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(* Wish #2154 by E. van der Weegen *)
(* auto was not using f_equal-style lemmas with metavariables occurring
only in the type of an evar of the concl, but not directly in the
concl itself *)
Parameters
(F: Prop -> Prop)
(G: forall T, (T -> Prop) -> Type)
(L: forall A (P: A -> Prop), G A P -> forall x, F (P x))
(Q: unit -> Prop).
Hint Resolve L.
Goal G unit Q -> F (Q tt).
intro.
eauto.
Qed.
(* Test implicit arguments in "using" clause *)
Goal forall n:nat, nat * nat.
auto using (pair O).
Undo.
eauto using (pair O).
Qed.
Create HintDb test discriminated.
Parameter foo : forall x, x = x + 0.
Hint Resolve foo : test.
Variable C : nat -> Type -> Prop.
Variable c_inst : C 0 nat.
Hint Resolve c_inst : test.
Hint Mode C - + : test.
Hint Resolve c_inst : test2.
Hint Mode C + + : test2.
Goal exists n, C n nat.
Proof.
eexists. Fail progress debug eauto with test2.
progress eauto with test.
Qed.
(** Patterns of Extern have a "matching" semantics.
It is not so for apply/exact hints *)
Class B (A : Type).
Class I.
Instance i : I.
Definition flip {A B C : Type} (f : A -> B -> C) := fun y x => f x y.
Class D (f : nat -> nat -> nat).
Definition ftest (x y : nat) := x + y.
Definition flipD (f : nat -> nat -> nat) : D f -> D (flip f).
Admitted.
Module Instnopat.
Local Instance: B nat.
(* pattern_of_constr -> B nat *)
(* exact hint *)
Check (_ : B nat).
(* map_eauto -> B_instance0 *)
(* NO Constr_matching.matches !!! *)
Check (_ : B _).
Goal exists T, B T.
eexists.
eauto with typeclass_instances.
Qed.
Local Instance: D ftest.
Local Hint Resolve flipD | 0 : typeclass_instances.
(* pattern: D (flip _) *)
Fail Timeout 1 Check (_ : D _). (* loops applying flipD *)
End Instnopat.
Module InstnopatApply.
Local Instance: I -> B nat.
(* pattern_of_constr -> B nat *)
(* apply hint *)
Check (_ : B nat).
(* map_eauto -> B_instance0 *)
(* NO Constr_matching.matches !!! *)
Check (_ : B _).
Goal exists T, B T.
eexists.
eauto with typeclass_instances.
Qed.
End InstnopatApply.
Module InstPat.
Hint Extern 3 (B nat) => split : typeclass_instances.
(* map_eauto -> Extern hint *)
(* Constr_matching.matches -> true *)
Check (_ : B nat).
(* map_eauto -> Extern hint *)
(* Constr_matching.matches -> false:
Because an inductive in the pattern does not match an evar in the goal *)
Check (_ : B _).
Goal exists T, B T.
eexists.
(* map_existential -> Extern hint *)
(* Constr_matching.matches -> false *)
Fail progress eauto with typeclass_instances.
(* map_eauto -> Extern hint *)
(* Constr_matching.matches -> false *)
Fail typeclasses eauto.
Abort.
Hint Extern 0 (D (flip _)) => apply flipD : typeclass_instances.
Module withftest.
Local Instance: D ftest.
Check (_ : D _).
(* D_instance_0 : D ftest *)
Check (_ : D (flip _)).
(* ... : D (flip ftest) *)
End withftest.
Module withoutftest.
Hint Extern 0 (D ftest) => split : typeclass_instances.
Check (_ : D _).
(* ? : D ?, _not_ looping *)
Check (_ : D (flip _)).
(* ? : D (flip ?), _not_ looping *)
Check (_ : D (flip ftest)).
(* flipD ftest {| |} : D (flip ftest) *)
End withoutftest.
End InstPat.
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