https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106067
Bug ID: 106067
Summary: Error on implicit conversion to std::function: 'static
constexpr bool std::_Function_handler<...>...' used
before its definition
Product: gcc
Version: 11.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: e.tadeu at gmail dot com
Target Milestone: ---
The following code started failing on GCC 11.3 (also fails on GCC 12):
#include <functional>
double fn();
template <double (*T)(std::function<double()>)>
void caller()
{
auto f = T(fn);
// auto f = T(std::function<double()>(fn)); // workaround (this works)
}
The snippet is also here: https://godbolt.org/z/zh7nr7vKc
The full error is:
In file included from
/opt/compiler-explorer/gcc-11.3.0/include/c++/11.3.0/bits/move.h:57,
from
/opt/compiler-explorer/gcc-11.3.0/include/c++/11.3.0/bits/stl_function.h:60,
from
/opt/compiler-explorer/gcc-11.3.0/include/c++/11.3.0/functional:49,
from <source>:1:
/opt/compiler-explorer/gcc-11.3.0/include/c++/11.3.0/type_traits: In
instantiation of 'struct std::is_trivially_copyable<double (*)()>':
/opt/compiler-explorer/gcc-11.3.0/include/c++/11.3.0/bits/std_function.h:69:12:
required from 'struct std::__is_location_invariant<double (*)()>'
/opt/compiler-explorer/gcc-11.3.0/include/c++/11.3.0/bits/std_function.h:125:38:
required from 'const bool std::_Function_base::_Base_manager<double
(*)()>::__stored_locally'
/opt/compiler-explorer/gcc-11.3.0/include/c++/11.3.0/bits/std_function.h:130:8:
required from 'class std::_Function_base::_Base_manager<double (*)()>'
/opt/compiler-explorer/gcc-11.3.0/include/c++/11.3.0/bits/std_function.h:260:11:
required from 'class std::_Function_handler<double(), double (*)()>'
/opt/compiler-explorer/gcc-11.3.0/include/c++/11.3.0/bits/std_function.h:436:65:
required from 'std::function<_Res(_ArgTypes ...)>::function(_Functor&&) [with
_Functor = double (*)(); _Constraints = void; _Res = double; _ArgTypes = {}]'
<source>:8:15: required from here
/opt/compiler-explorer/gcc-11.3.0/include/c++/11.3.0/type_traits:713:52: error:
non-constant condition for static assertion
713 |
static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-11.3.0/include/c++/11.3.0/type_traits:713:52: error:
'constexpr std::true_type
std::__is_complete_or_unbounded(std::__type_identity<_Tp>) [with _Tp = double
(*)(); long unsigned int <anonymous> = 8; std::true_type =
std::integral_constant<bool, true>]' used before its definition
In file included from
/opt/compiler-explorer/gcc-11.3.0/include/c++/11.3.0/functional:59,
from <source>:1:
/opt/compiler-explorer/gcc-11.3.0/include/c++/11.3.0/bits/std_function.h: In
instantiation of 'std::function<_Res(_ArgTypes ...)>::function(_Functor&&)
[with _Functor = double (*)(); _Constraints = void; _Res = double; _ArgTypes =
{}]':
<source>:8:15: required from here
/opt/compiler-explorer/gcc-11.3.0/include/c++/11.3.0/bits/std_function.h:436:72:
error: 'static constexpr bool std::_Function_handler<_Res(_ArgTypes ...),
_Functor>::_S_nothrow_init() [with _Fn = double (*)(); _Res = double; _Functor
= double (*)(); _ArgTypes = {}]' used before its definition
436 | noexcept(_Handler<_Functor>::template
_S_nothrow_init<_Functor>())
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~
ASM generation compiler returned: 1
In file included from
/opt/compiler-explorer/gcc-11.3.0/include/c++/11.3.0/bits/move.h:57,
from
/opt/compiler-explorer/gcc-11.3.0/include/c++/11.3.0/bits/stl_function.h:60,
from
/opt/compiler-explorer/gcc-11.3.0/include/c++/11.3.0/functional:49,
from <source>:1:
/opt/compiler-explorer/gcc-11.3.0/include/c++/11.3.0/type_traits: In
instantiation of 'struct std::is_trivially_copyable<double (*)()>':
/opt/compiler-explorer/gcc-11.3.0/include/c++/11.3.0/bits/std_function.h:69:12:
required from 'struct std::__is_location_invariant<double (*)()>'
/opt/compiler-explorer/gcc-11.3.0/include/c++/11.3.0/bits/std_function.h:125:38:
required from 'const bool std::_Function_base::_Base_manager<double
(*)()>::__stored_locally'
/opt/compiler-explorer/gcc-11.3.0/include/c++/11.3.0/bits/std_function.h:130:8:
required from 'class std::_Function_base::_Base_manager<double (*)()>'
/opt/compiler-explorer/gcc-11.3.0/include/c++/11.3.0/bits/std_function.h:260:11:
required from 'class std::_Function_handler<double(), double (*)()>'
/opt/compiler-explorer/gcc-11.3.0/include/c++/11.3.0/bits/std_function.h:436:65:
required from 'std::function<_Res(_ArgTypes ...)>::function(_Functor&&) [with
_Functor = double (*)(); _Constraints = void; _Res = double; _ArgTypes = {}]'
<source>:8:15: required from here
/opt/compiler-explorer/gcc-11.3.0/include/c++/11.3.0/type_traits:713:52: error:
non-constant condition for static assertion
713 |
static_assert(std::__is_complete_or_unbounded(__type_identity<_Tp>{}),
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
/opt/compiler-explorer/gcc-11.3.0/include/c++/11.3.0/type_traits:713:52: error:
'constexpr std::true_type
std::__is_complete_or_unbounded(std::__type_identity<_Tp>) [with _Tp = double
(*)(); long unsigned int <anonymous> = 8; std::true_type =
std::integral_constant<bool, true>]' used before its definition
In file included from
/opt/compiler-explorer/gcc-11.3.0/include/c++/11.3.0/functional:59,
from <source>:1:
/opt/compiler-explorer/gcc-11.3.0/include/c++/11.3.0/bits/std_function.h: In
instantiation of 'std::function<_Res(_ArgTypes ...)>::function(_Functor&&)
[with _Functor = double (*)(); _Constraints = void; _Res = double; _ArgTypes =
{}]':
<source>:8:15: required from here
/opt/compiler-explorer/gcc-11.3.0/include/c++/11.3.0/bits/std_function.h:436:72:
error: 'static constexpr bool std::_Function_handler<_Res(_ArgTypes ...),
_Functor>::_S_nothrow_init() [with _Fn = double (*)(); _Res = double; _Functor
= double (*)(); _ArgTypes = {}]' used before its definition
436 | noexcept(_Handler<_Functor>::template
_S_nothrow_init<_Functor>())
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~
Execution build compiler returned: 1
