Merge pr-3188.cpp into constructor.cpp.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@61370 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/SemaCXX/constructor.cpp b/test/SemaCXX/constructor.cpp
index 786d145..536593d 100644
--- a/test/SemaCXX/constructor.cpp
+++ b/test/SemaCXX/constructor.cpp
@@ -27,3 +27,13 @@
 extern const Anon anon;
 extern "C" const Anon anon2;
 
+// PR3188: The extern declaration complained about not having an appropriate
+// constructor.
+struct x;
+extern x a;
+
+// A similar case.
+struct y {
+  y(int);
+};
+extern y b;