Overloading over different numbers of arguments not fully supported

[ngeiswei]

What is your problem?

Overloading a function with structure with different numbers of arguments confuses the interpreter.

How to reproduce your problem?

Run the following code

;; Unary lambda
(: λ (-> Variable Atom Atom))
(= ((λ $x $f) $y) (let $x $y $f))
!((λ $x (+ 1 $x)) 1)

;; Binary lambda
(: λ (-> Variable Variable Atom Atom Atom))
(= ((λ $x $y $f) $z $w) (let* (($x $z) ($y $w)) $f))
!((λ $x $y (+ $x $y)) 1 2)

What would you normally expect?

[2]
[3]

What do you get instead?

[2]
[3, 3]

What else do you have to say?

The following code

;; Unary foo
(: foo (-> Number Number))
(= (foo $x) (+ 1 $x))
!(foo 1)

;; Binary foo
(: foo (-> Number Number Number))
(= (foo $x $y) (+ $x $y))
!(foo 1 2)

properly works, indicating that the problem comes from the fact that the function is an expression instead of a mere symbol.

[luketpeterson]

There was a discussion about var-args and arity in the context of the import op here: Much of the discussion is pertinent to var-args in general. #580 (comment)

[luketpeterson]

Also, it seems like var-args support might be gated on #346 Although that should be fixable.