Rationalize coercions

test/dart_codegen/expect/collection/linked_list.dart

Index: test/dart_codegen/expect/collection/linked_list.dart
diff --git a/test/dart_codegen/expect/collection/linked_list.dart b/test/dart_codegen/expect/collection/linked_list.dart
index b89245be42b5a862e6604eccefa908df2889cac8..5e2e8a9a6774902fd2a775c9e94e6f20b7fae6ba 100644
--- a/test/dart_codegen/expect/collection/linked_list.dart
+++ b/test/dart_codegen/expect/collection/linked_list.dart
@@ -19,7 +19,7 @@ part of dart.collection;
     }
   , __x10, __t8, DEVC$RT.type((__t6<E> _) {
     }
-  ), "WrapLiteral", """line 65, column 21 of dart:collection/linked_list.dart: """, __x10 is __t6<E>))((entry) => _insertAfter(_previous, DEVC$RT.cast(entry, dynamic, E, "CastGeneral", """line 65, column 56 of dart:collection/linked_list.dart: """, entry is E, false))));
+  ), "WrapLiteral", """line 65, column 21 of dart:collection/linked_list.dart: """, __x10 is __t6<E>))((entry) => _insertAfter(_previous, DEVC$RT.cast(entry, dynamic, E, "CompositeCast", """line 65, column 56 of dart:collection/linked_list.dart: """, entry is E, false))));
   }
  bool remove(E entry) {
   if (entry._list != this) return false;
@@ -32,7 +32,7 @@ part of dart.collection;
   _modificationCount++;
    _LinkedListLink next = _next;
    while (!identical(next, this)) {
-    E entry = DEVC$RT.cast(next, _LinkedListLink, E, "CastGeneral", """line 93, column 17 of dart:collection/linked_list.dart: """, next is E, false);
+    E entry = DEVC$RT.cast(next, _LinkedListLink, E, "CompositeCast", """line 93, column 17 of dart:collection/linked_list.dart: """, next is E, false);
      next = entry._next;
      entry._next = entry._previous = entry._list = null;
     }
@@ -43,13 +43,13 @@ part of dart.collection;
   if (identical(_next, this)) {
     throw new StateError('No such element');
     }
-   return DEVC$RT.cast(_next, _LinkedListLink, E, "CastGeneral", """line 105, column 12 of dart:collection/linked_list.dart: """, _next is E, false);
+   return DEVC$RT.cast(_next, _LinkedListLink, E, "CompositeCast", """line 105, column 12 of dart:collection/linked_list.dart: """, _next is E, false);
   }
  E get last {
   if (identical(_previous, this)) {
     throw new StateError('No such element');
     }
-   return DEVC$RT.cast(_previous, _LinkedListLink, E, "CastGeneral", """line 112, column 12 of dart:collection/linked_list.dart: """, _previous is E, false);
+   return DEVC$RT.cast(_previous, _LinkedListLink, E, "CompositeCast", """line 112, column 12 of dart:collection/linked_list.dart: """, _previous is E, false);
   }
  E get single {
   if (identical(_previous, this)) {
@@ -58,13 +58,13 @@ part of dart.collection;
    if (!identical(_previous, _next)) {
     throw new StateError('Too many elements');
     }
-   return DEVC$RT.cast(_next, _LinkedListLink, E, "CastGeneral", """line 122, column 12 of dart:collection/linked_list.dart: """, _next is E, false);
+   return DEVC$RT.cast(_next, _LinkedListLink, E, "CompositeCast", """line 122, column 12 of dart:collection/linked_list.dart: """, _next is E, false);
   }
  void forEach(void action(E entry)) {
   int modificationCount = _modificationCount;
    _LinkedListLink current = _next;
    while (!identical(current, this)) {
-    action(DEVC$RT.cast(current, _LinkedListLink, E, "CastGeneral", """line 134, column 14 of dart:collection/linked_list.dart: """, current is E, false));
+    action(DEVC$RT.cast(current, _LinkedListLink, E, "CompositeCast", """line 134, column 14 of dart:collection/linked_list.dart: """, current is E, false));
      if (modificationCount != _modificationCount) {
       throw new ConcurrentModificationError(this);
       }
@@ -108,7 +108,7 @@ if (identical(_next, _list)) {
  if (_modificationCount != _list._modificationCount) {
   throw new ConcurrentModificationError(this);
   }
- _current = DEVC$RT.cast(_next, _LinkedListLink, E, "CastGeneral", """line 192, column 16 of dart:collection/linked_list.dart: """, _next is E, false);
+ _current = DEVC$RT.cast(_next, _LinkedListLink, E, "CompositeCast", """line 192, column 16 of dart:collection/linked_list.dart: """, _next is E, false);
  _next = _next._next;
  return true;
 }
@@ -125,7 +125,7 @@ _list._unlink(this);
 }
  E get next {
 if (identical(_next, _list)) return null;
- E result = DEVC$RT.cast(_next, _LinkedListLink, E, "CastGeneral", """line 249, column 16 of dart:collection/linked_list.dart: """, _next is E, false);
+ E result = DEVC$RT.cast(_next, _LinkedListLink, E, "CompositeCast", """line 249, column 16 of dart:collection/linked_list.dart: """, _next is E, false);
  return result;
 }
  E get previous {