vim-patch:8.2.2533: Vim9: cannot use a range with :unlet

Problem:    Vim9: cannot use a range with :unlet.
Solution:   Implement ISN_UNLETRANGE.

https://github.com/vim/vim/commit/5b5ae29bd3d7b832b6f15320430f7f191e0abd1f

Co-authored-by: Bram Moolenaar <Bram@vim.org>

1 files changed, 28 insertions, 18 deletions

diff --git a/src/nvim/eval/vars.c b/src/nvim/eval/vars.c
index 0663c3c54c..f988a49e6c 100644
--- a/src/nvim/eval/vars.c
+++ b/src/nvim/eval/vars.c
@@ -1056,25 +1056,10 @@ static int do_unlet_var(lval_T *lp, char *name_end, exarg_T *eap, int deep FUNC_
                                      lp->ll_name_len))) {
     return FAIL;
   } else if (lp->ll_range) {
-    assert(lp->ll_list != NULL);
-    // Delete a range of List items.
-    listitem_T *const first_li = lp->ll_li;
-    listitem_T *last_li = first_li;
-    while (true) {
-      listitem_T *const li = TV_LIST_ITEM_NEXT(lp->ll_list, lp->ll_li);
-      if (value_check_lock(TV_LIST_ITEM_TV(lp->ll_li)->v_lock,
-                           lp->ll_name,
-                           lp->ll_name_len)) {
-        return false;
-      }
-      lp->ll_li = li;
-      lp->ll_n1++;
-      if (lp->ll_li == NULL || (!lp->ll_empty2 && lp->ll_n2 < lp->ll_n1)) {
-        break;
-      }
-      last_li = lp->ll_li;
+    if (list_unlet_range(lp->ll_list, lp->ll_li, lp->ll_name, lp->ll_name_len,
+                         lp->ll_n1, !lp->ll_empty2, lp->ll_n2) == FAIL) {
+      return FAIL;
     }
-    tv_list_remove_items(lp->ll_list, first_li, last_li);
   } else {
     if (lp->ll_list != NULL) {
       // unlet a List item.
@@ -1107,6 +1092,31 @@ static int do_unlet_var(lval_T *lp, char *name_end, exarg_T *eap, int deep FUNC_
   return ret;
 }
 
+/// Unlet one item or a range of items from a list.
+/// Return OK or FAIL.
+static int list_unlet_range(list_T *const l, listitem_T *const li_first, const char *const name,
+                            const size_t name_len, const long n1_arg, const bool has_n2,
+                            const long n2)
+{
+  assert(l != NULL);
+  // Delete a range of List items.
+  listitem_T *li_last = li_first;
+  long n1 = n1_arg;
+  while (true) {
+    if (value_check_lock(TV_LIST_ITEM_TV(li_last)->v_lock, name, name_len)) {
+      return FAIL;
+    }
+    listitem_T *const li = TV_LIST_ITEM_NEXT(l, li_last);
+    n1++;
+    if (li == NULL || (has_n2 && n2 < n1)) {
+      break;
+    }
+    li_last = li;
+  }
+  tv_list_remove_items(l, li_first, li_last);
+  return OK;
+}
+
 /// unlet a variable
 ///
 /// @param[in]  name  Variable name to unlet.