patch 8.2.1142: Vim9: return type of insert() is any
Problem: Vim9: return type of insert() is any.
Solution: Use type of the first argument.
diff --git a/src/testdir/test_vim9_func.vim b/src/testdir/test_vim9_func.vim
index 8b83d77..65b5257 100644
--- a/src/testdir/test_vim9_func.vim
+++ b/src/testdir/test_vim9_func.vim
@@ -918,6 +918,15 @@
assert_equal(6, res)
enddef
+def Test_insert_return_type()
+ let l = insert([2, 1], 3)
+ let res = 0
+ for n in l
+ res += n
+ endfor
+ assert_equal(6, res)
+enddef
+
def Test_filter_return_type()
let l = filter([1, 2, 3], {-> 1})
let res = 0