Use failedAt in more places

pkg/compiler/lib/src/elements/elements.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 elements;
 
 import '../common.dart';
 import '../common/resolution.dart' show Resolution;
 import '../constants/constructors.dart';
 import '../constants/expressions.dart';
@@ skipping 864 matching lines @@
    *
    * Returns [:true:] if the signature of the [caller] matches the
    * signature of the [callee], [:false:] otherwise.
    */
   static bool addForwardingElementArgumentsToList<T>(
       ConstructorElement caller,
       List<T> list,
       ConstructorElement callee,
       T compileArgument(ParameterElement element),
       T compileConstant(ParameterElement element)) {
-    assert(invariant(caller, !callee.isMalformed,
-        message: "Cannot compute arguments to malformed constructor: "
+    assert(
+        !callee.isMalformed,
+        failedAt(
+            caller,
+            "Cannot compute arguments to malformed constructor: "
             "$caller calling $callee."));
 
     FunctionSignature signature = caller.functionSignature;
     Map<Node, ParameterElement> mapping = <Node, ParameterElement>{};
 
     // TODO(ngeoffray): This is a hack that fakes up AST nodes, so
     // that we can call [addArgumentsToList].
     Link<Node> computeCallNodesFromParameters() {
       LinkBuilder<Node> builder = new LinkBuilder<Node>();
       signature.forEachRequiredParameter((ParameterElement element) {
@@ skipping 1080 matching lines @@
   /// by a field.
   bool get isDeclaredByField;
 
   /// Returns `true` if this member is abstract.
   bool get isAbstract;
 
   /// If abstract, [implementation] points to the overridden concrete member,
   /// if any. Otherwise [implementation] points to the member itself.
   Member get implementation;
 }