Use failedAt in more places

pkg/compiler/lib/src/js_backend/impact_transformer.dart

 // Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library js_backend.backend.impact_transformer;
 
 import '../common.dart';
 import '../common_elements.dart';
 import '../common/backend_api.dart' show ImpactTransformer;
 import '../common/codegen.dart' show CodegenImpact;
@@ skipping 245 matching lines @@
         case ConstantExpressionKind.INT:
           registerImpact(_impacts.intLiteral);
           break;
         case ConstantExpressionKind.DOUBLE:
           registerImpact(_impacts.doubleLiteral);
           break;
         case ConstantExpressionKind.STRING:
           registerImpact(_impacts.stringLiteral);
           break;
         default:
-          assert(invariant(NO_LOCATION_SPANNABLE, false,
-              message: "Unexpected constant literal: ${constant.kind}."));
+          assert(
+              false,
+              failedAt(NO_LOCATION_SPANNABLE,
+                  "Unexpected constant literal: ${constant.kind}."));
       }
     }
 
     for (native.NativeBehavior behavior in worldImpact.nativeData) {
       _nativeResolutionEnqueuer.registerNativeBehavior(
           transformed, behavior, worldImpact);
     }
 
     return transformed;
   }
@@ skipping 189 matching lines @@
           _impacts.asyncStarBody
               .registerImpact(transformed, _elementEnvironment);
           break;
       }
     }
 
     // TODO(johnniwinther): Remove eager registration.
     return transformed;
   }
 }