value class regression trying to do lub/glb of typevar #8602
Description
Related to #5559 obviously but a regression from 2.10.
class Foo[CC[X], D <: CC[Int]](val xs: D) extends AnyVal
// error: trying to do lub/glb of typevar ?D
// error: scala.reflect.internal.FatalError:
// trying to do lub/glb of typevar ?D
// while compiling: ./a.scala
// during phase: typer
// library version: version 2.11.0
// compiler version: version 2.11.0