Goal:
    A : Type  t : A  P : A → A → Type  hd' : A  tl : list A  p : P t hd'
  ============================
   ((t = hd') + P t hd')%type


DEBUG:Going to execute:
solve [ Ltac.left; t_tauto_intuit | Ltac.right; t_tauto_intuit ]
Level 2: evaluation returns
<coq-core.plugins.tauto::is_disj@0>
where
tauto_flags := 
of type
tauto_flags
X1 := ((t = hd') + P t hd')%type
of type
constr of type tacvalue