Unusual template specialisation behavior

[Christopher Wright]

Matthias Walter wrote:
> Hello guys,
> 
> Here's a (minimal) code snippet for my problem:
> 
> | struct Expression (R, E) { }
> | 
> | struct ResolveReference (T)
> | {
> |     alias T reference_type;
> | }
> | 
> | struct ResolveReference (T : Expression !(R, E))

The compiler should have caught this, I think. You have R and E, but 
they aren't defined. They default to int (which is why you saw that 
behavior), but not being defined, they should be a compile-time error.

The proper way to do this, unfortunately, involves static if rather than 
overloading. At least if you want your users to supply a single argument 
in all cases.