https://gcc.gnu.org/bugzilla/show_bug.cgi?id=57239
--- Comment #14 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
clang accepts the reduced testcase in comment #1 but MSVC and ICC both reject
it too.
MSVC:
<source>(18): error C3201: the template parameter list for class template 'Foo'
does not match the template parameter list for template parameter 'TT'
<source>(18): error C2955: 'is_instantiation_of_nontypes<bool,char>::check':
use of class template requires template argument list
<source>(12): note: see declaration of
'is_instantiation_of_nontypes<bool,char>::check'
<source>(18): error C2338: Ouch
ICC:
<source>(11): error: parameter pack "Ts" was referenced but not expanded
template<template<Ts...> class TT, typename T>
^
<source>(14): error: parameter pack "Ts" was referenced but not expanded
template<template<Ts...> class TT, Ts... Args>
^
<source>(14): warning #885: constant "Args" is not used in or cannot be deduced
from the template argument list of class template
"is_instantiation_of_nontypes<Ts...>::check<TT, TT<Args...>> [with Ts=<bool,
char>]"
template<template<Ts...> class TT, Ts... Args>
^
detected during instantiation of class
"is_instantiation_of_nontypes<Ts...> [with Ts=<bool, char>]" at line 18
<source>(18): error: static assertion failed with "Ouch"
static_assert(is_instantiation_of_nontypes<bool, char>::check<Foo, Foo<false,
'x'> >::value, "Ouch");
^
GCC rejects it with:
<source>:15:27: error: expansion pattern '<anonymous>' contains no parameter
packs
15 | struct check<TT, TT<Args...>> : true_type {};
| ^~~
<source>:15:30: error: template argument 2 is invalid
15 | struct check<TT, TT<Args...>> : true_type {};
| ^~
<source>:18:87: error: static assertion failed: Ouch
18 | static_assert(is_instantiation_of_nontypes<bool, char>::check<Foo,
Foo<false, 'x'> >::value, "Ouch");
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~
