Possible regression in refchecks when overriding a mutable variable

[KacperFKorban]

Compiler version

3.1.3-RC3, 3.2.0-RC1-bin-20220517-e5abec0-NIGHTLY

(compiles correctly on 3.1.2, 3.0.2, and 2.13.8)

Minimized code

//> using scala "3.1.3-RC3"
// //> using scala "3.1.2" // works
// //> using scala "3.0.2" // works
// //> using scala "2.13.8" // works

abstract trait A {
  var value: Int
}

abstract trait B {
  def value: Int = ???
}

class C extends A with B {
  override def value: Int = ???
  def value_=(newValue: Int): Unit = ???
}

Output

[error] ./main.scala:14:16: error overriding variable value in trait A of type Int;
[error]   method value of type => Int cannot override a mutable variable
[error]   override def value: Int = ???
[error]                ^

Expectation

Compile correctly

Additional info

This is most likely related to issue #14722 and PR that fixed it #14724

Also, note that the following code throws an error too

abstract trait A {
  var value: Int
}

class C extends A {
  override def value: Int = ???
  override def value_=(newValue: Int): Unit = ???
}

namely

[error] ./main.scala:11:16: error overriding variable value in trait A of type Int;
[error]   method value of type => Int cannot override a mutable variable
[error]   override def value: Int = ???
[error]                ^
[error] ./main.scala:12:16: error overriding variable value in trait A of type Int;
[error]   method value_= of type (newValue: Int): Unit cannot override a mutable variable
[error]   override def value_=(newValue: Int): Unit = ???
[error]                ^

[smarter]

Duplicate of #13019.