Revert "Implement interface types."

lib/compiler/implementation/ssa/builder.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 Interceptors {
   Compiler compiler;
   Interceptors(Compiler this.compiler);
 
   SourceString mapOperatorToMethodName(Operator op) {
     String name = op.source.stringValue;
@@ skipping 1698 matching lines @@
                const SourceString("||") == op.source) {
       visitLogicalAndOr(node, op);
     } else if (const SourceString("!") == op.source) {
       visitLogicalNot(node);
     } else if (node.argumentsNode is Prefix) {
       visitUnary(node, op);
     } else if (const SourceString("is") == op.source) {
       visit(node.receiver);
       HInstruction expression = pop();
       Node argument = node.arguments.head;
-      TypeAnnotation typeAnnotation = argument.asTypeAnnotation();
+      TypeAnnotation type = argument.asTypeAnnotation();
       bool isNot = false;
       // TODO(ngeoffray): Duplicating pattern in resolver. We should
       // add a new kind of node.
-      if (typeAnnotation == null) {
-        typeAnnotation = argument.asSend().receiver;
+      if (type == null) {
+        type = argument.asSend().receiver;
         isNot = true;
       }
-      Type type = elements.getType(typeAnnotation);
-      HInstruction instruction = new HIs(type, expression);
+      HInstruction instruction = new HIs(elements[type], expression);
       if (isNot) {
         add(instruction);
         instruction = new HNot(instruction);
       }
       push(instruction);
     } else {
       visit(node.receiver);
       visit(node.argumentsNode);
       var right = pop();
       var left = pop();
@@ skipping 1024 matching lines @@
 
       Link<Node> link = node.catchBlocks.nodes;
 
       void pushCondition(CatchBlock catchBlock) {
         VariableDefinitions declaration = catchBlock.formals.nodes.head;
         HInstruction condition = null;
         if (declaration.type == null) {
           condition = graph.addConstantBool(true);
           stack.add(condition);
         } else {
-          Type type = elements.getType(declaration.type);
-          if (type == null) {
+          Element typeElement = elements[declaration.type];
+          if (typeElement == null) {
             compiler.cancel('Catch with unresolved type', node: catchBlock);
           }
-          condition = new HIs(type, unwrappedException, nullOk: true);
+          condition = new HIs(typeElement, unwrappedException, nullOk: true);
           push(condition);
         }
       }
 
       void visitThen() {
         CatchBlock catchBlock = link.head;
         link = link.tail;
         localsHandler.updateLocal(elements[catchBlock.exception],
                                   unwrappedException);
         Node trace = catchBlock.trace;
@@ skipping 237 matching lines @@
                                         false,
                                         <HInstruction>[target, input]));
     return builder.pop();
   }
 
   HInstruction result() {
     flushLiterals();
     return prefix;
   }
 }