diff options
| -rw-r--r-- | pretyping/evarconv.ml | 49 | ||||
| -rw-r--r-- | test-suite/bugs/closed/4644.v | 52 |
2 files changed, 94 insertions, 7 deletions
diff --git a/pretyping/evarconv.ml b/pretyping/evarconv.ml index fc22b6cb1..cc202d73c 100644 --- a/pretyping/evarconv.ml +++ b/pretyping/evarconv.ml @@ -500,10 +500,13 @@ and evar_eqappr_x ?(rhs_is_already_stuck = false) ts env evd pbty match (flex_kind_of_term (fst ts) env evd term1 sk1, flex_kind_of_term (fst ts) env evd term2 sk2) with | Flexible (sp1,al1 as ev1), Flexible (sp2,al2 as ev2) -> + (* sk1[?ev1] =? sk2[?ev2] *) let f1 i = + (* Try first-order unification *) match ise_stack2 false env i (evar_conv_x ts) sk1 sk2 with - |None, Success i' -> - (* Evar can be defined in i' *) + | None, Success i' -> + (* We do have sk1[] = sk2[]: we now unify ?ev1 and ?ev2 *) + (* Note that ?ev1 and ?ev2, may have been instantiated in the meantime *) let ev1' = whd_evar i' (mkEvar ev1) in if isEvar ev1' then solve_simple_eqn (evar_conv_x ts) env i' @@ -511,7 +514,9 @@ and evar_eqappr_x ?(rhs_is_already_stuck = false) ts env evd pbty else evar_eqappr_x ts env evd pbty ((ev1', sk1), csts1) ((term2, sk2), csts2) - |Some (r,[]), Success i' -> + | Some (r,[]), Success i' -> + (* We have sk1'[] = sk2[] for some sk1' s.t. sk1[]=sk1'[r[]] *) + (* we now unify r[?ev1] and ?ev2 *) let ev2' = whd_evar i' (mkEvar ev2) in if isEvar ev2' then solve_simple_eqn (evar_conv_x ts) env i' @@ -519,16 +524,46 @@ and evar_eqappr_x ?(rhs_is_already_stuck = false) ts env evd pbty else evar_eqappr_x ts env evd pbty ((ev2', sk1), csts1) ((term2, sk2), csts2) - - |Some ([],r), Success i' -> + | Some ([],r), Success i' -> + (* Symmetrically *) + (* We have sk1[] = sk2'[] for some sk2' s.t. sk2[]=sk2'[r[]] *) + (* we now unify ?ev1 and r[?ev2] *) let ev1' = whd_evar i' (mkEvar ev1) in if isEvar ev1' then solve_simple_eqn (evar_conv_x ts) env i' (position_problem true pbty,destEvar ev1',Stack.zip(term2,r)) else evar_eqappr_x ts env evd pbty ((ev1', sk1), csts1) ((term2, sk2), csts2) - |_, (UnifFailure _ as x) -> x - |Some _, _ -> UnifFailure (i,NotSameArgSize) + | None, (UnifFailure _ as x) -> + (* sk1 and sk2 have no common outer part *) + if Stack.not_purely_applicative sk2 then + (* Ad hoc compatibility with 8.4 which treated non-app as rigid *) + flex_rigid true ev1 appr1 appr2 + else + if Stack.not_purely_applicative sk1 then + (* Ad hoc compatibility with 8.4 which treated non-app as rigid *) + flex_rigid false ev2 appr2 appr1 + else + (* We could instead try Miller unification, then + postpone to see if other equations help, as in: + [Check fun a b : unit => (eqᵣefl : _ a = _ a b)] *) + x + | Some _, Success _ -> + (* sk1 and sk2 have a common outer part *) + if Stack.not_purely_applicative sk2 then + (* Ad hoc compatibility with 8.4 which treated non-app as rigid *) + flex_rigid true ev1 appr1 appr2 + else + if Stack.not_purely_applicative sk1 then + (* Ad hoc compatibility with 8.4 which treated non-app as rigid *) + flex_rigid false ev2 appr2 appr1 + else + (* We could instead try Miller unification, then + postpone to see if other equations help, as in: + [Check fun a b c : unit => (eqᵣefl : _ a b = _ c a b)] *) + UnifFailure (i,NotSameArgSize) + | _, _ -> anomaly (Pp.str "Unexpected result from ise_stack2.") + and f2 i = if Evar.equal sp1 sp2 then match ise_stack2 false env i (evar_conv_x ts) sk1 sk2 with diff --git a/test-suite/bugs/closed/4644.v b/test-suite/bugs/closed/4644.v new file mode 100644 index 000000000..f09b27c2b --- /dev/null +++ b/test-suite/bugs/closed/4644.v @@ -0,0 +1,52 @@ +(* Testing a regression of unification in 8.5 in problems of the form + "match ?y with ... end = ?x args" *) + +Lemma foo : exists b, forall a, match a with tt => tt end = b a. +Proof. +eexists. intro. +refine (_ : _ = match _ with tt => _ end). +refine eq_refl. +Qed. + +(**********************************************************************) + +Axiom proof_admitted : False. +Tactic Notation "admit" := case proof_admitted. +Require Export Coq.Classes.Morphisms. +Require Import Coq.Lists.List. + +Global Set Implicit Arguments. + +Definition list_caset A (P : list A -> Type) (N : P nil) (C : forall x xs, P (x::xs)) + ls + : P ls + := match ls with + | nil => N + | x::xs => C x xs + end. + +Axiom list_caset_Proper' + : forall {A P}, + Proper (eq + ==> pointwise_relation _ (pointwise_relation _ eq) + ==> eq + ==> eq) + (@list_caset A (fun _ => P)). +Goal forall (T T' : Set) (a3 : list T), exists y2, forall (a4 : T' -> bool), + match a3 with + | nil => 0 + | (_ :: _)%list => 1 + end = y2 a4. + clear; eexists; intros. + reflexivity. Undo. + Local Ltac t := + lazymatch goal with + | [ |- match ?v with nil => ?N | cons x xs => @?C x xs end = _ :> ?P ] + => let T := type of v in + let A := match (eval hnf in T) with list ?A => A end in + refine (@list_caset_Proper' A P _ _ _ _ _ _ _ _ _ + : @list_caset A (fun _ => P) N C v = match _ with nil => _ | cons x xs => _ end) + end. + (etransitivity; [ t | reflexivity ]) || fail 0 "too early". + Undo. + t. |