//----
struct S
{
int[] r;
alias r this;
}
void main()
{
S s;
s.front(); //OK
s.popFront(); //No Match
static assert (isForwardRange!S); //Nope
}
//----
The problem, basically, is that front's signature is (basically):
@property ref T front(T)(T[] a)
if (isDynamicArray!(T[]))
popFront's signature though is:
void popFront(A)(A a)
if (isDynamicArray!A)
The problem is that the constraint "isDynamicArray" requires an
exact match. This means in the case of front, S is converted via
alias this to int[], and the constraints pass. In the case of
popFront, however, S is taken directly as is, and the test
isDynamicArray fails.
I tried changing the signature to popFront, and everything works
fine all over phobos. (except for a twisted unittest that tested
popFront specifying the template parameters, but doing that
sounds like nonsense to me, and is just badly written test).
Does anybody know if there is a reason other than "historical"
for this?
I find it stange that front and popFront have different
behaviors, so I think one of either should be "fixed".
IMO, I think accepting the S type makes sense. Thoughts?
