Lambda can't resolve a parameter

[sys27]

Describe the bug
Lambda can't resolve a parameter, probably it is related to nested scope. The lambda captured incorrect scope or something else. And can't find a parameter.

To Reproduce
Steps to reproduce the behavior:

1. c := (n, k) => n! / (k! * (n - k)!) - add a function (combination formula)
2. parts := (m, n) => c((m - 1) + (n - 1), m - 1) - use it another function
3. parts(23, 12) - call it, it throws an exception