[MS Compatibility] Handle cleanups we create for a ctor closure

This fixes PR23801.

llvm-svn: 239503
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index c80ef2d..7ed9bfc 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -9494,6 +9494,7 @@
 
       Expr *DefaultArg = S.BuildCXXDefaultArgExpr(Class->getLocation(), CD,
                                                   CD->getParamDecl(I)).get();
+      S.DiscardCleanupsInEvaluationContext();
       S.Context.addDefaultArgExprForConstructor(CD, I, DefaultArg);
     }
   }
diff --git a/clang/test/CodeGenCXX/dllexport.cpp b/clang/test/CodeGenCXX/dllexport.cpp
index 477e7dc..0eb6476 100644
--- a/clang/test/CodeGenCXX/dllexport.cpp
+++ b/clang/test/CodeGenCXX/dllexport.cpp
@@ -532,6 +532,22 @@
 
 // M32-DAG: define weak_odr dllexport x86_thiscallcc void @"\01??_F?$SomeTemplate@H@@QAEXXZ"
 
+namespace PR23801 {
+template <typename>
+struct S {
+  ~S() {}
+};
+struct A {
+  A(int);
+  S<int> s;
+};
+struct __declspec(dllexport) B {
+  B(A = 0) {}
+};
+}
+//
+// M32-DAG: define weak_odr dllexport x86_thiscallcc void @"\01??_FB@PR23801@@QAEXXZ"
+
 struct __declspec(dllexport) T {
   // Copy assignment operator:
   // M32-DAG: define weak_odr dllexport x86_thiscallcc dereferenceable({{[0-9]+}}) %struct.T* @"\01??4T@@QAEAAU0@ABU0@@Z"