Alternative fix for the js-interop crash.

pkg/compiler/lib/src/native/behavior.dart

 // Copyright (c) 2014, 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 native;
 
 /// This class is a temporary work-around until we get a more powerful DartType.
 class SpecialType {
   final String name;
   const SpecialType._(this.name);
@@ skipping 628 matching lines @@
         isBuiltin: false,
         validTags: const ['returns', 'creates']);
 
     return behavior;
   }
 
   static NativeBehavior ofMethod(FunctionElement method,  Compiler compiler) {
     FunctionType type = method.computeType(compiler.resolution);
     var behavior = new NativeBehavior();
     behavior.typesReturned.add(type.returnType);
+    JavaScriptBackend backend = compiler.backend;
+    // Note: For dart:html and other internal libraries, we trust the return
+    // type and use it to limit what we enqueue. We are more conservative about
+    // JS interop types and assume any other JS interop type can be returned
+    // from an interop call or getter.
+    if (backend.isJsInterop(method)) {
+      behavior.typesReturned.add(
+          backend.helpers.jsJavaScriptObjectClass.thisType);

[sra1, 2015/11/20 19:06:24]

It does seem crazy to do this for 'int'.

Perhaps we should do this instead of adding the declared type for types like
'dynamic' and 'Object', which otherwise will pull in all of dart:html and
friends.

[Siggi Cherem (dart-lang), 2015/11/25 21:15:25]

Agree - I can't do anything for int to be sound, but I added a flag to enable
trust-js-interop-types, and in that case, I made the change you mentioned to be
more precise when it comes to dynamic and object.

+      behavior.typesInstantiated.add(
+          backend.helpers.jsJavaScriptObjectClass.thisType);
+    }
     if (!type.returnType.isVoid) {
       // Declared types are nullable.
       behavior.typesReturned.add(compiler.coreTypes.nullType);
     }
     behavior._capture(type, compiler.resolution);
 
     // TODO(sra): Optional arguments are currently missing from the
     // DartType. This should be fixed so the following work-around can be
     // removed.
     method.functionSignature.forEachOptionalParameter(
         (ParameterElement parameter) {
           behavior._escape(parameter.type, compiler.resolution);
         });
 
     behavior._overrideWithAnnotations(method, compiler);
     return behavior;
   }
 
   static NativeBehavior ofFieldLoad(MemberElement field, Compiler compiler) {
     Resolution resolution = compiler.resolution;
     DartType type = field.computeType(resolution);
     var behavior = new NativeBehavior();
     behavior.typesReturned.add(type);
+    JavaScriptBackend backend = compiler.backend;
+    // See comment above on ofMethod
+    if (backend.isJsInterop(field)) {
+      behavior.typesReturned.add(
+          backend.helpers.jsJavaScriptObjectClass.thisType);
+      behavior.typesInstantiated.add(
+          backend.helpers.jsJavaScriptObjectClass.thisType);
+    }
     // Declared types are nullable.
     behavior.typesReturned.add(resolution.coreTypes.nullType);
     behavior._capture(type, resolution);
     behavior._overrideWithAnnotations(field, compiler);
     return behavior;
   }
 
   static NativeBehavior ofFieldStore(MemberElement field, Compiler compiler) {
     Resolution resolution = compiler.resolution;
     DartType type = field.computeType(resolution);
@@ skipping 128 matching lines @@
         MessageKind.GENERIC,
         {'text': "Type '$typeString' not found."});
     return const DynamicType();
   }
 
   static _errorNode(locationNodeOrElement, Parsing parsing) {
     if (locationNodeOrElement is Node) return locationNodeOrElement;
     return locationNodeOrElement.parseNode(parsing);
   }
 }