Gracefully degrade summarization when an annotation is not a valid const expression (issue 28992)

pkg/analyzer/lib/src/summary/summarize_ast.dart

Index: pkg/analyzer/lib/src/summary/summarize_ast.dart
diff --git a/pkg/analyzer/lib/src/summary/summarize_ast.dart b/pkg/analyzer/lib/src/summary/summarize_ast.dart
index 240fa8000cae17a4614eb07cb90d362c4ba6ccb7..7273e3f474e31696f5fb08a33670d44ee28c56b2 100644
--- a/pkg/analyzer/lib/src/summary/summarize_ast.dart
+++ b/pkg/analyzer/lib/src/summary/summarize_ast.dart
@@ -414,7 +414,11 @@ class _SummarizeAstVisitor extends RecursiveAstVisitor {
       Map<int, int> localClosureIndexMap = null;
       _ConstExprSerializer serializer =
           new _ConstExprSerializer(this, localClosureIndexMap, null);
-      serializer.serializeAnnotation(a);
+      try {
+        serializer.serializeAnnotation(a);
+      } on StateError {
+        return new UnlinkedExprBuilder()..isValidConst = false;
+      }
       return serializer.toBuilder();
     }).toList();
   }