[modules] Add testcase for a bug reduced from a selfhost issue. This bug was

never present in Clang trunk, but was present in some of my development work,
and it seems like a useful test to have.

llvm-svn: 214154

clang/test/Modules/Inputs/cxx-templates-a.h

@@ -75,3 +75,10 @@ template<typename T> struct MergeTemplateDefinitions {
 template<typename T> constexpr int MergeTemplateDefinitions<T>::f() { return 1; }
 
 template<typename T> using AliasTemplate = T;
+
+template<typename T> struct PartiallyInstantiatePartialSpec {};
+template<typename T> struct PartiallyInstantiatePartialSpec<T*> {
+  static T *foo() { return reinterpret_cast<T*>(0); }
+  static T *bar() { return reinterpret_cast<T*>(0); }
+};
+typedef PartiallyInstantiatePartialSpec<int*> PartiallyInstantiatePartialSpecHelper;

clang/test/Modules/Inputs/cxx-templates-b.h

@@ -73,4 +73,5 @@ template<typename T> void UseDefinedInBImplIndirectly(T &v) {
 void TriggerInstantiation() {
   UseDefinedInBImpl<void>();
   Std::f<int>();
+  PartiallyInstantiatePartialSpec<int*>::foo();
 }

clang/test/Modules/cxx-templates.cpp

@@ -105,6 +105,7 @@ void g() {
 
   int &p = WithPartialSpecializationUse().f();
   int &q = WithExplicitSpecializationUse().inner_template<int>();
+  int *r = PartiallyInstantiatePartialSpec<int*>::bar();
 }
 
 static_assert(Outer<int>::Inner<int>::f() == 1, "");