From 17a0dccfe91d6f837ce285e62b8d843720f8c1a1 Mon Sep 17 00:00:00 2001 From: Gaëtan Gilbert Date: Fri, 16 Feb 2018 15:44:44 +0100 Subject: Allow using cumulativity without forcing strict constraints. Previously [fun x : Ind@{i} => x : Ind@{j}] with Ind some cumulative inductive would try to generate a constraint [i = j] and use cumulativity only if this resulted in an inconsistency. This is confusingly different from the behaviour with [Type] and means cumulativity can only be used to lift between universes related by strict inequalities. (This isn't a kernel restriction so there might be some workaround to send the kernel the right constraints, but not in a nice way.) See modified test for more details of what is now possible. Technical notes: When universe constraints were inferred by comparing the shape of terms without reduction, cumulativity was not used and so too-strict equality constraints were generated. Then in order to use cumulativity we had to make this comparison fail to fall back to full conversion. When unifiying 2 instances of a cumulative inductive type, if there are any Irrelevant universes we try to unify them if they are flexible. --- engine/termops.ml | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) (limited to 'engine/termops.ml') diff --git a/engine/termops.ml b/engine/termops.ml index 35258762a..20b6b3504 100644 --- a/engine/termops.ml +++ b/engine/termops.ml @@ -914,12 +914,9 @@ let vars_of_global_reference env gr = (* Tests whether [m] is a subterm of [t]: [m] is appropriately lifted through abstractions of [t] *) -let dependent_main noevar univs sigma m t = +let dependent_main noevar sigma m t = let open EConstr in - let eqc x y = - if univs then not (Option.is_empty (eq_constr_universes sigma x y)) - else eq_constr_nounivs sigma x y - in + let eqc x y = eq_constr_nounivs sigma x y in let rec deprec m t = if eqc m t then raise Occur @@ -936,11 +933,8 @@ let dependent_main noevar univs sigma m t = in try deprec m t; false with Occur -> true -let dependent sigma c t = dependent_main false false sigma c t -let dependent_no_evar sigma c t = dependent_main true false sigma c t - -let dependent_univs sigma c t = dependent_main false true sigma c t -let dependent_univs_no_evar sigma c t = dependent_main true true sigma c t +let dependent sigma c t = dependent_main false sigma c t +let dependent_no_evar sigma c t = dependent_main true sigma c t let dependent_in_decl sigma a decl = let open NamedDecl in -- cgit v1.2.3