Inhabit bad bounds with recursive member val

[EugeneFlesselle]

Compiler version

Scala compiler version 3.7.3-RC1

Minimized code

object A:
  val p: { type X >: Any <: Nothing } = p // ok 

@main def Test =
  val y: Int = "hi" : A.p.X // java.lang.ClassCastException: class java.lang.String cannot be cast to class scala.runtime.Nothing

Expectation

I would expect this to type check (for recursive vals in objects) but diverge at run-time.

Note that we report an error for recursive vals when in a def:

def A =
  val p: { type X >: Any <: Nothing } = p
  // error: p is a forward reference extending over the definition of p

[olhotak]

This warns with //> using option -Ysafe-init-global but not with //> using option -Wsafe-init.

@liufengyun did we want -Wsafe-init to warn here too?

[liufengyun]

This warns with //> using option -Ysafe-init-global but not with //> using option -Wsafe-init.

@liufengyun did we want -Wsafe-init to warn here too?

The class instance initialization checker will warn for the case of class:

class A:
  val p: { type X >: Any <: Nothing } = p // warning: initialization error

@main
def test = 
  val a = new A
  val y: Int = "hi" : a.p.X

For global objects, it is only checked by the global object initialization checker.