How to get vim syntax highlighting to work along with concealing?

Question

I'm using HaskellConcealPlus to conceal certain elements of Haskell code, and haskell.vim from here to get better syntax highlighting for Haskell. Below is what it looks like :

The problem is that the div, after being concealed, loses it's orange highlighting, which leads to inconsistency when '/' is highlighted orange, but '÷' is white, even though they're both infix operators. Is there a way to get the syntax highlighting and concealing to both work?

Answer 1

As soon as parts of text get concealed they get colorized as defined by the highlighting group Conceal. :help hl-Conceal will tell you more details about the group. :highlight will show you all highlight groups and their color declarations. E.g. my conceal group looks like as shown below:

Conceal        xxx ctermfg=4 ctermbg=0 guifg=#8fa1b3 guibg=#2b303b

In order to get more decent colors you can of course set a custom color and properties for your conceal group inside your .vimrc. Below is an example which will use bold, underlined text, uses ANSI color 9 as the foreground color and ANSI color 0 as a background color for all files with an hs extension:

augroup AdjustConceal
    autocmd!
    autocmd ColorScheme *.hs highlight Conceal cterm=bold,underline ctermfg=9 ctermbg=0
augroup END

Alternatively you could simply link to an existing highlighting group. The example below would link from Conceal to Search:

augroup AdjustConceal
    autocmd!
    autocmd ColorScheme *.hs highlight link Conceal Search
augroup END