Distinguish between actual closure scopes and non-closure scopes.

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

 // Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'package:kernel/ast.dart' as ir;
 
 import '../closure.dart';
 import '../elements/entities.dart';
 import '../kernel/element_map.dart';
 import 'closure.dart';
 
 /// This builder walks the code to determine what variables are captured/free at
 /// various points to build ClosureScope that can respond to queries
 /// about how a particular variable is being used at any point in the code.
 class ClosureScopeBuilder extends ir.Visitor {
   /// A map of each visited call node with the associated information about what
   /// variables are captured/used. Each ir.Node key corresponds to a scope that
   /// was encountered while visiting a closure (initially called through
   /// [translateLazyIntializer] or [translateConstructorOrProcedure]).
   Map<ir.Node, ClosureScope> _closureInfoMap = <ir.Node, ClosureScope>{};
 
+  /// Map entities to their corresponding scope information (such as what
+  /// variables are captured/used). The distinction between this map and
+  /// [_closureInfoMap] is that [_closureInfoMap] stores this data for closures
+  /// specifically, whereas [_scopeInfoMap] stores this information for entities
+  /// that are *not* closures (this information is used by the locals handler).
+  /// The union of these two maps represents all the scopes encountered.
+  Map<Entity, ScopeInfo> _scopeInfoMap = <Entity, ScopeInfo>{};

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

final, don't initialize.

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

Done.

+
   /// A map of the nodes that we have flagged as necessary to generate closure
   /// classes for in a later stage. We map that node to information ascertained
   /// about variable usage in the surrounding scope.
   Map<ir.TreeNode /* ir.Field | ir.FunctionNode */, ScopeInfo>
       _closuresToGenerate = <ir.TreeNode, ScopeInfo>{};
 
   /// The local variables that have been declared in the current scope.
   List<ir.VariableDeclaration> _scopeVariables;
 
   /// Pointer to the context in which this closure is executed.
@@ skipping 22 matching lines @@
   bool _inTry = false;
 
   /// Lookup the local entity that corresponds to a kernel variable declaration.
   final KernelToLocalsMap _localsMap;
 
   /// The current scope we are in.
   KernelScopeInfo _currentScopeInfo;
 
   final KernelToElementMap _kernelToElementMap;
 
-  ClosureScopeBuilder(this._closureInfoMap, this._closuresToGenerate,
-      this._localsMap, this._kernelToElementMap);
+  ClosureScopeBuilder(this._closureInfoMap, this._scopeInfoMap,
+      this._closuresToGenerate, this._localsMap, this._kernelToElementMap);
 
   /// Update the [ClosureScope] object corresponding to
   /// this node if any variables are captured.
   void attachCapturedScopeVariables(ir.Node node) {
     Set<Local> capturedVariablesForScope = new Set<Local>();
 
     for (ir.VariableDeclaration variable in _scopeVariables) {
       // No need to box non-assignable elements.
       if (variable.isFinal || variable.isConst) continue;
       if (!_mutatedVariables.contains(variable)) continue;
@@ skipping 129 matching lines @@
 
   void visitInvokable(ir.TreeNode node) {
     bool oldIsInsideClosure = _isInsideClosure;
     ir.Node oldExecutableContext = _executableContext;
     KernelScopeInfo oldScopeInfo = _currentScopeInfo;
 
     // _outermostNode is only null the first time we enter the body of the
     // field, constructor, or method that is being analyzed.
     _isInsideClosure = _outermostNode != null;
     _executableContext = node;
-    if (!_isInsideClosure) {
+    _currentScopeInfo = new KernelScopeInfo(_nodeToThisLocal(node));
+    if (_isInsideClosure) {
+      _closuresToGenerate[node] = _currentScopeInfo;
+    } else {
       _outermostNode = node;
+      Entity entity;
+      ir.TreeNode tempNode = node;
+      if (tempNode is ir.Member) {
+        entity = _kernelToElementMap.getMember(tempNode);

[Johnni Winther, 2017/07/13 08:56:14]

Maybe the visitor should have the member entity as a final field instead. You
always know the member when you create the visitor (in _buildClosureModel)

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

done.

+      } else {
+        entity = _kernelToElementMap.getLocalFunction(tempNode);

[Johnni Winther, 2017/07/13 08:56:14]

Can this ever happen? We always start visiting on an ir.Member and only visit
local functions inside of the member.

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

You're right it won't. Took it out.

+      }
+      _scopeInfoMap[entity] = _currentScopeInfo;
     }
-    _currentScopeInfo = new KernelScopeInfo(_nodeToThisLocal(node));
-    _closuresToGenerate[node] = _currentScopeInfo;
 
     enterNewScope(node, () {
       node.visitChildren(this);
     });
 
     KernelScopeInfo savedScopeInfo = _currentScopeInfo;
     bool savedIsInsideClosure = _isInsideClosure;
 
     // Restore old values.
     _isInsideClosure = oldIsInsideClosure;
@@ skipping 55 matching lines @@
               nodeToConvert.isInstanceMember)) {
         return new ThisLocal(_kernelToElementMap.getConstructor(nodeToConvert));
       } else if (nodeToConvert is ir.Procedure &&
           nodeToConvert.isInstanceMember) {
         return new ThisLocal(_kernelToElementMap.getMethod(nodeToConvert));
       }
     }
     return null;
   }
 }