patch 8.2.2846: Vim9: "echo Func()" does not give an error for using void Commit: https://github.com/vim/vim/commit/68db996b621b98066fb7ab7028ed5c6aaa3954a8 Author: Bram Moolenaar <Bram@vim.org> Date: Sun May 9 23:19:22 2021 +0200 patch 8.2.2846: Vim9: "echo Func()" does not give an error for using void Problem: Vim9: "echo Func()" does not give an error for a function without a return value. Solution: Give an error. Be more specific about why a value is invalid.

INIT
WANTSTATE f
RESET

!Unrecognised control 
PUSH "\x03"
  control 03

!Unrecognised CSI
PUSH "\e[?15;2z"
  csi 0x7a L=3f 15,2

!Unrecognised OSC
PUSH "\e]27;Something\e\\"
  osc [27 "Something"]

!Unrecognised DCS
PUSH "\ePz123\e\\"
  dcs ["z123"]