec_state.stack(), result.mem_env, name) else {
                panic!("`{name}` should hold a bool");
            };
            assert_eq!(value, expected, "variable: {name}");
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn enum_usable_inside_sketch_block() {
        // Only enum declarations are restricted to the top level; uses are not
        // restricted at all. A sketch block executes its body with sketch-mode
        // skipping turned off, and memory lookups walk outward, so the enum
        // declared above resolves inside the block.
        //
        // `assertIs` runs inside the block because block-local bindings live in a
        // child scope that the root environment cannot read afterwards. A wrong
        // comparison therefore fails this test instead of passing unnoticed.
        let code = r#"@settings(experimentalFeatures = allow)
type Color { | Red | Green }
sketch(on = XY) {
  c = Color::Red
  assertIs(Color::Red != Color::Green)
  assertIs(!(Color::Red != Color::Red))
  l1 = line(start = [var 0mm, var 0mm], end = [var 10mm, var 0mm])
}
"#;
        parse_execute(code)
            .await
            .unwrap_or_else(|err| panic!("enum use inside a sketch block should work: {}", err.message()));
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn enum_eq_reserved_inside_sketch_block() {
        // Inside a sketch block, `==` declares an equivalence constraint, so it is
        // not available for ordinary comparison. Enums are not singled out: the
        // interception happens before any value-comparison arm is reached, and
        // strings and numbers are refused in the same words. The string and number
        // rows are here to keep that visible -- if a later change makes enums
        // report something different from the other types, this test says so.
        //
        // `!=` is deliberately absent: the interception tests `Eq` only, so `!=`
        // still compares, which `enum_usable_inside_sketch_block` covers.
        let allow = "@settings(experimentalFeatures = allow)\n";
        let tail = "  l1 = line(start = [var 0mm, var 0mm], end = [var 10mm, var 0mm])\n}\n";
        for (case, declaration, comparison, types) in [
            (
                "enums",
                "type Color { | Red | Green }\n",
                "Color::Red == Color::Green",
                "a value of enum `Color` and a value of enum `Color`",
            ),
            ("strings", "", "\"a\" == \"b\"", "a string and a string"),
            ("numbers", "", "1 == 2", "a number and a number"),
        ] {
            let code = format!("{allow}{declaration}sketch(on = XY) {{\n  x = {comparison}\n{tail}");
            assert_eq!(
                parse_execute(&code).await.unwrap_err().message(),
                format!("Cannot create an equivalence constraint between values of these types: {types}"),
                "case: {case}"
            );
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn enum_same_file_imported_twice_is_one_type() {
        // Two names for one declaration, so they are the same type and compare
        // equal. Identity is the declaration, not the binding, which is what makes
        // this different from two files that each declare a `Color`.
        let main = r#"@settings(experimentalFeatures = allow)
import Color as A from 'colors.kcl'
import Color as B from 'colors.kcl'
x = A::Red == B::Red
y = A::Red == B::Green
"#;
        let result = execute_with_modules(
            main,
            &[(
                "colors.kcl",
                "@settings(experimentalFeatures = allow)\nexport type Color { | Red | Green }\n",
            )],
        )
        .await
        .unwrap();

        for (name, expected) in [("x", true), ("y", false)] {
            let KclValue::Bool { value, .. } = mem_get_json(result.exec_state.stack(), result.mem_env, name) else {
                panic!("`{name}` should hold a bool");
            };
            assert_eq!(value, expected, "variable: {name}");
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn enum_rejects_comparison_across_types() {
        let allow = "@settings(experimentalFeatures = allow)\n";
        let color = (
            "a.kcl",
            "@settings(experimentalFeatures = allow)\nexport type Color { | Red }\n",
        );
        let other_color = (
            "b.kcl",
            "@settings(experimentalFeatures = allow)\nexport type Color { | Red }\n",
        );

        for (case, main, modules, message) in [
            (
                "two enums declared separately",
                format!("{allow}type Color {{ | Red }}\ntype Shade {{ | Red }}\nx = Color::Red == Shade::Red\n"),
                vec![],
                "Cannot compare enum `Color` with enum `Shade`. They are different types.",
            ),
            (
                // Identity is the declaration, not the name, so two enums that
                // share a name are still different types. Pins that the message
                // says so rather than naming `Color` twice.
                "two enums sharing a name",
                format!(
                    "{allow}import Color as A from 'a.kcl'\nimport Color as B from 'b.kcl'\nx = A::Red == B::Red\n"
                ),
                vec![color, other_color],
                "Cannot compare two different enums that are both named `Color`. They come from separate declarations.",
            ),
            (
                "an enum and a number",
                format!("{allow}type Color {{ | Red }}\nx = Color::Red == 5\n"),
                vec![],
                "Cannot compare enum `Color::Red` with a number.",
            ),
            (
                "a number and an enum, in that order",
                format!("{allow}type Color {{ | Red }}\nx = 5 == Color::Red\n"),
                vec![],
                "Cannot compare enum `Color::Red` with a number.",
            ),
            (
                "an enum and a string",
                format!("{allow}type Color {{ | Red }}\nx = Color::Red == \"Red\"\n"),
                vec![],
                "Cannot compare enum `Color::Red` with a string.",
            ),
        ] {
            let err = execute_with_modules(&main, &modules).await.unwrap_err();
            assert_eq!(err.message(), message, "case: {case}");
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn enum_rejects_bare_type_name_as_value() {
        let allow = "@settings(experimentalFeatures = allow)\n";
        let colors = (
            "colors.kcl",
            "@settings(experimentalFeatures = allow)\nexport type Color { | Red | Green }\n",
        );

        for (case, main, modules, message) in [
            (
                "enum suggests a variant",
                format!("{allow}type Color {{ | Red | Green }}\nx = Color\n"),
                vec![],
                "`Color` is a type, not a value. Use one of its variants, such as `Color::Red`.",
            ),
            (
                // The suggestion has to be pasteable into the file that produced
                // the error, so it uses the local name rather than the declared one.
                "suggestion uses the import alias",
                format!("{allow}import Color as Shade from 'colors.kcl'\nx = Shade\n"),
                vec![colors],
                "`Shade` is a type, not a value. Use one of its variants, such as `Shade::Red`.",
            ),
            (
                "enum with no variants suggests nothing",
                format!("{allow}type Empty {{ | }}\nx = Empty\n"),
                vec![],
                "`Empty` is a type, not a value.",
            ),
            (
                "a type alias reports the same way",
                format!("{allow}type T = number(_)\nx = T\n"),
                vec![],
                "`T` is a type, not a value.",
            ),
            (
                // Unchanged behavior: with no type of that name, the old message
                // is still the right one.
                "an unknown name is still undefined",
                "x = Nope\n".to_owned(),
                vec![],
                "`Nope` is not defined",
            ),
        ] {
            let err = execute_with_modules(&main, &modules).await.unwrap_err();
            assert_eq!(err.message(), message, "case: {case}");
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn enum_use_gated_by_consuming_module() {
        // The declaring module allows experimental features; the consuming one
        // does not, so using the imported enum is what trips the gate. Pins that
        // the gate follows the consumer's settings rather than the declaration's.
        //
        // Experimental use is reported as a compilation issue rather than by
        // aborting the run, which is how `RuntimeType::from_alias` reports it too,
        // so execution succeeds and the diagnostic is what carries the complaint.
        let main = r#"import "colors.kcl"
x = colors::Color::Red
"#;
        let result = execute_with_modules(
            main,
            &[(
                "colors.kcl",
                "@settings(experimentalFeatures = allow)\nexport type Color { | Red }\n",
            )],
        )
        .await
        .unwrap();

        let issues = &result.exec_state.global.issues;
        assert_eq!(issues.len(), 1, "issues: {issues:?}");
        assert_eq!(
            issues[0].message,
            "Use of the enum `Color` is experimental and may change or be removed."
        );
        assert_eq!(issues[0].severity, Severity::Error);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn enum_use_not_gated_when_consumer_allows_it() {
        // The other half of the gate: with the setting present, using an enum
        // raises nothing at all.
        let code = r#"@settings(experimentalFeatures = allow)
type Color { | Red }
x = Color::Red
"#;
        let result = parse_execute(code).await.unwrap();
        assert!(
            result.exec_state.global.issues.is_empty(),
            "issues: {:?}",
            result.exec_state.global.issues
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn enum_allows_name_sharing_outside_modules() {
        // Pins two deliberate exemptions from the clash rule above, so that
        // tightening it later has to be a decision rather than an accident.
        //
        // Only an enum or a module can head a `Color::Red` path, so only those two
        // can be ambiguous. A type alias cannot head a `::` path, and an ordinary
        // value is never looked up for a path head at all.
        for (case, main, modules) in [
            (
                // The module arrives second, which is the path carrying the
                // "only `TypeDef::Enum` conflicts" guard.
                "an alias may share a name with a module",
                "@settings(experimentalFeatures = allow)\ntype Temperature = number(_)\nimport \"Temperature.kcl\"\n",
                vec![("Temperature.kcl", "export x = 1\n")],
            ),
            (
                "a value may share a name with an enum",
                "@settings(experimentalFeatures = allow)\ntype Color { | Red }\nColor = 5\n",
                vec![],
            ),
        ] {
            if let Err(err) = execute_with_modules(main, &modules).await {
                panic!("case: {case}: {}", err.message());
            }
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn enum_declaration_rejects_redefinition() {
        let code = r#"@settings(experimentalFeatures = allow)
type Color { | Red }
type Color { | Green }
"#;
        assert_eq!(
            parse_execute(code).await.unwrap_err().message(),
            "Redefinition of type Color."
        );
    }

    /// Projection yields the variant's declared representation, which in V1 is
    /// always the variant name. Every row binds `x` so the rows differ only in the
    /// shape being projected, and the alias row is here because the target is
    /// resolved before projection decides anything, so an alias must behave
    /// exactly like the type it names.
    #[tokio::test(flavor = "multi_thread")]
    async fn enum_projects_to_string() {
        let header = r#"
            @settings(experimentalFeatures = allow)
            type Color { | Red | Green }
            type Label = string
        "#;

        for (case, body, expected) in [
            ("a variant", "x = Color::Red: string", "Red"),
            ("another variant of the same enum", "x = Color::Green: string", "Green"),
            ("an alias of the target type", "x = Color::Red: Label", "Red"),
            (
                "an element of a projected array",
                r#"
                    pair = [Color::Red, Color::Green]: [string]
                    x = pair[1]
                "#,
                "Green",
            ),
            (
                "an element of a nested projected array",
                r#"
                    grid = [[Color::Green]]: [[string]]
                    x = grid[0][0]
                "#,
                "Green",
            ),
            (
                "a one-element array against a bare string",
                "x = [Color::Red]: string",
                "Red",
            ),
        ] {
            let result = parse_execute(&format!("{header}{body}\n"))
                .await
                .unwrap_or_else(|err| panic!("case: {case}: {}", err.message()));
            let KclValue::String { value, .. } = mem_get_json(result.exec_state.stack(), result.mem_env, "x") else {
                panic!("case: {case}: `x` should hold a string");
            };
            assert_eq!(value, expected, "case: {case}");
        }
    }

    /// Ascribing the enum's own type, directly or through an alias, is a check
    /// rather than a conversion: the value stays an enum and still compares equal
    /// to the variant it came from.
    #[tokio::test(flavor = "multi_thread")]
    async fn enum_ascription_keeps_the_enum() {
        let header = r#"
            @settings(experimentalFeatures = allow)
            type Color { | Red | Green }
            type Paint = Color
        "#;

        for (case, expression, expected) in [
            ("its own type", "(Color::Red: Color) == Color::Red", true),
            ("an alias of its own type", "(Color::Red: Paint) == Color::Red", true),
            (
                "the ascription does not change which variant it is",
                "(Color::Red: Color) == Color::Green",
                false,
            ),
        ] {
            let result = parse_execute(&format!("{header}x = {expression}\n"))
                .await
                .unwrap_or_else(|err| panic!("case: {case}: {}", err.message()));
            let KclValue::Bool { value, .. } = mem_get_json(result.exec_state.stack(), result.mem_env, "x") else {
                panic!("case: {case}: `x` should hold a bool");
            };
            assert_eq!(value, expected, "case: {case}");
        }
    }

    /// A boundary the user did not write must not project, or a nominal parameter
    /// type would mean nothing. The rows are the separate coercion sites: the
    /// unlabeled argument, a labeled argument, and the return.
    #[tokio::test(flavor = "multi_thread")]
    async fn enum_projection_is_not_implicit() {
        let header = r#"
            @settings(experimentalFeatures = allow)
            type Color { | Red | Green }
        "#;
        let found = "but found a value of enum `Color` (with type `Color`).";

        for (case, body, expected) in [
            (
                "unlabeled argument",
                r#"
                    fn label(@text: string) { return text }
                    x = label(Color::Red)
                "#,
                format!("The input argument of `label` requires a value with type `string`, {found}"),
            ),
            (
                "labeled argument",
                r#"
                    fn label(text: string) { return text }
                    x = label(text = Color::Red)
                "#,
                format!("text requires a value with type `string`, {found}"),
            ),
            (
                "return",
                r#"
                    fn label(): string { return Color::Red }
                    x = label()
                "#,
                format!("This function requires its result to be a value with type `string`, {found}"),
            ),
            (
                // The reported type is `[any; 1]` rather than `[Color; 1]` because
                // an array literal does not infer a homogeneous element type. That
                // is pre-existing and unrelated to enums; it is pinned here so the
                // row is not read as an enum-specific quirk.
                "inside an array at an argument boundary",
                r#"
                    fn labels(@text: [string]) { return text }
                    x = labels([Color::Red])
                "#,
                "The input argument of `labels` requires an array of strings (`[string]`), but found an array of `Color` with 1 value (with type `[any; 1]`).".to_owned(),
            ),
        ] {
            assert_eq!(
                parse_execute(&format!("{header}{body}\n")).await.unwrap_err().message(),
                expected,
                "case: {case}"
            );
        }
    }

    /// What an explicit ascription refuses, and what it says about it. The numeric
    /// rows deliberately do not name the mechanism a later version would use.
    #[tokio::test(flavor = "multi_thread")]
    async fn enum_ascription_rejections() {
        let header = r#"
            @settings(experimentalFeatures = allow)
            type Color { | Red }
            type Shade { | Red }
        "#;
        let no_number = "Cannot project enum `Color` to a number. An enum projects to `string`; projecting to a number is not supported yet.";

        for (case, expression, expected) in [
            ("a number target", "Color::Red: number(_)", no_number.to_owned()),
            (
                "a number target reached through an array, so the reason survives the walk",
                "[Color::Red]: [number(_)]",
                no_number.to_owned(),
            ),
            (
                "a boolean target, which is not a projection at all",
                "Color::Red: bool",
                "could not coerce a value of enum `Color` (with type `Color`) to type `bool`".to_owned(),
            ),
            (
                "another enum whose variants happen to match",
                "Color::Red: Shade",
                "could not coerce a value of enum `Color` (with type `Color`) to type `Shade`".to_owned(),
            ),
        ] {
            assert_eq!(
                parse_execute(&format!("{header}x = {expression}\n"))
                    .await
                    .unwrap_err()
                    .message(),
                expected,
                "case: {case}"
            );
        }
    }

    /// The mirror of `enum_projection_is_not_implicit`: where the declared type is
    /// the enum itself, a value flows through every boundary unchanged. Each row
    /// binds `x` to a comparison that must hold, so a value that arrived altered
    /// would fail rather than pass unnoticed. `Some(message)` marks a row that must
    /// be refused instead, which is what keeps the check nominal rather than
    /// merely permissive.
    #[tokio::test(flavor = "multi_thread")]
    async fn enum_flows_through_declared_types() {
        let header = r#"
            @settings(experimentalFeatures = allow)
            type Color { | Red | Green }
            type Shade { | Red }
        "#;

        for (case, body, expected) in [
            (
                "an unlabeled parameter",
                r#"
                    fn paint(@c: Color) { return c }
                    x = paint(Color::Red) == Color::Red
                "#,
                None,
            ),
            (
                "a labeled parameter",
                r#"
                    fn paint(c: Color) { return c }
                    x = paint(c = Color::Green) == Color::Green
                "#,
                None,
            ),
            (
                "a declared return type",
                r#"
                    fn pick(): Color { return Color::Red }
                    x = pick() == Color::Red
                "#,
                None,
            ),
            (
                "an array parameter",
                r#"
                    fn firstOf(@cs: [Color]) { return cs[0] }
                    x = firstOf([Color::Red, Color::Green]) == Color::Red
                "#,
                None,
            ),
            (
                // The field check is `has_type`, which an enum satisfies, so an
                // object passes here while the projection row of
                // `enum_projects_by_target_shape` fails. Both behaviors come from
                // the same unfinished object coercion.
                "an object field",
                r#"
                    fn take(@o: { c: Color }) { return o.c }
                    x = take({ c = Color::Green }) == Color::Green
                "#,
                None,
            ),
            (
                "a union that names the enum",
                r#"
                    fn either(@v: Color | string) { return v }
                    x = either(Color::Red) == Color::Red
                "#,
                None,
            ),
            (
                "the same union given the other member",
                r#"
                    fn either(@v: Color | string) { return v }
                    x = either("plain") == "plain"
                "#,
                None,
            ),
            (
                "another declaration at the same boundary",
                r#"
                    fn paint(@c: Color) { return c }
                    x = paint(Shade::Red) == Shade::Red
                "#,
                Some(
                    "The input argument of `paint` requires a value with type `Color`, but found a value of enum `Shade` (with type `Shade`).",
                ),
            ),
        ] {
            let code = format!("{header}{body}\n");
            match expected {
                None => {
                    let result = parse_execute(&code)
                        .await
                        .unwrap_or_else(|err| panic!("case: {case}: {}", err.message()));
                    let KclValue::Bool { value, .. } = mem_get_json(result.exec_state.stack(), result.mem_env, "x")
                    else {
                        panic!("case: {case}: `x` should hold a bool");
                    };
                    assert!(value, "case: {case}: the value did not survive the boundary");
                }
                Some(message) => assert_eq!(
                    parse_execute(&code).await.unwrap_err().message(),
                    message,
                    "case: {case}"
                ),
            }
        }
    }
}