patch 8.2.3423: Vim9: list += list creates a new list in :def function
Problem: Vim9: list += list creates a new list in :def function.
Solution: Append to the existing list.
diff --git a/src/vim9execute.c b/src/vim9execute.c
index fdca977..9fc942d 100644
--- a/src/vim9execute.c
+++ b/src/vim9execute.c
@@ -3677,7 +3677,14 @@
// add two lists or blobs
if (iptr->isn_type == ISN_ADDLIST)
- eval_addlist(tv1, tv2);
+ {
+ if (iptr->isn_arg.op.op_type == EXPR_APPEND
+ && tv1->vval.v_list != NULL)
+ list_extend(tv1->vval.v_list, tv2->vval.v_list,
+ NULL);
+ else
+ eval_addlist(tv1, tv2);
+ }
else
eval_addblob(tv1, tv2);
clear_tv(tv2);