* eval.c (Fprogn): Check that BODY is a proper list.

1 files changed, 8 insertions, 0 deletions

diff --git a/etc/NEWS b/etc/NEWS
index facadac5c1c..e7d51a4033a 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -538,6 +538,14 @@ file using `set-file-extended-attributes'.
 ** `visited-file-modtime' now returns -1 for nonexistent files.
 Formerly it returned a list (-1 LOW USEC PSEC), but this was ambiguous
 in the presence of files with negative time stamps.
+
+** Special forms with implied progn now check for proper lists.
+Starting in Emacs 21.4, a special form with an implied progn of an
+improper list ignored the trailing value, treating it as nil.  For
+example, (cond (t (message "hello") . "there")) ignored the "there".
+This inadvertent change to Emacs's behavior has been reverted, and
+Emacs now signals an error for these improper forms, as it did in
+version 21.3 and earlier.
 
 * Lisp Changes in Emacs 24.4