brokk_bifrost_cpp/graph/

inverted.rs

//! Whole-workspace inverted edge builder for C++.
//!
//! Walks each file once and resolves every reference to the callee fqn it names,
//! via the shared `build_edges` driver in `brokk-bifrost-analysis`. C++ node fqns
//! are dotted: a namespace +
//! class + member reads `example.Service.run`, a free function `example.freeHelper`,
//! and a class `example.Service`. References resolve through the forward scanner's
//! visibility primitives ([`VisibilityIndex::resolve_type`] / `resolve_named`,
//! which honor the include closure and namespaces) plus a [`LocalInferenceEngine`]
//! (typed by [`CodeUnit`], like the forward scan) seeded with every local's and
//! parameter's declared type so a method call's receiver can be typed:
//!
//! - a type reference (`Foo x`, `new Foo()`, a base class) resolves to the class;
//! - `recv.m(..)` / `recv->m(..)` (`field_expression` under a call) types `recv`
//!   and gives `Owner.m`;
//! - `X::m(..)` (`qualified_identifier`) resolves `X` and gives `Owner.m`;
//! - a bare `m(..)` is a free function (`Namespace.m`); `this->m(..)` and other
//!   unqualified member calls attribute to the enclosing class;
//! - a chained receiver (`p->get()->m()`) follows the uniquely resolved persisted
//!   callable return type before recording `Owner.m`.
//!
//! The enclosing class is taken from a per-file class-range index (the analyzer's
//! own fqns), so `this->`/unqualified calls attribute to the right class without
//! re-deriving the namespace. Ambiguous receiver or return identities fail closed.

use crate::declarations::{
    CppSentinelRecoveredClass, cpp_sentinel_recovered_classes,
    cpp_sentinel_recovered_scope_for_node, node_text, recovered_macro_return_type_node,
};
use crate::graph::CppGraphSource;
use crate::graph::extractor::{
    BareCallTargetResolution, LexicalScopeResolution, enclosing_lexical_scope_components,
    initialized_ordinary_type_imports, ordinary_using_declaration_type_node,
    resolve_bare_call_target, resolve_ordinary_using_declaration_owner,
    resolve_type_components_lexically_at, resolve_type_node_lexically,
    resolve_using_enum_declaration_owner, using_enum_declaration_type_node,
};
use crate::graph::resolver::{
    CppTemplateResolutionError, DesignatedInitializerOwner, EnclosingMemberOwnerResolution,
    LexicalCallableValueResolution, LexicalTypeResolution, OrdinaryMacroReferenceResolution,
    OrdinaryTypeImportCell, TargetKind, VisibilityIndex, VisibleMemberResolution,
    canonical_cpp_scope_components, constructor_style_local_declaration, cpp_callable_arity,
    cpp_template_reference_arguments, cpp_type_name_components, declarator_name_node,
    designated_initializer_owner, extract_variable_name, first_type_child, function_terminal_node,
    has_ancestor_kind, infer_cpp_initializer_binding, infer_cpp_initializer_type, is_c_source_file,
    is_declaration_name, is_declarator_node, is_globally_qualified_cpp_name, is_nested_type_node,
    normalize_type_text, out_of_line_destructor_type_reference,
    out_of_line_member_definition_owner, parameter_belongs_to_callable_scope,
    qualified_owner_components, recovered_macro_decorated_type_node,
    resolve_declaring_member_owner, same_logical_symbol, same_visible_symbol,
    type_reference_hit_node,
};
use crate::graph::syntax::qualified_callable_value;
use brokk_bifrost_core::analyzer::tree_walk::{TreeWalkAction, walk_tree_iterative};
use brokk_bifrost_core::analyzer::usages::common::same_node;
use brokk_bifrost_core::analyzer::usages::inverted_edges::{
    ClassRangeIndex, FileEdgeScanInput, PerFileEdges, classify_reference_node, first_precise,
};
use brokk_bifrost_core::analyzer::usages::local_inference::{
    LocalInferenceConfig, LocalInferenceEngine,
};
use brokk_bifrost_core::analyzer::{CodeUnit, ProjectFile};
use brokk_bifrost_core::hash::{HashMap, HashSet};
use tree_sitter::Node;

/// The C++ half of one file's inverted pass: seed the scan context from the
/// already-parsed tree and walk it, recording every `caller -> callee` edge the
/// file names.
///
/// The pass's fan-out -- `build_edge_output` plus `parse_and_collect`, the
/// shared language-agnostic driver -- stays in `brokk-bifrost-analysis` and
/// calls this once per kept file.
pub fn scan_file(
    analyzer: &CppGraphSource<'_>,
    visibility: &VisibilityIndex<'_>,
    file: &ProjectFile,
    input: &FileEdgeScanInput<'_>,
) -> PerFileEdges {
    let ordinary_type_imports =
        initialized_ordinary_type_imports(input.root(), analyzer, visibility, file, input.source);
    let recovered_sentinel_classes = cpp_sentinel_recovered_classes(input.root(), input.source);
    let mut ctx = CppScan {
        analyzer: *analyzer,
        visibility,
        file,
        source: input.source,
        ordinary_type_imports,
        recovered_sentinel_classes,
        class_ranges: ClassRangeIndex::build(analyzer.index, file),
        declaring_member_cache: HashMap::default(),
        input,
        edges: PerFileEdges::default(),
    };
    let mut bindings = LocalInferenceEngine::new(LocalInferenceConfig::default());
    walk(input.root(), &mut ctx, &mut bindings);
    ctx.edges
}

struct CppScan<'a> {
    analyzer: CppGraphSource<'a>,
    visibility: &'a VisibilityIndex<'a>,
    file: &'a ProjectFile,
    source: &'a str,
    ordinary_type_imports: OrdinaryTypeImportCell,
    recovered_sentinel_classes: Vec<CppSentinelRecoveredClass>,
    class_ranges: ClassRangeIndex,
    declaring_member_cache: HashMap<CodeUnit, HashMap<String, EnclosingMemberOwnerResolution>>,
    input: &'a FileEdgeScanInput<'a>,
    edges: PerFileEdges,
}

impl CppScan<'_> {
    /// Resolve a type reference's text to a class `CodeUnit`.
    fn resolve_type(&self, text: &str) -> Option<CodeUnit> {
        self.visibility.resolve_type(self.file, text)
    }

    fn resolve_type_node_result(
        &self,
        node: Node<'_>,
    ) -> std::result::Result<Option<CodeUnit>, CppTemplateResolutionError> {
        self.visibility
            .resolve_type_node_result(self.file, node, self.source)
    }

    /// The fqn of the smallest class declaration containing `byte`.
    fn enclosing_class(&self, byte: usize) -> Option<&str> {
        self.class_ranges.enclosing(byte)
    }

    /// Return the smallest recovered sentinel owner scope containing `node`.
    /// Out-of-line definitions can sit beyond the recovered class range, so
    /// prefer an owner span over the class itself.  For references in a class
    /// body, append any parser-visible nested class names to the recovered
    /// top-level class path; the declaration visitor uses the same AST nesting
    /// when it re-owns those members.
    fn recovered_sentinel_scope(&self, node: Node<'_>) -> Option<Vec<String>> {
        cpp_sentinel_recovered_scope_for_node(node, self.source, &self.recovered_sentinel_classes)
    }

    fn record(&mut self, callee: String, node: Node<'_>) {
        self.edges.record_kind(
            self.input,
            callee,
            classify_reference_node(node),
            node.start_byte(),
            node.end_byte(),
        );
    }

    fn record_unproven(&mut self, name: &str, node: Node<'_>) {
        self.edges
            .record_unproven_name(self.input, name, node.start_byte(), node.end_byte());
    }
}

const SCOPE_NODES: &[&str] = &[
    "compound_statement",
    "field_declaration_list",
    "function_definition",
    "for_range_loop",
    "lambda_expression",
    "for_statement",
    "while_statement",
    "if_statement",
];

fn walk(node: Node<'_>, ctx: &mut CppScan<'_>, bindings: &mut LocalInferenceEngine<CodeUnit>) {
    let mut state = (ctx, bindings);
    walk_tree_iterative(
        node,
        &mut state,
        |node, (ctx, bindings)| {
            if walk_enter(node, ctx, bindings) {
                TreeWalkAction::DescendWithExit
            } else {
                TreeWalkAction::Descend
            }
        },
        |(_, bindings)| bindings.exit_scope(),
    );
}

fn walk_enter(
    node: Node<'_>,
    ctx: &mut CppScan<'_>,
    bindings: &mut LocalInferenceEngine<CodeUnit>,
) -> bool {
    let enters_scope = SCOPE_NODES.contains(&node.kind());
    if enters_scope {
        bindings.enter_scope();
    }
    seed_declaration(node, ctx, bindings);
    record_reference(node, ctx, bindings);
    enters_scope
}

fn record_reference(
    node: Node<'_>,
    ctx: &mut CppScan<'_>,
    bindings: &LocalInferenceEngine<CodeUnit>,
) {
    match ctx
        .visibility
        .resolve_ordinary_macro_reference(&ctx.analyzer, ctx.file, node, ctx.source)
    {
        OrdinaryMacroReferenceResolution::Resolved(macro_unit) => {
            ctx.record(macro_unit.fq_name(), node);
            return;
        }
        OrdinaryMacroReferenceResolution::Ambiguous => {
            ctx.record_unproven(node_text(node, ctx.source), node);
            return;
        }
        OrdinaryMacroReferenceResolution::Missing => {}
    }
    if let Some(return_type) = recovered_macro_return_type_node(node, ctx.source) {
        record_recovered_macro_return_type_reference(return_type, ctx);
        return;
    }
    if node.kind() == "using_declaration" {
        let (resolution, type_node) =
            if let Some(type_node) = using_enum_declaration_type_node(node) {
                (
                    resolve_using_enum_declaration_owner(
                        node,
                        &ctx.analyzer,
                        ctx.visibility,
                        &ctx.ordinary_type_imports,
                        ctx.file,
                        ctx.source,
                    ),
                    type_node,
                )
            } else if let Some(type_node) = ordinary_using_declaration_type_node(node) {
                (
                    resolve_ordinary_using_declaration_owner(
                        node,
                        &ctx.analyzer,
                        ctx.visibility,
                        ctx.file,
                        ctx.source,
                    ),
                    type_node,
                )
            } else {
                return;
            };
        match resolution {
            LexicalTypeResolution::Resolved { unit, .. } => ctx.record(unit.fq_name(), type_node),
            LexicalTypeResolution::Ambiguous | LexicalTypeResolution::Missing => {
                ctx.record_unproven(node_text(type_node, ctx.source), type_node);
            }
        }
        return;
    }
    if has_ancestor_kind(node, "using_declaration") {
        return;
    }
    if matches!(node.kind(), "qualified_identifier" | "scoped_identifier")
        && is_declaration_name(node)
        && let Some(owners) = out_of_line_member_definition_owner(
            &ctx.analyzer,
            ctx.visibility,
            ctx.file,
            ctx.source,
            node,
        )
    {
        let terminal_destructor = out_of_line_destructor_type_reference(node);
        let innermost = owners.innermost().map(|(_, owner)| owner.clone());
        for (owner_node, owner) in owners.owners {
            ctx.record(owner.fq_name(), owner_node);
        }
        if let (Some(terminal), Some(owner)) = (terminal_destructor, innermost) {
            ctx.record(owner.fq_name(), terminal);
        }
        return;
    }
    if let Some(value) = qualified_callable_value(node) {
        record_qualified_callable_value(
            value.qualified,
            value.global,
            &value.owner_components,
            value.member,
            ctx,
        );
        return;
    }
    if matches!(node.kind(), "identifier" | "field_identifier")
        && let Some(designator_owner) =
            designated_initializer_owner(ctx.visibility, ctx.file, ctx.source, node)
    {
        let name = node_text(node, ctx.source);
        match designator_owner {
            DesignatedInitializerOwner::Resolved(owner) => {
                if let Some(field) = ctx
                    .visibility
                    .visible_members_for_owner_name(ctx.file, &owner, name)
                    .into_iter()
                    .find(|unit| unit.is_field())
                {
                    ctx.record(field.fq_name(), node);
                }
            }
            DesignatedInitializerOwner::Unresolved => ctx.record_unproven(name, node),
        }
        return;
    }
    match node.kind() {
        "namespace_identifier"
            if let Some((type_node, _)) = recovered_macro_decorated_type_node(node) =>
        {
            record_recovered_macro_decorated_type_reference(node, type_node, ctx, bindings);
        }
        // A type reference (`Foo x`, base class, `new Foo()`'s type child) resolves
        // to the class. `new Foo()` reaches its type via this case (its type child
        // is itself one of these nodes), so there is no separate construction case.
        "type_identifier" | "qualified_identifier" | "scoped_type_identifier" | "template_type" => {
            if is_declaration_name(node) {
                if let Some(owners) = out_of_line_member_definition_owner(
                    &ctx.analyzer,
                    ctx.visibility,
                    ctx.file,
                    ctx.source,
                    node,
                ) {
                    let terminal_destructor = out_of_line_destructor_type_reference(node);
                    let innermost = owners.innermost().map(|(_, owner)| owner.clone());
                    for (owner_node, owner) in owners.owners {
                        ctx.record(owner.fq_name(), owner_node);
                    }
                    if let (Some(terminal), Some(owner)) = (terminal_destructor, innermost) {
                        ctx.record(owner.fq_name(), terminal);
                    }
                }
                return;
            }
            if is_nested_type_node(node) && !is_template_argument_type_leaf(node) {
                record_nested_type_terminal_reference(node, ctx);
                return;
            }
            // A `X::m(..)` static/scoped call appears as a `qualified_identifier`
            // function: resolve the `X` qualifier as a type and emit `Owner.m`.
            if let Some(function) = scoped_free_function(node, ctx) {
                ctx.record(function.fq_name(), function_terminal_node(node));
                return;
            }
            if let Some(call) = node.parent().filter(|parent| {
                parent.kind() == "call_expression"
                    && parent.child_by_field_name("function") == Some(node)
            }) && let LexicalTypeResolution::Resolved { unit, .. } = resolve_type_node_lexically(
                node,
                &ctx.analyzer,
                ctx.visibility,
                &ctx.ordinary_type_imports,
                ctx.file,
                ctx.source,
            ) {
                let Some(call_arity) = ctx
                    .visibility
                    .call_arity_evidence(ctx.file, call, ctx.source)
                    .exact()
                else {
                    ctx.record_unproven(node_text(node, ctx.source), function_terminal_node(node));
                    return;
                };
                if let VisibleMemberResolution::Callable(constructors) = ctx
                    .visibility
                    .visible_member_for_owner_name(ctx.file, &unit, unit.identifier())
                    && let Some(constructor) = constructors.iter().find(|constructor| {
                        cpp_callable_arity(&ctx.analyzer, constructor).accepts(call_arity)
                    })
                {
                    ctx.record(constructor.fq_name(), function_terminal_node(node));
                } else {
                    ctx.record(unit.fq_name(), function_terminal_node(node));
                }
                return;
            }
            if let Some(owner) = scoped_call_owner(node, ctx) {
                let member = scoped_call_member(node, ctx.source);
                if !member.is_empty() {
                    ctx.record(format!("{owner}.{member}"), function_terminal_node(node));
                    return;
                }
            }
            record_type_reference(node, ctx, bindings);
        }
        "call_expression" => record_call(node, ctx, bindings),
        _ => {}
    }
}

fn record_recovered_macro_return_type_reference(return_type: Node<'_>, ctx: &mut CppScan<'_>) {
    let name = node_text(return_type, ctx.source);
    let Some(scope) = recovered_or_indexed_lexical_scope(return_type, ctx) else {
        ctx.record_unproven(name, return_type);
        return;
    };
    let components = [name.to_string()];
    if let LexicalTypeResolution::Resolved { unit, .. } = ctx
        .visibility
        .resolve_type_components_lexically(&ctx.analyzer, ctx.file, &components, false, &scope)
    {
        ctx.record(unit.fq_name(), return_type);
        return;
    }

    let mut aliases = ctx
        .visibility
        .visible_identifier_candidates(ctx.file, name)
        .filter(|candidate| {
            ctx.analyzer
                .type_alias_provider()
                .is_some_and(|provider| provider.is_type_alias(candidate))
                && ctx.visibility.external_type_candidate_visible_in_context(
                    &ctx.analyzer,
                    ctx.file,
                    candidate,
                    return_type,
                )
        })
        .filter_map(|candidate| {
            let owner = ctx.analyzer.parent_of(candidate)?;
            let owner_components = canonical_cpp_scope_components(&owner);
            scope
                .starts_with(&owner_components)
                .then_some((candidate, owner_components.len()))
        })
        .collect::<Vec<_>>();
    let deepest = aliases.iter().map(|(_, depth)| *depth).max();
    aliases.retain(|(_, depth)| Some(*depth) == deepest);
    if aliases.len() == 1 {
        ctx.record(aliases[0].0.fq_name(), return_type);
    } else {
        ctx.record_unproven(name, return_type);
    }
}

/// A type node that is the direct type payload of a template argument.  The
/// outer template-id is recorded separately, but these leaves can name class
/// aliases (for example `expected<T, error_type>`) and therefore need their
/// own inverse edge as well.
fn is_template_argument_type_leaf(node: Node<'_>) -> bool {
    let Some(type_descriptor) = node.parent() else {
        return false;
    };
    if type_descriptor.kind() != "type_descriptor"
        || type_descriptor.child_by_field_name("type") != Some(node)
    {
        return false;
    }
    let Some(arguments) = type_descriptor.parent() else {
        return false;
    };
    if arguments.kind() != "template_argument_list" {
        return false;
    }
    arguments.parent().is_some_and(|parent| {
        matches!(parent.kind(), "template_type" | "template_function")
            && parent.child_by_field_name("arguments") == Some(arguments)
    })
}

fn record_type_reference(
    node: Node<'_>,
    ctx: &mut CppScan<'_>,
    bindings: &LocalInferenceEngine<CodeUnit>,
) {
    let ordinary_resolution = resolve_type_node_lexically(
        node,
        &ctx.analyzer,
        ctx.visibility,
        &ctx.ordinary_type_imports,
        ctx.file,
        ctx.source,
    );
    let resolution = match recovered_sentinel_type_resolution(node, ctx) {
        Some(recovered @ LexicalTypeResolution::Resolved { .. }) => recovered,
        Some(LexicalTypeResolution::Ambiguous | LexicalTypeResolution::Missing) | None => {
            ordinary_resolution
        }
    };
    let resolution = resolve_inverted_type_node(node, ctx, resolution);
    match resolution {
        LexicalTypeResolution::Resolved { unit, .. } => ctx.record(
            unit.fq_name(),
            type_reference_hit_node(node, ctx.file, ctx.source, bindings),
        ),
        LexicalTypeResolution::Ambiguous | LexicalTypeResolution::Missing => {}
    }
}

fn record_nested_type_terminal_reference(node: Node<'_>, ctx: &mut CppScan<'_>) {
    let Some(qualified) = node.parent().filter(|parent| {
        matches!(
            parent.kind(),
            "qualified_identifier" | "scoped_type_identifier"
        ) && parent.child_by_field_name("name") == Some(node)
    }) else {
        return;
    };
    let Some(owner) = qualified_owner_components(qualified, ctx.source) else {
        return;
    };
    let mut complete = qualified;
    while let Some(parent) = complete.parent().filter(|parent| {
        matches!(
            parent.kind(),
            "qualified_identifier" | "scoped_type_identifier"
        )
    }) {
        complete = parent;
    }
    if matches!(
        resolve_type_node_lexically(
            complete,
            &ctx.analyzer,
            ctx.visibility,
            &ctx.ordinary_type_imports,
            ctx.file,
            ctx.source,
        ),
        LexicalTypeResolution::Resolved { .. }
    ) {
        return;
    }

    let Some(enclosing_owner) = enclosing_callable_owner(node, ctx) else {
        return;
    };
    let lexical_scope = canonical_cpp_scope_components(&enclosing_owner);
    let owner_resolution = ctx.visibility.resolve_type_components_lexically(
        &ctx.analyzer,
        ctx.file,
        &owner.names,
        owner.global,
        &lexical_scope,
    );
    let owner_unit = match owner_resolution {
        LexicalTypeResolution::Resolved { unit, .. } => unit,
        LexicalTypeResolution::Missing if !owner.global && owner.names.len() == 1 => {
            let Some(unit) = ctx.visibility.inherited_injected_class_owner(
                &ctx.analyzer,
                ctx.file,
                &enclosing_owner,
                &owner.names[0],
            ) else {
                return;
            };
            unit
        }
        LexicalTypeResolution::Ambiguous | LexicalTypeResolution::Missing => return,
    };
    let name = node_text(node, ctx.source);
    let mut candidates = Vec::new();
    for candidate in ctx
        .visibility
        .visible_members_for_owner_name(ctx.file, &owner_unit, name)
        .into_iter()
        .filter(|candidate| {
            candidate.is_class()
                || ctx
                    .analyzer
                    .type_alias_provider()
                    .is_some_and(|provider| provider.is_type_alias(candidate))
        })
        .filter(|candidate| {
            ctx.visibility.external_type_candidate_visible_in_context(
                &ctx.analyzer,
                ctx.file,
                candidate,
                node,
            )
        })
    {
        if !candidates
            .iter()
            .any(|existing| same_logical_symbol(existing, candidate))
        {
            candidates.push(candidate.clone());
        }
    }
    if let [candidate] = candidates.as_slice() {
        ctx.record(candidate.fq_name(), complete);
    }
}

fn recovered_sentinel_type_resolution(
    node: Node<'_>,
    ctx: &CppScan<'_>,
) -> Option<LexicalTypeResolution> {
    let scope = recovered_or_indexed_lexical_scope(node, ctx)?;
    let components = cpp_type_name_components(node, ctx.source)?;
    let global = is_globally_qualified_cpp_name(node);
    Some(ctx.visibility.resolve_type_components_lexically(
        &ctx.analyzer,
        ctx.file,
        &components,
        global,
        &scope,
    ))
}

/// Forward and inverted C++ scans must agree on the owner scope when
/// tree-sitter's malformed wrapper hides the structural class/namespace. The
/// sentinel recovery is the most precise signal; otherwise use the shared
/// lexical-scope reconstruction, which falls back to the indexed enclosing
/// code-unit scope for displaced definitions.
fn recovered_or_indexed_lexical_scope(node: Node<'_>, ctx: &CppScan<'_>) -> Option<Vec<String>> {
    ctx.recovered_sentinel_scope(node).or_else(|| {
        match enclosing_lexical_scope_components(
            node,
            &ctx.analyzer,
            ctx.visibility,
            ctx.file,
            ctx.source,
        ) {
            LexicalScopeResolution::Resolved(scope) => Some(scope),
            LexicalScopeResolution::Ambiguous | LexicalScopeResolution::Missing => None,
        }
    })
}

/// Tree-sitter can place either side of a missing `::` in a recovered
/// declaration's qualified scope: a prefix macro may leave the real type in
/// the scope, while a suffix attribute can leave the macro there instead.
/// Resolve both structured candidates. Recovery is usable only when exactly
/// one candidate resolves; even two spellings that happen to resolve to the
/// same logical symbol are ambiguous because one may be a macro token.
fn record_recovered_macro_decorated_type_reference(
    scope_node: Node<'_>,
    type_node: Node<'_>,
    ctx: &mut CppScan<'_>,
    bindings: &LocalInferenceEngine<CodeUnit>,
) {
    let mut resolved = Vec::new();
    for candidate in [scope_node, type_node] {
        if resolved
            .iter()
            .any(|(_, existing): &(CodeUnit, Node<'_>)| same_node(*existing, candidate))
        {
            continue;
        }
        if let LexicalTypeResolution::Resolved { unit, .. } = resolve_type_node_lexically(
            candidate,
            &ctx.analyzer,
            ctx.visibility,
            &ctx.ordinary_type_imports,
            ctx.file,
            ctx.source,
        ) {
            resolved.push((unit, candidate));
        }
    }
    let [(unit, candidate)] = resolved.as_slice() else {
        return;
    };
    ctx.record(
        unit.fq_name(),
        type_reference_hit_node(*candidate, ctx.file, ctx.source, bindings),
    );
}

/// Resolve an inverted type edge to the concrete specialization named by a
/// template-id.  The lexical resolver intentionally resolves the primary
/// declaration: callers that need to preserve a concrete specialization (the
/// reference graph included) must apply the parsed arguments afterwards.  If
/// the primary cannot be specialized, retain the lexical result; that keeps
/// dependent or incomplete template uses conservative rather than dropping a
/// proven primary edge.
fn resolve_inverted_type_node(
    node: Node<'_>,
    ctx: &CppScan<'_>,
    resolution: LexicalTypeResolution,
) -> LexicalTypeResolution {
    let Some(arguments) = cpp_template_reference_arguments(node, ctx.source) else {
        return resolution;
    };
    let LexicalTypeResolution::Resolved {
        unit,
        components,
        candidates,
    } = resolution
    else {
        return resolution;
    };

    let mut specialized = Vec::new();
    for candidate in candidates.iter().chain(std::iter::once(&unit)) {
        if let Ok(resolved) =
            ctx.visibility
                .resolve_template_arguments(ctx.file, candidate.clone(), &arguments)
            && !specialized
                .iter()
                .any(|existing: &CodeUnit| same_visible_symbol(existing, &resolved))
        {
            specialized.push(resolved);
        }
    }
    match specialized.as_slice() {
        [specialized] => LexicalTypeResolution::Resolved {
            unit: specialized.clone(),
            components,
            candidates,
        },
        _ => LexicalTypeResolution::Resolved {
            unit,
            components,
            candidates,
        },
    }
}

fn record_qualified_callable_value(
    qualified: Node<'_>,
    global: bool,
    owner_components: &[Node<'_>],
    member_node: Node<'_>,
    ctx: &mut CppScan<'_>,
) {
    let member_name = node_text(member_node, ctx.source);
    if member_name.is_empty() {
        return;
    }
    let owner_components = owner_components
        .iter()
        .map(|component| node_text(*component, ctx.source))
        .map(str::to_string)
        .collect::<Vec<_>>();
    let lexical_scope = if global {
        Vec::new()
    } else {
        match enclosing_lexical_scope_components(
            qualified,
            &ctx.analyzer,
            ctx.visibility,
            ctx.file,
            ctx.source,
        ) {
            LexicalScopeResolution::Resolved(scope) => scope,
            LexicalScopeResolution::Ambiguous | LexicalScopeResolution::Missing => {
                ctx.record_unproven(member_name, member_node);
                return;
            }
        }
    };
    let owner = match ctx.visibility.resolve_callable_value_components_lexically(
        &ctx.analyzer,
        ctx.file,
        &owner_components,
        member_name,
        global,
        &lexical_scope,
    ) {
        LexicalCallableValueResolution::Type(owner) => owner,
        LexicalCallableValueResolution::FreeFunction(function) => {
            ctx.record(function.fq_name(), member_node);
            return;
        }
        LexicalCallableValueResolution::Ambiguous => {
            ctx.record_unproven(member_name, member_node);
            return;
        }
        LexicalCallableValueResolution::Missing => match resolve_type_components_lexically_at(
            qualified,
            &owner_components,
            global,
            &ctx.analyzer,
            ctx.visibility,
            &ctx.ordinary_type_imports,
            ctx.file,
            ctx.source,
        ) {
            LexicalTypeResolution::Resolved { unit, .. } => unit,
            LexicalTypeResolution::Ambiguous | LexicalTypeResolution::Missing => {
                ctx.record_unproven(member_name, member_node);
                return;
            }
        },
    };
    match ctx
        .visibility
        .visible_member_for_owner_name(ctx.file, &owner, member_name)
    {
        VisibleMemberResolution::Callable(callables) => {
            if let Some(callable) = callables.first() {
                ctx.record(callable.fq_name(), member_node);
            }
        }
        // Fields are intentionally absent from the workspace usage-graph node
        // catalog. A proven non-callable member is therefore a negative for this
        // callable edge pass, not an unresolved terminal-name fanout.
        VisibleMemberResolution::NonCallable => {}
        VisibleMemberResolution::AmbiguousKind | VisibleMemberResolution::Missing => {
            ctx.record_unproven(member_name, member_node);
        }
    }
}

fn record_call(node: Node<'_>, ctx: &mut CppScan<'_>, bindings: &LocalInferenceEngine<CodeUnit>) {
    let Some(function) = node.child_by_field_name("function") else {
        return;
    };
    let Some(call_arity) = ctx
        .visibility
        .call_arity_evidence(ctx.file, node, ctx.source)
        .exact()
    else {
        let name_node = function
            .child_by_field_name("field")
            .or_else(|| function.child_by_field_name("name"))
            .unwrap_or(function);
        let name = node_text(name_node, ctx.source);
        if !name.is_empty() {
            ctx.record_unproven(name, name_node);
        }
        return;
    };
    match function.kind() {
        // `obj.m()` / `ptr->m()`: type the receiver, emit `Owner.m`.
        "field_expression" => {
            let Some(field) = function.child_by_field_name("field") else {
                return;
            };
            let name = node_text(field, ctx.source);
            if name.is_empty() {
                return;
            }
            let Some(receiver) = function
                .child_by_field_name("argument")
                .or_else(|| function.named_child(0))
            else {
                return;
            };
            if receiver_is_self_like(receiver, ctx.file) {
                // `this->m()` / `(*this).m()` is a same-owner call (#1138):
                // record it as unproven inbound rather than dropping it, so a
                // member reachable only through same-owner calls reads
                // INCONCLUSIVE, never confidently dead — uniformly with the
                // other languages.
                ctx.record_unproven(name, field);
                return;
            }
            if let Some(receiver_owner) = receiver_type_unit(receiver, ctx, bindings, 32) {
                match resolve_declaring_member_owner_cached(ctx, &receiver_owner, name) {
                    EnclosingMemberOwnerResolution::Owner(owner) => {
                        match ctx
                            .visibility
                            .visible_member_for_owner_name(ctx.file, &owner, name)
                        {
                            VisibleMemberResolution::Callable(callables) => {
                                if let Some(callable) = callables.iter().find(|callable| {
                                    cpp_callable_arity(&ctx.analyzer, callable).accepts(call_arity)
                                }) {
                                    ctx.record(callable.fq_name(), field);
                                }
                            }
                            VisibleMemberResolution::AmbiguousKind => {
                                ctx.record_unproven(name, field);
                            }
                            VisibleMemberResolution::NonCallable
                            | VisibleMemberResolution::Missing => {}
                        }
                    }
                    EnclosingMemberOwnerResolution::Ambiguous => {
                        ctx.record_unproven(name, field);
                    }
                    EnclosingMemberOwnerResolution::Missing => {}
                }
            } else {
                ctx.record_unproven(name, field);
            }
        }
        // A bare `m(..)` is either a free function or an unqualified member call on
        // the enclosing class (`this`). `qualified_identifier` (`X::m`) is handled
        // by the type-reference case above.
        "identifier" | "template_function" => {
            let terminal = super::resolver::function_terminal_node(function);
            let name = node_text(terminal, ctx.source);
            if name.is_empty() {
                return;
            }
            if bindings.is_shadowed(name) {
                return;
            }
            if let Some(enclosing_owner) = enclosing_callable_owner(function, ctx) {
                match resolve_declaring_member_owner_cached(ctx, &enclosing_owner, name) {
                    EnclosingMemberOwnerResolution::Owner(owner)
                        if !same_visible_symbol(&owner, &enclosing_owner) =>
                    {
                        match ctx
                            .visibility
                            .visible_member_for_owner_name(ctx.file, &owner, name)
                        {
                            VisibleMemberResolution::Callable(callables) => {
                                if let Some(callable) = callables.iter().find(|callable| {
                                    cpp_callable_arity(&ctx.analyzer, callable).accepts(call_arity)
                                }) {
                                    ctx.record(callable.fq_name(), function);
                                }
                            }
                            VisibleMemberResolution::AmbiguousKind => {
                                ctx.record_unproven(name, function);
                            }
                            VisibleMemberResolution::NonCallable
                            | VisibleMemberResolution::Missing => {}
                        }
                        return;
                    }
                    EnclosingMemberOwnerResolution::Owner(_) => {
                        // Bare `m(..)` resolving to a method whose owner IS the
                        // enclosing class is a same-owner call (#1161, mirroring
                        // the `this->m()` fix at #1138): record it as unproven
                        // inbound rather than dropping it, so a member reachable
                        // only through bare implicit-this calls reads
                        // INCONCLUSIVE, never confidently dead — uniformly with
                        // the other languages and with the explicit-`this->m()`
                        // site above.
                        ctx.record_unproven(name, function);
                        return;
                    }
                    EnclosingMemberOwnerResolution::Ambiguous => {
                        ctx.record_unproven(name, function);
                        return;
                    }
                    EnclosingMemberOwnerResolution::Missing => {}
                }
            }
            let resolution = resolve_bare_call_target(
                node,
                function,
                &ctx.analyzer,
                ctx.visibility,
                &ctx.ordinary_type_imports,
                ctx.file,
                ctx.source,
            );
            match resolution {
                BareCallTargetResolution::FreeFunctions(units) => {
                    let mut recorded = HashSet::default();
                    for unit in units {
                        let fq_name = unit.fq_name();
                        if recorded.insert(fq_name.clone()) {
                            ctx.record(fq_name, terminal);
                        }
                    }
                }
                BareCallTargetResolution::Type(unit) => {
                    if let VisibleMemberResolution::Callable(constructors) = ctx
                        .visibility
                        .visible_member_for_owner_name(ctx.file, &unit, unit.identifier())
                        && let Some(constructor) = constructors.iter().find(|constructor| {
                            cpp_callable_arity(&ctx.analyzer, constructor).accepts(call_arity)
                        })
                    {
                        ctx.record(constructor.fq_name(), terminal);
                    } else {
                        ctx.record(unit.fq_name(), function);
                    }
                }
                BareCallTargetResolution::UnprovenFreeFunctions(_)
                | BareCallTargetResolution::CallableShadow
                | BareCallTargetResolution::Ambiguous => {}
                BareCallTargetResolution::Missing => {}
            }
            // Direct/self member calls are intentionally omitted above; unique inherited
            // callable owners are recorded, while an unresolved bare name adds no edge.
        }
        _ => {}
    }
}

fn resolve_declaring_member_owner_cached(
    ctx: &mut CppScan<'_>,
    receiver_owner: &CodeUnit,
    name: &str,
) -> EnclosingMemberOwnerResolution {
    if let Some(cached) = ctx
        .declaring_member_cache
        .get(receiver_owner)
        .and_then(|by_name| by_name.get(name))
        .cloned()
    {
        return cached;
    }
    let resolution = resolve_declaring_member_owner(
        &ctx.analyzer,
        ctx.visibility,
        ctx.file,
        receiver_owner,
        name,
    );
    ctx.declaring_member_cache
        .entry(receiver_owner.clone())
        .or_default()
        .insert(name.to_string(), resolution.clone());
    resolution
}

fn enclosing_callable_owner(node: Node<'_>, ctx: &CppScan<'_>) -> Option<CodeUnit> {
    let mut current = node.parent();
    while let Some(parent) = current {
        if parent.kind() == "function_definition" {
            let declarator = parent.child_by_field_name("declarator")?;
            let function = declarator_name_node(declarator)?;
            if let Some(owners) = out_of_line_member_definition_owner(
                &ctx.analyzer,
                ctx.visibility,
                ctx.file,
                ctx.source,
                function,
            ) && let Some((_, owner)) = owners.innermost()
            {
                return Some(owner.clone());
            }
            break;
        }
        current = parent.parent();
    }
    ctx.enclosing_class(node.start_byte()).and_then(|fqn| {
        ctx.analyzer
            .definitions(fqn)
            .find(|candidate| candidate.is_class())
    })
}

fn receiver_is_self_like(receiver: Node<'_>, file: &ProjectFile) -> bool {
    match receiver.kind() {
        "this" => !is_c_source_file(file),
        "parenthesized_expression" | "pointer_expression" => receiver
            .child_by_field_name("argument")
            .or_else(|| receiver.named_child(0))
            .is_some_and(|inner| receiver_is_self_like(inner, file)),
        _ => false,
    }
}

/// If `node` is the `function` of a namespace-qualified free-function call, its target.
fn scoped_free_function(node: Node<'_>, ctx: &CppScan<'_>) -> Option<CodeUnit> {
    if node.kind() != "qualified_identifier" {
        return None;
    }
    let parent = node.parent()?;
    if parent.kind() != "call_expression" || parent.child_by_field_name("function") != Some(node) {
        return None;
    }
    ctx.visibility.resolve_named(
        ctx.file,
        node_text(node, ctx.source),
        TargetKind::FreeFunction,
    )
}

/// If `node` is the `function` of a `X::m(..)` call, the fqn of `X`'s type.
fn scoped_call_owner(node: Node<'_>, ctx: &CppScan<'_>) -> Option<String> {
    if node.kind() != "qualified_identifier" {
        return None;
    }
    let parent = node.parent()?;
    if parent.kind() != "call_expression" || parent.child_by_field_name("function") != Some(node) {
        return None;
    }
    let scope = node.child_by_field_name("scope")?;
    match resolve_type_node_lexically(
        scope,
        &ctx.analyzer,
        ctx.visibility,
        &ctx.ordinary_type_imports,
        ctx.file,
        ctx.source,
    ) {
        LexicalTypeResolution::Resolved { unit, .. } => Some(unit.fq_name()),
        LexicalTypeResolution::Ambiguous | LexicalTypeResolution::Missing => None,
    }
}

/// The trailing member name of a `X::m` qualified identifier.
fn scoped_call_member(node: Node<'_>, source: &str) -> String {
    node.child_by_field_name("name")
        .map(|name| node_text(name, source).to_string())
        .unwrap_or_default()
}

fn receiver_type_unit(
    receiver: Node<'_>,
    ctx: &CppScan<'_>,
    bindings: &LocalInferenceEngine<CodeUnit>,
    remaining_call_depth: usize,
) -> Option<CodeUnit> {
    match receiver.kind() {
        "identifier" => {
            let name = node_text(receiver, ctx.source);
            // A typed local resolves to its type; otherwise the name may itself be a
            // type, unless it is a known (shadowed) untyped local — never reinterpret
            // a value as a static type.
            first_precise(bindings, name).or_else(|| {
                (!bindings.is_shadowed(name))
                    .then(|| resolve_type_node_with_recovered_scope(receiver, ctx))
                    .flatten()
                    .or_else(|| {
                        (!bindings.is_shadowed(name))
                            .then(|| ctx.resolve_type(name))
                            .flatten()
                    })
            })
        }
        "this" if is_c_source_file(ctx.file) => {
            first_precise(bindings, node_text(receiver, ctx.source))
        }
        "this" => ctx.enclosing_class(receiver.start_byte()).and_then(|fqn| {
            ctx.analyzer
                .definitions(fqn)
                .find(|candidate| candidate.is_class())
        }),
        // `(*p).m()` / `(p).m()` unwrap to the inner receiver.
        "parenthesized_expression" | "pointer_expression" => receiver
            .child_by_field_name("argument")
            .or_else(|| receiver.named_child(0))
            .and_then(|inner| receiver_type_unit(inner, ctx, bindings, remaining_call_depth)),
        "call_expression" if remaining_call_depth > 0 => infer_cpp_initializer_binding(
            &ctx.analyzer,
            ctx.visibility,
            ctx.file,
            ctx.source,
            receiver,
            Some(&|inner, _source| {
                receiver_type_unit(inner, ctx, bindings, remaining_call_depth - 1)
                    .into_iter()
                    .collect()
            }),
        )
        .and_then(|binding| binding.unit),
        _ => None,
    }
}

fn seed_declaration(
    node: Node<'_>,
    ctx: &mut CppScan<'_>,
    bindings: &mut LocalInferenceEngine<CodeUnit>,
) {
    if recovered_macro_return_type_node(node, ctx.source).is_some()
        || crate::declarations::is_direct_recovered_exported_class_field_declaration(
            node, ctx.source,
        )
    {
        return;
    }
    match node.kind() {
        "parameter_declaration" | "optional_parameter_declaration" => {
            seed_typed_binding(node, ctx, bindings)
        }
        "declaration" | "field_declaration" => seed_variable_declaration(node, ctx, bindings),
        "for_range_loop" => seed_range_binding(node, ctx, bindings),
        "expression_statement" => seed_function_macro_local_binding(node, ctx, bindings),
        _ => {}
    }
}

fn seed_function_macro_local_binding(
    node: Node<'_>,
    ctx: &CppScan<'_>,
    bindings: &mut LocalInferenceEngine<CodeUnit>,
) {
    let Some(binding) = ctx
        .visibility
        .function_macro_local_binding(ctx.file, node, ctx.source)
    else {
        return;
    };
    let unit = binding
        .type_node
        .and_then(|type_node| resolve_type_node_with_recovered_scope(type_node, ctx))
        .or_else(|| {
            binding
                .type_node
                .and_then(|type_node| ctx.resolve_type_node_result(type_node).ok().flatten())
        })
        .or_else(|| ctx.resolve_type(&binding.type_name));
    match unit {
        Some(unit) => bindings.seed_symbol(binding.name, unit),
        None => bindings.declare_shadow(binding.name),
    }
}

fn seed_typed_binding(
    node: Node<'_>,
    ctx: &CppScan<'_>,
    bindings: &mut LocalInferenceEngine<CodeUnit>,
) {
    if !parameter_belongs_to_callable_scope(node) {
        return;
    }
    let Some(declarator) = node.child_by_field_name("declarator") else {
        return;
    };
    let Some(name) = extract_variable_name(declarator, ctx.source) else {
        return;
    };
    let type_node = node
        .child_by_field_name("type")
        .or_else(|| first_type_child(node));
    seed_binding(&name, type_node, None, ctx, bindings);
}

fn seed_range_binding(
    node: Node<'_>,
    ctx: &CppScan<'_>,
    bindings: &mut LocalInferenceEngine<CodeUnit>,
) {
    let Some(declarator) = node.child_by_field_name("declarator") else {
        return;
    };
    let Some(name) = extract_variable_name(declarator, ctx.source) else {
        return;
    };
    let type_node = node
        .child_by_field_name("type")
        .or_else(|| first_type_child(node));
    seed_binding(&name, type_node, None, ctx, bindings);
}

fn seed_variable_declaration(
    node: Node<'_>,
    ctx: &CppScan<'_>,
    bindings: &mut LocalInferenceEngine<CodeUnit>,
) {
    let type_node = node
        .child_by_field_name("type")
        .or_else(|| first_type_child(node));
    let type_text =
        type_node.map(|type_node| normalize_type_text(node_text(type_node, ctx.source)));
    let mut cursor = node.walk();
    for child in node.named_children(&mut cursor) {
        let declarator = if child.kind() == "init_declarator" {
            child.child_by_field_name("declarator")
        } else if is_declarator_node(child) {
            Some(child)
        } else {
            None
        };
        let Some(declarator) = declarator else {
            continue;
        };
        if declarator.kind() == "function_declarator"
            && !constructor_style_local_declaration(
                ctx.visibility,
                ctx.file,
                ctx.source,
                declarator,
                type_text.as_deref(),
                bindings,
            )
        {
            if node.kind() == "declaration"
                && has_function_scope_ancestor(node)
                && let Some(name) = extract_variable_name(declarator, ctx.source)
            {
                bindings.declare_shadow(name);
            }
            continue;
        }
        let Some(name) = extract_variable_name(declarator, ctx.source) else {
            continue;
        };
        let value = child.child_by_field_name("value");
        seed_binding(&name, type_node, value, ctx, bindings);
    }
}

fn has_function_scope_ancestor(mut node: Node<'_>) -> bool {
    while let Some(parent) = node.parent() {
        if matches!(parent.kind(), "function_definition" | "lambda_expression") {
            return true;
        }
        node = parent;
    }
    false
}

fn seed_binding(
    name: &str,
    type_node: Option<Node<'_>>,
    value: Option<Node<'_>>,
    ctx: &CppScan<'_>,
    bindings: &mut LocalInferenceEngine<CodeUnit>,
) {
    if name.is_empty() {
        return;
    }
    // A declared type resolves directly; `auto x = new Foo()` infers from the
    // initializer. A declared-but-unresolved local is shadowed so a later
    // member access never falls back to static type resolution on its name.
    let declared_type =
        type_node.filter(|node| normalize_type_text(node_text(*node, ctx.source)) != "auto");
    let resolved = match declared_type {
        Some(node) => resolve_type_node_with_recovered_scope(node, ctx).or_else(|| {
            match ctx.resolve_type_node_result(node) {
                Ok(Some(unit)) => Some(unit),
                Ok(None) => ctx.resolve_type(node_text(node, ctx.source)),
                Err(_) => None,
            }
        }),
        None => value.and_then(|value| infer_type_from_value(value, ctx)),
    };
    match resolved {
        Some(unit) => bindings.seed_symbol(name.to_string(), unit),
        None => bindings.declare_shadow(name.to_string()),
    }
}

fn resolve_type_node_with_recovered_scope(node: Node<'_>, ctx: &CppScan<'_>) -> Option<CodeUnit> {
    let scope = recovered_or_indexed_lexical_scope(node, ctx)?;
    let components = cpp_type_name_components(node, ctx.source)?;
    let global = is_globally_qualified_cpp_name(node);
    match ctx.visibility.resolve_type_components_lexically(
        &ctx.analyzer,
        ctx.file,
        &components,
        global,
        &scope,
    ) {
        LexicalTypeResolution::Resolved { unit, .. } => Some(unit),
        LexicalTypeResolution::Ambiguous | LexicalTypeResolution::Missing => None,
    }
}

/// Infer a class type from an initializer expression for `auto`/untyped locals.
fn infer_type_from_value(node: Node<'_>, ctx: &CppScan<'_>) -> Option<CodeUnit> {
    infer_cpp_initializer_type(&ctx.analyzer, ctx.visibility, ctx.file, ctx.source, node)
}