Illegal import rename of a wildcard

[gkossakowski]

scalac allows one to rename wildcard to an arbitrary identifier:

scala> object Foo { class A }
defined object Foo

scala> import Foo.{_ => Bla}
import Foo._

// A is available because the import is a wildcard one despite the rename!
scala> new A
res1: Foo.A = Foo$A@687a0e40

// Bla is not available
scala> new Bla
<console>:16: error: not found: type Bla
       new Bla

This should be ruled out by the parser. dottyc does rule it out at the parsing time.

Discovered while carefully reading the scala spec for the purpose of implementing import renames in Kentucky Mule: gkossakowski/kentuckymule#6 (comment)

[som-snytt]

Relates to #6426

[som-snytt]

You don't even need the braces:

scala> import collection._ => foo
import collection._