Typeclasses eauto := bfs.

Class Foo := {}.
Class Bar := {}.

Instance: Bar.
Instance: Foo -> Bar -> Foo -> Foo | 1.
Instance: Bar -> Foo | 100.
Instance: Foo -> Bar -> Foo -> Foo | 1.

Set Typeclasses Debug.
Timeout 1 Check (_ : Foo). (* timeout *)
