default params with type classes

dptc.nim

let i: int64 = 0
let j: float64 = 1.1 

proc g(x: distinct SomeNumber = 1, y: distinct SomeNumber = 1.1) = discard

g(i,j) # OK
g(j,i) # Error

# I have tried other combinations without use of distinct. Not sure
# why the compiler complains about this, seems it should be ok?
# How does one give default args when type classes are involved?
# Ideally I would like to give a default arg of some concrete
# type but still have g(i, j) work given i and j as both arbitrary
# types independently satisfying SomeNumber constraint.