patch 8.2.1931: Vim9: arguments of extend() not checked at compile time Commit: https://github.com/vim/vim/commit/fbcbffe1ad327f4f0da518abfd5fd7be7fec22b5 Author: Bram Moolenaar <Bram@vim.org> Date: Sat Oct 31 19:33:38 2020 +0100 patch 8.2.1931: Vim9: arguments of extend() not checked at compile time Problem: Vim9: arguments of extend() not checked at compile time. Solution: Add argument type checking for extend().