Collect is checks to only emit the ones that are needed.

frog/leg/universe.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 Universe {
   Map<Element, String> generatedCode;
   Map<Element, String> generatedBailoutCode;
   final Set<ClassElement> instantiatedClasses;
   final Set<FunctionElement> staticFunctionsNeedingGetter;
   final Map<SourceString, Set<Selector>> invokedNames;
   final Set<SourceString> invokedGetters;
   final Set<SourceString> invokedSetters;
   final Map<String, LibraryElement> libraries;
+  // TODO(ngeoffray): This should be a Type.

[ahe, 2012/03/10 15:48:47]

Type -> Set<Type>

[ngeoffray, 2012/03/10 17:05:40]

Done.

+  final Set<ClassElement> isChecks;
 
   Universe() : generatedCode = new Map<Element, String>(),
                generatedBailoutCode = new Map<Element, String>(),
                libraries = new Map<String, LibraryElement>(),
                instantiatedClasses = new Set<ClassElement>(),
                staticFunctionsNeedingGetter = new Set<FunctionElement>(),
                invokedNames = new Map<SourceString, Set<Invocation>>(),
                invokedGetters = new Set<SourceString>(),
-               invokedSetters = new Set<SourceString>();
+               invokedSetters = new Set<SourceString>(),
+               isChecks = new Set<ClassElement>();
 
   void addGeneratedCode(WorkItem work, String code) {
     if (work.isBailoutVersion()) {
       generatedBailoutCode[work.element] = code;
     } else {
       generatedCode[work.element] = code;
     }
   }
 }
 
@@ skipping 110 matching lines @@
     if (!orderedNamedArguments.isEmpty()) return orderedNamedArguments;
 
     List<SourceString> list = new List<SourceString>.from(namedArguments);
     list.sort((SourceString first, SourceString second) {
       return first.slowToString().compareTo(second.slowToString());
     });
     orderedNamedArguments = list;
     return orderedNamedArguments;
   }
 }