diff options
| author |  Pierre-Marie Pédrot <pierre-marie.pedrot@inria.fr> | 2018-02-12 14:46:05 +0100 |
|---|---|---|
| committer | Pierre-Marie Pédrot <pierre-marie.pedrot@inria.fr> | 2018-02-15 18:02:14 +0100 |
| commit | d6ca9b2f71bced8711b184400fa7e80061497fd7 (patch) | |
| tree | 7d7591a2a1a9cf6e9bb0202e95c68902dae934b2 /checker | |
| parent | 8dd6d091ffbfa237f7266eeca60187263a9b521f (diff) | |
Adding a sanity check on inductive variance subtyping.
Diffstat (limited to 'checker')
| -rw-r--r-- | checker/subtyping.ml | 8 | ||||
| -rw-r--r-- | checker/univ.ml | 7 | ||||
| -rw-r--r-- | checker/univ.mli | 2 |
3 files changed, 16 insertions, 1 deletions
diff --git a/checker/subtyping.ml b/checker/subtyping.ml index 98a9c8250..77201c25b 100644 --- a/checker/subtyping.ml +++ b/checker/subtyping.ml @@ -108,6 +108,14 @@ let check_inductive env mp1 l info1 mib2 spec2 subst1 subst2= let env = check_polymorphic_instance error env auctx auctx' in env, Univ.make_abstract_instance auctx' | Cumulative_ind cumi, Cumulative_ind cumi' -> + (** Currently there is no way to control variance of inductive types, but + just in case we require that they are in a subtyping relation. *) + let () = + let v = Univ.ACumulativityInfo.variance cumi in + let v' = Univ.ACumulativityInfo.variance cumi' in + if not (Array.for_all2 Univ.Variance.check_subtype v' v) then + CErrors.anomaly Pp.(str "Variance mismatch for " ++ MutInd.print kn) + in let auctx = Univ.ACumulativityInfo.univ_context cumi in let auctx' = Univ.ACumulativityInfo.univ_context cumi' in let env = check_polymorphic_instance error env auctx auctx' in diff --git a/checker/univ.ml b/checker/univ.ml index 46b3ce680..ebc37bc10 100644 --- a/checker/univ.ml +++ b/checker/univ.ml @@ -1011,6 +1011,13 @@ struct A'] as opposed to [A' <= A]. *) type t = Irrelevant | Covariant | Invariant + let check_subtype x y = match x, y with + | (Irrelevant | Covariant | Invariant), Irrelevant -> true + | Irrelevant, Covariant -> false + | (Covariant | Invariant), Covariant -> true + | (Irrelevant | Covariant), Invariant -> false + | Invariant, Invariant -> true + let leq_constraint csts variance u u' = match variance with | Irrelevant -> csts diff --git a/checker/univ.mli b/checker/univ.mli index 8c0685e0b..32e48f593 100644 --- a/checker/univ.mli +++ b/checker/univ.mli @@ -225,7 +225,7 @@ sig case because [forall x : A, B <= forall x : A', B'] requires [A = A'] as opposed to [A' <= A]. *) type t = Irrelevant | Covariant | Invariant - + val check_subtype : t -> t -> bool val leq_constraints : t array -> Instance.t constraint_function val eq_constraints : t array -> Instance.t constraint_function end |