https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114394
Bug ID: 114394
Summary: std::bind uses std::result_of which is deprecated
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: romain.geissler at amadeus dot com
Target Milestone: ---
Created attachment 57738
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=57738&action=edit
Tentative patch
Hi,
Clang >= 18 now prints a valid deprecation warning with this snippet:
#include <functional>
void f();
void g()
{
std::function<void()> a = std::bind(&f);
}
Warning:
In file included from <source>:1:
/opt/compiler-explorer/gcc-13.2.0/lib/gcc/x86_64-linux-gnu/13.2.0/../../../../include/c++/13.2.0/functional:552:2:
warning: 'result_of<void (*&())()>' is deprecated: use 'std::invoke_result'
instead [-Wdeprecated-declarations]
552 | using _Res_type_impl
| ^
/opt/compiler-explorer/gcc-13.2.0/lib/gcc/x86_64-linux-gnu/13.2.0/../../../../include/c++/13.2.0/functional:556:2:
note: in instantiation of template type alias '_Res_type_impl' requested here
556 | using _Res_type = _Res_type_impl<_Functor, _CallArgs,
_Bound_args...>;
| ^
/opt/compiler-explorer/gcc-13.2.0/lib/gcc/x86_64-linux-gnu/13.2.0/../../../../include/c++/13.2.0/functional:586:28:
note: in instantiation of template type alias '_Res_type' requested here
586 | typename _Result = _Res_type<tuple<_Args...>>>
| ^
<source>:7:31: note: in instantiation of template class 'std::_Bind<void
(*())()>' requested here
7 | std::function<void()> a = std::bind(&f);
| ^
/opt/compiler-explorer/gcc-13.2.0/lib/gcc/x86_64-linux-gnu/13.2.0/../../../../include/c++/13.2.0/type_traits:2590:9:
note: 'result_of<void (*&())()>' has been explicitly marked deprecated here
2590 | { } _GLIBCXX17_DEPRECATED_SUGGEST("std::invoke_result");
| ^
/opt/compiler-explorer/gcc-13.2.0/lib/gcc/x86_64-linux-gnu/13.2.0/../../../../include/c++/13.2.0/x86_64-linux-gnu/bits/c++config.h:122:45:
note: expanded from macro '_GLIBCXX17_DEPRECATED_SUGGEST'
122 | # define _GLIBCXX17_DEPRECATED_SUGGEST(ALT)
_GLIBCXX_DEPRECATED_SUGGEST(ALT)
| ^
/opt/compiler-explorer/gcc-13.2.0/lib/gcc/x86_64-linux-gnu/13.2.0/../../../../include/c++/13.2.0/x86_64-linux-gnu/bits/c++config.h:98:19:
note: expanded from macro '_GLIBCXX_DEPRECATED_SUGGEST'
98 | __attribute__ ((__deprecated__ ("use '" ALT "' instead")))
| ^
1 warning generated.
Compiler returned: 0
(see on Compiler Explorer: https://godbolt.org/z/3jxGr77Ye).
I tried very quickly the attached patch, which seems to fix the warning for me
(however I didn't really test it, so maybe it's not correct).
Note: I guess the fix will qualify for a backport in releases branches, in my
case I have hit this with gcc 13.
