diff --git a/clang/test/Sema/MicrosoftExtensions.cpp b/clang/test/Sema/MicrosoftExtensions.cpp
--- a/clang/test/Sema/MicrosoftExtensions.cpp
+++ b/clang/test/Sema/MicrosoftExtensions.cpp
@@ -1,6 +1,5 @@
 // RUN: %clang_cc1 -triple i686-windows %s -fsyntax-only -Wmicrosoft -verify -fms-extensions
 // RUN: %clang_cc1 -triple x86_64-windows %s -fsyntax-only -Wmicrosoft -verify -fms-extensions
-// expected-no-diagnostics
 
 // Check that __ptr32/__ptr64 can be compared.
 int test_ptr_comparison(int *__ptr32 __uptr p32u, int *__ptr32 __sptr p32s,
@@ -9,3 +8,23 @@
          (p32u == p64) +
          (p32s == p64);
 }
+
+template<typename T>
+void bad(T __ptr32 a) { // expected-error {{'__ptr32' attribute only applies to pointer arguments}}`
+  (*a) += 1;
+}
+
+template<int size_expected, typename T>
+void f(T a) {
+  (*a) += sizeof(a);
+  static_assert(sizeof(a) == size_expected, "instantiated template argument has unexpected size");
+}
+void g(int *p) {
+  // instantiate for default sized pointer
+  f<sizeof(void*)>(p);
+}
+
+void h(int *__ptr32 p) {
+  // instantiate for 32-bit pointer
+  f<4>(p);
+}