[Bug c++/92158] Enum warning when -1 enum converted to unsigned int or int

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92158

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |NEW

--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Thank you for the corrected testcase, although compiling with -Werror when
asking for warnings is not very helpful (it obscures what's a warning and
what's an error) and posting code that doesn't even compile is not very helpful
either.

Confirming as a diagnostic enhancement for the following testcase:

enum E { a = -1 } ;
unsigned i = a;

Clang warns with -Wsign-conversion (not enabled by -Wall or -Wextra):

e.cc:2:14: warning: implicit conversion changes signedness: 'E' to 'unsigned
int' [-Wsign-conversion]
unsigned i = a;
         ~   ^
1 warning generated.