diff --git a/completions/cvs b/completions/cvs
index 9c3cabfb..0a397a48 100644
--- a/completions/cvs
+++ b/completions/cvs
@@ -282,7 +282,7 @@ _cvs()
             ;;
         diff)
             if [[ "$cur" == -* ]]; then
-                _longopt diff
+                _cvs_command_options "$1" $mode
             else
                 get_entries
                 COMPREPLY=( $( compgen -W '${entries[@]:-}' -- "$cur" ) )