Fix shadowing warning

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@309851 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/std/input.output/string.streams/stringstream.cons/string.pass.cpp b/test/std/input.output/string.streams/stringstream.cons/string.pass.cpp
index 43b9df6..f808bcd 100644
--- a/test/std/input.output/string.streams/stringstream.cons/string.pass.cpp
+++ b/test/std/input.output/string.streams/stringstream.cons/string.pass.cpp
@@ -22,7 +22,7 @@
 struct NoDefaultAllocator : std::allocator<T>
 {
   template<typename U> struct rebind { using other = NoDefaultAllocator<U>; };
-  NoDefaultAllocator(int id) : id(id) { }
+  NoDefaultAllocator(int id_) : id(id_) { }
   template<typename U> NoDefaultAllocator(const NoDefaultAllocator<U>& a) : id(a.id) { }
   int id;
 };