Address #4165: provide a highlight group for the detailed diagnostic …

…popup

This seems to work, but I have a few questions

  - What tests should I look at to understand how to write one for this
    change?
  - Are you happy with the name `YcmErrorPopup`?
  - What should I set as `'priority'`, `'combine'`, `'override'`?

autoload/youcompleteme.vim

@@ -512,6 +512,17 @@ function! s:SetUpSyntaxHighlighting()
           \ 'combine': 0,
           \ 'override': 1 } )
   endif
+
+  if !hlexists( 'YcmErrorPopup' )
+    highlight default link YcmErrorPopup ErrorMsg
+  endif
+  if s:PropertyTypeNotDefined( 'YcmErrorProperty' )
+    call prop_type_add( 'YcmErrorProperty', {
+          \ 'highlight': 'YcmErrorPopup',
+          \ 'priority': 30,
+          \ 'combine': 0,
+          \ 'override': 1 } )
+  endif
 endfunction
 
 

python/ycm/youcompleteme.py

@@ -849,7 +849,7 @@ def ShowDetailedDiagnostic( self, message_in_popup ):
           'maxwidth': available_columns,
           'close': 'click',
           'fixed': 0,
-          'highlight': 'ErrorMsg',
+          'highlight': 'YcmErrorPopup',
           'border': [ 1, 1, 1, 1 ],
           # Close when moving cursor
           'moved': 'expr',