https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99501
Bug ID: 99501
Summary: Can't forward declare partial specialization of
template with NTTP previously partially specialized
Product: gcc
Version: 11.0
URL: https://godbolt.org/z/Mhnxrf
Status: UNCONFIRMED
Keywords: rejects-valid
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: johelegp at gmail dot com
CC: johelegp at gmail dot com
Target Milestone: ---
See https://godbolt.org/z/Mhnxrf.
```C++
template<auto>struct X;
template<auto V>requires requires{V.a;}struct X<V>;
template<auto V>requires requires{V.b;}struct X<V>;
```
Completed:
```C++
template<auto>struct X{};
template<auto V>requires requires{V.a;}struct X<V>{static constexpr bool
v{false};};
template<auto V>requires requires{V.b;}struct X<V>;
struct A{int a;};
static_assert(!X<A{}>::v);
struct B{int b;};
template<auto V>requires requires{V.b;}struct X<V>{static constexpr bool
v{true};};
static_assert(X<B{}>::v);
```
