[cleanup] Unify all calls to the error function.

This is the continuation of #244, we now deprecate `CErrors.error`,
the single entry point in Coq is `user_err`.

The rationale is to allow for easier grepping, and to ease a future
cleanup of error messages. In particular, we would like to
systematically classify all error messages raised by Coq and be sure
they are properly documented.

We restore the two functions removed in #244 to improve compatibility,
but mark them deprecated.

3 files changed, 10 insertions, 10 deletions

diff --git a/interp/constrintern.ml b/interp/constrintern.ml
index c7078cf2a..4dcf287ef 100644
--- a/interp/constrintern.ml
+++ b/interp/constrintern.ml
@@ -579,7 +579,7 @@ let rec subordinate_letins letins = function
 let terms_of_binders bl =
   let rec term_of_pat pt = CAst.map_with_loc (fun ?loc -> function
     | PatVar (Name id)   -> CRef (Ident (loc,id), None)
-    | PatVar (Anonymous) -> error "Cannot turn \"_\" into a term."
+    | PatVar (Anonymous) -> user_err Pp.(str "Cannot turn \"_\" into a term.")
     | PatCstr (c,l,_) ->
        let r = Qualid (loc,qualid_of_path (path_of_global (ConstructRef c))) in
        let hole = CAst.make ?loc @@ CHole (None,Misctypes.IntroAnonymous,None) in
@@ -589,7 +589,7 @@ let terms_of_binders bl =
     | {loc; v = GLocalAssum (Name id,_,_)}::l -> (CAst.make ?loc @@ CRef (Ident (loc,id), None)) :: extract_variables l
     | {loc; v = GLocalDef (Name id,_,_,_)}::l -> extract_variables l
     | {loc; v = GLocalDef (Anonymous,_,_,_)}::l
-    | {loc; v = GLocalAssum (Anonymous,_,_)}::l -> error "Cannot turn \"_\" into a term."
+    | {loc; v = GLocalAssum (Anonymous,_,_)}::l -> user_err Pp.(str "Cannot turn \"_\" into a term.")
     | {loc; v = GLocalPattern ((u,_),_,_,_)}::l -> term_of_pat u :: extract_variables l
     | [] -> [] in
   extract_variables bl
@@ -1862,7 +1862,7 @@ let internalize globalenv env allow_patvar (_, ntnvars as lvar) c =
     let eargs, rargs = extract_explicit_arg l args in
     if !parsing_explicit then
       if Id.Map.is_empty eargs then intern_args env subscopes rargs
-      else error "Arguments given by name or position not supported in explicit mode."
+      else user_err Pp.(str "Arguments given by name or position not supported in explicit mode.")
     else
     let rec aux n impl subscopes eargs rargs =
       let (enva,subscopes') = apply_scope_env env subscopes in
diff --git a/interp/notation_ops.ml b/interp/notation_ops.ml
index 74644b206..6f9100911 100644
--- a/interp/notation_ops.ml
+++ b/interp/notation_ops.ml
@@ -42,7 +42,7 @@ let compare_glob_constr f add t1 t2 = match CAst.(t1.v,t2.v) with
     | GPatVar _ | GEvar _ | GLetTuple _ | GIf _ | GCast _),_
   | _,(GCases _ | GRec _
       | GPatVar _ | GEvar _ | GLetTuple _ | GIf _ | GCast _)
-      -> error "Unsupported construction in recursive notations."
+      -> user_err Pp.(str "Unsupported construction in recursive notations.")
   | (GRef _ | GVar _ | GApp _ | GLambda _ | GProd _
     | GHole _ | GSort _ | GLetIn _), _
       -> false
@@ -112,7 +112,7 @@ let rec eq_notation_constr (vars1,vars2 as vars) t1 t2 = match t1, t2 with
 (* Re-interpret a notation as a glob_constr, taking care of binders   *)
 
 let name_to_ident = function
-  | Anonymous -> CErrors.error "This expression should be a simple identifier."
+  | Anonymous -> CErrors.user_err Pp.(str "This expression should be a simple identifier.")
   | Name id -> id
 
 let to_id g e id = let e,na = g e (Name id) in e,name_to_ident na
@@ -377,7 +377,7 @@ let notation_constr_and_vars_of_glob_constr a =
       Array.iter (add_id found) idl;
       let dll = Array.map (List.map (fun (na,bk,oc,b) ->
 	 if bk != Explicit then
-	   error "Binders marked as implicit not allowed in notations.";
+	   user_err Pp.(str "Binders marked as implicit not allowed in notations.");
 	 add_name found na; (na,Option.map aux oc,aux b))) dll in
       NRec (fk,idl,dll,Array.map aux tl,Array.map aux bl)
   | GCast (c,k) -> NCast (aux c,Miscops.map_cast_type aux k)
@@ -387,7 +387,7 @@ let notation_constr_and_vars_of_glob_constr a =
      NHole (w, naming, arg)
   | GRef (r,_) -> NRef r
   | GEvar _ | GPatVar _ ->
-      error "Existential variables not allowed in notations."
+      user_err Pp.(str "Existential variables not allowed in notations.")
   ) x
   in
   let t = aux a in
@@ -415,9 +415,9 @@ let check_variables_and_reversibility nenv (found,foundrec,foundrecbinding) =
          Id.List.mem_assoc_sym x foundrec ||
          Id.List.mem_assoc_sym x foundrecbinding
       then
-	error
+	user_err Pp.(str
           (Id.to_string x ^
-          " should not be bound in a recursive pattern of the right-hand side.")
+          " should not be bound in a recursive pattern of the right-hand side."))
       else injective := false
   in
   let check_pair s x y where =
diff --git a/interp/topconstr.ml b/interp/topconstr.ml
index 1fe63c19c..a79f10df6 100644
--- a/interp/topconstr.ml
+++ b/interp/topconstr.ml
@@ -163,7 +163,7 @@ let split_at_annot bl na =
   match na with
   | None ->
       begin match names with
-      | [] -> error "A fixpoint needs at least one parameter."
+      | [] -> user_err (Pp.str "A fixpoint needs at least one parameter.")
       | _ -> ([], bl)
       end
   | Some (loc, id) ->