• Sobaya (15/15) Oct 14 2018 void func(T : int)(T value) if (is(T == int)) {
• Alex (8/23) Oct 14 2018 Removing constraint, but retaining specialization should be
• Sobaya (2/11) Oct 15 2018 Thank you!

Sobaya <sobaya007 gmail.com> writes:

void func(T : int)(T value) if (is(T == int)) {
}

struct S {
     int x;
     alias x this;
}

void main() {
     func(S()); // error
}

In above code, 'func' can accept only int as its argument type, 
so when 'S', which can be implicitly convertible into int, is 
passed on 'func', I expect S.x is passed, but this function call 
is failed.

Is there any way to solve it with keeping 'func' template 
function?

Alex <sascha.orlov gmail.com> writes:

On Monday, 15 October 2018 at 04:51:39 UTC, Sobaya wrote:
 void func(T : int)(T value) if (is(T == int)) {
 }

 struct S {
     int x;
     alias x this;
 }

 void main() {
     func(S()); // error
 }

 In above code, 'func' can accept only int as its argument type, 
 so when 'S', which can be implicitly convertible into int, is 
 passed on 'func', I expect S.x is passed, but this function 
 call is failed.

 Is there any way to solve it with keeping 'func' template 
 function?

Removing constraint, but retaining specialization should be 
enough, no?
Then, func is still a template, requiring the argument to be 
convertible to an int. When S is passed, then, it is checked, if 
it convertible, and because of the alias it is.
Still, passed value has the type of S. however, func can handle 
value directly, as it were an int.

Sobaya <sobaya007 gmail.com> writes:

On Monday, 15 October 2018 at 06:16:34 UTC, Alex wrote:
 On Monday, 15 October 2018 at 04:51:39 UTC, Sobaya wrote:
 [...]

 Removing constraint, but retaining specialization should be 
 enough, no?
 Then, func is still a template, requiring the argument to be 
 convertible to an int. When S is passed, then, it is checked, 
 if it convertible, and because of the alias it is.
 Still, passed value has the type of S. however, func can handle 
 value directly, as it were an int.

Thank you!