# HG changeset patch
# User Bram Moolenaar <Bram@vim.org>
# Date 1618082104 -7200
# Node ID e0fa539a9b349f55e17b29080d28ffbdc2334d6d
# Parent  05c9ccb777ecddc17d93d68a3be7163532ad01df
patch 8.2.2750: Vim9: error for using underscore in nested function

Commit: https://github.com/vim/vim/commit/da479c7597a61c4d50c842df21c9294bd9bf1037
Author: Bram Moolenaar <Bram@vim.org>
Date:   Sat Apr 10 21:01:38 2021 +0200

    patch 8.2.2750: Vim9: error for using underscore in nested function

    Problem:    Vim9: error for using underscore in nested function.
    Solution:   Do not consider "_" already defined. (closes https://github.com/vim/vim/issues/8096)

diff --git a/src/testdir/test_vim9_func.vim b/src/testdir/test_vim9_func.vim
--- a/src/testdir/test_vim9_func.vim
+++ b/src/testdir/test_vim9_func.vim
@@ -2637,6 +2637,8 @@ def Test_ignored_argument()
         return _
       endfunc
       assert_equal('too', Oktoo())
+
+      assert_equal([[1], [2], [3]], range(3)->mapnew((_, v) => [v]->map((_, w) => w + 1)))
   END
   CheckScriptSuccess(lines)
 
diff --git a/src/version.c b/src/version.c
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@ static char *(features[]) =
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2750,
+/**/
     2749,
 /**/
     2748,
diff --git a/src/vim9compile.c b/src/vim9compile.c
--- a/src/vim9compile.c
+++ b/src/vim9compile.c
@@ -422,6 +422,10 @@ check_defined(char_u *p, size_t len, cct
     int		c = p[len];
     ufunc_T	*ufunc = NULL;
 
+    // underscore argument is OK
+    if (len == 1 && *p == '_')
+	return OK;
+
     if (script_var_exists(p, len, cctx) == OK)
     {
 	if (is_arg)