| Index: pkg/compiler/lib/src/js_backend/js_interop_analysis.dart | 
| diff --git a/pkg/compiler/lib/src/js_backend/js_interop_analysis.dart b/pkg/compiler/lib/src/js_backend/js_interop_analysis.dart | 
| index da89b34344692aaae40b30318508edbea62755d5..e43fb682c7b0248d42e6a9d2d3dd1b67aae24478 100644 | 
| --- a/pkg/compiler/lib/src/js_backend/js_interop_analysis.dart | 
| +++ b/pkg/compiler/lib/src/js_backend/js_interop_analysis.dart | 
| @@ -116,7 +116,7 @@ class JsInteropAnalysis { | 
|  | 
| // Skip classes that are completely unreachable. This should only happen | 
| // when all of jsinterop types are unreachable from main. | 
| -      if (!backend.compiler.closedWorld.isImplemented(classElement)) return; | 
| +      if (!backend.compiler.openWorld.isImplemented(classElement)) return; | 
|  | 
| if (!classElement.implementsInterface(helpers.jsJavaScriptObjectClass)) { | 
| backend.reporter.reportErrorMessage(classElement, | 
|  |