[Bug c++/86306] New: Initializing atomic qualified type with another atomic qualified type leads to assertion failure

[zhonghao at pku dot org.cn]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86306

            Bug ID: 86306
           Summary: Initializing atomic qualified type with another atomic
                    qualified type leads to assertion failure
           Product: gcc
           Version: 8.0.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zhonghao at pku dot org.cn
  Target Milestone: ---

The code is as follow:

typedef _Atomic(int) A;
A a = A();

clang++ accepts it, but g++ rejects it:

code0.c.cpp:1:22: error: expected initializer before 'A'
 typedef _Atomic(int) A;
                      ^
code0.c.cpp:2:1: error: 'A' does not name a type
 A a = A();
 ^
The code comes from https://bugs.llvm.org/show_bug.cgi?id=22043