Change assert implementation to not depend on a top-level function called 'assert'.

lib/compiler/implementation/compiler.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.
 
 
 /**
  * If true, print a warning for each method that was resolved, but not
  * compiled.
  */
 const bool REPORT_EXCESS_RESOLUTION = false;
@@ skipping 185 matching lines @@
     backend = emitJavaScript ?
         new js_backend.JavaScriptBackend(this, generateSourceMap) :
         new dart_backend.DartBackend(this, cutDeclarationTypes);
     constantHandler = new ConstantHandler(this, backend.constantSystem);
     enqueuer = new EnqueueTask(this);
     tasks = [scanner, dietParser, parser, resolver, closureToClassMapper,
              checker, typesTask, constantHandler, enqueuer];
     tasks.addAll(backend.tasks);
   }
 
+  // TODO(floitsch): remove once the compile-time constant handler doesn't
+  // depend on it anymore.
+  js_backend.Namer get namer => (backend as js_backend.JavaScriptBackend).namer;
+
   Universe get resolverWorld => enqueuer.resolution.universe;
   Universe get codegenWorld => enqueuer.codegen.universe;
 
   int getNextFreeClassId() => nextFreeClassId++;
 
   void ensure(bool condition) {
     if (!condition) cancel('failed assertion in leg');
   }
 
   void unimplemented(String methodName,
@@ skipping 136 matching lines @@
     coreImplLibrary = scanBuiltinLibrary('coreimpl');
     jsHelperLibrary = scanBuiltinLibrary('_js_helper');
     interceptorsLibrary = scanBuiltinLibrary('_interceptors');
 
     addForeignFunctions(jsHelperLibrary);
     addForeignFunctions(interceptorsLibrary);
 
     libraries['dart:core'] = coreLibrary;
     libraries['dart:coreimpl'] = coreImplLibrary;
 
-    assertMethod = coreLibrary.find(const SourceString('assert'));
+    assertMethod = jsHelperLibrary.find(const SourceString('assert'));
 
     initializeSpecialClasses();
   }
 
   void importCoreLibrary(LibraryElement library) {
     Uri coreUri = new Uri.fromComponents(scheme: 'dart', path: 'core');
     if (coreLibrary === null) {
       coreLibrary = scanner.loadLibrary(coreUri, null, coreUri);
     }
     scanner.importLibrary(library,
@@ skipping 549 matching lines @@
     final endOffset = end.charOffset + end.slowCharCount;
 
     // [begin] and [end] might be the same for the same empty token. This
     // happens for instance when scanning '$$'.
     assert(endOffset >= beginOffset);
     return f(beginOffset, endOffset);
   }
 
   String toString() => 'SourceSpan($uri, $begin, $end)';
 }