Allow highlighting while popup menu is visible

autoload/matchup.vim

@@ -26,6 +26,7 @@ function! s:init_options()
   call s:init_option('matchup_matchparen_deferred_show_delay', 50)
   call s:init_option('matchup_matchparen_deferred_hide_delay', 700)
   call s:init_option('matchup_matchparen_stopline', 400)
+  call s:init_option('matchup_matchparen_pumvisible', 1)
 
   call s:init_option('matchup_matchparen_timeout',
     \ get(g:, 'matchparen_timeout', 300))

autoload/matchup/matchparen.vim

@@ -187,6 +187,8 @@ function! s:matchparen.highlight(...) abort dict " {{{1
 
   if has('vim_starting') | return | endif
 
+  if !g:matchup_matchparen_pumvisible && pumvisible() | return | endif
+
   if !get(b:, 'matchup_matchparen_enabled', 1)
         \ && get(b:, 'matchup_matchparen_fallback', 1) && s:pi_paren_sid()
     return call(s:pi_paren_fcn, [])
@@ -194,8 +196,6 @@ function! s:matchparen.highlight(...) abort dict " {{{1
 
   if !get(b:, 'matchup_matchparen_enabled', 1) | return | endif
 
-  if pumvisible() | return | endif
-
   let l:force_update    = a:0 >= 1 ? a:1 : 0
   let l:entering_insert = a:0 >= 2 ? a:2 : 0
 

doc/matchup.txt

@@ -522,6 +522,14 @@ will only work in nvim-0.2.1 and after.
 
   Defaults: 50, 700
 
+*g:matchup_matchparen_pumvisible*
+
+  If set to 1, matches will be made even when the |popupmenu-completion| is
+  visible.  If you use an auto-complete plugin which interacts badly with
+  matching, set this option to 0.
+
+  Default: 1
+
 Module motion~
 
 *g:matchup_motion_override_Npercent*