eval: prohibit variable sized types in concat expressions

Since we need to calculate the length of the entire concat type, we can
not support variable sized types where the length can't be determined
by the type.

This only affects base types since all higher types include a length.

Signed-off-by: Patrick McHardy <kaber@trash.net>

1 files changed, 7 insertions, 0 deletions

diff --git a/src/evaluate.c b/src/evaluate.c
index e260a803..d99b38f4 100644
--- a/src/evaluate.c
+++ b/src/evaluate.c
@@ -620,6 +620,13 @@ static int expr_evaluate_concat(struct eval_ctx *ctx, struct expr **expr)
 						 "expecting %s",
 						 dtype->desc);
 
+		if (dtype == NULL && i->dtype->size == 0)
+			return expr_binary_error(ctx->msgs, i, *expr,
+						 "can not use variable sized "
+						 "data types (%s) in concat "
+						 "expressions",
+						 i->dtype->name);
+
 		tmp = concat_subtype_lookup(type, --off);
 		expr_set_context(&ctx->ectx, tmp, tmp->size);