On Saturday, 11 December 2021 at 22:59:52 UTC, Adam Ruppe wrote:
On Saturday, 11 December 2021 at 22:50:45 UTC, apz28 wrote:
void foo2(T)(Unqual!T x) if(isUnsigned!T) {}
This means it treats foo2 as if it doesn't exist unless T is
unsigned...
onlineapp.d(15): Error: template `onlineapp.foo2` cannot
deduce function from argument types `!()(int)`
onlineapp.d(7): Candidate is: `foo2(T)(Unqual!T x)`
*/
And this is telling you it had a signed value - int - which
means it doesn't match.
For the other ones, the functions still exist, so it does
whatever conversion it needs. Whereas with the template that
constraint means the compiler acts like it doesn't exist at all
and thus doesn't even attempt an automatic conversion.
? No. If it was unsatisfied constraint, the error would've shown
that. What's going on here is that the argument being passed is
an int, when the parameter is an Unqual!T. So,
https://dlang.org/spec/template.html#ifti would fail because
there is no way of figuring out a T from an Unqual!T. Hence the
message: cannot deduce function.
