https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93211
Bug ID: 93211
Summary: equivalence of dependent function calls doesn't check
if the call is eligible for ADL
Product: gcc
Version: 9.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: vanyacpp at gmail dot com
Target Milestone: ---
Consider this code:
// https://gcc.godbolt.org/z/3U2TTd
#include <type_traits>
template<typename T>
void g(T);
template<typename T, decltype(g(T{})) = 0>
void f() {} // (1)
template<typename T, decltype(::g(T{})) = 0>
void f() {} // (2)
Question is whether (1) and (2) are (re)definition of the same function or
definitions of two different functions. Currently GCC believes that this is a
redefinition of the same function.
I think (1) and (2) should be definitions of two different functions, because
"decltype(g(T{}))" and "decltype(::g(T{}))" are susceptible to different SFINAE
errors: the overload candidate set of (2) is fixed and the overload candidate
set of (1) can be extended arbitrary by ADL.
