Add substitution for classes that use type variables.

sdk/lib/_internal/compiler/implementation/js_backend/emitter.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.
 
 part of js_backend;
 
 /**
  * A function element that represents a closure call. The signature is copied
  * from the given element.
  */
@@ skipping 1256 matching lines @@
       if (a.isClosure()) return true;
       return a.typeVariables == b.typeVariables;
     }
 
     if (superclass != null && superclass != compiler.objectClass &&
         !haveSameTypeVariables(cls, superclass)) {
       // We cannot inherit the generated substitutions, because the type
       // variable layout for this class is different.  Instead we generate
       // substitutions for all checks and make emitSubstitution a NOP for the
       // rest of this function.
-      for (ClassElement check in checkedClasses) {
-        for (DartType supertype in cls.allSupertypes) {
-          if (supertype.element == check) {
+      Set<ClassElement> emitted = new Set<ClassElement>();
+      // TODO(karlklose): move the computation of these checks to
+      // RuntimeTypeInformation.
+      if (compiler.world.needsRti(cls)) {
+        emitSubstitution(superclass, emitNull: true);
+        emitted.add(superclass);
+      }
+      for (DartType supertype in cls.allSupertypes) {
+        for (ClassElement check in checkedClasses) {
+          if (supertype.element == check && !emitted.contains(check)) {
             // Generate substitution.  If no substitution is necessary, emit
             // [:null:] to overwrite a (possibly) existing substitution from the
             // super classes.
             emitSubstitution(check, emitNull: true);
+            emitted.add(check);
           }
         }
       }
       void emitNothing(_, {emitNull}) {};
       emitSubstitution = emitNothing;
     }
 
     Set<Element> generated = new Set<Element>();
     // A class that defines a [:call:] method implicitly implements
     // [Function] and needs checks for all typedefs that are used in is-checks.
@@ skipping 1122 matching lines @@
 """;
 const String HOOKS_API_USAGE = """
 // The code supports the following hooks:
 // dartPrint(message)   - if this function is defined it is called
 //                        instead of the Dart [print] method.
 // dartMainRunner(main) - if this function is defined, the Dart [main]
 //                        method will not be invoked directly.
 //                        Instead, a closure that will invoke [main] is
 //                        passed to [dartMainRunner].
 """;