Unify ClassElement and TypedefElement.

lib/compiler/implementation/ssa/codegen.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 SsaCodeGeneratorTask extends CompilerTask {
   final JavaScriptBackend backend;
   SsaCodeGeneratorTask(JavaScriptBackend backend)
       : this.backend = backend,
         super(backend.compiler);
   String get name() => 'SSA code generator';
@@ skipping 2557 matching lines @@
       endExpression(JSPrecedence.LOGICAL_AND_PRECEDENCE);
     } else {
       checkType(input, element);
     }
     if (compiler.codegenWorld.rti.hasTypeArguments(type)) {
       InterfaceType interfaceType = type;
       ClassElement cls = type.element;
       Link<Type> arguments = interfaceType.arguments;
       buffer.add(' && ');
       checkObject(node.typeInfoCall, '===');
-      cls.typeParameters.forEach((name, _) {
+      for (TypeVariableType typeVariable in cls.typeVariables) {
         buffer.add(' && ');
         beginExpression(JSPrecedence.LOGICAL_AND_PRECEDENCE);
         use(node.typeInfoCall, JSPrecedence.EQUALITY_PRECEDENCE);
-        buffer.add(".${name.slowToString()} === '${arguments.head}'");
+        // TODO(johnniwinther): Retrieve the type name properly and not through
+        // [toString]. Note: Two cases below [typeVariable] and
+        // [arguments.head].
+        buffer.add(
+            ".${typeVariable} === '${arguments.head}'");
         endExpression(JSPrecedence.LOGICAL_AND_PRECEDENCE);
-      });
+      }
     }
     if (node.nullOk) {
       expectedPrecedence = oldPrecedence;
       endExpression(JSPrecedence.LOGICAL_OR_PRECEDENCE);
     }
   }
 
   void visitTypeConversion(HTypeConversion node) {
     Map<String, SourceString> castNames = const <SourceString> {
       "stringTypeCheck":
@@ skipping 584 matching lines @@
   if (leftType.canBeNull() && rightType.canBeNull()) {
     if (left.isConstantNull() || right.isConstantNull() ||
         (leftType.isPrimitive() && leftType == rightType)) {
       return '==';
     }
     return null;
   } else {
     return '===';
   }
 }