array of Expressions
optional array of names corresponding to Expressions
When there's a call f(10, pair: AliasSeq!(20, 30), single: 40), the input is: exps = [10, (20, 30), 40] names = [null, "pair", "single"] The arrays will be modified to: exps = [10, 20, 30, 40] names = [null, "pair", null, "single"]
Expand tuples in-place.