Even though new concepts exist I find they have many jagged edges as they're a
even less used than their old style counterparts. I imagine the `proc +(a, b:
T): T` is the problem here but I did not check. A working implementation that
uses the new style concepts is the following.
type
Addable = concept
proc `+`(x, y: Self): Self
Coll[T] = concept
iterator items(x: Self): T
AddableColl[T: Addable] = Coll[T]
proc sum[T](nums: AddableColl[T]): T =
for num in nums.items:
result += num
echo @[0, 1, 2].sum
Run
