fix #26393, treat tear offs as definite functions

pkg/analyzer/test/src/task/strong/checker_test.dart

Index: pkg/analyzer/test/src/task/strong/checker_test.dart
diff --git a/pkg/analyzer/test/src/task/strong/checker_test.dart b/pkg/analyzer/test/src/task/strong/checker_test.dart
index f7ce4b20f518dcefde77a55728b50f58ddc6dfe7..e7834b57bc938aebb531a454109cef48ec769418 100644
--- a/pkg/analyzer/test/src/task/strong/checker_test.dart
+++ b/pkg/analyzer/test/src/task/strong/checker_test.dart
@@ -1406,23 +1406,23 @@ void main() {
   }
   {
     Function2<B, B> f;
-    f = /*warning:DOWN_CAST_COMPOSITE*/c.top;
+    f = /*error:STATIC_TYPE_ERROR*/c.top;

[Leaf, 2016/08/05 23:33:05]

This doesn't feel right.  I think this is the "stupid cast" logic coming into
play?  But this cast could succeed: `c` could contain a subclass of C which
overrides top with the right type (since it is a subtype).  Assuming this is
right about where this comes from, then I think the cast logic that inserts this
error shouldn't do so for methods (since they can be overridden).

     f = c.left;
-    f = /*warning:DOWN_CAST_COMPOSITE*/c.right;
+    f = /*error:STATIC_TYPE_ERROR*/c.right;
     f = c.bot;
   }
   {
     Function2<A, A> f;
-    f = /*warning:DOWN_CAST_COMPOSITE*/c.top;
-    f = /*warning:DOWN_CAST_COMPOSITE*/c.left;
+    f = /*error:STATIC_TYPE_ERROR*/c.top;
+    f = /*error:STATIC_TYPE_ERROR*/c.left;
     f = c.right;
     f = c.bot;
   }
   {
     Function2<A, B> f;
-    f = /*warning:DOWN_CAST_COMPOSITE*/c.top;
-    f = /*warning:DOWN_CAST_COMPOSITE*/c.left;
-    f = /*warning:DOWN_CAST_COMPOSITE*/c.right;
+    f = /*error:STATIC_TYPE_ERROR*/c.top;
+    f = /*error:STATIC_TYPE_ERROR*/c.left;
+    f = /*error:STATIC_TYPE_ERROR*/c.right;
     f = c.bot;
   }
 }