[-fms-extensions] Don't crash on explicit class-scope specializations & default arguments

The code had a typo it was doing:
  Param->setUninstantiatedDefaultArg(Param->getUninstantiatedDefaultArg());

This is a no-op but may assert, we wanted to do:
  Param->setUninstantiatedDefaultArg(OldParam->getUninstantiatedDefaultArg());

This fixes PR28082.

llvm-svn: 272425

1 files changed, 9 insertions, 0 deletions

diff --git a/clang/test/SemaTemplate/ms-function-specialization-class-scope.cpp b/clang/test/SemaTemplate/ms-function-specialization-class-scope.cpp
index 5da00837cc0..3c7111d0583 100644
--- a/clang/test/SemaTemplate/ms-function-specialization-class-scope.cpp
+++ b/clang/test/SemaTemplate/ms-function-specialization-class-scope.cpp
@@ -75,3 +75,12 @@ namespace Duplicates {
   // here.
   template struct A<int>;
 }
+
+namespace PR28082 {
+struct S {
+  template <int>
+  int f(int = 0);
+  template <>
+  int f<0>(int); // expected-warning {{Microsoft extension}}
+};
+}