feat(hir,minifier): wire up identifier reference for mangle

crates/oxc_ast_lower/src/lib.rs

@@ -315,12 +315,12 @@ impl<'a> AstLower<'a> {
             ast::Expression::Super(expr) => self.lower_super(expr),
             ast::Expression::JSXElement(elem) => {
                 // TODO: implement JSX
-                let ident = self.hir.identifier_reference(elem.span, "undefined".into());
+                let ident = self.hir.identifier_reference(elem.span, "undefined".into(), None);
                 self.hir.identifier_reference_expression(ident)
             }
             ast::Expression::JSXFragment(elem) => {
                 // TODO: implement JSX
-                let ident = self.hir.identifier_reference(elem.span, "undefined".into());
+                let ident = self.hir.identifier_reference(elem.span, "undefined".into(), None);
                 self.hir.identifier_reference_expression(ident)
             }
 
@@ -698,7 +698,7 @@ impl<'a> AstLower<'a> {
             }
             expr => {
                 // return undefined because this is invalid syntax
-                let ident = self.hir.identifier_reference(expr.span(), "undefined".into());
+                let ident = self.hir.identifier_reference(expr.span(), "undefined".into(), None);
                 self.hir.assignment_target_identifier(ident)
             }
         }
@@ -915,7 +915,8 @@ impl<'a> AstLower<'a> {
         &mut self,
         ident: &ast::IdentifierReference,
     ) -> hir::IdentifierReference {
-        self.hir.identifier_reference(ident.span, ident.name.clone())
+        let symbol_id = self.semantic.enter_identifier_reference(&ident.name);
+        self.hir.identifier_reference(ident.span, ident.name.clone(), symbol_id)
     }
 
     fn lower_private_identifier(

crates/oxc_hir/src/hir.rs

@@ -370,6 +370,8 @@ pub struct IdentifierReference {
     #[cfg_attr(feature = "serde", serde(flatten))]
     pub span: Span,
     pub name: Atom,
+    #[cfg_attr(feature = "serde", serde(skip))]
+    pub symbol_id: Option<SymbolId>,
 }
 
 /// Binding Identifier
@@ -379,6 +381,7 @@ pub struct BindingIdentifier {
     #[cfg_attr(feature = "serde", serde(flatten))]
     pub span: Span,
     pub name: Atom,
+    #[cfg_attr(feature = "serde", serde(skip))]
     pub symbol_id: SymbolId,
 }
 

crates/oxc_hir/src/hir_builder.rs

@@ -174,8 +174,13 @@ impl<'a> HirBuilder<'a> {
         IdentifierName { span, name }
     }
 
-    pub fn identifier_reference(&mut self, span: Span, name: Atom) -> IdentifierReference {
-        IdentifierReference { span, name }
+    pub fn identifier_reference(
+        &mut self,
+        span: Span,
+        name: Atom,
+        symbol_id: Option<SymbolId>,
+    ) -> IdentifierReference {
+        IdentifierReference { span, name, symbol_id }
     }
 
     pub fn binding_identifier(

crates/oxc_minifier/src/printer/gen.rs

@@ -772,7 +772,11 @@ impl<'a> Gen for Expression<'a> {
 
 impl Gen for IdentifierReference {
     fn gen(&self, p: &mut Printer) {
-        p.print_str(self.name.as_bytes());
+        if let Some(symbol_id) = self.symbol_id {
+            p.print_symbol(symbol_id, &self.name);
+        } else {
+            p.print_str(self.name.as_bytes());
+        }
     }
 }
 

crates/oxc_semantic2/src/builder.rs

@@ -62,11 +62,11 @@ impl SemanticBuilder {
 
     /// Declares a `Symbol` for the node, adds it to symbol table, and binds it to the scope.
     ///
-    /// includes: the SymbolFlags that node has in addition to its declaration type (eg: export, ambient, etc.)
+    /// includes: the `SymbolFlags` that node has in addition to its declaration type (eg: export, ambient, etc.)
     /// excludes: the flags which node cannot be declared alongside in a symbol table. Used to report forbidden declarations.
     ///
     /// Reports errors for conflicting identifier names.
-    pub fn declare_symbol(
+    fn declare_symbol(
         &mut self,
         span: Span,
         name: &Atom,
@@ -77,6 +77,12 @@ impl SemanticBuilder {
         self.scope_tree.get_scope_mut(self.current_scope_id).add_symbol(name.clone(), symbol_id);
         symbol_id
     }
+
+    fn resolve_reference(&mut self, name: &Atom) -> Option<SymbolId> {
+        self.scope_tree
+            .ancestors(self.current_scope_id)
+            .find_map(|scope_id| self.scope_tree.get_scope(scope_id).get_binding(name))
+    }
 }
 
 impl SemanticBuilder {
@@ -85,4 +91,8 @@ impl SemanticBuilder {
         let excludes = SymbolFlags::FunctionScopedVariableExcludes;
         self.declare_symbol(span, name, includes, excludes)
     }
+
+    pub fn enter_identifier_reference(&mut self, name: &Atom) -> Option<SymbolId> {
+        self.resolve_reference(name)
+    }
 }

crates/oxc_semantic2/src/scope.rs

@@ -77,6 +77,10 @@ impl Scope {
         self.flags.intersects(ScopeFlags::Function)
     }
 
+    pub fn get_binding(&self, name: &Atom) -> Option<SymbolId> {
+        self.bindings.get(name).copied()
+    }
+
     pub fn bindings_entry(&mut self, name: Atom) -> Entry<Atom, SymbolId> {
         self.bindings.entry(name)
     }
@@ -94,14 +98,14 @@ impl ScopeTree {
         Self(IndexVec::new())
     }
 
-    pub fn get_scope(&self, scope_id: ScopeId) -> &Scope {
-        &self.0[scope_id]
-    }
-
     pub fn root_scope(&self) -> &Scope {
         self.get_scope(ScopeId::new(0))
     }
 
+    pub fn get_scope(&self, scope_id: ScopeId) -> &Scope {
+        &self.0[scope_id]
+    }
+
     pub fn get_scope_mut(&mut self, scope_id: ScopeId) -> &mut Scope {
         &mut self.0[scope_id]
     }
@@ -109,4 +113,8 @@ impl ScopeTree {
     pub fn add_scope(&mut self, scope: Scope) -> ScopeId {
         self.0.push(scope)
     }
+
+    pub fn ancestors(&self, scope_id: ScopeId) -> impl Iterator<Item = ScopeId> + '_ {
+        std::iter::successors(Some(scope_id), |scope_id| self.get_scope(*scope_id).parent_id())
+    }
 }