Fix another crash and actually make the test case work.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@72913 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/SemaTemplate/default-arguments.cpp b/test/SemaTemplate/default-arguments.cpp
index 0e4c366..5b6ab7d 100644
--- a/test/SemaTemplate/default-arguments.cpp
+++ b/test/SemaTemplate/default-arguments.cpp
@@ -11,5 +11,5 @@
 
 X<> *x4;
 
-template<typename T = int> struct Z;
+template<typename T = int> struct Z { };
 template struct Z<>;