Fix for serializing cascades with not-assignment access to properties.

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

Index: pkg/analyzer/lib/src/summary/summarize_const_expr.dart
diff --git a/pkg/analyzer/lib/src/summary/summarize_const_expr.dart b/pkg/analyzer/lib/src/summary/summarize_const_expr.dart
index fc3184bf0cc53e0dbab1eb7e7048cdd932793503..dcde920733b39fa7586c3118341441b29325bca8 100644
--- a/pkg/analyzer/lib/src/summary/summarize_const_expr.dart
+++ b/pkg/analyzer/lib/src/summary/summarize_const_expr.dart
@@ -632,7 +632,9 @@ abstract class AbstractConstExprSerializer {
       references.add(ref);
       operations.add(UnlinkedExprOperation.pushReference);
     } else {
-      _serialize(expr.target);
+      if (!expr.isCascaded) {
+        _serialize(expr.target);
+      }
       strings.add(expr.propertyName.name);
       operations.add(UnlinkedExprOperation.extractProperty);
     }