| Index: pkg/compiler/lib/src/js_backend/custom_elements_analysis.dart
 | 
| diff --git a/pkg/compiler/lib/src/js_backend/custom_elements_analysis.dart b/pkg/compiler/lib/src/js_backend/custom_elements_analysis.dart
 | 
| index e345a7c3b08426259622eca124ecb7ea1e061602..8ddbb43069d68ebd7927f69c5604fbe4ac91bdc7 100644
 | 
| --- a/pkg/compiler/lib/src/js_backend/custom_elements_analysis.dart
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| +++ b/pkg/compiler/lib/src/js_backend/custom_elements_analysis.dart
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| @@ -71,6 +71,9 @@ class CustomElementsAnalysis {
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|      if (!Elements.isNativeOrExtendsNative(classElement)) return;
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|      if (classElement.isMixinApplication) return;
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|      if (classElement.isAbstract) return;
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| +    // JsInterop classes are opaque interfaces without a concrete
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| +    // implementation.
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| +    if (classElement.isJsInterop) return;
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|      joinFor(enqueuer).instantiatedClasses.add(classElement);
 | 
|    }
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|  
 | 
| 
 |