Improve error for non-const implicit super constructor

pkg/compiler/lib/src/resolution/constructors.dart

Index: pkg/compiler/lib/src/resolution/constructors.dart
diff --git a/pkg/compiler/lib/src/resolution/constructors.dart b/pkg/compiler/lib/src/resolution/constructors.dart
index 28d5a3be33762a982e17fa9a63999f13a0a3c075..72ca1560f65c9d6e816d7be19430f22151cafeb6 100644
--- a/pkg/compiler/lib/src/resolution/constructors.dart
+++ b/pkg/compiler/lib/src/resolution/constructors.dart
@@ -192,8 +192,10 @@ class InitializerResolver {
         visitor.compiler.reportError(diagnosticNode, kind);
       } else if (caller.isConst
                  && !lookedupConstructor.isConst) {
-        visitor.compiler.reportError(
-            diagnosticNode, MessageKind.CONST_CALLS_NON_CONST);
+        MessageKind kind = isImplicitSuperCall
+                           ? MessageKind.CONST_CALLS_NON_CONST_FOR_IMPLICIT
+                           : MessageKind.CONST_CALLS_NON_CONST;
+        visitor.compiler.reportError(diagnosticNode, kind);
       }
     }
   }