[api] Move `Constrexpr` to the `interp` module.

Continuing the interface cleanup we place `Constrexpr` in the
internalization module, which is the one that eliminates it.

This slims down `pretyping` considerably, including removing the
`Univdecls` module which existed only due to bad dependency ordering
in the first place. Thanks to @ Skyskimmer we also remove a duplicate
`univ_decl` definition among `Misctypes` and `UState`.

This is mostly a proof of concept yet as it depends on quite a few
patches of the tree. For sure some tweaks will be necessary, but it
should be good for review now.

IMO the tree is now in a state where we can could easy eliminate more
than 10 modules without any impact, IMHO this is a net saving API-wise
and would help people to understand the structure of the code better.

45 files changed, 150 insertions, 171 deletions

diff --git a/dev/doc/changes.md b/dev/doc/changes.md
index 346b7c7dd..4838dd734 100644
--- a/dev/doc/changes.md
+++ b/dev/doc/changes.md
@@ -41,6 +41,15 @@ Printer.ml API
   pr_subgoal and pr_goal was removed to simplify the code.  It was
   earlierly used by PCoq.
 
+Source code organization
+
+- We have eliminated / fused some redundant modules and relocated a
+  few interfaces files. The `intf` folder is gone, and now for example
+  `Constrexpr` is located in `interp/`, `Vernacexpr` in `vernac/` and
+  so on. Changes should be compatible, but in a few cases stricter
+  layering requirements may mean that functions have moved. In all
+  cases adapting is a matter of changing the module name.
+
 Vernacular commands
 
 - The implementation of vernacular commands has been refactored so it
diff --git a/engine/uState.ml b/engine/uState.ml
index 15cf4d4c1..643c621fd 100644
--- a/engine/uState.ml
+++ b/engine/uState.ml
@@ -305,8 +305,20 @@ let reference_of_level uctx =
 let pr_uctx_level uctx l =
   Libnames.pr_reference (reference_of_level uctx l)
 
+type ('a, 'b) gen_universe_decl = {
+  univdecl_instance : 'a; (* Declared universes *)
+  univdecl_extensible_instance : bool; (* Can new universes be added *)
+  univdecl_constraints : 'b; (* Declared constraints *)
+  univdecl_extensible_constraints : bool (* Can new constraints be added *) }
+
 type universe_decl =
-  (Misctypes.lident list, Univ.Constraint.t) Misctypes.gen_universe_decl
+  (Misctypes.lident list, Univ.Constraint.t) gen_universe_decl
+
+let default_univ_decl =
+  { univdecl_instance = [];
+    univdecl_extensible_instance = true;
+    univdecl_constraints = Univ.Constraint.empty;
+    univdecl_extensible_constraints = true }
 
 let error_unbound_universes left uctx =
   let open Univ in
@@ -367,7 +379,6 @@ let check_implication uctx cstrs cstrs' =
       (str "Universe constraints are not implied by the ones declared.")
 
 let check_mono_univ_decl uctx decl =
-  let open Misctypes in
   let () =
     let names = decl.univdecl_instance in
     let extensible = decl.univdecl_extensible_instance in
@@ -380,7 +391,6 @@ let check_mono_univ_decl uctx decl =
   uctx.uctx_local
 
 let check_univ_decl ~poly uctx decl =
-  let open Misctypes in
   let ctx =
     let names = decl.univdecl_instance in
     let extensible = decl.univdecl_extensible_instance in
diff --git a/engine/uState.mli b/engine/uState.mli
index d1678a155..e2f25642e 100644
--- a/engine/uState.mli
+++ b/engine/uState.mli
@@ -138,8 +138,16 @@ val refresh_undefined_univ_variables : t -> t * Univ.universe_level_subst
 (** Universe minimization *)
 val minimize : t -> t
 
+type ('a, 'b) gen_universe_decl = {
+  univdecl_instance : 'a; (* Declared universes *)
+  univdecl_extensible_instance : bool; (* Can new universes be added *)
+  univdecl_constraints : 'b; (* Declared constraints *)
+  univdecl_extensible_constraints : bool (* Can new constraints be added *) }
+
 type universe_decl =
-  (Misctypes.lident list, Univ.Constraint.t) Misctypes.gen_universe_decl
+  (Misctypes.lident list, Univ.Constraint.t) gen_universe_decl
+
+val default_univ_decl : universe_decl
 
 (** [check_univ_decl ctx decl]
 
diff --git a/pretyping/constrexpr.ml b/interp/constrexpr.ml
index 1443dfb51..ca6ea94f0 100644
--- a/pretyping/constrexpr.ml
+++ b/interp/constrexpr.ml
@@ -16,8 +16,7 @@ open Decl_kinds
 (** {6 Concrete syntax for terms } *)
 
 (** [constr_expr] is the abstract syntax tree produced by the parser *)
-
-type universe_decl_expr = (lident list, Glob_term.glob_constraint list) gen_universe_decl
+type universe_decl_expr = (lident list, Glob_term.glob_constraint list) UState.gen_universe_decl
 
 type ident_decl = lident * universe_decl_expr option
 type name_decl = lname * universe_decl_expr option
diff --git a/interp/constrexpr_ops.ml b/interp/constrexpr_ops.ml
index 3eb5acfc5..1be1dd96c 100644
--- a/interp/constrexpr_ops.ml
+++ b/interp/constrexpr_ops.ml
@@ -600,3 +600,35 @@ let _ = Goptions.declare_bool_option {
   Goptions.optread = (fun () -> !asymmetric_patterns);
   Goptions.optwrite = (fun a -> asymmetric_patterns:=a);
 }
+
+(** Local universe and constraint declarations. *)
+
+let interp_univ_constraints env evd cstrs =
+  let interp (evd,cstrs) (u, d, u') =
+    let ul = Pretyping.interp_known_glob_level evd u in
+    let u'l = Pretyping.interp_known_glob_level evd u' in
+    let cstr = (ul,d,u'l) in
+    let cstrs' = Univ.Constraint.add cstr cstrs in
+    try let evd = Evd.add_constraints evd (Univ.Constraint.singleton cstr) in
+        evd, cstrs'
+    with Univ.UniverseInconsistency e ->
+      CErrors.user_err ~hdr:"interp_constraint"
+        (Univ.explain_universe_inconsistency (Termops.pr_evd_level evd) e)
+  in
+  List.fold_left interp (evd,Univ.Constraint.empty) cstrs
+
+let interp_univ_decl env decl =
+  let open UState in
+  let pl : lident list = decl.univdecl_instance in
+  let evd = Evd.from_ctx (UState.make_with_initial_binders (Environ.universes env) pl) in
+  let evd, cstrs = interp_univ_constraints env evd decl.univdecl_constraints in
+  let decl = { univdecl_instance = pl;
+    univdecl_extensible_instance = decl.univdecl_extensible_instance;
+    univdecl_constraints = cstrs;
+    univdecl_extensible_constraints = decl.univdecl_extensible_constraints }
+  in evd, decl
+
+let interp_univ_decl_opt env l =
+  match l with
+  | None -> Evd.from_env env, UState.default_univ_decl
+  | Some decl -> interp_univ_decl env decl
diff --git a/interp/constrexpr_ops.mli b/interp/constrexpr_ops.mli
index 2df9e5a8c..b4f0886ac 100644
--- a/interp/constrexpr_ops.mli
+++ b/interp/constrexpr_ops.mli
@@ -116,3 +116,10 @@ val error_invalid_pattern_notation : ?loc:Loc.t -> unit -> 'a
 
 (** Placeholder for global option, should be moved to a parameter *)
 val asymmetric_patterns : bool ref
+
+(** Local universe and constraint declarations. *)
+val interp_univ_decl : Environ.env -> universe_decl_expr ->
+                       Evd.evar_map * UState.universe_decl
+
+val interp_univ_decl_opt : Environ.env -> universe_decl_expr option ->
+                       Evd.evar_map * UState.universe_decl
diff --git a/pretyping/genredexpr.ml b/interp/genredexpr.ml
index 80697461a..80697461a 100644
--- a/pretyping/genredexpr.ml
+++ b/interp/genredexpr.ml
diff --git a/interp/implicit_quantifiers.ml b/interp/implicit_quantifiers.ml
index 289890544..b48db9ac5 100644
--- a/interp/implicit_quantifiers.ml
+++ b/interp/implicit_quantifiers.ml
@@ -17,12 +17,14 @@ open Glob_term
 open Constrexpr
 open Libnames
 open Typeclasses
-open Typeclasses_errors
 open Pp
 open Libobject
 open Nameops
 open Context.Rel.Declaration
 
+exception MismatchedContextInstance of Environ.env * Typeclasses_errors.contexts * constr_expr list * Context.Rel.t (* found, expected *)
+let mismatched_ctx_inst_err env c n m = raise (MismatchedContextInstance (env, c, n, m))
+
 module RelDecl = Context.Rel.Declaration
 (*i*)
 
@@ -238,7 +240,7 @@ let implicit_application env ?(allow_partial=true) f ty =
 	      let applen = List.fold_left (fun acc (x, y) -> opt_succ y acc) 0 par in
 	      let needlen = List.fold_left (fun acc x -> opt_succ x acc) 0 ci in
 		if not (Int.equal needlen applen) then
-		  Typeclasses_errors.mismatched_ctx_inst (Global.env ()) Parameters (List.map fst par) rd
+                  mismatched_ctx_inst_err (Global.env ()) Typeclasses_errors.Parameters (List.map fst par) rd
 	    end;
 	  let pars = List.rev (List.combine ci rd) in
 	  let args, avoid = combine_params avoid f par pars in
diff --git a/interp/implicit_quantifiers.mli b/interp/implicit_quantifiers.mli
index 39d0174f9..e64c5c542 100644
--- a/interp/implicit_quantifiers.mli
+++ b/interp/implicit_quantifiers.mli
@@ -45,3 +45,7 @@ val implicit_application : Id.Set.t -> ?allow_partial:bool ->
   (Id.Set.t -> GlobRef.t option * Context.Rel.Declaration.t ->
     Constrexpr.constr_expr * Id.Set.t) ->
   constr_expr -> constr_expr * Id.Set.t
+
+(* Should be likely located elsewhere *)
+exception MismatchedContextInstance of Environ.env * Typeclasses_errors.contexts * constr_expr list * Context.Rel.t (* found, expected *)
+val mismatched_ctx_inst_err : Environ.env -> Typeclasses_errors.contexts -> constr_expr list -> Context.Rel.t -> 'a
diff --git a/interp/interp.mllib b/interp/interp.mllib
index 37a327a7d..8ed2b9fad 100644
--- a/interp/interp.mllib
+++ b/interp/interp.mllib
@@ -1,3 +1,6 @@
+Constrexpr
+Genredexpr
+Redops
 Tactypes
 Stdarg
 Genintern
diff --git a/interp/modintern.ml b/interp/modintern.ml
index dc93d8dc4..fefd2ab6f 100644
--- a/interp/modintern.ml
+++ b/interp/modintern.ml
@@ -63,7 +63,7 @@ let transl_with_decl env = function
   | CWith_Module ({CAst.v=fqid},qid) ->
       WithMod (fqid,lookup_module qid), Univ.ContextSet.empty
   | CWith_Definition ({CAst.v=fqid},udecl,c) ->
-    let sigma, udecl = Univdecls.interp_univ_decl_opt env udecl in
+    let sigma, udecl = Constrexpr_ops.interp_univ_decl_opt env udecl in
     let c, ectx = interp_constr env sigma c in
     begin match UState.check_univ_decl ~poly:(Flags.is_universe_polymorphism()) ectx udecl with
       | Entries.Polymorphic_const_entry ctx ->
diff --git a/pretyping/redops.ml b/interp/redops.ml
index 90c3bdfae..b9a74136e 100644
--- a/pretyping/redops.ml
+++ b/interp/redops.ml
@@ -42,3 +42,23 @@ let make_red_flag l =
 let all_flags =
   {rBeta = true; rMatch = true; rFix = true; rCofix = true;
    rZeta = true; rDelta = true; rConst = []}
+
+(** Mapping [red_expr_gen] *)
+
+let map_flags f flags =
+  { flags with rConst = List.map f flags.rConst }
+
+let map_occs f (occ,e) = (occ,f e)
+
+let map_red_expr_gen f g h = function
+  | Fold l -> Fold (List.map f l)
+  | Pattern occs_l -> Pattern (List.map (map_occs f) occs_l)
+  | Simpl (flags,occs_o) ->
+     Simpl (map_flags g flags, Option.map (map_occs (Util.map_union g h)) occs_o)
+  | Unfold occs_l -> Unfold (List.map (map_occs g) occs_l)
+  | Cbv flags -> Cbv (map_flags g flags)
+  | Lazy flags -> Lazy (map_flags g flags)
+  | CbvVm occs_o -> CbvVm (Option.map (map_occs (Util.map_union g h)) occs_o)
+  | CbvNative occs_o -> CbvNative (Option.map (map_occs (Util.map_union g h)) occs_o)
+  | Cbn flags -> Cbn (map_flags g flags)
+  | ExtraRedExpr _ | Red _ | Hnf as x -> x
diff --git a/pretyping/redops.mli b/interp/redops.mli
index 285931ecd..7254f29b2 100644
--- a/pretyping/redops.mli
+++ b/interp/redops.mli
@@ -13,3 +13,8 @@ open Genredexpr
 val make_red_flag : 'a red_atom list -> 'a glob_red_flag
 
 val all_flags : 'a glob_red_flag
+
+(** Mapping [red_expr_gen] *)
+
+val map_red_expr_gen : ('a -> 'd) -> ('b -> 'e) -> ('c -> 'f) ->
+  ('a,'b,'c) red_expr_gen -> ('d,'e,'f) red_expr_gen
diff --git a/library/misctypes.ml b/library/misctypes.ml
index a3c887045..cfae07484 100644
--- a/library/misctypes.ml
+++ b/library/misctypes.ml
@@ -112,9 +112,3 @@ type multi =
   | UpTo of int
   | RepeatStar
   | RepeatPlus
-
-type ('a, 'b) gen_universe_decl = {
-  univdecl_instance : 'a; (* Declared universes *)
-  univdecl_extensible_instance : bool; (* Can new universes be added *)
-  univdecl_constraints : 'b; (* Declared constraints *)
-  univdecl_extensible_constraints : bool (* Can new constraints be added *) }
diff --git a/plugins/ltac/tacsubst.ml b/plugins/ltac/tacsubst.ml
index a1d8b087e..50bf687b1 100644
--- a/plugins/ltac/tacsubst.ml
+++ b/plugins/ltac/tacsubst.ml
@@ -112,7 +112,7 @@ let subst_glob_constr_or_pattern subst (bvars,c,p) =
   (bvars,subst_glob_constr subst c,subst_pattern subst p)
 
 let subst_redexp subst =
-  Miscops.map_red_expr_gen
+  Redops.map_red_expr_gen
     (subst_glob_constr subst)
     (subst_evaluable subst)
     (subst_glob_constr_or_pattern subst)
diff --git a/pretyping/miscops.ml b/pretyping/miscops.ml
index 1b536bfda..1697e54ab 100644
--- a/pretyping/miscops.ml
+++ b/pretyping/miscops.ml
@@ -10,7 +10,6 @@
 
 open Util
 open Misctypes
-open Genredexpr
 
 (** Mapping [cast_type] *)
 
@@ -42,26 +41,6 @@ let intro_pattern_naming_eq nam1 nam2 = match nam1, nam2 with
 | IntroFresh id1, IntroFresh id2 -> Names.Id.equal id1 id2
 | _ -> false
 
-(** Mapping [red_expr_gen] *)
-
-let map_flags f flags =
-  { flags with rConst = List.map f flags.rConst }
-
-let map_occs f (occ,e) = (occ,f e)
-
-let map_red_expr_gen f g h = function
-  | Fold l -> Fold (List.map f l)
-  | Pattern occs_l -> Pattern (List.map (map_occs f) occs_l)
-  | Simpl (flags,occs_o) ->
-     Simpl (map_flags g flags, Option.map (map_occs (map_union g h)) occs_o)
-  | Unfold occs_l -> Unfold (List.map (map_occs g) occs_l)
-  | Cbv flags -> Cbv (map_flags g flags)
-  | Lazy flags -> Lazy (map_flags g flags)
-  | CbvVm occs_o -> CbvVm (Option.map (map_occs (map_union g h)) occs_o)
-  | CbvNative occs_o -> CbvNative (Option.map (map_occs (map_union g h)) occs_o)
-  | Cbn flags -> Cbn (map_flags g flags)
-  | ExtraRedExpr _ | Red _ | Hnf as x -> x
-
 (** Mapping bindings *)
 
 let map_explicit_bindings f l =
diff --git a/pretyping/miscops.mli b/pretyping/miscops.mli
index 1d4504541..6a84fb9eb 100644
--- a/pretyping/miscops.mli
+++ b/pretyping/miscops.mli
@@ -9,7 +9,6 @@
 (************************************************************************)
 
 open Misctypes
-open Genredexpr
 
 (** Mapping [cast_type] *)
 
@@ -25,11 +24,6 @@ val glob_sort_eq : Glob_term.glob_sort -> Glob_term.glob_sort -> bool
 val intro_pattern_naming_eq :
   intro_pattern_naming_expr -> intro_pattern_naming_expr -> bool
 
-(** Mapping [red_expr_gen] *)
-
-val map_red_expr_gen : ('a -> 'd) -> ('b -> 'e) -> ('c -> 'f) ->
-  ('a,'b,'c) red_expr_gen -> ('d,'e,'f) red_expr_gen
-
 (** Mapping bindings *)
 
 val map_bindings : ('a -> 'b) -> 'a bindings -> 'b bindings
diff --git a/pretyping/pretyping.mllib b/pretyping/pretyping.mllib
index c48decdb0..3d9b5d3cf 100644
--- a/pretyping/pretyping.mllib
+++ b/pretyping/pretyping.mllib
@@ -16,13 +16,10 @@ Evarsolve
 Recordops
 Evarconv
 Typing
-Constrexpr
-Genredexpr
 Miscops
 Glob_term
 Ltac_pretype
 Glob_ops
-Redops
 Pattern
 Patternops
 Constr_matching
@@ -37,4 +34,3 @@ Indrec
 Cases
 Pretyping
 Unification
-Univdecls
diff --git a/pretyping/typeclasses_errors.ml b/pretyping/typeclasses_errors.ml
index 89c5d7e7b..a1ac53c73 100644
--- a/pretyping/typeclasses_errors.ml
+++ b/pretyping/typeclasses_errors.ml
@@ -12,7 +12,6 @@
 open Names
 open EConstr
 open Environ
-open Constrexpr
 (*i*)
 
 type contexts = Parameters | Properties
@@ -20,7 +19,6 @@ type contexts = Parameters | Properties
 type typeclass_error =
     | NotAClass of constr
     | UnboundMethod of GlobRef.t * Misctypes.lident (* Class name, method *)
-    | MismatchedContextInstance of contexts * constr_expr list * Context.Rel.t (* found, expected *)
 
 exception TypeClassError of env * typeclass_error
 
@@ -29,5 +27,3 @@ let typeclass_error env err = raise (TypeClassError (env, err))
 let not_a_class env c = typeclass_error env (NotAClass c)
 
 let unbound_method env cid id = typeclass_error env (UnboundMethod (cid, id))
-
-let mismatched_ctx_inst env c n m = typeclass_error env (MismatchedContextInstance (c, n, m))
diff --git a/pretyping/typeclasses_errors.mli b/pretyping/typeclasses_errors.mli
index 4aabc0aee..1003f2ae1 100644
--- a/pretyping/typeclasses_errors.mli
+++ b/pretyping/typeclasses_errors.mli
@@ -11,14 +11,12 @@
 open Names
 open EConstr
 open Environ
-open Constrexpr
 
 type contexts = Parameters | Properties
 
 type typeclass_error =
   | NotAClass of constr
   | UnboundMethod of GlobRef.t * Misctypes.lident (** Class name, method *)
-  | MismatchedContextInstance of contexts * constr_expr list * Context.Rel.t (** found, expected *)
 
 exception TypeClassError of env * typeclass_error
 
@@ -26,5 +24,3 @@ val not_a_class : env -> constr -> 'a
 
 val unbound_method : env -> GlobRef.t -> Misctypes.lident -> 'a
 
-val mismatched_ctx_inst : env -> contexts -> constr_expr list -> Context.Rel.t -> 'a
-
diff --git a/pretyping/univdecls.ml b/pretyping/univdecls.ml
deleted file mode 100644
index 8864be576..000000000
--- a/pretyping/univdecls.ml
+++ /dev/null
@@ -1,52 +0,0 @@
-(************************************************************************)
-(*         *   The Coq Proof Assistant / The Coq Development Team       *)
-(*  v      *   INRIA, CNRS and contributors - Copyright 1999-2018       *)
-(* <O___,, *       (see CREDITS file for the list of authors)           *)
-(*   \VV/  **************************************************************)
-(*    //   *    This file is distributed under the terms of the         *)
-(*         *     GNU Lesser General Public License Version 2.1          *)
-(*         *     (see LICENSE file for the text of the license)         *)
-(************************************************************************)
-
-open CErrors
-
-(** Local universes and constraints declarations *)
-type universe_decl =
-  (Misctypes.lident list, Univ.Constraint.t) Misctypes.gen_universe_decl
-
-let default_univ_decl =
-  let open Misctypes in
-  { univdecl_instance = [];
-    univdecl_extensible_instance = true;
-    univdecl_constraints = Univ.Constraint.empty;
-    univdecl_extensible_constraints = true }
-
-let interp_univ_constraints env evd cstrs =
-  let interp (evd,cstrs) (u, d, u') =
-    let ul = Pretyping.interp_known_glob_level evd u in
-    let u'l = Pretyping.interp_known_glob_level evd u' in
-    let cstr = (ul,d,u'l) in
-    let cstrs' = Univ.Constraint.add cstr cstrs in
-    try let evd = Evd.add_constraints evd (Univ.Constraint.singleton cstr) in
-        evd, cstrs'
-    with Univ.UniverseInconsistency e ->
-      user_err ~hdr:"interp_constraint"
-        (Univ.explain_universe_inconsistency (Termops.pr_evd_level evd) e)
-  in
-  List.fold_left interp (evd,Univ.Constraint.empty) cstrs
-
-let interp_univ_decl env decl =
-  let open Misctypes in
-  let pl : lident list = decl.univdecl_instance in
-  let evd = Evd.from_ctx (UState.make_with_initial_binders (Environ.universes env) pl) in
-  let evd, cstrs = interp_univ_constraints env evd decl.univdecl_constraints in
-  let decl = { univdecl_instance = pl;
-    univdecl_extensible_instance = decl.univdecl_extensible_instance;
-    univdecl_constraints = cstrs;
-    univdecl_extensible_constraints = decl.univdecl_extensible_constraints }
-  in evd, decl
-
-let interp_univ_decl_opt env l =
-  match l with
-  | None -> Evd.from_env env, default_univ_decl
-  | Some decl -> interp_univ_decl env decl
diff --git a/pretyping/univdecls.mli b/pretyping/univdecls.mli
deleted file mode 100644
index 305d045b1..000000000
--- a/pretyping/univdecls.mli
+++ /dev/null
@@ -1,21 +0,0 @@
-(************************************************************************)
-(*         *   The Coq Proof Assistant / The Coq Development Team       *)
-(*  v      *   INRIA, CNRS and contributors - Copyright 1999-2018       *)
-(* <O___,, *       (see CREDITS file for the list of authors)           *)
-(*   \VV/  **************************************************************)
-(*    //   *    This file is distributed under the terms of the         *)
-(*         *     GNU Lesser General Public License Version 2.1          *)
-(*         *     (see LICENSE file for the text of the license)         *)
-(************************************************************************)
-
-(** Local universe and constraint declarations. *)
-type universe_decl =
-  (Misctypes.lident list, Univ.Constraint.t) Misctypes.gen_universe_decl
-
-val default_univ_decl : universe_decl
-
-val interp_univ_decl : Environ.env -> Constrexpr.universe_decl_expr ->
-                       Evd.evar_map * universe_decl
-
-val interp_univ_decl_opt : Environ.env -> Constrexpr.universe_decl_expr option ->
-                       Evd.evar_map * universe_decl
diff --git a/proofs/pfedit.mli b/proofs/pfedit.mli
index 805635dfa..7b7973224 100644
--- a/proofs/pfedit.mli
+++ b/proofs/pfedit.mli
@@ -24,7 +24,7 @@ open Decl_kinds
     proof of mutually dependent theorems) *)
 
 val start_proof :
-  Id.t -> ?pl:Univdecls.universe_decl -> goal_kind -> Evd.evar_map -> named_context_val -> EConstr.constr ->
+  Id.t -> ?pl:UState.universe_decl -> goal_kind -> Evd.evar_map -> named_context_val -> EConstr.constr ->
   ?init_tac:unit Proofview.tactic ->
   Proof_global.proof_terminator -> unit
 
diff --git a/proofs/proof_global.ml b/proofs/proof_global.ml
index d5cb5b09f..3abdd129e 100644
--- a/proofs/proof_global.ml
+++ b/proofs/proof_global.ml
@@ -97,7 +97,7 @@ type pstate = {
   proof : Proof.t;
   strength : Decl_kinds.goal_kind;
   mode : proof_mode CEphemeron.key;
-  universe_decl: Univdecls.universe_decl;
+  universe_decl: UState.universe_decl;
 }
 
 type t = pstate list
@@ -238,13 +238,6 @@ let activate_proof_mode mode =
 let disactivate_current_proof_mode () =
   CEphemeron.iter_opt !current_proof_mode (fun x -> x.reset ())
 
-let default_universe_decl =
-  let open Misctypes in
-  { univdecl_instance = [];
-    univdecl_extensible_instance = true;
-    univdecl_constraints = Univ.Constraint.empty;
-    univdecl_extensible_constraints = true }
-
 (** [start_proof sigma id pl str goals terminator] starts a proof of name
     [id] with goals [goals] (a list of pairs of environment and
     conclusion); [str] describes what kind of theorem/definition this
@@ -253,7 +246,7 @@ let default_universe_decl =
     end of the proof to close the proof. The proof is started in the
     evar map [sigma] (which can typically contain universe
     constraints), and with universe bindings pl. *)
-let start_proof sigma id ?(pl=default_universe_decl) str goals terminator =
+let start_proof sigma id ?(pl=UState.default_univ_decl) str goals terminator =
   let initial_state = {
     pid = id;
     terminator = CEphemeron.create terminator;
@@ -265,7 +258,7 @@ let start_proof sigma id ?(pl=default_universe_decl) str goals terminator =
     universe_decl = pl } in
   push initial_state pstates
 
-let start_dependent_proof id ?(pl=default_universe_decl) str goals terminator =
+let start_dependent_proof id ?(pl=UState.default_univ_decl) str goals terminator =
   let initial_state = {
     pid = id;
     terminator = CEphemeron.create terminator;
diff --git a/proofs/proof_global.mli b/proofs/proof_global.mli
index de4cec488..0141cacb9 100644
--- a/proofs/proof_global.mli
+++ b/proofs/proof_global.mli
@@ -71,14 +71,14 @@ val apply_terminator : proof_terminator -> proof_ending -> unit
     evar map [sigma] (which can typically contain universe
     constraints), and with universe bindings pl. *)
 val start_proof :
-  Evd.evar_map -> Names.Id.t -> ?pl:Univdecls.universe_decl ->
+  Evd.evar_map -> Names.Id.t -> ?pl:UState.universe_decl ->
   Decl_kinds.goal_kind -> (Environ.env * EConstr.types) list  ->
     proof_terminator -> unit
 
 (** Like [start_proof] except that there may be dependencies between
     initial goals. *)
 val start_dependent_proof :
-  Names.Id.t -> ?pl:Univdecls.universe_decl -> Decl_kinds.goal_kind ->
+  Names.Id.t -> ?pl:UState.universe_decl -> Decl_kinds.goal_kind ->
   Proofview.telescope -> proof_terminator -> unit
 
 (** Update the proofs global environment after a side-effecting command
@@ -130,7 +130,7 @@ val set_used_variables :
 val get_used_variables : unit -> Context.Named.t option
 
 (** Get the universe declaration associated to the current proof. *)
-val get_universe_decl : unit -> Univdecls.universe_decl
+val get_universe_decl : unit -> UState.universe_decl
 
 module V82 : sig
   val get_current_initial_conclusions : unit -> Names.Id.t *(EConstr.types list *
diff --git a/proofs/redexpr.ml b/proofs/redexpr.ml
index f9e7bbfac..03ebc3275 100644
--- a/proofs/redexpr.ml
+++ b/proofs/redexpr.ml
@@ -263,7 +263,7 @@ let subst_mps subst c =
   EConstr.of_constr (Mod_subst.subst_mps subst (EConstr.Unsafe.to_constr c))
 
 let subst_red_expr subs =
-  Miscops.map_red_expr_gen
+  Redops.map_red_expr_gen
     (subst_mps subs)
     (Mod_subst.subst_evaluable_reference subs)
     (Patternops.subst_pattern subs)
diff --git a/vernac/classes.ml b/vernac/classes.ml
index c82208980..946a7bb32 100644
--- a/vernac/classes.ml
+++ b/vernac/classes.ml
@@ -77,8 +77,8 @@ let existing_instance glob g info =
                          ~hdr:"declare_instance"
                          (Pp.str "Constant does not build instances of a declared type class.")
 
-let mismatched_params env n m = mismatched_ctx_inst env Parameters n m
-let mismatched_props env n m = mismatched_ctx_inst env Properties n m
+let mismatched_params env n m = Implicit_quantifiers.mismatched_ctx_inst_err env Parameters n m
+let mismatched_props env n m = Implicit_quantifiers.mismatched_ctx_inst_err env Properties n m
 
 (* Declare everything in the parameters as implicit, and the class instance as well *)
 
@@ -137,7 +137,7 @@ let new_instance ?(abstract=false) ?(global=false) ?(refine= !refine_instance)
   ?(tac:unit Proofview.tactic option) ?hook pri =
   let env = Global.env() in
   let ({CAst.loc;v=instid}, pl) = instid in
-  let sigma, decl = Univdecls.interp_univ_decl_opt env pl in
+  let sigma, decl = Constrexpr_ops.interp_univ_decl_opt env pl in
   let tclass, ids =
     match bk with
     | Decl_kinds.Implicit ->
diff --git a/vernac/classes.mli b/vernac/classes.mli
index 631da8400..eea2a211d 100644
--- a/vernac/classes.mli
+++ b/vernac/classes.mli
@@ -32,7 +32,7 @@ val declare_instance_constant :
   Impargs.manual_explicitation list -> (** implicits *)
   ?hook:(GlobRef.t -> unit) ->
   Id.t -> (** name *)
-  Univdecls.universe_decl ->
+  UState.universe_decl ->
   bool -> (* polymorphic *)
   Evd.evar_map -> (* Universes *)
   Constr.t -> (** body *)
diff --git a/vernac/comAssumption.ml b/vernac/comAssumption.ml
index 492ae1d9b..a8ac52846 100644
--- a/vernac/comAssumption.ml
+++ b/vernac/comAssumption.ml
@@ -136,7 +136,7 @@ let do_assumptions kind nl l =
   let open Context.Named.Declaration in
   let env = Global.env () in
   let udecl, l = process_assumptions_udecls kind l in
-  let sigma, udecl = Univdecls.interp_univ_decl_opt env udecl in
+  let sigma, udecl = interp_univ_decl_opt env udecl in
   let l =
     if pi2 kind (* poly *) then
       (* Separate declarations so that A B : Type puts A and B in different levels. *)
diff --git a/vernac/comDefinition.ml b/vernac/comDefinition.ml
index 2d4bd6779..f55c852c0 100644
--- a/vernac/comDefinition.ml
+++ b/vernac/comDefinition.ml
@@ -65,7 +65,7 @@ let interp_definition pl bl poly red_option c ctypopt =
   let open EConstr in
   let env = Global.env() in
   (* Explicitly bound universes and constraints *)
-  let evd, decl = Univdecls.interp_univ_decl_opt env pl in
+  let evd, decl = Constrexpr_ops.interp_univ_decl_opt env pl in
   (* Build the parameters *)
   let evd, (impls, ((env_bl, ctx), imps1)) = interp_context_evars env evd bl in
   (* Build the type *)
diff --git a/vernac/comDefinition.mli b/vernac/comDefinition.mli
index 6f81c4575..7f1c902c0 100644
--- a/vernac/comDefinition.mli
+++ b/vernac/comDefinition.mli
@@ -29,4 +29,4 @@ val do_definition : program_mode:bool ->
 val interp_definition :
   universe_decl_expr option -> local_binder_expr list -> polymorphic -> red_expr option -> constr_expr ->
   constr_expr option -> Safe_typing.private_constants definition_entry * Evd.evar_map *
-                        Univdecls.universe_decl * Impargs.manual_implicits
+                        UState.universe_decl * Impargs.manual_implicits
diff --git a/vernac/comFixpoint.ml b/vernac/comFixpoint.ml
index d996443d6..ea731b34c 100644
--- a/vernac/comFixpoint.ml
+++ b/vernac/comFixpoint.ml
@@ -173,11 +173,12 @@ let interp_recursive ~program_mode ~cofix fixl notations =
         | None , acc -> acc
         | x , None -> x
         | Some ls , Some us ->
-           let lsu = ls.univdecl_instance and usu = us.univdecl_instance in
+          let open UState in
+          let lsu = ls.univdecl_instance and usu = us.univdecl_instance in
            if not (CList.for_all2eq (fun x y -> Id.equal x.CAst.v y.CAst.v) lsu usu) then
              user_err Pp.(str "(co)-recursive definitions should all have the same universe binders");
            Some us) fixl None in
-  let sigma, decl = Univdecls.interp_univ_decl_opt env all_universes in
+  let sigma, decl = interp_univ_decl_opt env all_universes in
   let sigma, (fixctxs, fiximppairs, fixannots) =
     on_snd List.split3 @@
       List.fold_left_map (fun sigma -> interp_fix_context env sigma ~cofix) sigma fixl in
diff --git a/vernac/comFixpoint.mli b/vernac/comFixpoint.mli
index 36c2993af..a6992a30b 100644
--- a/vernac/comFixpoint.mli
+++ b/vernac/comFixpoint.mli
@@ -49,7 +49,7 @@ val interp_recursive :
   structured_fixpoint_expr list -> decl_notation list ->
 
   (* env / signature / univs / evar_map *)
-  (Environ.env * EConstr.named_context * Univdecls.universe_decl * Evd.evar_map) *
+  (Environ.env * EConstr.named_context * UState.universe_decl * Evd.evar_map) *
   (* names / defs / types *)
   (Id.t list * Constr.constr option list * Constr.types list) *
   (* ctx per mutual def / implicits / struct annotations *)
@@ -74,19 +74,19 @@ type recursive_preentry =
 val interp_fixpoint :
   cofix:bool ->
   structured_fixpoint_expr list -> decl_notation list ->
-  recursive_preentry * Univdecls.universe_decl * UState.t *
+  recursive_preentry * UState.universe_decl * UState.t *
   (EConstr.rel_context * Impargs.manual_implicits * int option) list
 
 (** Registering fixpoints and cofixpoints in the environment *)
 (** [Not used so far] *)
 val declare_fixpoint :
   locality -> polymorphic ->
-  recursive_preentry * Univdecls.universe_decl * UState.t *
+  recursive_preentry * UState.universe_decl * UState.t *
   (Context.Rel.t * Impargs.manual_implicits * int option) list ->
   Proof_global.lemma_possible_guards -> decl_notation list -> unit
 
 val declare_cofixpoint : locality -> polymorphic ->
-  recursive_preentry * Univdecls.universe_decl * UState.t *
+  recursive_preentry * UState.universe_decl * UState.t *
   (Context.Rel.t * Impargs.manual_implicits * int option) list ->
   decl_notation list -> unit
 
diff --git a/vernac/comInductive.ml b/vernac/comInductive.ml
index 790e83dbe..101c14266 100644
--- a/vernac/comInductive.ml
+++ b/vernac/comInductive.ml
@@ -333,7 +333,7 @@ let interp_mutual_inductive (paramsl,indl) notations cum poly prv finite =
   List.iter check_param paramsl;
   let env0 = Global.env() in
   let pl = (List.hd indl).ind_univs in
-  let sigma, decl = Univdecls.interp_univ_decl_opt env0 pl in
+  let sigma, decl = interp_univ_decl_opt env0 pl in
   let sigma, (impls, ((env_params, ctx_params), userimpls)) =
     interp_context_evars env0 sigma paramsl
   in
diff --git a/vernac/comProgramFixpoint.ml b/vernac/comProgramFixpoint.ml
index f41e0fc44..a6d7fccf3 100644
--- a/vernac/comProgramFixpoint.ml
+++ b/vernac/comProgramFixpoint.ml
@@ -91,7 +91,7 @@ let build_wellfounded (recname,pl,n,bl,arityc,body) poly r measure notation =
   let lift_rel_context n l = Termops.map_rel_context_with_binders (liftn n) l in
   Coqlib.check_required_library ["Coq";"Program";"Wf"];
   let env = Global.env() in
-  let sigma, decl = Univdecls.interp_univ_decl_opt env pl in
+  let sigma, decl = Constrexpr_ops.interp_univ_decl_opt env pl in
   let sigma, (_, ((env', binders_rel), impls)) = interp_context_evars env sigma bl in
   let len = List.length binders_rel in
   let top_env = push_rel_context binders_rel env in
diff --git a/vernac/explainErr.ml b/vernac/explainErr.ml
index f68dcae26..504e7095b 100644
--- a/vernac/explainErr.ml
+++ b/vernac/explainErr.ml
@@ -66,6 +66,8 @@ let process_vernac_interp_error exn = match fst exn with
       wrap_vernac_error exn (Himsg.explain_pretype_error ctx sigma te)
   | Typeclasses_errors.TypeClassError(env, te) ->
       wrap_vernac_error exn (Himsg.explain_typeclass_error env te)
+  | Implicit_quantifiers.MismatchedContextInstance(e,c,l,x) ->
+    wrap_vernac_error exn (Himsg.explain_mismatched_contexts e c l x)
   | InductiveError e ->
       wrap_vernac_error exn (Himsg.explain_inductive_error e)
   | Modops.ModuleTypingError e ->
diff --git a/vernac/g_vernac.ml4 b/vernac/g_vernac.ml4
index 6c7df8cfa..0964d46ac 100644
--- a/vernac/g_vernac.ml4
+++ b/vernac/g_vernac.ml4
@@ -230,6 +230,7 @@ GEXTEND Gram
                 ext = [ "+" -> true | -> false ]; "}" -> (l',ext)
               | ext = [ "}" -> true | "|}" -> false ] -> ([], ext) ]
          ->
+         let open UState in
          { univdecl_instance = l;
            univdecl_extensible_instance = ext;
            univdecl_constraints = fst cs;
diff --git a/vernac/himsg.ml b/vernac/himsg.ml
index d4c5def6f..5d671ef52 100644
--- a/vernac/himsg.ml
+++ b/vernac/himsg.ml
@@ -1033,7 +1033,6 @@ let explain_mismatched_contexts env c i j =
 let explain_typeclass_error env = function
   | NotAClass c -> explain_not_a_class env c
   | UnboundMethod (cid, id) -> explain_unbound_method env cid id
-  | MismatchedContextInstance (c,i,j) -> explain_mismatched_contexts env c i j
 
 (* Refiner errors *)
 
diff --git a/vernac/himsg.mli b/vernac/himsg.mli
index 0e20d18c6..1d3807502 100644
--- a/vernac/himsg.mli
+++ b/vernac/himsg.mli
@@ -25,6 +25,8 @@ val explain_pretype_error : env -> Evd.evar_map -> pretype_error -> Pp.t
 
 val explain_inductive_error : inductive_error -> Pp.t
 
+val explain_mismatched_contexts : env -> contexts -> Constrexpr.constr_expr list -> Context.Rel.t -> Pp.t
+
 val explain_typeclass_error : env -> typeclass_error -> Pp.t
 
 val explain_recursion_scheme_error : recursion_scheme_error -> Pp.t
diff --git a/vernac/lemmas.ml b/vernac/lemmas.ml
index 3c7ede3c9..ce74f2344 100644
--- a/vernac/lemmas.ml
+++ b/vernac/lemmas.ml
@@ -436,7 +436,7 @@ let start_proof_with_initialization kind sigma decl recguard thms snl hook =
 let start_proof_com ?inference_hook kind thms hook =
   let env0 = Global.env () in
   let decl = fst (List.hd thms) in
-  let evd, decl = Univdecls.interp_univ_decl_opt env0 (snd decl) in
+  let evd, decl = Constrexpr_ops.interp_univ_decl_opt env0 (snd decl) in
   let evd, thms = List.fold_left_map (fun evd ((id, _), (bl, t)) ->
     let evd, (impls, ((env, ctx), imps)) = interp_context_evars env0 evd bl in
     let evd, (t', imps') = interp_type_evars_impls ~impls env evd t in
@@ -456,7 +456,7 @@ let start_proof_com ?inference_hook kind thms hook =
      you look at the previous lines... *)
   let thms = List.map (fun (n, (t, info)) -> (n, (nf_evar evd t, info))) thms in
   let () =
-    let open Misctypes in
+    let open UState in
     if not (decl.univdecl_extensible_instance && decl.univdecl_extensible_constraints) then
        ignore (Evd.check_univ_decl ~poly:(pi2 kind) evd decl)
   in
diff --git a/vernac/lemmas.mli b/vernac/lemmas.mli
index 398f7d6d0..c9e4876ee 100644
--- a/vernac/lemmas.mli
+++ b/vernac/lemmas.mli
@@ -21,13 +21,13 @@ val call_hook :
 (** A hook start_proof calls on the type of the definition being started *)
 val set_start_hook : (EConstr.types -> unit) -> unit
 
-val start_proof : Id.t -> ?pl:Univdecls.universe_decl -> goal_kind -> Evd.evar_map ->
+val start_proof : Id.t -> ?pl:UState.universe_decl -> goal_kind -> Evd.evar_map ->
   ?terminator:(Proof_global.lemma_possible_guards -> unit declaration_hook -> Proof_global.proof_terminator) ->
   ?sign:Environ.named_context_val -> EConstr.types ->
   ?init_tac:unit Proofview.tactic -> ?compute_guard:Proof_global.lemma_possible_guards -> 
    unit declaration_hook -> unit
 
-val start_proof_univs : Id.t -> ?pl:Univdecls.universe_decl -> goal_kind -> Evd.evar_map ->
+val start_proof_univs : Id.t -> ?pl:UState.universe_decl -> goal_kind -> Evd.evar_map ->
   ?terminator:(Proof_global.lemma_possible_guards -> (UState.t option -> unit declaration_hook) -> Proof_global.proof_terminator) ->
   ?sign:Environ.named_context_val -> EConstr.types ->
   ?init_tac:unit Proofview.tactic -> ?compute_guard:Proof_global.lemma_possible_guards -> 
@@ -39,7 +39,7 @@ val start_proof_com :
   unit declaration_hook -> unit
 
 val start_proof_with_initialization :
-  goal_kind -> Evd.evar_map -> Univdecls.universe_decl ->
+  goal_kind -> Evd.evar_map -> UState.universe_decl ->
   (bool * Proof_global.lemma_possible_guards * unit Proofview.tactic list option) option ->
   (Id.t (* name of thm *) *
      (EConstr.types (* type of thm *) * (Name.t list (* names to pre-introduce *) * Impargs.manual_explicitation list))) list
diff --git a/vernac/obligations.ml b/vernac/obligations.ml
index 6ef8294df..1a3b1f39b 100644
--- a/vernac/obligations.ml
+++ b/vernac/obligations.ml
@@ -308,7 +308,7 @@ type program_info_aux = {
   prg_body: constr;
   prg_type: constr;
   prg_ctx:  UState.t;
-  prg_univdecl: Univdecls.universe_decl;
+  prg_univdecl: UState.universe_decl;
   prg_obligations: obligations;
   prg_deps : Id.t list;
   prg_fixkind : fixpoint_kind option ;
@@ -1099,7 +1099,7 @@ let show_term n =
              Printer.pr_constr_env env sigma prg.prg_type ++ spc () ++ str ":=" ++ fnl ()
             ++ Printer.pr_constr_env env sigma prg.prg_body)
 
-let add_definition n ?term t ctx ?(univdecl=Univdecls.default_univ_decl)
+let add_definition n ?term t ctx ?(univdecl=UState.default_univ_decl)
                    ?(implicits=[]) ?(kind=Global,false,Definition) ?tactic
     ?(reduce=reduce) ?(hook=Lemmas.mk_hook (fun _ _ _ -> ())) ?(opaque = false) obls =
   let sign = Decls.initialize_named_context_for_proof () in
@@ -1119,7 +1119,7 @@ let add_definition n ?term t ctx ?(univdecl=Univdecls.default_univ_decl)
 	| Remain rem -> Flags.if_verbose (fun () -> show_obligations ~msg:false (Some n)) (); res
 	| _ -> res)
 
-let add_mutual_definitions l ctx ?(univdecl=Univdecls.default_univ_decl) ?tactic
+let add_mutual_definitions l ctx ?(univdecl=UState.default_univ_decl) ?tactic
                            ?(kind=Global,false,Definition) ?(reduce=reduce)
     ?(hook=Lemmas.mk_hook (fun _ _ _ -> ())) ?(opaque = false) notations fixkind =
   let sign = Decls.initialize_named_context_for_proof () in
diff --git a/vernac/obligations.mli b/vernac/obligations.mli
index 4b6165fb1..b1eaf51ac 100644
--- a/vernac/obligations.mli
+++ b/vernac/obligations.mli
@@ -54,7 +54,7 @@ val default_tactic : unit Proofview.tactic ref
 
 val add_definition : Names.Id.t -> ?term:constr -> types -> 
   UState.t ->
-  ?univdecl:Univdecls.universe_decl -> (* Universe binders and constraints *)
+  ?univdecl:UState.universe_decl -> (* Universe binders and constraints *)
   ?implicits:(Constrexpr.explicitation * (bool * bool * bool)) list ->
   ?kind:Decl_kinds.definition_kind ->
   ?tactic:unit Proofview.tactic ->
@@ -72,7 +72,7 @@ val add_mutual_definitions :
   (Names.Id.t * constr * types *
       (Constrexpr.explicitation * (bool * bool * bool)) list * obligation_info) list ->
   UState.t ->
-  ?univdecl:Univdecls.universe_decl -> (* Universe binders and constraints *)
+  ?univdecl:UState.universe_decl -> (* Universe binders and constraints *)
   ?tactic:unit Proofview.tactic ->
   ?kind:Decl_kinds.definition_kind ->
   ?reduce:(constr -> constr) ->
diff --git a/vernac/ppvernac.ml b/vernac/ppvernac.ml
index 3655947a5..7e67e12cb 100644
--- a/vernac/ppvernac.ml
+++ b/vernac/ppvernac.ml
@@ -55,7 +55,7 @@ open Pputils
            (if extensible then str"+" else mt())
 
   let pr_universe_decl l =
-    let open Misctypes in
+    let open UState in
     match l with
     | None -> mt ()
     | Some l ->
diff --git a/vernac/record.ml b/vernac/record.ml
index 5ff118473..e6a3afe4e 100644
--- a/vernac/record.ml
+++ b/vernac/record.ml
@@ -102,7 +102,7 @@ let binders_of_decls = List.map binder_of_decl
 
 let typecheck_params_and_fields finite def id poly pl t ps nots fs =
   let env0 = Global.env () in
-  let sigma, decl = Univdecls.interp_univ_decl_opt env0 pl in
+  let sigma, decl = Constrexpr_ops.interp_univ_decl_opt env0 pl in
   let _ =
     let error bk {CAst.loc; v=name} =
       match bk, name with