Given: ```vim syn match foo +\(\\\\\|.\)\{-}[^\\]"+ ``` Results in: > t-synerror.vim:1:25:Error: EVP_E492: Not an editor command: \)\{-}[^\\]"+ It seems to mistake the (escaped) "|" for a command separator (bar) therein. (seen in Vim's own `syntax/vim.vim`: https://github.com/blueyed/vim/blob/a4f4d62696782db3aa336e0bc576ddf5263ff36a/runtime/syntax/vim.vim#L310)