Default arguments of final method are not final

[nicolasstucki]

Compiler version

3.0.0 to 3.3.0-RC4

Minimized example

class A:
  final def foo(x: Int = 1): Any = ???

Output

Compiled with -Xprint:typer shows

[[syntax trees at end of                     typer]] 
package <empty> {
  class A() extends Object() {
    final def foo(x: Int): Any = ???
    def foo$default$1: Int @uncheckedVariance = 1
  }
}

Expectation

Default argument methods of final methods should be final.

class A() extends Object() {
  final def foo(x: Int): Any = ???
  final def foo$default$1: Int @uncheckedVariance = 1
}

[sjrd]

That is unfortunate. I don't think we can fix this in 3.x. If we fix it, when libraries upgrade, they will have plenty of MiMa errors for all their default accessor methods, and there will be nothing they can do about them except adding zillions of filters.

[dwijnand]

We could teach MiMa to account for fixing this.