Use predicates to check simple function types.

sdk/lib/_internal/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.
 
 part of ssa;
 
 class SsaCodeGeneratorTask extends CompilerTask {
 
   final JavaScriptBackend backend;
 
@@ skipping 2242 matching lines @@
         backend.getInterceptorMethod, backend.interceptedClasses);
     backend.registerSpecializedGetInterceptor(backend.interceptedClasses);
     backend.registerUseInterceptor(world);
 
     var isolate = new js.VariableUse(backend.namer.CURRENT_ISOLATE);
     List<js.Expression> arguments = <js.Expression>[pop()];
     push(jsPropertyCall(isolate, interceptorName, arguments));
     world.registerIsCheck(type, work.resolutionTree);
 
     js.PropertyAccess field =
-        new js.PropertyAccess.field(pop(), backend.namer.operatorIs(element));
+        new js.PropertyAccess.field(pop(), backend.namer.operatorIsType(type));
     // We always negate at least once so that the result is boolified.
     push(new js.Prefix('!', field));
     // If the result is not negated, put another '!' in front.
     if (!negative) push(new js.Prefix('!', pop()));
   }
 
   void handleNumberOrStringSupertypeCheck(HInstruction input,
                                           DartType type,
                                           { bool negative: false }) {
     assert(!identical(type.element, compiler.listClass)
@@ skipping 715 matching lines @@
   if (leftType.canBeNull() && rightType.canBeNull()) {
     if (left.isConstantNull() || right.isConstantNull() ||
         (leftType.isPrimitive(compiler) && leftType == rightType)) {
       return '==';
     }
     return null;
   } else {
     return '===';
   }
 }