[libcxx-commits] [libcxx] [libcxx] Add a missing include for __enable_if_t (PR #127016)

[Takuto Ikuta via libcxx-commits]

https://github.com/atetubou created https://github.com/llvm/llvm-project/pull/127016

This is to fix compile error with explicit Clang modules like
```
../../third_party/libc++/src/include/__filesystem/path.h:80:26: error: declaration of '__enable_if_t' must be imported from module 'std_core.type_traits.enable_if' before it is required
   80 | template <class _ECharT, __enable_if_t<__can_convert_char<_ECharT>::value, int> = 0>
      |                          ^
../../third_party/libc++/src/include/__type_traits/enable_if.h:34:1: note: declaration here is not visible
   34 | using __enable_if_t _LIBCPP_NODEBUG = typename enable_if<_Bp, _Tp>::type;
      | ^
```

>From f618a0362d276a60d8cf02429526c95accfdd9cf Mon Sep 17 00:00:00 2001
From: Takuto Ikuta <tikuta at google.com>
Date: Thu, 13 Feb 2025 16:18:31 +0900
Subject: [PATCH] [libcxx] Add a missing include for __enable_if_t

This is to fix compile error with explicit Clang modules like
```
../../third_party/libc++/src/include/__filesystem/path.h:80:26: error: declaration of '__enable_if_t' must be imported from module 'std_core.type_traits.enable_if' before it is required
   80 | template <class _ECharT, __enable_if_t<__can_convert_char<_ECharT>::value, int> = 0>
      |                          ^
../../third_party/libc++/src/include/__type_traits/enable_if.h:34:1: note: declaration here is not visible
   34 | using __enable_if_t _LIBCPP_NODEBUG = typename enable_if<_Bp, _Tp>::type;
      | ^
```
---
 libcxx/include/__filesystem/path.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/libcxx/include/__filesystem/path.h b/libcxx/include/__filesystem/path.h
index 0a751ba32954f..698ae209ae1f8 100644
--- a/libcxx/include/__filesystem/path.h
+++ b/libcxx/include/__filesystem/path.h
@@ -18,6 +18,7 @@
 #include <__iterator/back_insert_iterator.h>
 #include <__iterator/iterator_traits.h>
 #include <__type_traits/decay.h>
+#include <__type_traits/enable_if.h>
 #include <__type_traits/is_pointer.h>
 #include <__type_traits/remove_const.h>
 #include <__type_traits/remove_pointer.h>