Reapply "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..218b9a4bea21c5cc7595b370687814ba5a33dd43 100644
--- a/pkg/compiler/lib/src/js_model/closure.dart
+++ b/pkg/compiler/lib/src/js_model/closure.dart
@@ -31,7 +31,11 @@ import 'locals.dart';
 class KernelClosureConversionTask extends ClosureConversionTask<ir.Node> {
   final KernelToElementMapForBuilding _elementMap;
   final GlobalLocalsMap _globalLocalsMap;
-  Map<ir.Node, ClosureScope> _closureScopeMap = <ir.Node, ClosureScope>{};
+
+  /// Map of the scoping information that corresponds to a particular entity.
+  Map<Entity, ScopeInfo> _scopeMap = <Entity, ScopeInfo>{};
+  Map<ir.Node, ClosureScope> _scopesCapturedInClosureMap =
+      <ir.Node, ClosureScope>{};
 
   Map<Entity, ClosureRepresentationInfo> _closureRepresentationMap =
       <Entity, ClosureRepresentationInfo>{};
@@ -81,10 +85,16 @@ class KernelClosureConversionTask extends ClosureConversionTask<ir.Node> {
       MemberEntity entity,
       Map<ir.TreeNode, ScopeInfo> closuresToGenerate,
       ClosedWorldRefiner closedWorldRefiner) {
+    if (_scopeMap.keys.contains(entity)) return;
     ir.Node node = _elementMap.getMemberNode(entity);
-    if (_closureScopeMap.keys.contains(node)) return;
-    ClosureScopeBuilder translator = new ClosureScopeBuilder(_closureScopeMap,
-        closuresToGenerate, _globalLocalsMap.getLocalsMap(entity), _elementMap);
+    if (_scopesCapturedInClosureMap.keys.contains(node)) return;
+    ClosureScopeBuilder translator = new ClosureScopeBuilder(
+        _scopesCapturedInClosureMap,
+        _scopeMap,
+        entity,
+        closuresToGenerate,
+        _globalLocalsMap.getLocalsMap(entity),
+        _elementMap);
     if (entity.isField) {
       if (node is ir.Field && node.initializer != null) {
         translator.translateLazyInitializer(node);
@@ -129,36 +139,34 @@ 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;
+    }
 
-  // TODO(efortuna): Eventually closureScopeMap[node] should always be non-null,
-  // and we should just test that with an assert.
-  ClosureScope _getClosureScope(ir.Node node) =>
-      _closureScopeMap[node] ?? const ClosureScope();
+    return _scopeMap[entity] ?? getClosureRepresentationInfo(entity);
+  }
 
+  // TODO(efortuna): Eventually scopesCapturedInClosureMap[node] should always
+  // be non-null, and we should just test that with an assert.
   @override
-  ClosureScope getClosureScope(MemberEntity entity) {
-    return _getClosureScope(_elementMap.getMemberNode(entity));
-  }
+  ClosureScope getClosureScope(MemberEntity entity) =>
+      _scopesCapturedInClosureMap[_elementMap.getMemberNode(entity)] ??
+      const ClosureScope();
 
   @override
-  // TODO(efortuna): Eventually closureScopeMap[node] should always be non-null,
-  // and we should just test that with an assert.
+  // TODO(efortuna): Eventually scopesCapturedInClosureMap[node] should always
+  // be non-null, and we should just test that with an assert.
   LoopClosureScope getLoopClosureScope(ir.Node loopNode) =>
-      _closureScopeMap[loopNode] ?? const LoopClosureScope();
+      _scopesCapturedInClosureMap[loopNode] ?? const LoopClosureScope();
 
   @override
   // 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();
   }