patch 8.1.1723: heredoc assignment has no room for new features commit https://github.com/vim/vim/commit/24582007294b0db3be9669d3b583ea45fc4f19b8 Author: Bram Moolenaar <Bram@vim.org> Date: Sun Jul 21 14:14:26 2019 +0200 patch 8.1.1723: heredoc assignment has no room for new features Problem: Heredoc assignment has no room for new features. (FUJIWARA Takuya) Solution: Require the marker does not start with a lower case character. (closes #4705)

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