Goal:
    A : Type  P : A → Type  a : A  X : All P [a]
  ============================
   (let H := CoreTactics.block in let H0 := CoreTactics.block in P a)


DEBUG:Going to execute:
progress (autounfold with equations in e; simpl in e)
Level 1: evaluation returns
repeat progress (autounfold with equations in e; simpl in e)
where
e := X
of type
constr of type tacvalue