Automatically generate names for universes.

The names are `uXXX` with `XXX` some number avoiding collision.

Note that there may be some collisions with polymorphic binders, eg
something like

~~~
Set Universe Polymorphism.
Section foo.
  Universe u0.
  Definition bar := Type.
  (* bar@{u0} = Type@{u0} but this isn't the section u0 *)

  Definition baz := Type@{u0}. (* this one is the section u0 *)
  Definition foobar := Eval compute in baz -> Type.
  (* Type@{u0} -> Type@{u0} but these aren't the same u0 *)
~~~
So maybe we should do a nametab lookup too. This is strictly a
printing issue (polymorphic binder names have no other use).

In the monomorphic case names are qualified by the parent definition
so it should be fine (barring module/definition collision but we
already have those).

Note that there are still unnamed universes as they didn't go through
UState (eg schemes).

1 files changed, 2 insertions, 2 deletions

diff --git a/test-suite/output/UnivBinders.out b/test-suite/output/UnivBinders.out
index 2501ce4f26..d63b6dbfce 100644
--- a/test-suite/output/UnivBinders.out
+++ b/test-suite/output/UnivBinders.out
@@ -191,12 +191,12 @@ Type@{UnivBinders.57} -> Type@{i}
 axbar is universe polymorphic
 Argument scope is [type_scope]
 Expands to: Constant UnivBinders.axbar
-axfoo' : Type@{UnivBinders.59} -> Type@{axbar'.i}
+axfoo' : Type@{axbar'.u0} -> Type@{axbar'.i}
 
 axfoo' is not universe polymorphic
 Argument scope is [type_scope]
 Expands to: Constant UnivBinders.axfoo'
-axbar' : Type@{UnivBinders.59} -> Type@{axbar'.i}
+axbar' : Type@{axbar'.u0} -> Type@{axbar'.i}
 
 axbar' is not universe polymorphic
 Argument scope is [type_scope]