Scala 2 less generous than 3 on import ambiguity

[som-snytt]

Reproduction steps

Scala version: 2.13.15

package testsamepackageimport {
  package p {
    class C
  }

  package p {
    package q {
      import p._ // warn
      class U {
        def f = new C
      }
    }
  }
}

errors

pkg-import.scala:11: error: reference to C is ambiguous;
it is both defined in package p and imported subsequently by
import p._
        def f = new C
                    ^
pkg-import.scala:9: warning: Unused import
      import p._ // warn
               ^
1 warning
1 error

but does not error at the same nesting level

package testsamepackageimport {
  package p {
    class C
  }

  package p {
    import p._ // warn
    package q {
      class U {
        def f = new C
      }
    }
  }
}

Problem

It should only error if the competing import and definition resolve to different symbols.

The import is unused but not erroneous.

Scala 3 does not error.