Refactor the way we emit no such method handlers so it's easier to optimize it later.

lib/compiler/implementation/world.dart

 // Copyright (c) 2012, 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.
 
 class World {
+  Compiler compiler;  // Set in populate().
   final Map<ClassElement, Set<ClassElement>> subtypes;
 
   World() : subtypes = new Map<ClassElement, Set<ClassElement>>();
 
   void populate(Compiler compiler, Collection<LibraryElement> libraries) {
     void addSubtypes(ClassElement cls) {
       for (Type type in cls.allSupertypes) {
         Set<Element> subtypesOfCls = subtypes.putIfAbsent(
           type.element,
           () => new Set<ClassElement>());
         subtypesOfCls.add(cls);
       }
     }
 
     libraries.forEach((LibraryElement library) {
       for (Link<Element> link = library.topLevelElements;
            !link.isEmpty();
            link = link.tail) {
         Element element = link.head;
         if (!element.isClass()) continue;
         ClassElement cls = element;
         compiler.resolveClass(cls);
         addSubtypes(cls);
       }
     });
+
+    // Mark the world as populated.
+    assert(compiler !== null);
+    this.compiler = compiler;
   }
 
   /**
    * Returns a [MemberSet] that contains the possible targets of a
    * selector named [member] on a receiver whose type is [type].
    */
   MemberSet _memberSetFor(Type type, SourceString member) {
+    assert(compiler !== null);
     ClassElement cls = type.element;
     MemberSet result = new MemberSet(member);
     Element element = cls.lookupMember(member);
     if (element !== null) result.add(element);
 
     Set<ClassElement> subtypesOfCls = subtypes[cls];
     if (subtypesOfCls !== null) {
       for (ClassElement sub in subtypesOfCls) {
         element = sub.lookupLocalMember(member);
         if (element !== null) result.add(element);
@@ skipping 14 matching lines @@
     memberSet.elements.forEach((Element element) {
       if (element.isField()) {
         field = element;
         fieldCount++;
       } else {
         nonFieldCount++;
       }
     });
     return (fieldCount == 1 && nonFieldCount == 0) ? field : null;
   }
+
+  bool mayHaveUserDefinedNoSuchMethod(Type type) {

[ahe, 2012/08/02 17:15:05]

We should consider this class as "delete-only" as it should be superseded by
Enqueuer :-)

[kasperl, 2012/08/03 05:21:00]

Yeah, that's probably better.

+    MemberSet memberSet = _memberSetFor(type, Compiler.NO_SUCH_METHOD);
+    // TODO(kasperl): Only return true if the set contains an instance
+    // method with the right signature. Remember to disregard the
+    // implementation in Object.
+    for (Element element in memberSet.elements) {
+      if (element.getEnclosingClass() !== compiler.objectClass) return true;
+    }
+    return false;
+  }
 }
 
 /**
  * A [MemberSet] contains all the possible targets for a selector.
  */
 class MemberSet {
   final Set<Element> elements;
   final SourceString name;
 
   MemberSet(SourceString this.name) : elements = new Set<Element>();
 
   void add(Element element) {
     elements.add(element);
   }
 
   bool isEmpty() => elements.isEmpty();
 }