multiple steps required to diagnose error when matching with an incompatible pattern

[bishabosha]

Example here is taken from "Hands-on Scala Programming" by @lihaoyi

Problem: if you use a disjoint pattern, then the error is basically delayed until after errors of using bindings inferred as Any from the pattern holes, e.g. trying to extract a Tuple2 with a Tuple3 pattern.

The origin of the error: the wrong pattern, should be prioritised IMO, or at least shown at the same time as the usage error.

Compiler version

3.8.0-RC2

Minimized code

//> using scala 3.8.0-RC2

case class Phrase(isHello: Boolean, place: String)

case class P[T](result: T) {
  def map[U](f: T => U): P[U] = ???
}

object Test {
  def main(args: Array[String]): Unit =
    P(("resultA", "resultB")).map{
      case ("hello", spaces, place) => new Phrase(true, place)
    }
}

Output

[error] ./foo.scala:12:57
[error] Found:    (place : Any)
[error] Required: String
[error]       case ("hello", spaces, place) => new Phrase(true, place)
[error]                                                         ^^^^^

Expectation

in scala 2.13 its not even allowed to try and match with the pattern:

[error] ./foo.scala:12:12
[error] constructor cannot be instantiated to expected type;
[error]  found   : (T1, T2, T3)
[error]  required: (String, String)
[error]       case ("hello", spaces, place) => new Phrase(true, place)
[error]            ^

if course in Scala 3 if we remove the use of the binding then the error for the pattern comes through:

[warn] ./foo.scala:12:7
[warn] match may not be exhaustive.
[warn]
[warn] It would fail on pattern case: (_, _)
[warn]       case ("hello", spaces, place) => "hello" // new Phrase(true, place)
[warn]       ^
[error] ./foo.scala:12:12
[error] this case is unreachable since type (String, String) is not a subclass of class Tuple3
[error]       case ("hello", spaces, place) => "hello" // new Phrase(true, place)
[error]            ^