[libc++] Remove unused <iosfwd> include from <__debug>

[philnik]

libcxx/include/module.modulemap

622

Why are you exporting iosfwd from iterator?

[ldionne]

libcxx/include/module.modulemap

622

It is needed because std::ostreambuf_iterator & friends have a default template argument of std::char_traits. I could also try to use something more restricted in scope like exporting char_traits directly from __iterator/ostreambuf_iterator.h. I'll take a look.

[ldionne]

Try more localized fix

libcxx/include/__debug

 // -*- C++ -*-
 //===----------------------------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef _LIBCPP___DEBUG
 #define _LIBCPP___DEBUG
 
 #include <__assert>
 #include <__config>
-#include <iosfwd>
 #include <type_traits>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 #if _LIBCPP_DEBUG_LEVEL >= 1 || defined(_LIBCPP_BUILDING_LIBRARY)
 #   include <cstddef>

libcxx/include/experimental/iterator

 
 */
 
 #include <__assert> // all public C++ headers provide the assertion handler
 #include <__memory/addressof.h>
 #include <__utility/forward.h>
 #include <__utility/move.h>
 #include <experimental/__config>
+#include <iosfwd> // char_traits
 #include <iterator>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 
 #if _LIBCPP_STD_VER > 11
 

libcxx/include/module.modulemap

module std [system] {
   }
   module istream {
     header "istream"
     // FIXME: should re-export ios, streambuf?
     export *
   }
   module iterator {
     header "iterator"
+    export iosfwd
     export *
 
     module __iterator {
       module access                { private header "__iterator/access.h" }
       module advance               { private header "__iterator/advance.h" }
       module back_insert_iterator  { private header "__iterator/back_insert_iterator.h" }
       module common_iterator       { private header "__iterator/common_iterator.h" }
       module concepts              { private header "__iterator/concepts.h" }