https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85118
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Known to fail| |6.4.0, 7.3.0, 8.0.1
--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> ---
GCC 5, Clang and EDG all compile it.
GCC 6 onwards fail with:
85118.C: In instantiation of 'main()::<lambda(auto:1&& ...)> [with auto:1 =
{volatile char}]':
85118.C:114:51: required by substitution of 'template<class ... auto:1>
main()::<lambda(auto:1&& ...)>::operator decltype (((const
main()::<lambda(auto:1&& ...)>*)((const main()::<lambda(auto:1&& ...)>*
const)0u))->operator()(static_cast<auto:1&>(main::__lambda0::_FUN::<unnamed>)
...)) (*)(auto:1&& ...)() const [with auto:1 = {volatile char}]'
85118.C:79:56: required by substitution of 'template<class _Args, class
_Result> _Result std::_Bind<_Functor, _Bound_args>::operator()(_Args&&)
volatile [with _Args = char; _Result = <missing>]'
85118.C:121:12: required from here
85118.C:116:23: error: no matching function for call to 'isOneOf(volatile
char)'
return isOneOf(std::forward<decltype(params)>(params)...);
~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
85118.C:101:6: note: candidate: bool isOneOf(const T&) [with T = volatile char]
<near match>
bool isOneOf(const T& )
^~~~~~~
85118.C:101:6: note: conversion of argument 1 would be ill-formed:
85118.C:116:23: error: invalid initialization of non-const reference of type
'const volatile char&' from an rvalue of type 'volatile char'
return isOneOf(std::forward<decltype(params)>(params)...);
~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
85118.C:107:6: note: candidate: template<class T, class FirstType, class ...
Tail> bool isOneOf(const T&, const FirstType&, const Tail& ...)
bool isOneOf(const T& t, const FirstType& firstValue, const Tail&... tail)
^~~~~~~
85118.C:107:6: note: template argument deduction/substitution failed:
85118.C:116:23: note: candidate expects at least 2 arguments, 1 provided
return isOneOf(std::forward<decltype(params)>(params)...);
~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
85118.C:76:10: warning: '_Result std::_Bind<_Functor,
_Bound_args>::operator()(_Args&&) [with _Args = char; _Result = bool; _Functor
= const main()::<lambda(auto:1&& ...)>; _Bound_args = char]' used but never
defined
operator()(_Args&& __args);
^~~~~~~~
The error says "invalid initialization of non-const reference of type 'const
volatile char&' from an rvalue of type 'volatile char'" which is bogus, because
const volatile char& is not a non-const reference.
