Mix in [TreeElementMixin] only on nodes that need it.

sdk/lib/_internal/compiler/implementation/resolution/registry.dart

 // Copyright (c) 2014, 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.
 
 part of resolution;
 
 /// [ResolutionRegistry] collects all resolution information. It stores node
 /// related information in a [TreeElements] mapping and registers calls with
 /// [Backend], [World] and [Enqueuer].
 // TODO(johnniwinther): Split this into an interface and implementation class.
@@ skipping 13 matching lines @@
   ResolutionEnqueuer get world => compiler.enqueuer.resolution;
 
   World get universe => compiler.world;
 
   Backend get backend => compiler.backend;
 
   //////////////////////////////////////////////////////////////////////////////
   //  Node-to-Element mapping functionality.
   //////////////////////////////////////////////////////////////////////////////
 
+  /// Register [node] as the declaration of [element].
+  void defineFunction(FunctionExpression node, FunctionElement element) {
+    mapping[node] = element;
+  }
+
   /// Register [node] as a reference to [element].
   Element useElement(Node node, Element element) {
     if (element == null) return null;
     return mapping[node] = element;
   }
 
-  /// Register [node] as a declaration of [element].
+  /// Register [node] as the declaration of [element].
   void defineElement(Node node, Element element) {
     mapping[node] = element;
   }
 
   /// Returns the [Element] defined by [node].
   Element getDefinition(Node node) {
     return mapping[node];
   }
 
+  /// Sets the loop variable of the for-in [node] to be [element].
+  void setForInVariable(ForIn node, Element element) {
+    mapping[node] = element;
+  }
+
+  /// Sets the target constructor [node] to be [element].
+  void setRedirectingTargetConstructor(RedirectingFactoryBody node,
+                                       ConstructorElement element) {
+    useElement(node, element);
+  }
+
   //////////////////////////////////////////////////////////////////////////////
   //  Node-to-Selector mapping functionality.
   //////////////////////////////////////////////////////////////////////////////
 
   void setSelector(Node node, Selector selector) {
     mapping.setSelector(node, selector);
   }
 
   Selector getSelector(Node node) => mapping.getSelector(node);
 
@@ skipping 17 matching lines @@
     mapping.setCurrentSelector(node, selector);
   }
 
   //////////////////////////////////////////////////////////////////////////////
   //  Node-to-Type mapping functionality.
   //////////////////////////////////////////////////////////////////////////////
 
   DartType useType(Node annotation, DartType type) {
     if (type != null) {
       mapping.setType(annotation, type);
-      useElement(annotation, type.element);
     }
     return type;
   }
 
   void setType(Node node, DartType type) => mapping.setType(node, type);
 
   DartType getType(Node node) => mapping.getType(node);
 
   //////////////////////////////////////////////////////////////////////////////
   //  Node-to-Constant mapping functionality.
@@ skipping 244 matching lines @@
 
   void registerAssert(Send node) {
     mapping.setAssert(node);
     backend.resolutionCallbacks.onAssert(node, this);
   }
 
   bool isAssert(Send node) {
     return mapping.isAssert(node);
   }
 }