(Fdefvar): Warn when var is let-bound but globally void.

2 files changed, 25 insertions, 8 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 0d74afca197..cd09604d4e2 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,7 @@
+2004-11-22  Stefan Monnier  <monnier@iro.umontreal.ca>
+
+        * eval.c (Fdefvar): Warn when var is let-bound but globally void.
+
 2004-11-21  Kim F. Storm  <storm@cua.dk>
 
         * xdisp.c (erase_phys_cursor): Clear hollow cursor inside TEXT_AREA.
@@ -11,9 +15,9 @@
         * macterm.c (x_clip_to_row): Add area arg.  Callers changed.
         (x_draw_hollow_cursor, x_draw_bar_cursor): Clip to TEXT_AREA.
 
-        * xdisp.c (move_it_in_display_line_to, display_line): Restore
-        saved_face_id if overflow-newline-into-fringe is enabled and line
-        is continued before or in middle of element from display vector.
+        * xdisp.c (move_it_in_display_line_to, display_line):
+        Restore saved_face_id if overflow-newline-into-fringe is enabled and
+        line is continued before or in middle of element from display vector.
 
         * indent.c (Fvertical_motion): Fix last change.  Use another
         method to detect if iterator moved too far ahead after reseat.
@@ -27,8 +31,7 @@
 
 2004-11-20  Luc Teirlinck  <teirllm@auburn.edu>
 
-        * fns.c (Fyes_or_no_p): Call Fread_from_minibuffer with extra
-        argument.
+        * fns.c (Fyes_or_no_p): Call Fread_from_minibuffer with extra argument.
         * callint.c (Fcall_interactively): Ditto.
 
 2004-11-20  Stefan Monnier  <monnier@iro.umontreal.ca>
@@ -44,7 +47,7 @@
         (Fread_from_minibuffer): New arg KEEP_ALL.  Callers changed.
 
         * search.c (Vsearch_spaces_regexp):
-        Renamed from Vsearch_whitespace_regexp.  All uses changed.
+        Rename from Vsearch_whitespace_regexp.  All uses changed.
 
 2004-11-20  Thien-Thi Nguyen  <ttn@gnu.org>
 
@@ -86,8 +89,7 @@
 
 2004-11-16  Jan Dj,Ad(Brv  <jan.h.d@swipnet.se>
 
-        * gtkutil.c (xg_get_file_name): Fix typo in
-        HAVE_GTK_FILE_SELECTION_NEW.
+        * gtkutil.c (xg_get_file_name): Typo in HAVE_GTK_FILE_SELECTION_NEW.
 
         * xmenu.c (x_menu_in_use): Remove.
         (x_menu_set_in_use): Also set popup_activated_flag.
diff --git a/src/eval.c b/src/eval.c
index adff3e8670c..e8a8e4668e4 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -786,6 +786,21 @@ usage: (defvar SYMBOL &optional INITVALUE DOCSTRING)  */)
     {
       if (NILP (tem))
         Fset_default (sym, Feval (Fcar (tail)));
+      else
+        { /* Check if there is really a global binding rather than just a let
+             binding that shadows the global unboundness of the var.  */
+          struct specbinding *pdl = specpdl_ptr;
+          while (--pdl >= specpdl)
+            {
+              if (EQ (pdl->symbol, sym) && !pdl->func
+                  && EQ (pdl->old_value, Qunbound))
+                {
+                  message_with_string ("Warning: defvar ignored because %s is let-bound",
+                                       SYMBOL_NAME (sym), 1);
+                  break;
+                }
+            }
+        }
       tail = Fcdr (tail);
       tem = Fcar (tail);
       if (!NILP (tem))