Normalize the representation so the expressions list in EXPR_SET always
contains EXPR_SET_ELEM. Add assert() to validate this.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 src/evaluate.c     | 3 ++-
 src/parser_bison.y | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/evaluate.c b/src/evaluate.c
index 3ed6f1b3f8ca..b0a3e990e476 100644
--- a/src/evaluate.c
+++ b/src/evaluate.c
@@ -2059,7 +2059,8 @@ static int expr_evaluate_set(struct eval_ctx *ctx, struct expr **expr)
 	const struct expr *elem;
 
 	list_for_each_entry_safe(i, next, &expr_set(set)->expressions, list) {
-		/* recursive EXPR_SET are merged here. */
+		assert(i->etype == EXPR_SET_ELEM);
+
 		if (list_member_evaluate(ctx, &i) < 0)
 			return -1;
 
diff --git a/src/parser_bison.y b/src/parser_bison.y
index d0cb2f7f929f..dcbdc4514298 100644
--- a/src/parser_bison.y
+++ b/src/parser_bison.y
@@ -4599,7 +4599,7 @@ set_list_expr		:	set_list_member_expr
 
 set_list_member_expr	:	opt_newline	set_expr	opt_newline
 			{
-				$$ = $2;
+				$$ = set_elem_expr_alloc(&@$, $2);
 			}
 			|	opt_newline	set_elem_expr	opt_newline
 			{
-- 
2.30.2