False positive of "Unreachable case" warning under macro type match

[soronpo]

Compiler version

Fails on 3.3.1-RC7
Fails on latest nightly (3.4.0-RC1-bin-20230901-89e8dba-NIGHTLY)
Last good release: 3.3.1-RC1-bin-20230301-0df5ae2-NIGHTLY
First bad release: 3.3.1-RC1-bin-20230302-8020c77-NIGHTLY
First bad commit: 6b36cd9

Minimized code

//> using options -Xfatal-warnings
import scala.quoted.*

trait DFValOf[T]

def calcWidth(x: List[Type[Any]])(using Quotes): Unit =
  x.collect { case '[DFValOf[t]] => ???}

Output

7 |  x.collect { case '[DFValOf[t]] => ???}
  |                   ^^^^^^^^^^^^^
  |                   Unreachable case

Expectation

No warning (no error under fatal-warnings).

[dwijnand]

The compiler is right here (not a regression) because Type[DFValOf[t]] is provably disjoint from Type[Any], seeing as Type is invariant.

However, if I switch to List[Type[?]] then the compiler also thinks that Type[DFValOf[t]] and Type[?] are disjoint... So I'll submit a fix for that version of the program.