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-rw-r--r--compiler/rustc_resolve/src/def_collector.rs293
1 files changed, 293 insertions, 0 deletions
diff --git a/compiler/rustc_resolve/src/def_collector.rs b/compiler/rustc_resolve/src/def_collector.rs
new file mode 100644
index 00000000000..5d5088de31b
--- /dev/null
+++ b/compiler/rustc_resolve/src/def_collector.rs
@@ -0,0 +1,293 @@
+use crate::Resolver;
+use rustc_ast::token::{self, Token};
+use rustc_ast::visit::{self, FnKind};
+use rustc_ast::walk_list;
+use rustc_ast::*;
+use rustc_ast_lowering::ResolverAstLowering;
+use rustc_expand::expand::AstFragment;
+use rustc_hir::def_id::LocalDefId;
+use rustc_hir::definitions::*;
+use rustc_span::hygiene::ExpnId;
+use rustc_span::symbol::{kw, sym};
+use rustc_span::Span;
+use tracing::debug;
+
+crate fn collect_definitions(
+    resolver: &mut Resolver<'_>,
+    fragment: &AstFragment,
+    expansion: ExpnId,
+) {
+    let parent_def = resolver.invocation_parents[&expansion];
+    fragment.visit_with(&mut DefCollector { resolver, parent_def, expansion });
+}
+
+/// Creates `DefId`s for nodes in the AST.
+struct DefCollector<'a, 'b> {
+    resolver: &'a mut Resolver<'b>,
+    parent_def: LocalDefId,
+    expansion: ExpnId,
+}
+
+impl<'a, 'b> DefCollector<'a, 'b> {
+    fn create_def(&mut self, node_id: NodeId, data: DefPathData, span: Span) -> LocalDefId {
+        let parent_def = self.parent_def;
+        debug!("create_def(node_id={:?}, data={:?}, parent_def={:?})", node_id, data, parent_def);
+        self.resolver.create_def(parent_def, node_id, data, self.expansion, span)
+    }
+
+    fn with_parent<F: FnOnce(&mut Self)>(&mut self, parent_def: LocalDefId, f: F) {
+        let orig_parent_def = std::mem::replace(&mut self.parent_def, parent_def);
+        f(self);
+        self.parent_def = orig_parent_def;
+    }
+
+    fn collect_field(&mut self, field: &'a StructField, index: Option<usize>) {
+        let index = |this: &Self| {
+            index.unwrap_or_else(|| {
+                let node_id = NodeId::placeholder_from_expn_id(this.expansion);
+                this.resolver.placeholder_field_indices[&node_id]
+            })
+        };
+
+        if field.is_placeholder {
+            let old_index = self.resolver.placeholder_field_indices.insert(field.id, index(self));
+            assert!(old_index.is_none(), "placeholder field index is reset for a node ID");
+            self.visit_macro_invoc(field.id);
+        } else {
+            let name = field.ident.map_or_else(|| sym::integer(index(self)), |ident| ident.name);
+            let def = self.create_def(field.id, DefPathData::ValueNs(name), field.span);
+            self.with_parent(def, |this| visit::walk_struct_field(this, field));
+        }
+    }
+
+    fn visit_macro_invoc(&mut self, id: NodeId) {
+        let old_parent =
+            self.resolver.invocation_parents.insert(id.placeholder_to_expn_id(), self.parent_def);
+        assert!(old_parent.is_none(), "parent `LocalDefId` is reset for an invocation");
+    }
+}
+
+impl<'a, 'b> visit::Visitor<'a> for DefCollector<'a, 'b> {
+    fn visit_item(&mut self, i: &'a Item) {
+        debug!("visit_item: {:?}", i);
+
+        // Pick the def data. This need not be unique, but the more
+        // information we encapsulate into, the better
+        let def_data = match &i.kind {
+            ItemKind::Impl { .. } => DefPathData::Impl,
+            ItemKind::Mod(..) if i.ident.name == kw::Invalid => {
+                return visit::walk_item(self, i);
+            }
+            ItemKind::Mod(..)
+            | ItemKind::Trait(..)
+            | ItemKind::TraitAlias(..)
+            | ItemKind::Enum(..)
+            | ItemKind::Struct(..)
+            | ItemKind::Union(..)
+            | ItemKind::ExternCrate(..)
+            | ItemKind::ForeignMod(..)
+            | ItemKind::TyAlias(..) => DefPathData::TypeNs(i.ident.name),
+            ItemKind::Static(..) | ItemKind::Const(..) | ItemKind::Fn(..) => {
+                DefPathData::ValueNs(i.ident.name)
+            }
+            ItemKind::MacroDef(..) => DefPathData::MacroNs(i.ident.name),
+            ItemKind::MacCall(..) => return self.visit_macro_invoc(i.id),
+            ItemKind::GlobalAsm(..) => DefPathData::Misc,
+            ItemKind::Use(..) => {
+                return visit::walk_item(self, i);
+            }
+        };
+        let def = self.create_def(i.id, def_data, i.span);
+
+        self.with_parent(def, |this| {
+            match i.kind {
+                ItemKind::Struct(ref struct_def, _) | ItemKind::Union(ref struct_def, _) => {
+                    // If this is a unit or tuple-like struct, register the constructor.
+                    if let Some(ctor_hir_id) = struct_def.ctor_id() {
+                        this.create_def(ctor_hir_id, DefPathData::Ctor, i.span);
+                    }
+                }
+                _ => {}
+            }
+            visit::walk_item(this, i);
+        });
+    }
+
+    fn visit_fn(&mut self, fn_kind: FnKind<'a>, span: Span, _: NodeId) {
+        if let FnKind::Fn(_, _, sig, _, body) = fn_kind {
+            if let Async::Yes { closure_id, return_impl_trait_id, .. } = sig.header.asyncness {
+                self.create_def(return_impl_trait_id, DefPathData::ImplTrait, span);
+
+                // For async functions, we need to create their inner defs inside of a
+                // closure to match their desugared representation. Besides that,
+                // we must mirror everything that `visit::walk_fn` below does.
+                self.visit_fn_header(&sig.header);
+                visit::walk_fn_decl(self, &sig.decl);
+                let closure_def = self.create_def(closure_id, DefPathData::ClosureExpr, span);
+                self.with_parent(closure_def, |this| walk_list!(this, visit_block, body));
+                return;
+            }
+        }
+
+        visit::walk_fn(self, fn_kind, span);
+    }
+
+    fn visit_use_tree(&mut self, use_tree: &'a UseTree, id: NodeId, _nested: bool) {
+        self.create_def(id, DefPathData::Misc, use_tree.span);
+        visit::walk_use_tree(self, use_tree, id);
+    }
+
+    fn visit_foreign_item(&mut self, foreign_item: &'a ForeignItem) {
+        if let ForeignItemKind::MacCall(_) = foreign_item.kind {
+            return self.visit_macro_invoc(foreign_item.id);
+        }
+
+        let def = self.create_def(
+            foreign_item.id,
+            DefPathData::ValueNs(foreign_item.ident.name),
+            foreign_item.span,
+        );
+
+        self.with_parent(def, |this| {
+            visit::walk_foreign_item(this, foreign_item);
+        });
+    }
+
+    fn visit_variant(&mut self, v: &'a Variant) {
+        if v.is_placeholder {
+            return self.visit_macro_invoc(v.id);
+        }
+        let def = self.create_def(v.id, DefPathData::TypeNs(v.ident.name), v.span);
+        self.with_parent(def, |this| {
+            if let Some(ctor_hir_id) = v.data.ctor_id() {
+                this.create_def(ctor_hir_id, DefPathData::Ctor, v.span);
+            }
+            visit::walk_variant(this, v)
+        });
+    }
+
+    fn visit_variant_data(&mut self, data: &'a VariantData) {
+        // The assumption here is that non-`cfg` macro expansion cannot change field indices.
+        // It currently holds because only inert attributes are accepted on fields,
+        // and every such attribute expands into a single field after it's resolved.
+        for (index, field) in data.fields().iter().enumerate() {
+            self.collect_field(field, Some(index));
+        }
+    }
+
+    fn visit_generic_param(&mut self, param: &'a GenericParam) {
+        if param.is_placeholder {
+            self.visit_macro_invoc(param.id);
+            return;
+        }
+        let name = param.ident.name;
+        let def_path_data = match param.kind {
+            GenericParamKind::Lifetime { .. } => DefPathData::LifetimeNs(name),
+            GenericParamKind::Type { .. } => DefPathData::TypeNs(name),
+            GenericParamKind::Const { .. } => DefPathData::ValueNs(name),
+        };
+        self.create_def(param.id, def_path_data, param.ident.span);
+
+        visit::walk_generic_param(self, param);
+    }
+
+    fn visit_assoc_item(&mut self, i: &'a AssocItem, ctxt: visit::AssocCtxt) {
+        let def_data = match &i.kind {
+            AssocItemKind::Fn(..) | AssocItemKind::Const(..) => DefPathData::ValueNs(i.ident.name),
+            AssocItemKind::TyAlias(..) => DefPathData::TypeNs(i.ident.name),
+            AssocItemKind::MacCall(..) => return self.visit_macro_invoc(i.id),
+        };
+
+        let def = self.create_def(i.id, def_data, i.span);
+        self.with_parent(def, |this| visit::walk_assoc_item(this, i, ctxt));
+    }
+
+    fn visit_pat(&mut self, pat: &'a Pat) {
+        match pat.kind {
+            PatKind::MacCall(..) => self.visit_macro_invoc(pat.id),
+            _ => visit::walk_pat(self, pat),
+        }
+    }
+
+    fn visit_anon_const(&mut self, constant: &'a AnonConst) {
+        let def = self.create_def(constant.id, DefPathData::AnonConst, constant.value.span);
+        self.with_parent(def, |this| visit::walk_anon_const(this, constant));
+    }
+
+    fn visit_expr(&mut self, expr: &'a Expr) {
+        let parent_def = match expr.kind {
+            ExprKind::MacCall(..) => return self.visit_macro_invoc(expr.id),
+            ExprKind::Closure(_, asyncness, ..) => {
+                // Async closures desugar to closures inside of closures, so
+                // we must create two defs.
+                let closure_def = self.create_def(expr.id, DefPathData::ClosureExpr, expr.span);
+                match asyncness {
+                    Async::Yes { closure_id, .. } => {
+                        self.create_def(closure_id, DefPathData::ClosureExpr, expr.span)
+                    }
+                    Async::No => closure_def,
+                }
+            }
+            ExprKind::Async(_, async_id, _) => {
+                self.create_def(async_id, DefPathData::ClosureExpr, expr.span)
+            }
+            _ => self.parent_def,
+        };
+
+        self.with_parent(parent_def, |this| visit::walk_expr(this, expr));
+    }
+
+    fn visit_ty(&mut self, ty: &'a Ty) {
+        match ty.kind {
+            TyKind::MacCall(..) => return self.visit_macro_invoc(ty.id),
+            TyKind::ImplTrait(node_id, _) => {
+                self.create_def(node_id, DefPathData::ImplTrait, ty.span);
+            }
+            _ => {}
+        }
+        visit::walk_ty(self, ty);
+    }
+
+    fn visit_stmt(&mut self, stmt: &'a Stmt) {
+        match stmt.kind {
+            StmtKind::MacCall(..) => self.visit_macro_invoc(stmt.id),
+            _ => visit::walk_stmt(self, stmt),
+        }
+    }
+
+    fn visit_token(&mut self, t: Token) {
+        if let token::Interpolated(nt) = t.kind {
+            if let token::NtExpr(ref expr) = *nt {
+                if let ExprKind::MacCall(..) = expr.kind {
+                    self.visit_macro_invoc(expr.id);
+                }
+            }
+        }
+    }
+
+    fn visit_arm(&mut self, arm: &'a Arm) {
+        if arm.is_placeholder { self.visit_macro_invoc(arm.id) } else { visit::walk_arm(self, arm) }
+    }
+
+    fn visit_field(&mut self, f: &'a Field) {
+        if f.is_placeholder { self.visit_macro_invoc(f.id) } else { visit::walk_field(self, f) }
+    }
+
+    fn visit_field_pattern(&mut self, fp: &'a FieldPat) {
+        if fp.is_placeholder {
+            self.visit_macro_invoc(fp.id)
+        } else {
+            visit::walk_field_pattern(self, fp)
+        }
+    }
+
+    fn visit_param(&mut self, p: &'a Param) {
+        if p.is_placeholder { self.visit_macro_invoc(p.id) } else { visit::walk_param(self, p) }
+    }
+
+    // This method is called only when we are visiting an individual field
+    // after expanding an attribute on it.
+    fn visit_struct_field(&mut self, field: &'a StructField) {
+        self.collect_field(field, None);
+    }
+}