diff --git a/src/keyboard.c b/src/keyboard.c
index e9a9cd30d6b..894ecbda056 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -4578,7 +4578,7 @@ The elements of this list correspond to the arguments of\n\
   val[0] = interrupt_input ? Qt : Qnil;
   val[1] = flow_control ? Qt : Qnil;
   val[2] = meta_key == 2 ? make_number (0) : meta_key == 1 ? Qt : Qnil;
-  XFASTINT (val[3], quit_char);
+  XFASTINT (val[3]) = quit_char;
 
   return Flist (val, sizeof (val) / sizeof (val[0]));
 }