private[this] doesn't work

[Bersier]

Compiler version

3.3.1

Minimized code

class A:
  private[this] def foo: Int = 1

  def bar(other: A): Int = other.foo

Compiler output

Compiles fine.

Expectation

Compiler warning or error, either

1. about foo not being visible on other (as in Scala 2).
2. about private[this] being deprecated/dropped in Scala 3, and having the same meaning as private.

In Scala 3.4.0 Nightly, the compiler warning still does not mention the unexpected semantics of [this] in this context, which doesn't seem documented anywhere. Being deprecated is not the same as being ignored.

[hamzaremmal]

Related to #18819

[nicolasstucki]

The migration warning was added in 3.4. I will update the documentation to mke this clear.

The current warning is

-- Warning: t/Test.scala:2:16 --------------------------------------------------
2 |  private[this] def foo: Int = 1
  |                ^
  |The [this] qualifier will be deprecated in the future; it should be dropped.
  |See: https://docs.scala-lang.org/scala3/reference/dropped-features/this-qualifier.html
  |This construct can be rewritten automatically under -rewrite -source 3.4-migration.