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pkg/compiler/lib/src/js_backend/js_interop_analysis.dart

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 448f97992225ff4ddf68fdf4c064f58cb67f2812..e2ebe39130a3b4ea5222bcd94f3abdba770da85f 100644
--- a/pkg/compiler/lib/src/js_backend/js_interop_analysis.dart
+++ b/pkg/compiler/lib/src/js_backend/js_interop_analysis.dart
@@ -5,6 +5,7 @@
 /// Analysis to determine how to generate code for typed JavaScript interop.
 library compiler.src.js_backend.js_interop_analysis;
 
+import '../common.dart';
 import '../constants/values.dart'
     show ConstantValue, ConstructedConstantValue, StringConstantValue;
 import '../diagnostics/messages.dart' show MessageKind;
@@ -54,6 +55,8 @@ class JsInteropAnalysis {
 
   void processJsInteropAnnotation(Element e) {
     for (MetadataAnnotation annotation in e.implementation.metadata) {
+      // TODO(johnniwinther): Avoid processing unresolved elements.
+      if (annotation.constant == null) continue;
       ConstantValue constant =
           backend.compiler.constants.getConstantValue(annotation.constant);
       if (constant == null || constant is! ConstructedConstantValue) continue;