Distinguish between actual closure scopes and non-closure scopes.

pkg/compiler/lib/src/js_model/closure.dart

Index: pkg/compiler/lib/src/js_model/closure.dart
diff --git a/pkg/compiler/lib/src/js_model/closure.dart b/pkg/compiler/lib/src/js_model/closure.dart
index 04611ad1e686c9f951d81e5691bb07bfaafb95ca..88bc909a8091aa117c2dd403119056b2b4ba4b03 100644
--- a/pkg/compiler/lib/src/js_model/closure.dart
+++ b/pkg/compiler/lib/src/js_model/closure.dart
@@ -31,6 +31,12 @@ import 'locals.dart';
 class KernelClosureConversionTask extends ClosureConversionTask<ir.Node> {
   final KernelToElementMapForBuilding _elementMap;
   final GlobalLocalsMap _globalLocalsMap;
+
+  /// Map of the scoping information that corresponds to a particular entity.
+  /// This particular map contains ScopeInfos only for entities that are *not*
+  /// closures. Entities that are closures are stored in the
+  /// [_closureScopeMap].

[sra1, 2017/07/12 23:57:41]

Say why are they separate. Is it so these can be GC-ed after the closure task
but the others cannot?

[Emily Fortuna, 2017/07/13 21:03:39]

see comment below.

+  Map<Entity, ScopeInfo> _scopeMap = <Entity, ScopeInfo>{};
   Map<ir.Node, ClosureScope> _closureScopeMap = <ir.Node, ClosureScope>{};

[sra1, 2017/07/12 23:57:41]

Can this be Entity too?

[Emily Fortuna, 2017/07/13 21:03:39]

yes, ended up combining with the above, since these don't always get garbage
collected.

 
   Map<Entity, ClosureRepresentationInfo> _closureRepresentationMap =
@@ -83,8 +89,12 @@ class KernelClosureConversionTask extends ClosureConversionTask<ir.Node> {
       ClosedWorldRefiner closedWorldRefiner) {
     ir.Node node = _elementMap.getMemberNode(entity);
     if (_closureScopeMap.keys.contains(node)) return;
-    ClosureScopeBuilder translator = new ClosureScopeBuilder(_closureScopeMap,
-        closuresToGenerate, _globalLocalsMap.getLocalsMap(entity), _elementMap);
+    ClosureScopeBuilder translator = new ClosureScopeBuilder(
+        _closureScopeMap,
+        _scopeMap,
+        closuresToGenerate,
+        _globalLocalsMap.getLocalsMap(entity),
+        _elementMap);
     if (entity.isField) {
       if (node is ir.Field && node.initializer != null) {
         translator.translateLazyInitializer(node);
@@ -129,7 +139,15 @@ class KernelClosureConversionTask extends ClosureConversionTask<ir.Node> {
 
   @override
   ScopeInfo getScopeInfo(Entity entity) {
-    return getClosureRepresentationInfo(entity);
+    // TODO(johnniwinther): Remove this check when constructor bodies a created
+    // eagerly with the J-model; a constructor body should have it's own
+    // [ClosureRepresentationInfo].
+    if (entity is ConstructorBodyEntity) {
+      ConstructorBodyEntity constructorBody = entity;
+      entity = constructorBody.constructor;
+    }
+
+    return _scopeMap[entity] ?? getClosureRepresentationInfo(entity);
   }
 
   // TODO(efortuna): Eventually closureScopeMap[node] should always be non-null,
@@ -152,13 +170,6 @@ class KernelClosureConversionTask extends ClosureConversionTask<ir.Node> {
   // TODO(efortuna): Eventually closureRepresentationMap[node] should always be
   // non-null, and we should just test that with an assert.
   ClosureRepresentationInfo getClosureRepresentationInfo(Entity entity) {
-    // TODO(johnniwinther): Remove this check when constructor bodies a created
-    // eagerly with the J-model; a constructor body should have it's own
-    // [ClosureRepresentationInfo].
-    if (entity is ConstructorBodyEntity) {
-      ConstructorBodyEntity constructorBody = entity;
-      entity = constructorBody.constructor;
-    }
     return _closureRepresentationMap[entity] ??
         const ClosureRepresentationInfo();
   }