https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105718
Bug ID: 105718
Summary: Forward Declarations of Constrained Partially
Specialized Class Templates Rejected
Product: gcc
Version: 11.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: mate.kelemen.12 at gmail dot com
Target Milestone: ---
Created attachment 53029
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53029&action=edit
Preprocessed source run with: g++ -v --save-temps -std=c++20.
Multiple forward declarations of partially specialized class templates with
constraints (C++20 concepts) get rejected at the second declaration. Equivalent
code with explicit specializations compiles without issues. See the
[example](https://godbolt.org/z/1hd8Y6Ghh) on godbolt (Clang and MSVC don't
reject it). Source and preprocessed file in the attachments.
This issue seems to be a duplicate of #99501 from 03.2021, which hasn't gotten
any attention yet.
