patch 8.1.0019: error when defining a Lambda with index of a function result commit https://github.com/vim/vim/commit/b4518563c73460150344a57879bf5b22cb8b1c77 Author: Bram Moolenaar <Bram@vim.org> Date: Tue May 22 18:31:35 2018 +0200 patch 8.1.0019: error when defining a Lambda with index of a function result Problem: Error when defining a Lambda with index of a function result. Solution: When not evaluating an expression and skipping a function call, set the return value to VAR_UNKNOWN.

--- a/src/testdir/test_lambda.vim
+++ b/src/testdir/test_lambda.vim
@@ -284,3 +284,9 @@ func Test_named_function_closure()
   call test_garbagecollect_now()
   call assert_equal(14, s:Abar())
 endfunc
+
+func Test_lambda_with_index()
+  let List = {x -> [x]}
+  let Extract = {-> function(List, ['foobar'])()[0]}
+  call assert_equal('foobar', Extract())
+endfunc