[Bug c++/104358] Assignable template lambda as function parameter is incorrectly reduced to type of "int"

[nickhuang99 at hotmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104358

--- Comment #1 from qingzhe huang <nickhuang99 at hotmail dot com> ---
Sorry about the long description and here is the short version to highlight the
core issue. Given this template function with a templated lambda as parameter:

template<typename T>
using Lambda=decltype(+[](T){});

template<typename T>
auto foo(T&&, Lambda<T>)->T;



GCC considers the parameter "Lambda<T>" as type "int" which is wrong:

static_assert(is_same_v<decltype(&foo<int>), 
                 int(*)(int&&, /*"Lambda<T>"*/ int)>);