https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94057
Bug ID: 94057
Summary: [9/10 Regression] -std=gnu++20 causes failure naming
nested templated class
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: romain.geissler at amadeus dot com
Target Milestone: ---
Hi,
The following snippet fails with gcc trunk and with gcc 9 if I compile with
-std=gnu++20, but not with -std=gnu++17. gcc <= 8 or any clang version happily
compiles it whatever -std value I use.
template <typename T> class A
{
template <typename... Types> class B
{
B(const A<T>::B<Types...>&) = default;
};
};
It reads:
<source>:5:23: error: 'typename A<T>::B' names 'template<class T>
template<class ... Types> class A<T>::B', which is not a type
5 | B(const A<T>::B<Types...>&) = default;
| ^~~~~~~~~~~
<source>:5:34: error: expected unqualified-id before '&' token
5 | B(const A<T>::B<Types...>&) = default;
| ^
<source>:5:34: error: expected ')' before '&' token
5 | B(const A<T>::B<Types...>&) = default;
| ~ ^
| )
<source>:5:34: error: constructors may not be ref-qualified
<source>:5:34: error: expected ';' at end of member declaration
5 | B(const A<T>::B<Types...>&) = default;
| ^
| ;
<source>:5:35: error: expected unqualified-id before ')' token
5 | B(const A<T>::B<Types...>&) = default;
| ^
Compiler returned: 1
Cheers,
Romain
