Tuple.Union doesn't work if all types in a tuple are singletons

[prolativ]

Minimized code

import Tuple.Union

object Foo

val x = summon[Union[(Foo.type, 1)] =:= (Foo.type | 1)] // doesn't compile
val y = summon[Union[(Foo.type, 1, String)] =:= (Foo.type | 1 | String)] // compiles

Output

val x = summon[Union[(Foo.type, 1)] =:= (Foo.type | 1)] // doesn't compile
                                                       ^
Cannot prove that Tuple.Union[(Foo.type, (1 : Int))] =:= Foo.type | (1 : Int).

Expectation

Tuple.Union should work for tuples containing any types

[Swoorup]

Was wondering the other day in gitter what was wrong with your code. 😄

[Swoorup]

Just wondering if there is a timeline of this being fixed in future releases?

[Swoorup]

This still seems to have issues in other areas, i.e the following doesn't compile

import Tuple.Union

type Channel = "orders" | "trades"

def getChannelList[Channels <: NonEmptyTuple](c: Channels)(using Union[Channels] <:< Channel) = 
  val channels: List[Channel] = c.toList
  channels