Unexpected level-correctness interaction with type alias

[fhackett]

class C {
    type T = Int
    def fn(e : Expr[T]) : Expr[T] = '{ ~e }
}

This fails to compile under Dotty 0.13.0-RC1 (specifically; 0.12.0 accepts this) with the following error:

3 |    def fn(e : Expr[T]) : Expr[T] = '{ ~e }
  |                                       ^^
  |                                access to C.this from wrong staging level:
  |                                 - the definition is at level 0,
  |                                 - but the access is at level 1.

Changing the code like this acts as a workaround:

class C {
    type T = Int
    def fn(e : Expr[Int]) : Expr[T] = '{ ~e }
}

The weird part is that this suddenly started happening in version 0.13.0-RC1. So, either I was taking advantage of a bug that is now fixed, or there is a new bug.

At least, it doesn't make sense to me how adding this layer of indirection changes the meaning of the program. Since it's a plain = alias, there's no chance of T ever not being an Int. In turn, there should be no reason for '{ ~e } to be looking up C.this.

[biboudis]

Thanks for reporting @fhackett

On a side note this code works on the master branch (note the syntax change due to #5918):

import scala.quoted._

class C {
    type T = Int
    def fn(e : Expr[T]) : Expr[T] = '{ $e }
}

[fhackett]

Hello again - as per our discussion on #6007, I moved my project over to track nightly and found that this issue persists with one tiny difference:

import scala.quoted._

class C {
    type T = Int
    def fn(e : Expr[T]) : Expr[T] = '{ (); $e }
} 

Moving the () to the right of the $e shows the same issue (though fn returns Expr[Unit] then).

[biboudis]

Thx for reporting!