[Bug c++/80151] Add a warning to catch implicit string to bool conversion (-Wstring-conversion)

[redi at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80151

--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Jonny Grant from comment #4)
> Could this bug cover warning when size_t is converted to bool? and int as
> well.

It's extremely common to do:

if (strlen(str))
 ...

or:

void copy(const X* from, X* to, size_t n)
{
  if (n)
    memcpy(from, to, sizeof(X) * n);
}