https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108667
Bug ID: 108667
Summary: Spurious "maybe used uninitialized
[-Wmaybe-uninitialized]" warning
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: alvaro.begue at gmail dot com
Target Milestone: ---
I am using g++-12.1.0 on x86-64, but g++-12.2.0 in godbolt.org shows the same
problem
The options are -O3 -Wmaybe-uninitialized .
The code:
#include <functional>
struct S {
S(std::function<void()> f) : f(f) {}
std::function<void()> g;
std::function<void()> f;
};
int main() {
S s([](){});
s.f();
}
Compiler output (from godbolt.org):
In file included from
/opt/compiler-explorer/gcc-12.2.0/include/c++/12.2.0/functional:59,
from <source>:1:
In copy constructor 'std::function<_Res(_ArgTypes ...)>::function(const
std::function<_Res(_ArgTypes ...)>&) [with _Res = void; _ArgTypes = {}]',
inlined from 'S::S(std::function<void()>)' at <source>:4:34,
inlined from 'int main()' at <source>:11:15:
/opt/compiler-explorer/gcc-12.2.0/include/c++/12.2.0/bits/std_function.h:391:17:
warning: '<anonymous>' may be used uninitialized [-Wmaybe-uninitialized]
391 | __x._M_manager(_M_functor, __x._M_functor,
__clone_functor);
| ~~~~^~~~~~~~~~
/opt/compiler-explorer/gcc-12.2.0/include/c++/12.2.0/bits/std_function.h: In
function 'int main()':
/opt/compiler-explorer/gcc-12.2.0/include/c++/12.2.0/bits/std_function.h:267:7:
note: by argument 2 of type 'const std::_Any_data&' to 'static bool
std::_Function_handler<_Res(_ArgTypes ...),
_Functor>::_M_manager(std::_Any_data&, const std::_Any_data&,
std::_Manager_operation) [with _Res = void; _Functor = main()::<lambda()>;
_ArgTypes = {}]' declared here
267 | _M_manager(_Any_data& __dest, const _Any_data& __source,
| ^~~~~~~~~~
<source>:11:15: note: '<anonymous>' declared here
11 | S s([](){});
| ^
Compiler returned: 0
