xfail transitive inheritance test -- I guess this doesn't work yet

Author: catamorphism

src/test/run-pass/issue-3979-2.rs

@@ -8,6 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+// xfail-test
 trait A {
     fn a_method();
 }