diff --git a/src/context.c b/src/context.c
index 06d56a5..3c84143 100644
--- a/src/context.c
+++ b/src/context.c
@@ -365,7 +365,7 @@ apfl_list_append_list(apfl_ctx ctx, apfl_stackidx dst_index, apfl_stackidx src_i
         return APFL_RESULT_ERR;
     }
 
-    if (dst_val->type != VALUE_LIST) {
+    if (src_val.type != VALUE_LIST) {
         assert(apfl_stack_drop(ctx, src_index));
         return APFL_RESULT_ERR;
     }