[libcxx-commits] [libcxx] [libc++] Fix negate and bit_xor in C++03 frozen headers (PR #187573)

[Louis Dionne via libcxx-commits]

https://github.com/ldionne created https://github.com/llvm/llvm-project/pull/187573

An unintended change in #134045 gave them a default template argument, which is supposed to be from C++14 onwards.

I considered adding a test for this but it is really awkward to test that we don't support passing no template argument in C++03 mode and that provides little value, so I decided against it.

>From 99b087580d104d3744d7d2b3cb22c52974e72aa6 Mon Sep 17 00:00:00 2001
From: Louis Dionne <ldionne.2 at gmail.com>
Date: Thu, 19 Mar 2026 16:01:10 -0400
Subject: [PATCH] [libc++] Fix negate and bit_xor in C++03 frozen headers

An unintended change in #134045 gave them a default template
argument, which is supposed to be from C++14 onwards.

I considered adding a test for this but it is really awkward to
test that we don't support passing no template argument in C++03
mode and that provides little value, so I decided against it.
---
 libcxx/include/__cxx03/__functional/operations.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libcxx/include/__cxx03/__functional/operations.h b/libcxx/include/__cxx03/__functional/operations.h
index 43bfbddc41cce..83840a2e5af27 100644
--- a/libcxx/include/__cxx03/__functional/operations.h
+++ b/libcxx/include/__cxx03/__functional/operations.h
@@ -67,7 +67,7 @@ struct _LIBCPP_TEMPLATE_VIS modulus : __binary_function<_Tp, _Tp, _Tp> {
 };
 _LIBCPP_CTAD_SUPPORTED_FOR_TYPE(modulus);
 
-template <class _Tp = void>
+template <class _Tp>
 struct _LIBCPP_TEMPLATE_VIS negate : __unary_function<_Tp, _Tp> {
   typedef _Tp __result_type; // used by valarray
   _LIBCPP_HIDE_FROM_ABI _Tp operator()(const _Tp& __x) const { return -__x; }
@@ -90,7 +90,7 @@ struct _LIBCPP_TEMPLATE_VIS bit_or : __binary_function<_Tp, _Tp, _Tp> {
 };
 _LIBCPP_CTAD_SUPPORTED_FOR_TYPE(bit_or);
 
-template <class _Tp = void>
+template <class _Tp>
 struct _LIBCPP_TEMPLATE_VIS bit_xor : __binary_function<_Tp, _Tp, _Tp> {
   typedef _Tp __result_type; // used by valarray
   _LIBCPP_HIDE_FROM_ABI _Tp operator()(const _Tp& __x, const _Tp& __y) const { return __x ^ __y; }