Use failedAt in more places

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

Index: pkg/compiler/lib/src/resolution/member_impl.dart
diff --git a/pkg/compiler/lib/src/resolution/member_impl.dart b/pkg/compiler/lib/src/resolution/member_impl.dart
index 70f2a7aa36f095dcdd9af2db2d38fe9c2f6cbfba..bb2bab7a3edcf259d5e67050ad58fc6ea70a4221 100644
--- a/pkg/compiler/lib/src/resolution/member_impl.dart
+++ b/pkg/compiler/lib/src/resolution/member_impl.dart
@@ -143,17 +143,18 @@ class InheritedMember implements DeclaredMember {
   }
 
   DeclaredMember inheritFrom(ResolutionInterfaceType newInstance) {
-    assert(invariant(declaration.element, () {
+    assert(() {
       // Assert that if [instance] contains type variables, then these are
       // defined in the declaration of [newInstance] and will therefore be
       // substituted into the context of [newInstance] in the created member.
       ClassElement contextClass = Types.getClassContext(instance);
       return contextClass == null || contextClass == newInstance.element;
-    }, message: () {
-      return "Context mismatch: Context class "
-          "${Types.getClassContext(instance)} from $instance does match "
-          "the new instance $newInstance.";
-    }));
+    },
+        failedAt(
+            declaration.element,
+            "Context mismatch: Context class "
+            "${Types.getClassContext(instance)} from $instance does match "
+            "the new instance $newInstance."));
     return _newInheritedMember(newInstance);
   }