Pattern matching type variable does not infer bounds

[KacperFKorban]

Compiler version

master

Minimized code

import scala.quoted.*

trait A:
  type B <: C
type C
def takesC[X <: C] = ???

def f(using Quotes) = {
  import quotes.reflect.*

  '{new A {}} match {
    case '{ $a : A { type B = b } } =>
      takesC[b]
  }
}

Output

-- [E057] Type Mismatch Error: tests/pos/type-bound-match.scala:13:13 --------------------------------------------------
13 |      takesC[b]
   |             ^
   |             Type argument b does not conform to upper bound C

Expectation

No error.

Workaround:

//...
  '{new A {}} match {
    case '{ type b <: C; $a : A { type B = `b` } } =>
      takesC[b]
  }
//...

[nicolasstucki]

We will not be able to infer the bounds of type variables. These should be stated explicitly.

Solution

case '{ type b <: C; $a : A { type B = b } } =>