Automatic expansion of Tuple1

[Adam-Vandervorst]

Compiler version

3.0.0

Minimized code

def g(a: Tuple1[Int]) = a._1*2

@main def main_f = 
    println(g(1))

Output

Found:    (1 : Int)
Required: Tuple1[Int]
    println(g(1))

Expectation

Work the same as

def f(a: Tuple2[Int, Int]) = a._1 + a._2

@main def main_f = 
    println(f(1, 2))

or work with g((1)), g((1,)), or g(1,).

[smarter]

Scala 2 has the same behavior so this isn't a regression but more like a feature request. And the direction we're trying to go in involves less auto-tupling, not more of it, cf #4311 which is closed but the discussion isn't settled yet.

[Adam-Vandervorst]

In my opinion, this inconsistent with

def op[T <: NonEmptyTuple](name: String)(ps: Map[T, AOp]) = AOp[T](name, ps)

where you can define your ops and do biop(x, y) but not uop(x).
EDIT:
Ideally this would use varargs, but that can not be used with the partial application.