[Bug c++/94844] New: Simple nonsensical program accepted by g++ (rejected by clang++)

[Bug c++/94844] New: Simple nonsensical program accepted by g++ (rejected by clang++)

[robert at ocallahan dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94844

            Bug ID: 94844
           Summary: Simple nonsensical program accepted by g++ (rejected
                    by clang++)
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: robert at ocallahan dot org
  Target Milestone: ---

Testcase:

#include <stdio.h>
template <typename T> void func(T s) {
  if (s < 0) {
    puts("WHAT");
  }
}
typedef long unsigned Foo;
int main(void) {
  func<long Foo>(-1);
}

g++ (GCC) 9.3.1 20200408 (Red Hat 9.3.1-2):
compiles it and generates code that prints "WHAT".

clang version 9.0.1 (Fedora 9.0.1-2.fc31):
rejects it:
/home/roc/tmp/test.cc:9:13: error: type-id cannot have a name
  func<long Foo>(-1);
            ^~~

clang++ looks right to me. It doesn't seem right to allow 'unsigned' to modify
'Foo' here. Doing that in a variable declaration is rejected.

[Bug c++/94844] Simple nonsensical program accepted by g++ (rejected by clang++)

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94844

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |DUPLICATE

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
This is intentional. You get a diagnostic with -pedantic or -pedantic-errors

94844.cc: In function ‘int main()’:
94844.cc:9:8: warning: ‘long’ specified with ‘Foo’ {aka ‘long unsigned int’}
[-Wpedantic]
    9 |   func<long Foo>(-1);
      |        ^~~~

*** This bug has been marked as a duplicate of bug 80516 ***

[Bug c++/94844] Simple nonsensical program accepted by g++ (rejected by clang++)

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94844

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Jonathan Wakely from comment #1)
> This is intentional. You get a diagnostic with -pedantic or -pedantic-errors
> 
> 94844.cc: In function ‘int main()’:
> 94844.cc:9:8: warning: ‘long’ specified with ‘Foo’ {aka ‘long unsigned int’}
> [-Wpedantic]
>     9 |   func<long Foo>(-1);
>       |        ^~~~
> 

One which is even better than clang produces even.