[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.

4 files changed, 9 insertions, 9 deletions

diff --git a/engine/eConstr.ml b/engine/eConstr.ml
index e5ac3792d..c0485e4e7 100644
--- a/engine/eConstr.ml
+++ b/engine/eConstr.ml
@@ -295,7 +295,7 @@ let decompose_lam_assum sigma c =
 let decompose_lam_n_assum sigma n c =
   let open Rel.Declaration in
   if n < 0 then
-    error "decompose_lam_n_assum: integer parameter must be positive";
+    user_err Pp.(str "decompose_lam_n_assum: integer parameter must be positive");
   let rec lamdec_rec l n c =
     if Int.equal n 0 then l,c
     else
@@ -303,14 +303,14 @@ let decompose_lam_n_assum sigma n c =
       | Lambda (x,t,c)  -> lamdec_rec (Context.Rel.add (LocalAssum (x,t)) l) (n-1) c
       | LetIn (x,b,t,c) -> lamdec_rec (Context.Rel.add (LocalDef (x,b,t)) l) n c
       | Cast (c,_,_)      -> lamdec_rec l n c
-      | c -> error "decompose_lam_n_assum: not enough abstractions"
+      | c -> user_err Pp.(str "decompose_lam_n_assum: not enough abstractions")
   in
   lamdec_rec Context.Rel.empty n c
 
 let decompose_lam_n_decls sigma n =
   let open Rel.Declaration in
   if n < 0 then
-    error "decompose_lam_n_decls: integer parameter must be positive";
+    user_err Pp.(str "decompose_lam_n_decls: integer parameter must be positive");
   let rec lamdec_rec l n c =
     if Int.equal n 0 then l,c
     else
@@ -318,7 +318,7 @@ let decompose_lam_n_decls sigma n =
       | Lambda (x,t,c)  -> lamdec_rec (Context.Rel.add (LocalAssum (x,t)) l) (n-1) c
       | LetIn (x,b,t,c) -> lamdec_rec (Context.Rel.add (LocalDef (x,b,t)) l) (n-1) c
       | Cast (c,_,_)      -> lamdec_rec l n c
-      | c -> error "decompose_lam_n_decls: not enough abstractions"
+      | c -> user_err Pp.(str "decompose_lam_n_decls: not enough abstractions")
   in
   lamdec_rec Context.Rel.empty n
 
@@ -363,7 +363,7 @@ let decompose_prod_assum sigma c =
 let decompose_prod_n_assum sigma n c =
   let open Rel.Declaration in
   if n < 0 then
-    error "decompose_prod_n_assum: integer parameter must be positive";
+    user_err Pp.(str "decompose_prod_n_assum: integer parameter must be positive");
   let rec prodec_rec l n c =
     if Int.equal n 0 then l,c
     else
@@ -371,7 +371,7 @@ let decompose_prod_n_assum sigma n c =
       | Prod (x,t,c)    -> prodec_rec (Context.Rel.add (LocalAssum (x,t)) l) (n-1) c
       | LetIn (x,b,t,c) -> prodec_rec (Context.Rel.add (LocalDef (x,b,t)) l) (n-1) c
       | Cast (c,_,_)      -> prodec_rec l n c
-      | c -> error "decompose_prod_n_assum: not enough assumptions"
+      | c -> user_err Pp.(str "decompose_prod_n_assum: not enough assumptions")
   in
   prodec_rec Context.Rel.empty n c
 
diff --git a/engine/evd.ml b/engine/evd.ml
index 8ade6cb99..b677705bc 100644
--- a/engine/evd.ml
+++ b/engine/evd.ml
@@ -952,7 +952,7 @@ let declare_principal_goal evk evd =
   | None -> { evd with
     future_goals = evk::evd.future_goals;
     principal_future_goal=Some evk; }
-  | Some _ -> CErrors.error "Only one main subgoal per instantiation."
+  | Some _ -> CErrors.user_err Pp.(str "Only one main subgoal per instantiation.")
 
 let future_goals evd = evd.future_goals
 
diff --git a/engine/proofview.ml b/engine/proofview.ml
index 7f80d40d6..ddfc0e39d 100644
--- a/engine/proofview.ml
+++ b/engine/proofview.ml
@@ -289,7 +289,7 @@ let tclONCE = Proof.once
 
 exception MoreThanOneSuccess
 let _ = CErrors.register_handler begin function
-  | MoreThanOneSuccess -> CErrors.error "This tactic has more than one success."
+  | MoreThanOneSuccess -> CErrors.user_err Pp.(str "This tactic has more than one success.")
   | _ -> raise CErrors.Unhandled
 end
 
diff --git a/engine/uState.ml b/engine/uState.ml
index dc6822057..acef90143 100644
--- a/engine/uState.ml
+++ b/engine/uState.ml
@@ -188,7 +188,7 @@ let process_universe_constraints ctx cstrs =
               | _ -> local
             else
               begin match Univ.Universe.level r with
-              | None -> error ("Algebraic universe on the right")
+              | None -> user_err Pp.(str "Algebraic universe on the right")
               | Some r' ->
                 if Univ.Level.is_small r' then
                   let levels = Univ.Universe.levels l in