Use failedAt in more places

pkg/compiler/lib/src/enqueue.dart

 // Copyright (c) 2012, 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 dart2js.enqueue;
 
 import 'dart:collection' show Queue;
 
 import 'common/tasks.dart' show CompilerTask;
 import 'common/work.dart' show WorkItem;
@@ skipping 28 matching lines @@
 
   EnqueueTask(Compiler compiler)
       : this.compiler = compiler,
         super(compiler.measurer);
 
   // TODO(johnniwinther): Remove the need for this.
   bool get hasResolution => _resolution != null;
 
   // TODO(johnniwinther): Remove the need for this.
   ResolutionEnqueuer get resolution {
-    assert(invariant(NO_LOCATION_SPANNABLE, _resolution != null,
-        message: "ResolutionEnqueuer has not been created yet."));
+    assert(
+        _resolution != null,
+        failedAt(NO_LOCATION_SPANNABLE,
+            "ResolutionEnqueuer has not been created yet."));
     return _resolution;
   }
 
   ResolutionEnqueuer createResolutionEnqueuer() {
     return _resolution ??=
         compiler.backend.createResolutionEnqueuer(this, compiler);
   }
 
   Enqueuer createCodegenEnqueuer(ClosedWorld closedWorld) {
     return compiler.backend.createCodegenEnqueuer(this, compiler, closedWorld);
@@ skipping 531 matching lines @@
   final Entity element;
   final DeferredActionFunction action;
 
   DeferredAction(this.element, this.action);
 }
 
 /// Interface for creating work items for enqueued member entities.
 abstract class WorkItemBuilder {
   WorkItem createWorkItem(MemberEntity entity);
 }