diff --git a/src/textprop.c b/src/textprop.c
index 539269b48dd..78ff080d97e 100644
--- a/src/textprop.c
+++ b/src/textprop.c
@@ -159,6 +159,7 @@ validate_interval_range (object, begin, end, force)
 
 static Lisp_Object
 validate_plist (list)
+     Lisp_Object list;
 {
   if (NILP (list))
     return Qnil;