Illegal match type case inconsistently reported

[Bersier]

Compiler version

3.5.0-RC1

Minimized code

type At[V, L <: TList[R[V]], K <: Long] <: Option[?] = L match
  case Empty.type => None.type // When this line is commented out, the code does not compile
  case Cons[R[V], (k, v), tail] => None.type

trait TList[+T]
object Empty extends TList[Nothing]
class Cons[+E, +H <: E, +T <: TList[E]] extends TList[E]

type R[+T] = (Long, T)

Output

Compiles fine

Expectation

Compiler error, similarly to what happens for

type At[V, L <: TList[R[V]], K <: Long] <: Option[?] = L match
  // case Empty.type => None.type
  case Cons[R[V], (k, v), tail] => None.type

trait TList[+T]
object Empty extends TList[Nothing]
class Cons[+E, +H <: E, +T <: TList[E]] extends TList[E]

type R[+T] = (Long, T)

Error message:

The match type contains an illegal case