Unused type parameter confuses typer, broke in 2.12.4

[blast-hardcheese]

Code to repro (repository), with some comments for different cases that actually work:

package bug

class Foo[A]

object Bar {
  // Traceback in https://github.com/blast-hardcheese/scala-issue/blob/master/README.md
  (new Foo).bogus[(Long, Long)]

  // [error] /private/tmp/bug/src/main/scala/bug.scala:10:16: value bogus is not a member of bug.Foo[A]
  // [error]   (new Foo).bogus[Long]
  // [error]             ^
  // [error] one error found
  //
  // (new Foo).bogus[Long] // Gives an appropriate error message

  // [error] /private/tmp/bug/src/main/scala/bug.scala:7:19: value bogus is not a member of bug.Foo[Long]
  // [error]   (new Foo[Long]).bogus[(Long, Long)]
  // [error]                   ^
  // [error] one error found
  //
  // (new Foo[Long]).bogus[(Long, Long)]
}

I tried against 2.12.8-bin-5fca7b2 and got the same unhelpful error, but 2.12.0-2.12.3 give helpful errors.

[hrhino]

I think this was fixed by scala/scala#8515.