:help undercurl states:
"undercurl" is a curly underline. When "undercurl" is not possible then "underline" is used. In general "undercurl" and "strikethrough" is only available in the GUI.
But if I run Vim with
vim --clean and then issue the following commands, then the text
curl is not highlighted in any way:
:hi Curl cterm=undercurl :match Curl /curl/
However, if I change
curl is now underlined:
:hi Curl cterm=underline
Is the documentation wrong? Or am I just misinterpreting it?*
Or is the problem that Vim thinks that undercurl is possible and is therefore (unsuccessfully) attempting to use it? If this is the case, then what causes this?
:set t_Cs? and
:set t_Ce? both report that the settings are not set:
I'm running Vim 8.0.1420 inside iTerm2 v3.2.6 on macOS.
* It could be read to mean that there are some circumstances when undercurl is available but isn't possible and only in those cases will it be replaced with an underline.