patch 8.1.1844: buffer no longer unloaded when adding text properties commit https://github.com/vim/vim/commit/45311b5274a6ac6e44235dfd4588c6b1bf0d4850 Author: Bram Moolenaar <Bram@vim.org> Date: Tue Aug 13 22:27:32 2019 +0200 patch 8.1.1844: buffer no longer unloaded when adding text properties Problem: Buffer no longer unloaded when adding text properties to it. Solution: Do not create the memfile. (closes https://github.com/vim/vim/issues/4808)

function Test_Comparators()
  try
    let oldisident=&isident
    set isident+=#
    call assert_equal(1, 1 is#1)
  finally
    let &isident=oldisident
  endtry
endfunction