kcl_lib/execution/

fn_call.rs

use indexmap::IndexMap;
use kcl_api::Group;
use kcl_api::OpArg;

use crate::CompilationIssue;
use crate::NodePath;
use crate::NodePathExt;
use crate::SourceRange;
use crate::errors::KclError;
use crate::errors::KclErrorDetails;
use crate::execution::BodyType;
use crate::execution::ExecState;
use crate::execution::ExecutorContext;
use crate::execution::Geometry;
use crate::execution::KclValue;
use crate::execution::KclValueControlFlow;
use crate::execution::Metadata;
use crate::execution::Solid;
use crate::execution::TagEngineInfo;
use crate::execution::TagIdentifier;
use crate::execution::annotations;
use crate::execution::cad_op::Operation;
use crate::execution::cad_op::op_from_kcl_value;
use crate::execution::kcl_value::FunctionBody;
use crate::execution::kcl_value::FunctionSource;
use crate::execution::kcl_value::NamedParam;
use crate::execution::kcl_value::ParamUnavailable;
use crate::execution::memory;
use crate::execution::types::CoercionMode;
use crate::execution::types::RuntimeType;
use crate::parsing::ast::types::Type;
use crate::std::ConsumedSolidArgCheck;
use crate::std::RegionBehavior;
use crate::std::StaleRegionPolicy;
use crate::std::region_consumption::PendingRegionConsumption;
use crate::std::region_consumption::prepare_region_consumption;
use crate::std::region_consumption::record_consumed_regions;
use crate::std::region_consumption::validate_region_args_not_consumed;
use crate::std::region_consumption::warn_if_region_args_consumed;
use crate::std::solid_consumption::validate_value_not_consumed;
use crate::std::solid_consumption::warn_if_value_consumed_for_deprecated_call;

#[derive(Debug, Clone)]
pub struct Args<Status: ArgsStatus = Desugared> {
    /// Name of the function these args are being passed into.
    pub fn_name: Option<String>,
    /// Unlabeled keyword args. Currently only the first formal arg can be unlabeled.
    /// If the argument was a local variable, then the first element of the tuple is its name
    /// which may be used to treat this arg as a labelled arg.
    pub unlabeled: Vec<(Option<String>, Arg)>,
    /// Labeled args.
    pub labeled: IndexMap<String, Arg>,
    pub source_range: SourceRange,
    pub node_path: Option<NodePath>,
    pub ctx: ExecutorContext,
    /// If this call happens inside a pipe (|>) expression, this holds the LHS of that |>.
    /// Otherwise it's None.
    pub pipe_value: Option<Arg>,
    _status: std::marker::PhantomData<Status>,
}

pub trait ArgsStatus: std::fmt::Debug + Clone {}

#[derive(Debug, Clone)]
pub struct Sugary;
impl ArgsStatus for Sugary {}

// Invariants guaranteed by the `Desugared` status:
// - There is either 0 or 1 unlabeled arguments
// - Any lableled args are in the labeled map, and not the unlabeled Vec.
// - The arguments match the type signature of the function exactly
// - pipe_value.is_none()
#[derive(Debug, Clone)]
pub struct Desugared;
impl ArgsStatus for Desugared {}

impl Args<Sugary> {
    /// Collect the given keyword arguments.
    pub fn new(
        labeled: IndexMap<String, Arg>,
        unlabeled: Vec<(Option<String>, Arg)>,
        source_range: SourceRange,
        node_path: Option<NodePath>,
        exec_state: &mut ExecState,
        ctx: ExecutorContext,
        fn_name: Option<String>,
    ) -> Args<Sugary> {
        Args {
            fn_name,
            labeled,
            unlabeled,
            source_range,
            node_path,
            ctx,
            pipe_value: exec_state.pipe_value().map(|v| Arg::new(v.clone(), source_range)),
            _status: std::marker::PhantomData,
        }
    }
}

impl<Status: ArgsStatus> Args<Status> {
    /// How many arguments are there?
    pub fn len(&self) -> usize {
        self.labeled.len() + self.unlabeled.len()
    }

    /// Are there no arguments?
    pub fn is_empty(&self) -> bool {
        self.labeled.is_empty() && self.unlabeled.is_empty()
    }
}

impl Args<Desugared> {
    pub fn new_no_args(
        source_range: SourceRange,
        node_path: Option<NodePath>,
        ctx: ExecutorContext,
        fn_name: Option<String>,
    ) -> Args {
        Args {
            fn_name,
            unlabeled: Default::default(),
            labeled: Default::default(),
            source_range,
            node_path,
            ctx,
            pipe_value: None,
            _status: std::marker::PhantomData,
        }
    }

    /// Get the unlabeled keyword argument. If not set, returns None.
    pub(crate) fn unlabeled_kw_arg_unconverted(&self) -> Option<&Arg> {
        self.unlabeled.first().map(|(_, a)| a)
    }
}

#[derive(Debug, Clone)]
pub struct Arg {
    /// The evaluated argument.
    pub value: KclValue,
    /// The source range of the unevaluated argument.
    pub source_range: SourceRange,
}

impl Arg {
    pub fn new(value: KclValue, source_range: SourceRange) -> Self {
        Self { value, source_range }
    }

    pub fn synthetic(value: KclValue) -> Self {
        Self {
            value,
            source_range: SourceRange::synthetic(),
        }
    }

    pub fn source_ranges(&self) -> Vec<SourceRange> {
        vec![self.source_range]
    }
}

/// Guidance included in deprecation warnings for sketch v1 stdlib functions.
/// The warning must stand on its own: a human or AI agent reading it should
/// learn what replaces the function and where to find conversion examples
/// without any other context.
const SKETCH_V1_MIGRATION_HELP: &str = "It is part of the legacy sketch API (sketch v1), which is replaced by the sketch-solve API.

See https://zoo.dev/docs/kcl-book/sketch2d_constraints.html for an introduction to sketch-solve with examples.

Draw profiles inside a `sketch(on = XY) { ... }` block using segment functions with absolute points, e.g. `line(start = [0, 0], end = [4, 3])`, optionally marking values as adjustable with `var` and constraining them with constraint functions like `coincident()` or `horizontal()`. ";

/// Migration guidance for a deprecated stdlib function, when it has a
/// dedicated replacement story beyond its docs page.
fn migration_help(fn_src: &FunctionSource) -> Option<&'static str> {
    let name = &fn_src.std_props.as_ref()?.name;
    // Every deprecated function in std::sketch is part of sketch v1, which
    // sketch-solve replaces in KCL 2.0.
    name.starts_with("std::sketch::").then_some(SKETCH_V1_MIGRATION_HELP)
}

impl FunctionSource {
    pub(crate) async fn call_kw(
        &self,
        fn_name: Option<String>,
        exec_state: &mut ExecState,
        ctx: &ExecutorContext,
        args: Args<Sugary>,
        callsite: SourceRange,
    ) -> Result<Option<KclValueControlFlow>, KclError> {
        exec_state.inc_call_stack_size(callsite)?;

        let result = self.inner_call_kw(fn_name, exec_state, ctx, args, callsite).await;

        exec_state.dec_call_stack_size(callsite)?;
        result
    }

    async fn inner_call_kw(
        &self,
        fn_name: Option<String>,
        exec_state: &mut ExecState,
        ctx: &ExecutorContext,
        args: Args<Sugary>,
        callsite: SourceRange,
    ) -> Result<Option<KclValueControlFlow>, KclError> {
        let (state, args) = self.call_setup(&fn_name, exec_state, args, callsite)?;
        // Do not early return via ? or something until we've called
        // call_finish (or call_abort_on_arg_binding_failure), so that the
        // ambient flags are restored and the callee env is popped.
        let result = match &self.body {
            FunctionBody::Rust(f) => f(exec_state, args).await.map(Some),
            FunctionBody::Kcl(_) => {
                if let Err(e) = assign_args_to_params_kw(self, args, exec_state) {
                    return Err(Self::call_abort_on_arg_binding_failure(state, e, exec_state));
                }

                let block_result = ctx.exec_block(&self.ast.body, exec_state, BodyType::Block).await;
                self.kcl_body_result(block_result, exec_state)
            }
        };
        self.call_finish(state, result, exec_state)
    }

    /// The first half of a function call: warnings, argument type checking,
    /// operation setup, pushing the callee environment, and stdlib
    /// ambient-flag tracking. After this succeeds, the callee environment is
    /// pushed and the ambient flags are set, so every path must reach
    /// [`Self::call_finish`] (or [`Self::call_abort_on_arg_binding_failure`])
    /// to balance them. The machine parks the returned [`CallState`] in a
    /// call-boundary continuation; native callbacks keep it across the body await.
    pub(super) fn call_setup(
        &self,
        fn_name: &Option<String>,
        exec_state: &mut ExecState,
        args: Args<Sugary>,
        callsite: SourceRange,
    ) -> Result<(CallState, Args), KclError> {
        // The KCL stdlib is allowed to use deprecated sketch1 functions inside.
        let warn_on_deprecated_usage = !exec_state.mod_local.inside_stdlib;
        if warn_on_deprecated_usage {
            let subject = match &fn_name {
                Some(n) => format!("`{n}`"),
                None => "This function".to_owned(),
            };
            let message = if self.deprecated {
                Some(match migration_help(self) {
                    Some(help) => format!("{subject} is deprecated. {help}"),
                    None => format!("{subject} is deprecated, see the docs for a recommended replacement"),
                })
            } else if let Some(since) = &self.deprecated_since
                && annotations::version_ge(exec_state.deprecation_version(), since)
            {
                Some(match migration_help(self) {
                    Some(help) => format!("{subject} is deprecated as of KCL {since}. {help}"),
                    None => {
                        format!(
                            "{subject} is deprecated as of KCL {since}. See the docs for a recommended replacement."
                        )
                    }
                })
            } else {
                None
            };
            if let Some(message) = message {
                let mut issue = CompilationIssue::err(callsite, message);
                issue.tag = crate::errors::Tag::Deprecated;
                exec_state.warn(issue, annotations::WARN_DEPRECATED);
            }
        }
        if self.experimental {
            exec_state.warn_experimental(
                &match &fn_name {
                    Some(n) => format!("`{n}`"),
                    None => "This function".to_owned(),
                },
                callsite,
            );
        }

        let args = type_check_params_kw(fn_name.as_deref(), self, args, exec_state)?;
        let face_tag_names = face_tag_names_for_call(self, &args);
        let pending_region_consumption = prepare_region_consumption(
            self.std_props
                .as_ref()
                .map_or(RegionBehavior::WarnOnConsumed, |props| props.region_behavior),
            &args,
            exec_state,
        )?;

        // Warn if experimental or deprecated arguments are used after desugaring.
        for (label, arg) in &args.labeled {
            let Some(param) = self.named_args.get(label.as_str()) else {
                continue;
            };
            if param.experimental {
                exec_state.warn_experimental(
                    &match &fn_name {
                        Some(f) => format!("`{f}({label})`"),
                        None => label.to_owned(),
                    },
                    arg.source_range,
                );
            }
            // `deprecated` deprecates the parameter for all versions, whereas
            // `deprecated_since` only deprecates it at or after a given version.
            let deprecation_suffix = if !warn_on_deprecated_usage {
                None
            } else if param.deprecated {
                Some("is deprecated, see the docs for a recommended replacement".to_owned())
            } else if let Some(since) = &param.deprecated_since
                && annotations::version_ge(exec_state.deprecation_version(), since)
            {
                Some(format!(
                    "is deprecated as of KCL {since}. See the docs for a recommended replacement."
                ))
            } else {
                None
            };
            if let Some(suffix) = deprecation_suffix {
                let qualified = match &fn_name {
                    Some(f) => format!("`{f}({label})`"),
                    None => format!("`{label}`"),
                };
                let mut issue = CompilationIssue::err(arg.source_range, format!("{qualified} {suffix}"));
                issue.tag = crate::errors::Tag::Deprecated;
                exec_state.warn(issue, annotations::WARN_DEPRECATED);
            }
        }

        // Don't early return until the stack frame is popped!
        self.body.prep_mem(exec_state)?;

        // Some function calls might get added to the feature tree.
        // We do this by adding an "operation".

        // Don't add operations if the KCL code being executed is
        // just the KCL stdlib calling other KCL stdlib,
        // because the stdlib internals aren't relevant to users,
        // that would just be pointless noise.
        //
        // Do add operations if the KCL being executed is
        // user-defined, or the calling code is user-defined,
        // because that's relevant to the user.
        let would_trace_stdlib_internals = exec_state.mod_local.inside_stdlib && self.is_std();
        // self.include_in_feature_tree is set by the KCL annotation `@(feature_tree = true)`.
        let should_track_operation = !would_trace_stdlib_internals && self.include_in_feature_tree;
        let op = if should_track_operation {
            let op_labeled_args = args
                .labeled
                .iter()
                .map(|(k, arg)| (k.clone(), OpArg::new(op_from_kcl_value(&arg.value), arg.source_range)))
                .collect();

            // If you're calling a stdlib function, track that call as an operation.
            if self.is_std() {
                Some(Operation::StdLibCall {
                    name: fn_name.clone().unwrap_or_else(|| "unknown function".to_owned()),
                    unlabeled_arg: args
                        .unlabeled_kw_arg_unconverted()
                        .map(|arg| OpArg::new(op_from_kcl_value(&arg.value), arg.source_range)),
                    labeled_args: op_labeled_args,
                    node_path: NodePath::placeholder(),
                    source_range: callsite,
                    stdlib_entry_source_range: exec_state.mod_local.stdlib_entry_source_range,
                    is_error: false,
                })
            } else {
                // Otherwise, you're calling a user-defined function, track that call as an operation.
                exec_state.push_op(Operation::GroupBegin {
                    group: Group::FunctionCall {
                        name: fn_name.clone(),
                        function_source_range: self.ast.as_source_range(),
                        unlabeled_arg: args
                            .unlabeled_kw_arg_unconverted()
                            .map(|arg| OpArg::new(op_from_kcl_value(&arg.value), arg.source_range)),
                        labeled_args: op_labeled_args,
                    },
                    node_path: NodePath::placeholder(),
                    source_range: callsite,
                });

                None
            }
        } else {
            None
        };

        let is_calling_into_stdlib = match &self.body {
            FunctionBody::Rust(_) => true,
            FunctionBody::Kcl(_) => self.is_std(),
        };
        let is_crossing_into_stdlib = is_calling_into_stdlib && !exec_state.mod_local.inside_stdlib;
        let is_crossing_out_of_stdlib = !is_calling_into_stdlib && exec_state.mod_local.inside_stdlib;
        let stdlib_entry_source_range = if is_crossing_into_stdlib {
            // When we're calling into the stdlib, for example calling hole(),
            // track the location so that any further stdlib calls like
            // subtract() can point to the hole() call. The frontend needs this.
            Some(callsite)
        } else if is_crossing_out_of_stdlib {
            // When map() calls a user-defined function, and it calls extrude()
            // for example, we want it to point the the extrude() call, not
            // the map() call.
            None
        } else {
            // When we're not crossing the stdlib boundary, keep the previous
            // value.
            exec_state.mod_local.stdlib_entry_source_range
        };

        let prev_inside_stdlib = std::mem::replace(&mut exec_state.mod_local.inside_stdlib, is_calling_into_stdlib);
        let prev_stdlib_entry_source_range = std::mem::replace(
            &mut exec_state.mod_local.stdlib_entry_source_range,
            stdlib_entry_source_range,
        );

        Ok((
            CallState {
                prev_inside_stdlib,
                prev_stdlib_entry_source_range,
                op,
                should_track_operation,
                is_calling_into_stdlib,
                face_tag_names,
                pending_region_consumption,
            },
            args,
        ))
    }

    /// Compute a KCL function body's result while the callee environment is
    /// still pushed: an `Exit` or `Return` passes through untouched;
    /// otherwise the function's result is the `__return` value recorded in
    /// the callee environment, if any.
    ///
    /// NOTE: under a pre-KCL-3.0 entry point, a `return` statement does NOT
    /// stop the body -- it records `__return` and execution continues to the
    /// following statements (see the machine's return handling). The block's
    /// own trailing value is deliberately ignored here; only `__return` counts.
    /// Under KCL 3.0, `return` stops the body and arrives here as a `Return`
    /// control flow instead; `__return` is never written.
    pub(super) fn kcl_body_result(
        &self,
        block_result: Result<Option<KclValueControlFlow>, KclError>,
        exec_state: &mut ExecState,
    ) -> Result<Option<KclValueControlFlow>, KclError> {
        block_result.map(|cf| {
            if let Some(cf) = cf
                && cf.is_some_return()
            {
                return Some(cf);
            }
            // Ignore the block's value and extract the return value
            // from memory.
            exec_state
                .stack()
                .get(memory::RETURN_NAME, self.ast.as_source_range())
                .ok()
                .map(KclValue::normal)
        })
    }

    /// The failure path when binding a KCL function's arguments fails, before
    /// the body ran: restore `inside_stdlib` and pop the callee environment.
    /// Deliberately asymmetric with [`Self::call_finish`] -- it does not
    /// restore `stdlib_entry_source_range` and does not finalize the
    /// operation, preserving historical behavior.
    pub(super) fn call_abort_on_arg_binding_failure(
        state: CallState,
        e: KclError,
        exec_state: &mut ExecState,
    ) -> KclError {
        exec_state.mod_local.inside_stdlib = state.prev_inside_stdlib;
        match exec_state.mut_stack().pop_env() {
            Ok(_) => e,
            Err(pop_err) => pop_err,
        }
    }

    /// The second half of a function call: restore the ambient stdlib flags,
    /// pop the callee environment, finalize the operation, and then -- for
    /// normal completions only -- apply tag updates and return-type coercion.
    /// `Exit` control flow bypasses tags and coercion (it terminates the whole
    /// evaluation rather than completing this function normally), and errors
    /// skip them too; both still restore ambient state and finalize the
    /// operation. `Return` control flow (a KCL 3.0 early return) is absorbed
    /// here: it completes this function normally, so tags and coercion apply to
    /// it exactly as they do to a `__return` value.
    pub(super) fn call_finish(
        &self,
        state: CallState,
        result: Result<Option<KclValueControlFlow>, KclError>,
        exec_state: &mut ExecState,
    ) -> Result<Option<KclValueControlFlow>, KclError> {
        let CallState {
            prev_inside_stdlib,
            prev_stdlib_entry_source_range,
            op,
            should_track_operation,
            is_calling_into_stdlib,
            face_tag_names,
            pending_region_consumption,
        } = state;
        exec_state.mod_local.inside_stdlib = prev_inside_stdlib;
        exec_state.mod_local.stdlib_entry_source_range = prev_stdlib_entry_source_range;
        exec_state.mut_stack().pop_env()?;

        if result.is_ok()
            && let Some(pending_region_consumption) = pending_region_consumption
        {
            record_consumed_regions(exec_state, pending_region_consumption);
        }

        if should_track_operation {
            if let Some(mut op) = op {
                op.set_std_lib_call_is_error(result.is_err());
                // Track call operation.  We do this after the call
                // since things like patternTransform may call user code
                // before running, and we will likely want to use the
                // return value. The call takes ownership of the args,
                // so we need to build the op before the call.
                exec_state.push_op(op);
            } else if !is_calling_into_stdlib {
                exec_state.push_op(Operation::GroupEnd);
            }
        }

        let mut result = match result {
            Ok(Some(value)) => {
                if value.is_exit() {
                    // `Exit` terminates the whole evaluation rather than completing this
                    // function normally, so it bypasses return-type validation, including
                    // the `never` contract.
                    return Ok(Some(value));
                } else {
                    // `Normal` and `Return` both complete this function
                    // normally.
                    Ok(Some(value.into_value()))
                }
            }
            Ok(None) => Ok(None),
            Err(e) => Err(e),
        };

        if self.is_std()
            && let Ok(Some(result)) = &mut result
        {
            update_memory_for_tags_of_geometry(result, exec_state)?;
            if !face_tag_names.is_empty() {
                attach_face_tags_to_geometry(result, exec_state, &face_tag_names);
            }
        }

        coerce_result_type(result, self, exec_state).map(|r| r.map(KclValue::normal))
    }
}

/// State captured by [`FunctionSource::call_setup`] that
/// [`FunctionSource::call_finish`] needs to complete the call: the ambient
/// flags to restore, the deferred operation, and details of what was called.
#[derive(Debug)]
pub(super) struct CallState {
    prev_inside_stdlib: bool,
    prev_stdlib_entry_source_range: Option<SourceRange>,
    /// Deferred stdlib-call operation, pushed by call_finish.
    op: Option<Operation>,
    should_track_operation: bool,
    is_calling_into_stdlib: bool,
    face_tag_names: Vec<String>,
    pending_region_consumption: Option<PendingRegionConsumption>,
}

impl FunctionBody {
    fn prep_mem(&self, exec_state: &mut ExecState) -> Result<(), KclError> {
        match self {
            FunctionBody::Rust(_) => exec_state.mut_stack().push_new_root_env(true),
            FunctionBody::Kcl(memory) => exec_state.mut_stack().push_new_env_for_call(*memory),
        }
    }
}

/// Whether `value` may have come from a legacy (v1) sketch rather than a
/// sketch block, which is what gates the legacy tag-memory updates in
/// `update_memory_for_tags_of_geometry`.
///
/// Anything that is not a sketch or a solid answers `false`: a number or an
/// enum variant is not a sketch of either generation, so it must not pull in
/// legacy behavior. The match stays exhaustive so that adding a `KclValue`
/// variant forces an explicit answer here instead of inheriting one.
fn might_be_legacy_sketch(value: &KclValue) -> bool {
    match value {
        KclValue::Uuid { .. } => false,
        KclValue::Bool { .. } => false,
        KclValue::Number { .. } => false,
        KclValue::String { .. } => false,
        KclValue::Enum { .. } => false,
        KclValue::SketchVar { .. } => false,
        KclValue::SketchConstraint { .. } => false,
        KclValue::Tuple { value, .. } => value.iter().any(might_be_legacy_sketch),
        KclValue::HomArray { value, .. } => value.iter().any(might_be_legacy_sketch),
        // TODO: sketch block result should return false.
        KclValue::Object { value, .. } => value.values().any(might_be_legacy_sketch),
        KclValue::TagIdentifier(_) => false,
        KclValue::TagDeclarator(_) => false,
        KclValue::GdtAnnotation { .. } => false,
        KclValue::CameraView { .. } => false,
        KclValue::NamedView { .. } => false,
        KclValue::Plane { .. } => false,
        KclValue::Face { .. } => false,
        KclValue::BoundedEdge { .. } => false,
        KclValue::Segment { .. } => false,
        KclValue::Sketch { value: sketch } => sketch.origin_sketch_id.is_none(),
        // A solid with no sketch has no tag container, so the caller returns
        // early without consulting this answer; `true` keeps it the exact
        // negation of the previous `originates_from_sketch_block`.
        KclValue::Solid { value: solid } => solid
            .sketch()
            .map(|sketch| sketch.origin_sketch_id.is_none())
            .unwrap_or(true),
        KclValue::Helix { .. } => false,
        KclValue::ImportedGeometry(_) => false,
        KclValue::Function { .. } => false,
        KclValue::Module { .. } => false,
        KclValue::Type { .. } => false,
        KclValue::KclNone { .. } => false,
    }
}

fn face_tag_names_for_call(fn_def: &FunctionSource, args: &Args<Desugared>) -> Vec<String> {
    let Some(std_props) = &fn_def.std_props else {
        return Vec::new();
    };

    if !std_function_allows_face_tags(&std_props.name) {
        return Vec::new();
    }

    args.labeled
        .iter()
        .filter(|(label, _)| matches!(label.as_str(), "tag" | "tagStart" | "tagEnd"))
        .filter_map(|(_, arg)| match &arg.value {
            KclValue::TagDeclarator(tag) => Some(tag.name.clone()),
            _ => None,
        })
        .collect()
}

fn std_function_allows_face_tags(std_fn_name: &str) -> bool {
    matches!(
        std_fn_name,
        "std::sketch::extrude"
            | "std::solid::chamfer"
            | "std::solid::fillet"
            | "std::sketch::sweep"
            | "std::sketch::loft"
            | "std::sketch::revolve"
    )
}

fn attach_face_tags_to_geometry(result: &mut KclValue, exec_state: &ExecState, tag_names: &[String]) {
    match result {
        KclValue::Solid { value } => attach_face_tags_to_solid(value, exec_state, tag_names),
        KclValue::Tuple { value, .. } | KclValue::HomArray { value, .. } => {
            for v in value {
                attach_face_tags_to_geometry(v, exec_state, tag_names);
            }
        }
        _ => {}
    }
}

fn attach_face_tags_to_solid(solid: &mut Solid, exec_state: &ExecState, tag_names: &[String]) {
    let surfaces = solid.value.clone();
    for surface in surfaces {
        let Some(tag) = surface.get_tag() else {
            continue;
        };
        if !tag_names.iter().any(|tag_name| tag_name == &tag.name) {
            continue;
        }

        let tag_id = solid
            .sketch()
            .and_then(|sketch| sketch.tags.get(&tag.name))
            .cloned()
            .unwrap_or_else(|| {
                let mut solid_copy = solid.clone();
                clear_tags_from_solid_copy(&mut solid_copy);
                TagIdentifier {
                    value: tag.name.clone(),
                    info: vec![(
                        exec_state.stack().current_epoch(),
                        TagEngineInfo {
                            id: surface.get_id(),
                            surface: Some(surface.clone()),
                            path: None,
                            geometry: Geometry::Solid(solid_copy),
                        },
                    )],
                    meta: vec![Metadata {
                        source_range: tag.clone().into(),
                    }],
                }
            });

        match solid.faces.get_mut(&tag.name) {
            Some(existing_tag) => existing_tag.merge_info(&tag_id),
            None => {
                solid.faces.insert(tag.name.clone(), tag_id);
            }
        }
    }
}

fn clear_tags_from_solid_copy(solid: &mut Solid) {
    if let Some(sketch) = solid.sketch_mut() {
        sketch.tags.clear(); // Avoid recursive tags.
    }
    solid.faces.clear();
}

fn update_memory_for_tags_of_geometry(result: &mut KclValue, exec_state: &mut ExecState) -> Result<(), KclError> {
    let might_be_legacy = might_be_legacy_sketch(&*result);
    // If the return result is a sketch or solid, we want to update the
    // memory for the tags of the group.
    // TODO: This could probably be done in a better way, but as of now this was my only idea
    // and it works.
    match result {
        KclValue::Sketch { value } if might_be_legacy => {
            for (name, tag) in value.tags.iter() {
                if exec_state.stack().cur_frame_contains(name)? {
                    exec_state.mut_stack().update(name, |v, _| {
                        if let Some(existing_tag) = v.as_mut_tag() {
                            existing_tag.merge_info(tag);
                        }
                    })?;
                } else {
                    exec_state.mut_stack().add(
                        name.to_owned(),
                        KclValue::TagIdentifier(Box::new(tag.clone())),
                        SourceRange::default(),
                    )?;
                }
            }
        }
        KclValue::Solid { value } => {
            if value.sketch().is_none() {
                // If the solid isn't based on a sketch, then it doesn't have a tag container,
                // so there's nothing to do here.
                return Ok(());
            };
            // Only tagged surfaces need solid snapshots. Copying the entire solid for every
            // untagged surface would take quadratic time and memory in the number of surfaces.
            let surfaces: Vec<_> = value
                .value
                .iter()
                .filter(|surface| surface.get_tag().is_some())
                .cloned()
                .collect();
            // Capture all snapshots before updating tags so they refer to the same original solid.
            let solid_copies: Vec<Box<Solid>> = surfaces.iter().map(|_| value.clone()).collect();
            // Get the tag container. We expect it to always succeed because we already checked
            // for a tag container above.
            let Some(sketch) = value.sketch_mut() else {
                return Ok(());
            };
            for (v, mut solid_copy) in surfaces.iter().zip(solid_copies) {
                clear_tags_from_solid_copy(&mut solid_copy);
                if let Some(tag) = v.get_tag() {
                    // Get the past tag and update it.
                    let mut is_part_of_sketch = false;
                    let tag_id = if let Some(t) = sketch.tags.get(&tag.name) {
                        is_part_of_sketch = true;
                        let mut t = t.clone();
                        let Some(info) = t.get_cur_info() else {
                            return Err(KclError::new_internal(KclErrorDetails::new(
                                format!("Tag {} does not have path info", tag.name),
                                vec![tag.into()],
                            )));
                        };

                        let mut info = info.clone();
                        info.id = v.get_id();
                        info.surface = Some(v.clone());
                        info.geometry = Geometry::Solid(*solid_copy);
                        t.info.push((exec_state.stack().current_epoch(), info));
                        t
                    } else {
                        // It's probably a fillet or a chamfer.
                        // Initialize it.
                        TagIdentifier {
                            value: tag.name.clone(),
                            info: vec![(
                                exec_state.stack().current_epoch(),
                                TagEngineInfo {
                                    id: v.get_id(),
                                    surface: Some(v.clone()),
                                    path: None,
                                    geometry: Geometry::Solid(*solid_copy),
                                },
                            )],
                            meta: vec![Metadata {
                                source_range: tag.clone().into(),
                            }],
                        }
                    };

                    // update the sketch tags.
                    sketch.merge_tags(Some(&tag_id).into_iter());

                    if exec_state.stack().cur_frame_contains(&tag.name)? {
                        exec_state.mut_stack().update(&tag.name, |v, _| {
                            if let Some(existing_tag) = v.as_mut_tag() {
                                existing_tag.merge_info(&tag_id);
                            }
                        })?;
                    } else if might_be_legacy || !is_part_of_sketch {
                        // The above condition is saying that we add a tag to
                        // the stack in either of these cases:
                        //
                        // 1. It originates from a legacy sketch v1.
                        //
                        // 2. It originates from a sketch block and it's not
                        // part of the sketch. Instead, it's part of the solid,
                        // as in tagging a cap face `extrude(tagEnd, tagStart)`
                        // or chamfer face `chamfer(tag)`.
                        exec_state.mut_stack().add(
                            tag.name.clone(),
                            KclValue::TagIdentifier(Box::new(tag_id)),
                            SourceRange::default(),
                        )?;
                    }
                }
            }

            // Find the stale sketch in memory and update it.
            if let Some(sketch) = value.sketch() {
                if sketch.tags.is_empty() {
                    return Ok(());
                }
                let sketch_tags: Vec<_> = sketch.tags.values().cloned().collect();
                let sketches_to_update: Vec<_> = exec_state.stack().find_keys_in_current_env(|v| match v {
                    KclValue::Sketch { value: sk } => match value.tag_update_source_artifact_id {
                        Some(source) => sk.artifact_id == source,
                        None => sk.original_id == sketch.original_id,
                    },
                    _ => false,
                })?;

                for k in sketches_to_update {
                    exec_state.mut_stack().update(&k, |v, _| {
                        if let Some(sketch) = v.as_mut_sketch() {
                            sketch.merge_tags(sketch_tags.iter());
                        }
                    })?;
                }
            }
        }
        KclValue::Tuple { value, .. } | KclValue::HomArray { value, .. } => {
            for v in value {
                update_memory_for_tags_of_geometry(v, exec_state)?;
            }
        }
        _ => {}
    }
    Ok(())
}

fn type_err_str(expected: &Type, found: &KclValue, source_range: &SourceRange, exec_state: &mut ExecState) -> String {
    fn strip_backticks(s: &str) -> &str {
        let mut result = s;
        if s.starts_with('`') {
            result = &result[1..]
        }
        if s.ends_with('`') {
            result = &result[..result.len() - 1]
        }
        result
    }

    let expected_human = expected.human_friendly_type();
    let expected_ty = expected.to_string();
    let expected_str =
        if expected_human == expected_ty || expected_human == format!("a value with type `{expected_ty}`") {
            format!("a value with type `{expected_ty}`")
        } else {
            format!("{expected_human} (`{expected_ty}`)")
        };
    let found_human = found.human_friendly_type();
    let found_ty = found.principal_type_string();
    let found_str = if found_human == found_ty || found_human == format!("a {}", strip_backticks(&found_ty)) {
        format!("a value with type {found_ty}")
    } else {
        format!("{found_human} (with type {found_ty})")
    };

    let mut result = format!("{expected_str}, but found {found_str}.");

    if found.is_unknown_number() {
        exec_state.clear_units_warnings(source_range);
        result.push_str("\nThe found value is a number but has incomplete units information. You can probably fix this error by specifying the units using type ascription, e.g., `len: mm` or `(a * b): deg`.");
    }

    result
}

/// Build the error message for a labeled argument whose label doesn't match any
/// parameter of the callee. Shared between keyword function calls and sketch
/// blocks so the wording stays consistent.
pub(crate) fn unexpected_kw_arg_message(label: &str, callee_name: Option<&str>) -> String {
    format!(
        "`{label}` is not an argument of {}",
        callee_name
            .map(|n| format!("`{n}`"))
            .unwrap_or_else(|| "this function".to_owned()),
    )
}

/// Build the error message for a labeled argument whose parameter the callee
/// declares, but not on the KCL version governing this execution. Extends
/// [`unexpected_kw_arg_message`] with the version that made the parameter
/// unavailable and the version this program uses, so the user can tell a
/// version mismatch apart from a typo.
fn unavailable_kw_arg_message(
    label: &str,
    callee_name: Option<&str>,
    reason: ParamUnavailable<'_>,
    program_version: &str,
) -> String {
    let base = unexpected_kw_arg_message(label, callee_name);
    match reason {
        ParamUnavailable::NotYetAdded(added) => {
            format!("{base}; it was added in KCL {added}, but this program uses KCL {program_version}")
        }
        ParamUnavailable::Removed(removed) => {
            format!("{base}; it was removed in KCL {removed}, but this program uses KCL {program_version}")
        }
    }
}

/// Fetch the definition-time resolution of a type written in a function
/// signature.
///
/// [`FunctionSource::resolve_signature_types`] runs whenever a function
/// declaration executes, so a written type without a stored resolution is a
/// bug in KCL, not in the user's program.
fn resolved_signature_type<'a>(
    resolved: Option<&'a RuntimeType>,
    written: &Type,
    source_range: SourceRange,
) -> Result<&'a RuntimeType, KclError> {
    resolved.ok_or_else(|| {
        KclError::new_internal(KclErrorDetails::new(
            format!(
                "The type `{written}` in this function's signature was not resolved when the function was declared. This is a bug in KCL and not in your code, please report this to Zoo."
            ),
            vec![source_range],
        ))
    })
}

fn type_check_params_kw(
    fn_name: Option<&str>,
    fn_def: &FunctionSource,
    mut args: Args<Sugary>,
    exec_state: &mut ExecState,
) -> Result<Args<Desugared>, KclError> {
    let fn_name = fn_name.or(args.fn_name.as_deref());
    let mut result = Args::new_no_args(
        args.source_range,
        args.node_path.clone(),
        args.ctx,
        fn_name.map(|f| f.to_string()).or_else(|| args.fn_name.clone()),
    );

    // If it's possible the input arg was meant to be labelled and we probably don't want to use
    // it as the input arg, then treat it as labelled.
    if let Some((Some(label), _)) = args.unlabeled.first()
        && args.unlabeled.len() == 1
        && (fn_def.input_arg.is_none() || args.pipe_value.is_some())
        && fn_def.active_named_arg(label, exec_state).is_some()
        && !args.labeled.contains_key(label)
    {
        let Some((label, arg)) = args.unlabeled.pop() else {
            let message = "Expected unlabeled arg to be present".to_owned();
            debug_assert!(false, "{}", &message);
            return Err(KclError::new_internal(KclErrorDetails::new(
                message,
                vec![args.source_range],
            )));
        };
        args.labeled.insert(label.unwrap(), arg);
    }

    // Apply the `a == a: a` shorthand by desugaring unlabeled args into labeled ones.
    let (labeled_unlabeled, unlabeled_unlabeled) = args.unlabeled.into_iter().partition(|(l, _)| {
        if let Some(l) = l
            && fn_def.active_named_arg(l, exec_state).is_some()
            && !args.labeled.contains_key(l)
        {
            true
        } else {
            false
        }
    });
    args.unlabeled = unlabeled_unlabeled;
    for (l, arg) in labeled_unlabeled {
        let previous = args.labeled.insert(l.unwrap(), arg);
        debug_assert!(previous.is_none());
    }

    if let Some((name, ty)) = &fn_def.input_arg {
        // Expecting an input arg

        if args.unlabeled.is_empty() {
            // No args provided

            if let Some(pipe) = args.pipe_value {
                // But there is a pipeline
                result.unlabeled = vec![(None, pipe)];
            } else if let Some(arg) = args.labeled.swap_remove(name) {
                // Mistakenly labelled
                exec_state.err(CompilationIssue::err(
                    arg.source_range,
                    format!(
                        "{} expects an unlabeled first argument (`@{name}`), but it is labelled in the call. You might try removing the `{name} = `",
                        fn_name
                            .map(|n| format!("The function `{n}`"))
                            .unwrap_or_else(|| "This function".to_owned()),
                    ),
                ));
                result.unlabeled = vec![(Some(name.clone()), arg)];
            } else {
                // Just missing
                return Err(KclError::new_argument(KclErrorDetails::new(
                    "This function expects an unlabeled first parameter, but you haven't passed it one.".to_owned(),
                    fn_def.ast.as_source_ranges(),
                )));
            }
        } else if args.unlabeled.len() == 1
            && let Some(unlabeled_arg) = args.unlabeled.pop()
        {
            let mut arg = unlabeled_arg.1;
            if let Some(ty) = ty {
                let rty = resolved_signature_type(fn_def.resolved_input_ty.as_ref(), ty, arg.source_range)?;
                arg.value = arg
                    .value
                    .coerce(rty, CoercionMode::implicit(), exec_state)
                    .map_err(|_| {
                        KclError::new_argument(KclErrorDetails::new(
                            format!(
                                "The input argument of {} requires {}",
                                fn_name
                                    .map(|n| format!("`{n}`"))
                                    .unwrap_or_else(|| "this function".to_owned()),
                                type_err_str(ty, &arg.value, &arg.source_range, exec_state),
                            ),
                            vec![arg.source_range],
                        ))
                    })?;
            }
            result.unlabeled = vec![(None, arg)]
        } else {
            // Multiple unlabelled args

            // Try to un-spread args into an array
            if let Some(Type::Array { len, .. }) = ty {
                if len.satisfied(args.unlabeled.len(), false).is_none() {
                    exec_state.err(CompilationIssue::err(
                        args.source_range,
                        format!(
                            "{} expects an array input argument with {} elements",
                            fn_name
                                .map(|n| format!("The function `{n}`"))
                                .unwrap_or_else(|| "This function".to_owned()),
                            len.human_friendly_type(),
                        ),
                    ));
                }

                let source_range = SourceRange::merge(args.unlabeled.iter().map(|(_, a)| a.source_range));
                exec_state.warn_experimental("array input arguments", source_range);
                result.unlabeled = vec![(
                    None,
                    Arg {
                        source_range,
                        value: KclValue::HomArray {
                            value: args.unlabeled.drain(..).map(|(_, a)| a.value).collect(),
                            ty: RuntimeType::any(),
                        },
                    },
                )]
            }
        }
    }

    // Either we didn't move the arg above, or we're not expecting one.
    if !args.unlabeled.is_empty() {
        // Not expecting an input arg, but found one or more
        let actuals = args.labeled.keys();
        let formals: Vec<_> = fn_def
            .active_named_args(exec_state)
            .filter_map(|(name, _)| {
                if actuals.clone().any(|a| a == name) {
                    return None;
                }

                Some(format!("`{name}`"))
            })
            .collect();

        let suggestion = if formals.is_empty() {
            String::new()
        } else {
            format!("; suggested labels: {}", formals.join(", "))
        };

        let mut errors = args.unlabeled.iter().map(|(_, arg)| {
            CompilationIssue::err(
                arg.source_range,
                format!("This argument needs a label, but it doesn't have one{suggestion}"),
            )
        });

        let first = errors.next().unwrap();
        errors.for_each(|e| exec_state.err(e));

        return Err(KclError::new_argument(first.into()));
    }

    for (label, mut arg) in args.labeled {
        let param = fn_def.named_args.get(&label);
        match param.map(|param| (param, param.unavailable_reason(exec_state))) {
            Some((
                NamedParam {
                    experimental: _,
                    added_in: _,
                    deprecated: _,
                    deprecated_since: _,
                    removed_in: _,
                    default_value: def,
                    ty,
                    resolved_ty,
                },
                None,
            )) => {
                // For optional args, passing None should be the same as not passing an arg.
                if !(def.is_some() && matches!(arg.value, KclValue::KclNone { .. })) {
                    if let Some(ty) = ty {
                        let rty = resolved_signature_type(resolved_ty.as_ref(), ty, arg.source_range)?;
                        arg.value = arg
                                .value
                                .coerce(
                                    rty,
                                    CoercionMode::implicit(),
                                    exec_state,
                                )
                                .map_err(|e| {
                                    let mut message = format!(
                                        "{label} requires {}",
                                        type_err_str(ty, &arg.value, &arg.source_range, exec_state),
                                    );
                                    if let Some(ty) = e.explicit_coercion {
                                        // TODO if we have access to the AST for the argument we could choose which example to suggest.
                                        message = format!("{message}\n\nYou may need to add information about the type of the argument, for example:\n  using a numeric suffix: `42{ty}`\n  or using type ascription: `foo(): {ty}`");
                                    }
                                    KclError::new_argument(KclErrorDetails::new(
                                        message,
                                        vec![arg.source_range],
                                    ))
                                })?;
                    }
                    result.labeled.insert(label, arg);
                }
            }
            Some((_, Some(reason))) => {
                let message = unavailable_kw_arg_message(&label, fn_name, reason, exec_state.kcl_version().as_str());
                exec_state.err(CompilationIssue::err(arg.source_range, message));
            }
            None => {
                exec_state.err(CompilationIssue::err(
                    arg.source_range,
                    unexpected_kw_arg_message(&label, fn_name),
                ));
            }
        }
    }

    let consumed_solid_arg_check = fn_def
        .std_props
        .as_ref()
        .map_or(ConsumedSolidArgCheck::Error, |props| props.consumed_solid_arg_check);
    if matches!(fn_def.body, FunctionBody::Rust(_))
        && let Some(props) = fn_def.std_props.as_ref()
    {
        match props.region_behavior.stale_region_policy() {
            Some(StaleRegionPolicy::Error) => validate_region_args_not_consumed(&result, exec_state)?,
            Some(StaleRegionPolicy::Warning) => {
                warn_if_region_args_consumed(&result, exec_state, &props.name)?;
            }
            None => {}
        }
    }
    match consumed_solid_arg_check {
        ConsumedSolidArgCheck::Error => {
            result
                .unlabeled
                .iter()
                .map(|(_, arg)| arg)
                .chain(result.labeled.values())
                .try_for_each(|arg| validate_value_not_consumed(&arg.value, exec_state, arg.source_range))?;
        }
        ConsumedSolidArgCheck::WarnDeprecated => {
            let std_fn_name = fn_def
                .std_props
                .as_ref()
                .map(|props| props.name.as_str())
                .unwrap_or("function");
            for arg in result
                .unlabeled
                .iter()
                .map(|(_, arg)| arg)
                .chain(result.labeled.values())
            {
                warn_if_value_consumed_for_deprecated_call(&arg.value, exec_state, arg.source_range, std_fn_name)?;
            }
        }
    }

    Ok(result)
}

pub(super) fn assign_args_to_params_kw(
    fn_def: &FunctionSource,
    args: Args<Desugared>,
    exec_state: &mut ExecState,
) -> Result<(), KclError> {
    // Add the arguments to the memory.  A new call frame should have already
    // been created.
    let source_ranges = fn_def.ast.as_source_ranges();

    for (name, param) in fn_def.named_args.iter() {
        let arg = args.labeled.get(name);
        match arg {
            Some(arg) => {
                exec_state.mut_stack().add(
                    name.clone(),
                    arg.value.clone(),
                    arg.source_ranges().pop().unwrap_or(SourceRange::synthetic()),
                )?;
            }
            None => match &param.default_value {
                Some(default_val) => {
                    let value = KclValue::from_default_param(default_val.clone(), exec_state);
                    exec_state
                        .mut_stack()
                        .add(name.clone(), value, default_val.source_range())?;
                }
                None => {
                    return Err(KclError::new_argument(KclErrorDetails::new(
                        format!("This function requires a parameter {name}, but you haven't passed it one."),
                        source_ranges,
                    )));
                }
            },
        }
    }

    if let Some((param_name, _)) = &fn_def.input_arg {
        let Some(unlabeled) = args.unlabeled_kw_arg_unconverted() else {
            debug_assert!(false, "Bad args");
            return Err(KclError::new_internal(KclErrorDetails::new(
                "Desugared arguments are inconsistent".to_owned(),
                source_ranges,
            )));
        };
        exec_state.mut_stack().add(
            param_name.clone(),
            unlabeled.value.clone(),
            unlabeled.source_ranges().pop().unwrap_or(SourceRange::synthetic()),
        )?;
    }

    Ok(())
}

fn coerce_result_type(
    result: Result<Option<KclValue>, KclError>,
    fn_def: &FunctionSource,
    exec_state: &mut ExecState,
) -> Result<Option<KclValue>, KclError> {
    let result = result?;

    let Some(ret_ty) = &fn_def.return_type else {
        return Ok(result);
    };

    let ty = resolved_signature_type(
        fn_def.resolved_return_ty.as_ref(),
        &ret_ty.inner,
        ret_ty.as_source_range(),
    )?;

    // `never` describes the absence of normal completion, so either successful
    // result shape violates the function's declared contract.
    if ty.subtype(&RuntimeType::never()) {
        let message = if result.is_some() {
            "This function returned a value, but its return type is `never`. A function with return type `never` must stop evaluation abnormally. You may want to use `fail(...)` to stop evaluation and provide a message."
        } else {
            "This function completed without returning a value, but its return type is `never`. A function with return type `never` must stop evaluation abnormally. You may want to use `fail(...)` to stop evaluation and provide a message."
        };
        return Err(KclError::new_type(KclErrorDetails::new(
            message.to_owned(),
            ret_ty.as_source_ranges(),
        )));
    }

    let Some(val) = result else {
        return Ok(None);
    };

    let val = val.coerce(ty, CoercionMode::implicit(), exec_state).map_err(|_| {
        KclError::new_type(KclErrorDetails::new(
            format!(
                "This function requires its result to be {}",
                type_err_str(ret_ty, &val, &(&val).into(), exec_state)
            ),
            ret_ty.as_source_ranges(),
        ))
    })?;
    Ok(Some(val))
}

#[cfg(test)]
mod test {
    use std::sync::Arc;

    use super::*;
    use crate::engine::engine_manager::EngineManager;
    use crate::errors::Severity;
    use crate::execution::ContextType;
    use crate::execution::EnvironmentRef;
    use crate::execution::ExecTestResults;
    use crate::execution::memory::Stack;
    use crate::execution::parse_execute;
    use crate::execution::types::NumericType;
    use crate::execution::types::NumericTypeExt;
    use crate::parsing::ast::types::DefaultParamVal;
    use crate::parsing::ast::types::FunctionExpression;
    use crate::parsing::ast::types::Identifier;
    use crate::parsing::ast::types::Node;
    use crate::parsing::ast::types::Parameter;
    use crate::parsing::ast::types::Program;

    fn source_texts<'a>(program: &'a str, error: &KclError) -> Vec<&'a str> {
        error
            .source_ranges()
            .into_iter()
            .map(|range| &program[range.start()..range.end()])
            .collect()
    }

    fn get_var(result: &ExecTestResults, name: &str) -> KclValue {
        result
            .exec_state
            .stack()
            .memory
            .get_from_owned(name, result.mem_env, SourceRange::default(), 0)
            .unwrap_or_else(|err| panic!("expected variable `{name}` to exist: {err:?}"))
    }

    fn var_exists(result: &ExecTestResults, name: &str) -> bool {
        result
            .exec_state
            .stack()
            .memory
            .get_from_owned(name, result.mem_env, SourceRange::default(), 0)
            .is_ok()
    }

    fn assert_vars_are_tags(result: &ExecTestResults, names: &[&str]) {
        for name in names {
            assert!(
                matches!(get_var(result, name), KclValue::TagIdentifier(_)),
                "expected variable `{name}` to be a tag identifier"
            );
        }
    }

    fn assert_vars_are_missing(result: &ExecTestResults, names: &[&str]) {
        for name in names {
            assert!(!var_exists(result, name), "expected variable `{name}` to be absent");
        }
    }

    fn assert_body_face_tags(result: &ExecTestResults, expected: &[&str], unexpected: &[&str]) {
        let body = get_var(result, "body");
        let KclValue::Solid { value: body } = body else {
            panic!("expected `body` to be a solid");
        };

        for tag in expected {
            assert!(body.faces.contains_key(*tag), "expected body.faces to contain `{tag}`");
        }

        for tag in unexpected {
            assert!(
                !body.faces.contains_key(*tag),
                "expected body.faces not to contain sketch tag `{tag}`"
            );
        }
    }

    fn deprecated_solid_tag_access_warnings(result: &ExecTestResults) -> Vec<&CompilationIssue> {
        result
            .exec_state
            .issues()
            .iter()
            .filter(|issue| issue.message.contains("Accessing solid-created face"))
            .collect()
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_assign_args_to_params() {
        // Set up a little framework for this test.
        fn mem(number: usize) -> KclValue {
            KclValue::Number {
                value: number as f64,
                ty: NumericType::count(),
                meta: Default::default(),
            }
        }
        fn ident(s: &'static str) -> Node<Identifier> {
            Node::no_src(Identifier {
                name: s.to_owned(),
                digest: None,
            })
        }
        fn opt_param(s: &'static str) -> Parameter {
            Parameter {
                experimental: false,
                added_in: None,
                deprecated: false,
                deprecated_since: None,
                removed_in: None,
                identifier: ident(s),
                param_type: None,
                default_value: Some(DefaultParamVal::none()),
                labeled: true,
                digest: None,
            }
        }
        fn req_param(s: &'static str) -> Parameter {
            Parameter {
                experimental: false,
                added_in: None,
                deprecated: false,
                deprecated_since: None,
                removed_in: None,
                identifier: ident(s),
                param_type: None,
                default_value: None,
                labeled: true,
                digest: None,
            }
        }
        fn additional_program_memory(items: &[(String, KclValue)]) -> Stack {
            let mut program_memory = Stack::new_for_tests();
            for (name, item) in items {
                program_memory
                    .add(name.clone(), item.clone(), SourceRange::default())
                    .unwrap();
            }
            program_memory
        }
        // Declare the test cases.
        for (test_name, params, args, expected) in [
            ("empty", Vec::new(), Vec::new(), Ok(additional_program_memory(&[]))),
            (
                "all params required, and all given, should be OK",
                vec![req_param("x")],
                vec![("x", mem(1))],
                Ok(additional_program_memory(&[("x".to_owned(), mem(1))])),
            ),
            (
                "all params required, none given, should error",
                vec![req_param("x")],
                vec![],
                Err(KclError::new_argument(KclErrorDetails::new(
                    "This function requires a parameter x, but you haven't passed it one.".to_owned(),
                    vec![SourceRange::default()],
                ))),
            ),
            (
                "all params optional, none given, should be OK",
                vec![opt_param("x")],
                vec![],
                Ok(additional_program_memory(&[("x".to_owned(), KclValue::none())])),
            ),
            (
                "mixed params, too few given",
                vec![req_param("x"), opt_param("y")],
                vec![],
                Err(KclError::new_argument(KclErrorDetails::new(
                    "This function requires a parameter x, but you haven't passed it one.".to_owned(),
                    vec![SourceRange::default()],
                ))),
            ),
            (
                "mixed params, minimum given, should be OK",
                vec![req_param("x"), opt_param("y")],
                vec![("x", mem(1))],
                Ok(additional_program_memory(&[
                    ("x".to_owned(), mem(1)),
                    ("y".to_owned(), KclValue::none()),
                ])),
            ),
            (
                "mixed params, maximum given, should be OK",
                vec![req_param("x"), opt_param("y")],
                vec![("x", mem(1)), ("y", mem(2))],
                Ok(additional_program_memory(&[
                    ("x".to_owned(), mem(1)),
                    ("y".to_owned(), mem(2)),
                ])),
            ),
        ] {
            // Run each test.
            let func_expr = Node::no_src(FunctionExpression {
                name: None,
                params,
                body: Program::empty(),
                return_type: None,
                digest: None,
            });
            let func_src = FunctionSource::kcl(
                crate::parsing::ast::types::BoxNode::new(func_expr),
                EnvironmentRef::dummy(),
                crate::execution::kcl_value::KclFunctionSourceParams {
                    std_props: None,
                    experimental: false,
                    include_in_feature_tree: false,
                },
            );
            let labeled = args
                .iter()
                .map(|(name, value)| {
                    let arg = Arg::new(value.clone(), SourceRange::default());
                    ((*name).to_owned(), arg)
                })
                .collect::<IndexMap<_, _>>();
            let exec_ctxt = ExecutorContext {
                engine: Arc::new(EngineManager::new_mock()),
                cache: crate::Cache::default(),
                engine_batch: crate::engine::EngineBatchContext::default(),
                fs: crate::fs::new_file_system_handle(crate::fs::FileManager::new()),
                settings: Default::default(),
                context_type: ContextType::Mock,
                execution_callbacks: Default::default(),
                machine_call_depth_limit: crate::execution::machine::DEFAULT_MACHINE_CALL_DEPTH_LIMIT,
                configure_engine_render: true,
                needs_oit: Default::default(),
            };
            let mut exec_state = ExecState::new(&exec_ctxt);
            exec_state.mod_local.stack = Stack::new_for_tests();

            let args = Args {
                fn_name: Some("test".to_owned()),
                labeled,
                unlabeled: Vec::new(),
                source_range: SourceRange::default(),
                node_path: None,
                ctx: exec_ctxt,
                pipe_value: None,
                _status: std::marker::PhantomData,
            };

            let actual = assign_args_to_params_kw(&func_src, args, &mut exec_state).map(|_| exec_state.mod_local.stack);
            assert_eq!(
                actual, expected,
                "failed test '{test_name}':\ngot {actual:?}\nbut expected\n{expected:?}"
            );
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn type_check_user_args() {
        let program = r#"fn makeMessage(prefix: string, suffix: string) {
  return prefix + suffix
}

msg1 = makeMessage(prefix = "world", suffix = " hello")
msg2 = makeMessage(prefix = 1, suffix = 3)"#;
        let err = parse_execute(program).await.unwrap_err();
        assert_eq!(
            err.message(),
            "prefix requires a value with type `string`, but found a value with type `number`.\nThe found value is a number but has incomplete units information. You can probably fix this error by specifying the units using type ascription, e.g., `len: mm` or `(a * b): deg`."
        )
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn never_function_cannot_return_a_value() {
        let program = r#"@settings(kclVersion = "3.0-preview")
fn bad(): never {
  return 42
}

bad()
"#;
        let err = parse_execute(program).await.unwrap_err();

        assert!(matches!(&err, KclError::Type { .. }));
        assert_eq!(
            err.message(),
            "This function returned a value, but its return type is `never`. A function with return type `never` must stop evaluation abnormally. You may want to use `fail(...)` to stop evaluation and provide a message."
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn never_function_cannot_fall_through() {
        let program = r#"@settings(kclVersion = "3.0-preview")
fn alsoBad(): never {
  x = 42
}

alsoBad()
"#;
        let err = parse_execute(program).await.unwrap_err();

        assert!(matches!(&err, KclError::Type { .. }));
        assert_eq!(
            err.message(),
            "This function completed without returning a value, but its return type is `never`. A function with return type `never` must stop evaluation abnormally. You may want to use `fail(...)` to stop evaluation and provide a message."
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn never_union_function_cannot_return_a_value() {
        let program = r#"@settings(kclVersion = "3.0-preview")
fn bad(): never | never {
  return 42
}

bad()
"#;
        let err = parse_execute(program).await.unwrap_err();

        assert!(matches!(&err, KclError::Type { .. }));
        assert_eq!(
            err.message(),
            "This function returned a value, but its return type is `never`. A function with return type `never` must stop evaluation abnormally. You may want to use `fail(...)` to stop evaluation and provide a message."
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn never_union_function_cannot_fall_through() {
        let program = r#"@settings(kclVersion = "3.0-preview")
fn alsoBad(): never | never {
  x = 42
}

alsoBad()
"#;
        let err = parse_execute(program).await.unwrap_err();

        assert!(matches!(&err, KclError::Type { .. }));
        assert_eq!(
            err.message(),
            "This function completed without returning a value, but its return type is `never`. A function with return type `never` must stop evaluation abnormally. You may want to use `fail(...)` to stop evaluation and provide a message."
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn never_function_contract_is_path_dependent() {
        let function = r#"@settings(kclVersion = "3.0-preview")
fn failOrReturn(@shouldFail: bool): never {
  return if shouldFail {
    fail("requested failure")
  } else {
    42
  }
}
"#;

        let err = parse_execute(&format!("{function}\nfailOrReturn(true)\n"))
            .await
            .unwrap_err();
        assert!(matches!(&err, KclError::UserDefined { .. }));
        assert_eq!(err.message(), "requested failure");

        let err = parse_execute(&format!("{function}\nfailOrReturn(false)\n"))
            .await
            .unwrap_err();
        assert!(matches!(&err, KclError::Type { .. }));
        assert_eq!(
            err.message(),
            "This function returned a value, but its return type is `never`. A function with return type `never` must stop evaluation abnormally. You may want to use `fail(...)` to stop evaluation and provide a message."
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn never_type_alias_contract_is_path_dependent() {
        let function = r#"@settings(kclVersion = "3.0-preview")
type impossible = never
fn failOrReturn(@shouldFail: bool): impossible {
  return if shouldFail {
    fail("requested failure")
  } else {
    42
  }
}
"#;

        let err = parse_execute(&format!("{function}\nfailOrReturn(true)\n"))
            .await
            .unwrap_err();
        assert!(matches!(&err, KclError::UserDefined { .. }));
        assert_eq!(err.message(), "requested failure");

        let err = parse_execute(&format!("{function}\nfailOrReturn(false)\n"))
            .await
            .unwrap_err();
        assert!(matches!(&err, KclError::Type { .. }));
        assert_eq!(
            err.message(),
            "This function returned a value, but its return type is `never`. A function with return type `never` must stop evaluation abnormally. You may want to use `fail(...)` to stop evaluation and provide a message."
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn union_with_never_can_return_a_value_or_fail() {
        let function = r#"@settings(kclVersion = "3.0-preview")
fn stringOrFail(@shouldFail: bool): string | never {
  return if shouldFail {
    fail("requested failure")
  } else {
    "ok"
  }
}
"#;

        let result = parse_execute(&format!("{function}\nresult = stringOrFail(false)\n"))
            .await
            .unwrap();
        let KclValue::String { value, .. } = get_var(&result, "result") else {
            panic!("expected `result` to be a string")
        };
        assert_eq!(value, "ok");

        let err = parse_execute(&format!("{function}\nstringOrFail(true)\n"))
            .await
            .unwrap_err();
        assert!(matches!(&err, KclError::UserDefined { .. }));
        assert_eq!(err.message(), "requested failure");
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn fail_reports_user_defined_message_and_callsite_once() {
        let program = r#"@settings(kclVersion = "3.0-preview")
fail("custom failure")
"#;

        let err = parse_execute(program).await.unwrap_err();

        assert!(matches!(&err, KclError::UserDefined { .. }));
        assert_eq!(err.message(), "custom failure");
        assert_eq!(err.get_message(), "user-defined: custom failure");
        assert_eq!(serde_json::to_value(&err).unwrap()["kind"], "user_defined");
        assert_eq!(source_texts(program, &err), [r#"fail("custom failure")"#]);
        assert_eq!(err.backtrace().len(), 1);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn fail_is_unavailable_before_v3_even_with_experimental_opt_in() {
        for version in ["1.0", "2.0"] {
            for opt_in in ["", ", experimentalFeatures = allow"] {
                let program = format!("@settings(kclVersion = {version}{opt_in})\nfail(\"custom failure\")\n");
                let err = parse_execute(&program).await.unwrap_err();
                assert!(
                    err.message()
                        .contains("it was added in KCL 3.0, but this program uses KCL"),
                    "{program}: {err:#?}"
                );
            }
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn fail_unwinds_through_nested_never_functions_once() {
        let program = r#"@settings(kclVersion = "3.0-preview")
fn inner(): never {
  fail("nested failure")
}

fn outer(): never {
  inner()
}

outer()
"#;

        let err = parse_execute(program).await.unwrap_err();

        assert!(matches!(&err, KclError::UserDefined { .. }));
        assert_eq!(err.message(), "nested failure");
        assert_eq!(
            source_texts(program, &err),
            [r#"fail("nested failure")"#, "inner()", "outer()"]
        );
        assert_eq!(
            err.backtrace()
                .iter()
                .map(|item| item.fn_name.as_deref())
                .collect::<Vec<_>>(),
            [Some("inner"), Some("outer"), None]
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn fail_is_valid_in_a_function_with_a_value_return_type() {
        let function = r#"@settings(kclVersion = "3.0-preview")
fn valueOrFail(@shouldFail: bool): number {
  return if shouldFail {
    fail("no value")
  } else {
    42
  }
}
"#;

        parse_execute(&format!("{function}\nresult = valueOrFail(false)\n"))
            .await
            .unwrap();

        let err = parse_execute(&format!("{function}\nvalueOrFail(true)\n"))
            .await
            .unwrap_err();
        assert!(matches!(&err, KclError::UserDefined { .. }));
        assert_eq!(err.message(), "no value");
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn never_function_with_fail_or_fallthrough_is_path_dependent() {
        let function = r#"@settings(kclVersion = "3.0-preview")
fn failOrFallThrough(@shouldFail: bool): never {
  result = if shouldFail {
    fail("requested failure")
  } else {
    42
  }
}
"#;

        let err = parse_execute(&format!("{function}\nfailOrFallThrough(true)\n"))
            .await
            .unwrap_err();
        assert!(matches!(&err, KclError::UserDefined { .. }));
        assert_eq!(err.message(), "requested failure");

        let err = parse_execute(&format!("{function}\nfailOrFallThrough(false)\n"))
            .await
            .unwrap_err();
        assert!(matches!(&err, KclError::Type { .. }));
        assert_eq!(
            err.message(),
            "This function completed without returning a value, but its return type is `never`. A function with return type `never` must stop evaluation abnormally. You may want to use `fail(...)` to stop evaluation and provide a message."
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn fail_argument_evaluation_errors_take_precedence() {
        let program = r#"@settings(kclVersion = "3.0-preview")
fn stop(): never {
  fail(missingMessage)
}

stop()
"#;

        let err = parse_execute(program).await.unwrap_err();

        assert!(matches!(&err, KclError::UndefinedValue { .. }));
        assert_eq!(err.message(), "`missingMessage` is not defined");
        assert_eq!(source_texts(program, &err), ["missingMessage", "stop()"]);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn fail_rejects_invalid_message_arguments_before_invocation() {
        for program in [
            "@settings(kclVersion = \"3.0-preview\")\nfail()\n",
            "@settings(kclVersion = \"3.0-preview\")\nfail(42)\n",
        ] {
            let err = parse_execute(program).await.unwrap_err();
            assert!(matches!(&err, KclError::Argument { .. }), "{err:?}");
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn map_closure_error_mentions_fn_name() {
        let program = r#"
arr = ["hello"]
map(array = arr, f = fn(@item: number) { return item })
"#;
        let err = parse_execute(program).await.unwrap_err();
        assert!(
            err.message().contains("map closure"),
            "expected map closure errors to include the closure name, got: {}",
            err.message()
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn array_input_arg() {
        let ast = r#"fn f(@input: [mm]) { return 1 }
f([1, 2, 3])
f(1, 2, 3)
"#;
        parse_execute(ast).await.unwrap();
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn extrude_tagged_body_gets_face_tags_and_keeps_legacy_bindings() {
        let program = r#"@settings(kclVersion = 2.0)
profile = sketch(on = XY) {
  line1 = line(start = [var 0mm, var 0mm], end = [var 10mm, var 0mm])
  line2 = line(start = [var 10mm, var 0mm], end = [var 10mm, var 10mm])
  line3 = line(start = [var 10mm, var 10mm], end = [var 0mm, var 10mm])
  line4 = line(start = [var 0mm, var 10mm], end = [var 0mm, var 0mm])
  coincident([line1.end, line2.start])
  coincident([line2.end, line3.start])
  coincident([line3.end, line4.start])
  coincident([line4.end, line1.start])
}
region1 = region(point = [5mm, 5mm], sketch = profile)

body = extrude(region1, length = 5mm, tagStart = $bottom, tagEnd = $top)
bottomFromBody = body.faces.bottom
topFromBody = body.faces.top
lineFromSketch = region1.tags.line1
legacyBottom = bottom
legacyTop = top
"#;

        let result = parse_execute(program).await.unwrap();
        assert_body_face_tags(&result, &["bottom", "top"], &["line1"]);
        assert_vars_are_tags(
            &result,
            &[
                "bottom",
                "top",
                "bottomFromBody",
                "topFromBody",
                "lineFromSketch",
                "legacyBottom",
                "legacyTop",
            ],
        );
        assert_vars_are_missing(&result, &["line1"]);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn extrude_without_tag_arguments_does_not_get_face_tags() {
        let program = r#"@settings(kclVersion = 2.0)
profile = sketch(on = XY) {
  line1 = line(start = [var 0mm, var 0mm], end = [var 10mm, var 0mm])
  line2 = line(start = [var 10mm, var 0mm], end = [var 10mm, var 10mm])
  line3 = line(start = [var 10mm, var 10mm], end = [var 0mm, var 10mm])
  line4 = line(start = [var 0mm, var 10mm], end = [var 0mm, var 0mm])
  coincident([line1.end, line2.start])
  coincident([line2.end, line3.start])
  coincident([line3.end, line4.start])
  coincident([line4.end, line1.start])
}
region1 = region(point = [5mm, 5mm], sketch = profile)

body = extrude(region1, length = 5mm)
"#;

        let result = parse_execute(program).await.unwrap();
        let body = get_var(&result, "body");
        let KclValue::Solid { value: body } = body else {
            panic!("expected `body` to be a solid");
        };

        assert!(
            body.faces.is_empty(),
            "body faces should only be populated for tagged calls"
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn sketch_segment_extrude_exposes_its_generated_face() {
        let program = r#"@settings(defaultLengthUnit = mm)
sketch001 = sketch(on = XY) {
  line1 = line(start = [0, 0], end = [20, 0])
  line2 = line(start = [20, 0], end = [20, 12])
}
surface001 = extrude(
  sketch001.line1,
  length = 10,
  bodyType = SURFACE,
  method = NEW,
)
generatedFace = surface001.faces.line1
surface002 = extrude(
  {
    sideFaces = [surface001.faces.line1],
    index = 2
  },
  length = 5,
  bodyType = SURFACE,
  method = NEW,
)
"#;

        let result = parse_execute(program).await.unwrap();
        let surface = get_var(&result, "surface001");
        let KclValue::Solid { value: surface } = surface else {
            panic!("expected `surface001` to be a solid");
        };
        assert!(surface.faces.contains_key("line1"));
        assert_vars_are_tags(&result, &["generatedFace"]);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn revolve_tagged_body_gets_face_tags() {
        let program = r#"@settings(kclVersion = 2.0)
profile = sketch(on = XY) {
  side = line(start = [var 5mm, var 0mm], end = [var 5mm, var 10mm])
  line2 = line(start = [var 5mm, var 10mm], end = [var 6mm, var 10mm])
  line3 = line(start = [var 6mm, var 10mm], end = [var 6mm, var 0mm])
  line4 = line(start = [var 6mm, var 0mm], end = [var 5mm, var 0mm])
  coincident([side.end, line2.start])
  coincident([line2.end, line3.start])
  coincident([line3.end, line4.start])
  coincident([line4.end, side.start])
}
region1 = region(point = [5.5mm, 5mm], sketch = profile)

body = revolve(region1, axis = Y, angle = 90deg, tagStart = $startCap, tagEnd = $endCap)
startFromBody = body.faces.startCap
endFromBody = body.faces.endCap
sideFromSketch = region1.tags.side
legacyStart = startCap
legacyEnd = endCap
"#;

        let result = parse_execute(program).await.unwrap();
        assert_body_face_tags(&result, &["startCap", "endCap"], &["side"]);
        assert_vars_are_tags(
            &result,
            &[
                "startCap",
                "endCap",
                "startFromBody",
                "endFromBody",
                "sideFromSketch",
                "legacyStart",
                "legacyEnd",
            ],
        );
        assert_vars_are_missing(&result, &["side"]);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn sweep_tagged_body_gets_face_tags() {
        let program = r#"@settings(kclVersion = 2.0)
profile = sketch(on = XZ) {
  edge1 = line(start = [var 0mm, var 0mm], end = [var 2mm, var 0mm])
  edge2 = line(start = [var 2mm, var 0mm], end = [var 2mm, var 2mm])
  edge3 = line(start = [var 2mm, var 2mm], end = [var 0mm, var 2mm])
  edge4 = line(start = [var 0mm, var 2mm], 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])
}
profileRegion = region(point = [1mm, 1mm], sketch = profile)

pathSketch = sketch(on = offsetPlane(YZ, offset = -2mm)) {
  pathLine = line(start = [var 0mm, var 0mm], end = [var 0mm, var 5mm])
}

body = sweep(profileRegion, path = pathSketch.pathLine, tagStart = $startCap, tagEnd = $endCap)
startFromBody = body.faces.startCap
endFromBody = body.faces.endCap
edgeFromSketch = profileRegion.tags.edge1
pathFromSketch = pathSketch.pathLine
legacyStart = startCap
legacyEnd = endCap
"#;

        let result = parse_execute(program).await.unwrap();
        assert_body_face_tags(&result, &["startCap", "endCap"], &["edge1", "pathLine"]);
        assert_vars_are_tags(
            &result,
            &[
                "startCap",
                "endCap",
                "startFromBody",
                "endFromBody",
                "edgeFromSketch",
                "legacyStart",
                "legacyEnd",
            ],
        );
        assert_vars_are_missing(&result, &["edge1", "pathLine"]);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn loft_tagged_body_gets_face_tags() {
        let program = r#"@settings(kclVersion = 2.0)
lowerProfile = sketch(on = XY) {
  edge1 = line(start = [var 0mm, var 0mm], end = [var 6mm, var 0mm])
  edge2 = line(start = [var 6mm, var 0mm], end = [var 6mm, var 4mm])
  edge3 = line(start = [var 6mm, var 4mm], end = [var 0mm, var 4mm])
  edge4 = line(start = [var 0mm, var 4mm], 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])
}
lowerRegion = region(point = [3mm, 2mm], sketch = lowerProfile)

upperProfile = sketch(on = offsetPlane(XY, offset = 8mm)) {
  edge5 = line(start = [var 1mm, var 1mm], end = [var 5mm, var 1mm])
  edge6 = line(start = [var 5mm, var 1mm], end = [var 4mm, var 3mm])
  edge7 = line(start = [var 4mm, var 3mm], end = [var 2mm, var 3mm])
  edge8 = line(start = [var 2mm, var 3mm], 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])
}
upperRegion = region(point = [3mm, 2mm], sketch = upperProfile)

body = loft([lowerRegion, upperRegion], tagStart = $startCap, tagEnd = $endCap)
startFromBody = body.faces.startCap
endFromBody = body.faces.endCap
edgeFromSketch = lowerRegion.tags.edge1
legacyStart = startCap
legacyEnd = endCap
"#;

        let result = parse_execute(program).await.unwrap();
        assert_body_face_tags(&result, &["startCap", "endCap"], &["edge1"]);
        assert_vars_are_tags(
            &result,
            &[
                "startCap",
                "endCap",
                "startFromBody",
                "endFromBody",
                "edgeFromSketch",
                "legacyStart",
                "legacyEnd",
            ],
        );
        assert_vars_are_missing(&result, &["edge1"]);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn chamfer_tagged_body_gets_face_tags() {
        let program = r#"@settings(kclVersion = 2.0)
profile = sketch(on = XY) {
  edge1 = line(start = [var 0mm, var 0mm], end = [var 10mm, var 0mm])
  edge2 = line(start = [var 10mm, var 0mm], end = [var 10mm, var 10mm])
  edge3 = line(start = [var 10mm, var 10mm], end = [var 0mm, var 10mm])
  edge4 = line(start = [var 0mm, var 10mm], 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])
}
profileRegion = region(point = [5mm, 5mm], sketch = profile)

base = extrude(profileRegion, length = 5mm, tagEnd = $top)
body = chamfer(base, tags = getCommonEdge(faces = [profileRegion.tags.edge1, top]), length = 1mm, tag = $chamferFace)
chamferFromBody = body.faces.chamferFace
topFromBody = body.faces.top
edgeFromSketch = profileRegion.tags.edge1
legacyChamfer = chamferFace
legacyTop = top
"#;

        let result = parse_execute(program).await.unwrap();
        assert_body_face_tags(&result, &["top", "chamferFace"], &["edge1"]);
        assert_vars_are_tags(
            &result,
            &[
                "top",
                "chamferFace",
                "chamferFromBody",
                "topFromBody",
                "edgeFromSketch",
                "legacyChamfer",
                "legacyTop",
            ],
        );
        assert_vars_are_missing(&result, &["edge1"]);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn fillet_tagged_body_gets_face_tags() {
        let program = r#"@settings(kclVersion = 2.0)
profile = sketch(on = XY) {
  edge1 = line(start = [var 0mm, var 0mm], end = [var 10mm, var 0mm])
  edge2 = line(start = [var 10mm, var 0mm], end = [var 10mm, var 10mm])
  edge3 = line(start = [var 10mm, var 10mm], end = [var 0mm, var 10mm])
  edge4 = line(start = [var 0mm, var 10mm], 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])
}
profileRegion = region(point = [5mm, 5mm], sketch = profile)

base = extrude(profileRegion, length = 5mm, tagEnd = $top)
body = fillet(base, tags = getCommonEdge(faces = [profileRegion.tags.edge1, top]), radius = 1mm, tag = $filletFace)
filletFromBody = body.faces.filletFace
topFromBody = body.faces.top
edgeFromSketch = profileRegion.tags.edge1
legacyFillet = filletFace
legacyTop = top
"#;

        let result = parse_execute(program).await.unwrap();
        assert_body_face_tags(&result, &["top", "filletFace"], &["edge1"]);
        assert_vars_are_tags(
            &result,
            &[
                "top",
                "filletFace",
                "filletFromBody",
                "topFromBody",
                "edgeFromSketch",
                "legacyFillet",
                "legacyTop",
            ],
        );
        assert_vars_are_missing(&result, &["edge1"]);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn accessing_body_tag_through_body_sketch_tags_warns() {
        let program = r#"@settings(kclVersion = 2.0)
profile = startSketchOn(XY)
  |> startProfile(at = [0, 0])
  |> line(end = [10, 0], tag = $line1)
  |> line(end = [0, 10])
  |> line(end = [-10, 0])
  |> close()

body = extrude(profile, length = 5, tagEnd = $top)
topFromSketch = body.sketch.tags.top
topFromBody = body.faces.top
"#;

        let result = parse_execute(program).await.unwrap();
        assert!(matches!(get_var(&result, "topFromSketch"), KclValue::TagIdentifier(_)));
        assert!(matches!(get_var(&result, "topFromBody"), KclValue::TagIdentifier(_)));

        let warnings = deprecated_solid_tag_access_warnings(&result);
        assert_eq!(warnings.len(), 1, "expected one deprecation warning, got {warnings:#?}");
        assert_eq!(warnings[0].severity, Severity::Warning);
        assert!(warnings[0].message.contains("`top`"), "found {}", warnings[0].message);
        assert!(
            warnings[0].message.contains("Accessing solid-created face `top` through sketch tags is deprecated. Use the body's faces instead, e.g. `body.faces.top`."),
            "found {}",
            warnings[0].message
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn accessing_sketch_path_tag_through_body_sketch_tags_does_not_warn() {
        let program = r#"@settings(kclVersion = 2.0)
profile = startSketchOn(XY)
  |> startProfile(at = [0, 0])
  |> line(end = [10, 0], tag = $line1)
  |> line(end = [0, 10])
  |> line(end = [-10, 0])
  |> close()

body = extrude(profile, length = 5, tagEnd = $top)
lineFromSketch = body.sketch.tags.line1
"#;

        let result = parse_execute(program).await.unwrap();
        assert!(matches!(get_var(&result, "lineFromSketch"), KclValue::TagIdentifier(_)));
        let warnings = deprecated_solid_tag_access_warnings(&result);
        assert!(
            warnings.is_empty(),
            "sketch path tags should not get body-tag deprecation warnings: {warnings:#?}"
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn accessing_body_tag_through_sketch_block_region_tags_warns() {
        let program = r#"@settings(kclVersion = 2.0)
profile = sketch(on = XY) {
  line1 = line(start = [0, 0], end = [10, 0])
  line2 = line(start = [10, 0], end = [10, 10])
  line3 = line(start = [10, 10], end = [0, 10])
  line4 = line(start = [0, 10], end = [0, 0])
}

profileRegion = region(point = [1, 1], sketch = profile)
body = extrude(profileRegion, length = 5, tagEnd = $top)
topFromRegion = profileRegion.tags.top
"#;

        let result = parse_execute(program).await.unwrap();
        assert!(matches!(get_var(&result, "topFromRegion"), KclValue::TagIdentifier(_)));

        let warnings = deprecated_solid_tag_access_warnings(&result);
        assert_eq!(warnings.len(), 1, "expected one deprecation warning, got {warnings:#?}");
        assert_eq!(warnings[0].severity, Severity::Warning);
        assert!(warnings[0].message.contains("`top`"), "found {}", warnings[0].message);
    }

    fn deprecation_warnings(result: &ExecTestResults) -> Vec<&CompilationIssue> {
        result
            .exec_state
            .issues()
            .iter()
            .filter(|issue| issue.message.contains("is deprecated"))
            .collect()
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn passing_param_deprecated_for_all_versions_warns() {
        // `@(deprecated = true)` deprecates the parameter regardless of the KCL
        // version, so even on the latest version the call should warn.
        let program = r#"@settings(kclVersion = 2.0)
fn f(
  @a: number,
  @(deprecated = true)
  oldArg?: number,
) {
  return a
}
x = f(1, oldArg = 2)
"#;

        let result = parse_execute(program).await.unwrap();
        let warnings = deprecation_warnings(&result);
        assert_eq!(warnings.len(), 1, "expected one deprecation warning, got {warnings:#?}");
        assert_eq!(warnings[0].severity, Severity::Warning);
        assert_eq!(warnings[0].tag, crate::errors::Tag::Deprecated);
        assert!(
            warnings[0].message.contains("`f(oldArg)` is deprecated"),
            "found {}",
            warnings[0].message
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn not_passing_deprecated_param_does_not_warn() {
        let program = r#"fn f(
  @a: number,
  @(deprecated = true)
  oldArg?: number,
) {
  return a
}
x = f(1)
"#;

        let result = parse_execute(program).await.unwrap();
        let warnings = deprecation_warnings(&result);
        assert!(
            warnings.is_empty(),
            "unused deprecated parameter should not warn: {warnings:#?}"
        );
    }

    fn unexpected_arg_errors(result: &ExecTestResults) -> Vec<&CompilationIssue> {
        result
            .exec_state
            .issues()
            .iter()
            .filter(|issue| issue.message.contains("is not an argument of"))
            .collect()
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn passing_removed_param_on_removed_version_errors_like_unknown_arg() {
        // "3.0-preview" is a pre-release of 3.0, so a parameter removed in
        // 3.0 is already gone there.
        let program = r#"@settings(kclVersion = "3.0-preview")
fn f(
  @a: number,
  @(deprecated_since = "2.0", removed_in = "3.0")
  oldArg?: number,
) {
  return a
}
x = f(1, oldArg = 2)
"#;

        let result = parse_execute(program).await.unwrap();
        let errors = unexpected_arg_errors(&result);
        assert_eq!(
            errors.len(),
            1,
            "expected one unknown-argument error, got {:#?}",
            result.issues()
        );
        assert_eq!(errors[0].severity, Severity::Error);
        // Same path as an unknown argument, plus the two versions that explain
        // the mismatch.
        assert_eq!(
            errors[0].message,
            "`oldArg` is not an argument of `f`; it was removed in KCL 3.0, but this program uses KCL 3.0-preview"
        );
        // The error replaces the deprecation warning rather than adding to it.
        assert!(
            deprecation_warnings(&result).is_empty(),
            "removed parameter should not also warn: {:#?}",
            result.issues()
        );
        // Execution continues as if the argument had not been passed.
        assert!(matches!(get_var(&result, "x"), KclValue::Number { value, .. } if value == 1.0));
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn passing_removed_param_before_removed_version_still_works() {
        let program = r#"@settings(kclVersion = 2.0)
fn f(
  @a: number,
  @(deprecated_since = "2.0", removed_in = "3.0")
  oldArg?: number,
) {
  return oldArg
}
x = f(1, oldArg = 2)
"#;

        let result = parse_execute(program).await.unwrap();
        assert!(
            unexpected_arg_errors(&result).is_empty(),
            "parameter is not removed until 3.0: {:#?}",
            result.issues()
        );
        let warnings = deprecation_warnings(&result);
        assert_eq!(warnings.len(), 1, "expected one deprecation warning, got {warnings:#?}");
        assert!(
            warnings[0].message.contains("`f(oldArg)` is deprecated as of KCL 2.0"),
            "found {}",
            warnings[0].message
        );
        assert!(matches!(get_var(&result, "x"), KclValue::Number { value, .. } if value == 2.0));
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn removed_optional_param_binds_its_default() {
        let program = r#"@settings(kclVersion = "3.0-preview")
fn f(
  @(removed_in = "3.0")
  oldArg?: number = 7,
) {
  return oldArg
}
x = f()
"#;

        let result = parse_execute(program).await.unwrap();
        assert!(result.issues().is_empty(), "unexpected issues: {:#?}", result.issues());
        assert!(matches!(get_var(&result, "x"), KclValue::Number { value, .. } if value == 7.0));
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn removed_param_is_not_matched_by_label_shorthand() {
        // Before 3.0, `f(oldArg)` desugars to `f(oldArg = oldArg)`. Once the
        // parameter is removed, the argument is just an unlabeled argument the
        // function does not accept, and the removed parameter must not be
        // suggested as a label.
        let program = r#"@settings(kclVersion = "3.0-preview")
fn f(
  @(removed_in = "3.0")
  oldArg?: number,
) {
  return 1
}
oldArg = 2
x = f(oldArg)
"#;

        let err = parse_execute(program).await.unwrap_err();
        assert_eq!(err.message(), "This argument needs a label, but it doesn't have one");
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn passing_not_yet_added_param_errors_like_unknown_arg() {
        let program = r#"@settings(kclVersion = 2.0)
fn f(
  @a: number,
  @(added_in = "3.0")
  newArg?: number,
) {
  return a
}
x = f(1, newArg = 2)
"#;

        let result = parse_execute(program).await.unwrap();
        let errors = unexpected_arg_errors(&result);
        assert_eq!(
            errors.len(),
            1,
            "expected one unknown-argument error, got {:#?}",
            result.issues()
        );
        assert_eq!(errors[0].severity, Severity::Error);
        assert_eq!(
            errors[0].message,
            "`newArg` is not an argument of `f`; it was added in KCL 3.0, but this program uses KCL 2.0"
        );
        // Execution continues as if the argument had not been passed.
        assert!(matches!(get_var(&result, "x"), KclValue::Number { value, .. } if value == 1.0));
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn not_yet_added_param_error_reports_default_kcl_version() {
        // No `@settings(kclVersion = ...)`, so the program runs on the
        // default version, and the message says which one that is.
        let program = r#"fn f(
  @(added_in = "2.0")
  newArg?: number,
) {
  return 1
}
x = f(newArg = 2)
"#;

        let result = parse_execute(program).await.unwrap();
        let errors = unexpected_arg_errors(&result);
        assert_eq!(errors.len(), 1, "got {:#?}", result.issues());
        assert_eq!(
            errors[0].message,
            "`newArg` is not an argument of `f`; it was added in KCL 2.0, but this program uses KCL 1.0"
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn passing_added_param_on_or_after_added_version_works() {
        // The boundary is inclusive, and a pre-release such as "3.0-preview"
        // counts as the release it precedes.
        for (kcl_version, added_in) in [("2.0", "1.0"), ("2.0", "2.0"), ("\"3.0-preview\"", "3.0")] {
            let program = format!(
                r#"@settings(kclVersion = {kcl_version})
fn f(
  @(added_in = "{added_in}")
  newArg?: number,
) {{
  return newArg
}}
x = f(newArg = 2)
"#
            );

            let result = parse_execute(&program).await.unwrap();
            assert!(
                result.issues().is_empty(),
                "kclVersion {kcl_version}, added_in {added_in}: {:#?}",
                result.issues()
            );
            assert!(
                matches!(get_var(&result, "x"), KclValue::Number { value, .. } if value == 2.0),
                "kclVersion {kcl_version}, added_in {added_in}"
            );
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn not_yet_added_optional_param_binds_its_default() {
        let program = r#"@settings(kclVersion = 2.0)
fn f(
  @(added_in = "3.0")
  newArg?: number = 7,
) {
  return newArg
}
x = f()
"#;

        let result = parse_execute(program).await.unwrap();
        assert!(result.issues().is_empty(), "unexpected issues: {:#?}", result.issues());
        assert!(matches!(get_var(&result, "x"), KclValue::Number { value, .. } if value == 7.0));
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn not_yet_added_param_is_not_matched_by_label_shorthand() {
        // Once the parameter exists, `f(newArg)` desugars to
        // `f(newArg = newArg)`. Before that, the argument is just an unlabeled
        // argument the function does not accept, and the parameter must not
        // be suggested as a label.
        let program = r#"@settings(kclVersion = 2.0)
fn f(
  @(added_in = "3.0")
  newArg?: number,
) {
  return 1
}
newArg = 2
x = f(newArg)
"#;

        let err = parse_execute(program).await.unwrap_err();
        assert_eq!(err.message(), "This argument needs a label, but it doesn't have one");
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn param_lifecycle_added_then_deprecated_then_removed() {
        let body = r#"fn f(
  @(added_in = "2.0", deprecated_since = "2.0", removed_in = "3.0")
  arg?: number,
) {
  return arg
}
x = f(arg = 2)
"#;
        for (kcl_version, expected_error) in [
            (
                "1.0",
                Some("`arg` is not an argument of `f`; it was added in KCL 2.0, but this program uses KCL 1.0"),
            ),
            ("2.0", None),
            (
                "\"3.0-preview\"",
                Some(
                    "`arg` is not an argument of `f`; it was removed in KCL 3.0, but this program uses KCL 3.0-preview",
                ),
            ),
        ] {
            let program = format!("@settings(kclVersion = {kcl_version})\n{body}");
            let result = parse_execute(&program).await.unwrap();
            let errors = unexpected_arg_errors(&result);
            match expected_error {
                Some(message) => {
                    assert_eq!(errors.len(), 1, "kclVersion {kcl_version}: {:#?}", result.issues());
                    assert_eq!(errors[0].message, message, "kclVersion {kcl_version}");
                    assert!(
                        deprecation_warnings(&result).is_empty(),
                        "kclVersion {kcl_version}: an unavailable parameter should not also warn: {:#?}",
                        result.issues()
                    );
                }
                None => {
                    assert!(errors.is_empty(), "kclVersion {kcl_version}: {:#?}", result.issues());
                    // Available and deprecated on this version.
                    assert_eq!(
                        deprecation_warnings(&result).len(),
                        1,
                        "kclVersion {kcl_version}: {:#?}",
                        result.issues()
                    );
                    assert!(
                        matches!(get_var(&result, "x"), KclValue::Number { value, .. } if value == 2.0),
                        "kclVersion {kcl_version}"
                    );
                }
            }
        }
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn stdlib_legacy_method_is_removed_in_kcl_3() {
        let solids = r#"left = startSketchOn(XY)
  |> circle(center = [0, 0], radius = 2)
  |> extrude(length = 1)
right = startSketchOn(XY)
  |> circle(center = [1, 0], radius = 2)
  |> extrude(length = 1)
both = union([left, right], legacyMethod = true)
"#;

        let program = format!("@settings(kclVersion = \"3.0-preview\")\n{solids}");
        let result = parse_execute(&program).await.unwrap();
        let errors = unexpected_arg_errors(&result);
        assert_eq!(errors.len(), 1, "got {:#?}", result.issues());
        assert_eq!(
            errors[0].message,
            "`legacyMethod` is not an argument of `union`; it was removed in KCL 3.0, but this program uses KCL 3.0-preview"
        );

        // Still accepted, with a deprecation warning, before KCL 3.0.
        let program = format!("@settings(kclVersion = 2.0)\n{solids}");
        let result = parse_execute(&program).await.unwrap();
        assert!(unexpected_arg_errors(&result).is_empty(), "got {:#?}", result.issues());
        assert!(
            deprecation_warnings(&result)
                .iter()
                .any(|w| w.message.contains("`union(legacyMethod)` is deprecated as of KCL 2.0")),
            "got {:#?}",
            result.issues()
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn deprecated_calls_inside_kcl_stdlib_do_not_warn() {
        let program = include_str!("../../tests/cube_with_hole/input.kcl");

        let result = parse_execute(program).await.unwrap();
        let warnings = deprecation_warnings(&result);
        assert!(
            warnings.is_empty(),
            "KCL stdlib internals should not emit deprecation warnings: {warnings:#?}"
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn deprecated_stdlib_call_from_user_code_still_warns() {
        let program = r#"@settings(kclVersion = 2.0)
plane = startSketchOn(XY)
"#;

        let result = parse_execute(program).await.unwrap();
        let warnings = deprecation_warnings(&result);
        assert_eq!(warnings.len(), 1, "expected one deprecation warning, got {warnings:#?}");
        assert!(
            warnings[0].message.contains("`startSketchOn` is deprecated"),
            "found {}",
            warnings[0].message
        );
        assert_eq!(warnings[0].tag, crate::errors::Tag::Deprecated);
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn deprecated_since_warns_for_prerelease_kcl_version() {
        let program = r#"@settings(kclVersion = "3.0-preview")
plane = startSketchOn(XY)
"#;

        let result = parse_execute(program).await.unwrap();
        let warnings = deprecation_warnings(&result);
        assert_eq!(warnings.len(), 1, "expected one deprecation warning, got {warnings:#?}");
        assert_eq!(warnings[0].severity, Severity::Warning);
        assert_eq!(warnings[0].tag, crate::errors::Tag::Deprecated);
        assert!(
            warnings[0]
                .message
                .contains("`startSketchOn` is deprecated as of KCL 2.0"),
            "found {}",
            warnings[0].message
        );
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn deprecation_version_override_does_not_change_program_version() {
        let program = crate::Program::parse_no_errs(
            r#"@settings(kclVersion = 1.0)
plane = startSketchOn(XY)
"#,
        )
        .unwrap();
        let exec_ctxt = ExecutorContext {
            engine: Arc::new(EngineManager::new_mock()),
            cache: crate::Cache::default(),
            engine_batch: crate::engine::EngineBatchContext::default(),
            fs: crate::fs::new_file_system_handle(crate::fs::FileManager::new()),
            settings: Default::default(),
            context_type: ContextType::Mock,
            execution_callbacks: Default::default(),
            machine_call_depth_limit: crate::execution::machine::DEFAULT_MACHINE_CALL_DEPTH_LIMIT,
            configure_engine_render: true,
            needs_oit: Default::default(),
        };
        let mut exec_state = ExecState::new(&exec_ctxt);
        exec_state.set_deprecation_version_override(Some("2.0"));

        exec_ctxt.run(&program, &mut exec_state).await.unwrap();

        assert_eq!(exec_state.mod_local.settings.kcl_version, crate::KclVersion::V1);
        let warnings = exec_state
            .issues()
            .iter()
            .filter(|issue| issue.tag == crate::errors::Tag::Deprecated)
            .collect::<Vec<_>>();
        assert_eq!(warnings.len(), 1, "expected one deprecation warning, got {warnings:#?}");
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn deprecated_sketch_v1_warning_explains_sketch_solve() {
        // Sketch v1 deprecation warnings must be self-contained: they should
        // say what replaces the function and link the conversion docs so both
        // humans and AI agents can act on the warning alone.
        let program = r#"@settings(kclVersion = 2.0)
exampleSketch = startSketchOn(XZ)
  |> startProfile(at = [0, 0])
  |> line(end = [10, 0])
"#;

        let result = parse_execute(program).await.unwrap();
        let warnings = deprecation_warnings(&result);
        assert_eq!(
            warnings.len(),
            3,
            "expected one warning per sketch v1 call, got {warnings:#?}"
        );
        for warning in warnings {
            assert!(
                warning.message.contains("sketch-solve"),
                "expected sketch-solve context in {}",
                warning.message
            );
            assert!(
                warning
                    .message
                    .contains("https://zoo.dev/docs/kcl-book/sketch2d_constraints.html"),
                "expected docs URL in {}",
                warning.message
            );
        }
    }
}