Use failedAt in more places

pkg/compiler/lib/src/elements/elements.dart

Index: pkg/compiler/lib/src/elements/elements.dart
diff --git a/pkg/compiler/lib/src/elements/elements.dart b/pkg/compiler/lib/src/elements/elements.dart
index 2557a03400ae751a2bbcf868f809959d223ed5b0..7c7f01b0fae911945ed010d90149ed220d632ebf 100644
--- a/pkg/compiler/lib/src/elements/elements.dart
+++ b/pkg/compiler/lib/src/elements/elements.dart
@@ -882,8 +882,11 @@ class Elements {
       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;