diff --git a/src/eval.c b/src/eval.c
index bd8e7cf..c2856fe 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -2050,7 +2050,7 @@
 	var2.v_type = VAR_UNKNOWN;
     }
 
-    if (lp->ll_tuple != NULL)
+    if (lp->ll_tuple != NULL && (flags & GLV_READ_ONLY) == 0)
     {
 	if (!quiet)
 	    emsg(_(e_tuple_is_immutable));