Index: pkg/compiler/lib/src/elements/modelx.dart |
diff --git a/pkg/compiler/lib/src/elements/modelx.dart b/pkg/compiler/lib/src/elements/modelx.dart |
index f1d4c5bb04fe6dd1ea4afdecb656901fe57a8e12..90574fbc956f40f9c87109a2633cbc2d85ecedcc 100644 |
--- a/pkg/compiler/lib/src/elements/modelx.dart |
+++ b/pkg/compiler/lib/src/elements/modelx.dart |
@@ -2593,7 +2593,8 @@ abstract class BaseClassElementX extends ElementX |
* The returned element may not be resolved yet. |
*/ |
ClassElement get superclass { |
- assert(supertypeLoadState == STATE_DONE); |
+ assert(invariant(this, supertypeLoadState == STATE_DONE, |
+ message: "Superclass has not been computed for $this.")); |
return supertype == null ? null : supertype.element; |
} |