Dynamic dispatch doesn't work properly when types are generic

[adlertz]

type X = object of RootObj
type Y[T] = object of X
    op*: T
type Z = object of X
    op*: int

proc newY[T](op: T): ref Y[T] =
    new(result)
    result.op = op

proc newZ(op: int): ref Z =
    new(result)
    result.op = op

proc y(): ref X =
    newY(6)

proc z(): ref X =
    newZ(5)

method desc(i: ref X): string =
    quit "Must override"

method desc[T](i: ref Y[T]): string =
    $i.op

method desc(i: ref Z): string =
    $i.op

let i1 = z()
let i2 = y()
echo i1.desc() # prints "5"
echo i2.desc() # exits with "Must override", should print "6"

[Araq]

Quite sure this is only a quirk that needs to be finally documented.

[adlertz]

You mean this is the intended behaviour?

[Araq]

Since 0.15 the behaviour changed and it should now work as "expected" for some value of "expected".