Given patterns are never exhaustive, causing withFilter desugaring

[oleg-py]

Compiler version

3.0.0-RC2

Minimized code

import scala.compiletime.error

object BadFilters {
  inline def withFilter(f: Int => Boolean): BadFilters.type = error("Unexpected withFilter call")
  def foreach(f: Int => Unit): Unit = f(42)
}

@main def works = 
  for {
    x: Int <- BadFilters
  } println(x)

@main def breaks =
  for {
    given Int <- BadFilters
  } println(summon[Int])

Output

Fails to compile breaks with Unexpected withFilter call

Expectation

Compiles and prints:

42
42

---

The pattern x: Int is considered exhaustive, causing withFilter to not be emitted in works, while the pattern given Int isn't, so withFilter is emitted and breaks breaks.