Regression in 3.3.3 and 3.4.0

[lbialy]

Compiler version

3.3.3 and 3.4.0

Minimized code

trait Zippable[-A, -B]:
  type Out
  def zip(left: A, right: B): Out

object Zippable extends ZippableLowPrio:
  given append[A <: Tuple, B]: (Zippable[A, B] { type Out = Tuple.Append[A, B] }) =
    (left, right) => left :* right

trait ZippableLowPrio:
  given pair[A, B]: (Zippable[A, B] { type Out = (A, B) }) =
    (left, right) => (left, right)

@main def main =
  println("ok")

Output

λ scala-cli -S 3.3.1 main.scala
Compiling project (Scala 3.3.1, JVM (17))
Compiled project (Scala 3.3.1, JVM (17))
ok

λ scala-cli -S 3.3.3 main.scala
Compiling project (Scala 3.3.3, JVM (17))
[error] ./main.scala:7:22
[error] value :* is not a member of A
[error]     (left, right) => left :* right
[error]                      ^^^^^^^
[error] ./main.scala:11:22
[error] Found:    (A, B)
[error] Required: Zippable.this.Out
[error]     (left, right) => (left, right)
[error]                      ^^^^^^^^^^^^^
Error compiling project (Scala 3.3.3, JVM (17))
Compilation failed

λ scala-cli -S 3.4.0 main.scala
Compiling project (Scala 3.4.0, JVM (17))
[error] ./main.scala:7:22
[error] value :* is not a member of A
[error]     (left, right) => left :* right
[error]                      ^^^^^^^
Error compiling project (Scala 3.4.0, JVM (17))
Compilation failed

Expectation

No regressions 🙏

[Gedochao]

full output (the initial post has adjustments made by Bloop)

-- [E008] Not Found Error: /Users/pchabelski/IdeaProjects/scala-cli-tests/compiler-repro/repro.scala:7:26 
7 |    (left, right) => left :* right
  |                     ^^^^^^^
  |                     value :* is not a member of A

[odersky]

Should this not be *:?

[lbialy]

A <: Tuple and A is in left position. After changing to *: it stops compiling on any version.

[prolativ]

The bisect script seems to point to 18f90d9 (back-ported to LTS in 66f8992)

[odersky]

@lbialy Ah sorry, I thought this was left-cons. I was not aware there was also the symmetric operation :*.

[EugeneFlesselle]

Minimisation:

trait Fun1:
  type Out
  def apply(x: Any): Out

type M[X] = X match
  case String => X

def works[A]: Fun1 { type Out = M[A] } =
  new Fun1:
    type Out = M[A]
    def apply(x: Any): Out = ???

def fails[A]: Fun1 { type Out = M[A] } =
  (x: Any) => ???