From 9d32d891087bde292ec53783f9c9a8d95fd87add Mon Sep 17 00:00:00 2001
From: Alain Frisch <alain@frisch.fr>
Date: Fri, 29 Jun 2012 09:49:52 +0000
Subject: [PATCH] Better error report.

git-svn-id: http://caml.inria.fr/svn/ocaml/trunk@12654 f963ae5c-01c2-4b8c-9fe0-0dff7051ff02
---
 experimental/frisch/ifdef.ml      | 6 ++++--
 experimental/frisch/test_ifdef.ml | 4 +++-
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/experimental/frisch/ifdef.ml b/experimental/frisch/ifdef.ml
index 166736032..78278f71e 100644
--- a/experimental/frisch/ifdef.ml
+++ b/experimental/frisch/ifdef.ml
@@ -27,8 +27,10 @@ let ifdef =
            else
              this # module_expr body_not_def
 
-      | {pmod_desc = Pmod_ident {txt = Lident "IFDEF"}} ->
-          failwith "Improper use of IFDEF" (* todo: location *)
+      | {pmod_desc = Pmod_ident {txt = Lident "IFDEF"}; pmod_loc = loc} ->
+          Format.printf "%a@.Improper use of IFDEF. The correct form is: IFDEF(<var_name:uident>)(<then:modtype>)(<body:modtype>)@."
+            Location.print_loc loc;
+          exit 2
       | x -> super # module_expr x
   end
 
diff --git a/experimental/frisch/test_ifdef.ml b/experimental/frisch/test_ifdef.ml
index 77fe01568..18fdaf87a 100644
--- a/experimental/frisch/test_ifdef.ml
+++ b/experimental/frisch/test_ifdef.ml
@@ -1,5 +1,7 @@
 include IFDEF(XHOME)(struct
   let () = print_endline "Defined!"
-end)(struct
+end)
+(*(struct
   let () = print_endline "Not defined!"
 end)
+*)