Use failedAt in more places

pkg/compiler/lib/src/ordered_typeset.dart

Index: pkg/compiler/lib/src/ordered_typeset.dart
diff --git a/pkg/compiler/lib/src/ordered_typeset.dart b/pkg/compiler/lib/src/ordered_typeset.dart
index 829a2d9a958d54334e950955cd4c348e0ddec5e7..bbc71c9b08bc83d274adbb84a41ed2f017255370 100644
--- a/pkg/compiler/lib/src/ordered_typeset.dart
+++ b/pkg/compiler/lib/src/ordered_typeset.dart
@@ -52,8 +52,11 @@ class OrderedTypeSet {
   /// class which this set represents. This is for instance used to create the
   /// type set for [ClosureClassElement] which extends [Closure].
   OrderedTypeSet extendClass(InterfaceType type) {
-    assert(invariant(type.element, types.head.treatAsRaw,
-        message: 'Cannot extend generic class ${types.head} using '
+    assert(
+        types.head.treatAsRaw,
+        failedAt(
+            type.element,
+            'Cannot extend generic class ${types.head} using '
             'OrderedTypeSet.extendClass'));
     Link<InterfaceType> extendedTypes =
         new LinkEntry<InterfaceType>(type, types);
@@ -197,8 +200,11 @@ abstract class OrderedTypeSetBuilderBase implements OrderedTypeSetBuilder {
   void _addAllSupertypes(InterfaceType type) {
     ClassEntity classElement = type.element;
     Link<InterfaceType> supertypes = getOrderedTypeSet(classElement).supertypes;
-    assert(invariant(cls, supertypes != null,
-        message: "Supertypes not computed on $classElement "
+    assert(
+        supertypes != null,
+        failedAt(
+            cls,
+            "Supertypes not computed on $classElement "
             "during resolution of $cls"));
     while (!supertypes.isEmpty) {
       InterfaceType supertype = supertypes.head;
@@ -235,8 +241,7 @@ abstract class OrderedTypeSetBuilderBase implements OrderedTypeSetBuilder {
             'secondType': type
           });
         } else {
-          assert(invariant(cls, false,
-              message: 'Invalid ordered typeset for $cls'));
+          assert(false, failedAt(cls, 'Invalid ordered typeset for $cls'));
         }
         return;
       }