patch 7.4.1740
Problem: syn-cchar defined with matchadd() does not appear if there are no
other syntax definitions which matches buffer text.
Solution: Check for startcol. (Ozaki Kiichi, haya14busa, closes #757)
diff --git a/src/testdir/test_matchadd_conceal_utf8.vim b/src/testdir/test_matchadd_conceal_utf8.vim
new file mode 100644
index 0000000..8293fbe
--- /dev/null
+++ b/src/testdir/test_matchadd_conceal_utf8.vim
@@ -0,0 +1,45 @@
+" Test for matchadd() and conceal feature using utf-8.
+if !has('conceal') || !has('multi_byte')
+ finish
+endif
+set encoding=utf-8
+scriptencoding utf-8
+
+if !has('gui_running') && has('unix')
+ set term=ansi
+endif
+
+function! s:screenline(lnum) abort
+ let line = []
+ for c in range(1, winwidth(0))
+ call add(line, nr2char(screenchar(a:lnum, c)))
+ endfor
+ return s:trim(join(line, ''))
+endfunction
+
+function! s:trim(str) abort
+ return matchstr(a:str,'^\s*\zs.\{-}\ze\s*$')
+endfunction
+
+function! Test_match_using_multibyte_conceal_char()
+ new
+ setlocal concealcursor=n conceallevel=1
+
+ 1put='# This is a Test'
+ " 1234567890123456
+ let expect = '#ˑThisˑisˑaˑTest'
+
+ call cursor(1, 1)
+ call matchadd('Conceal', '\%2l ', 20, -1, {'conceal': "\u02d1"})
+ redraw!
+
+ let lnum = 2
+ call assert_equal(expect, s:screenline(lnum))
+ call assert_notequal(screenattr(lnum, 1), screenattr(lnum, 2))
+ call assert_equal(screenattr(lnum, 2), screenattr(lnum, 7))
+ call assert_equal(screenattr(lnum, 2), screenattr(lnum, 10))
+ call assert_equal(screenattr(lnum, 2), screenattr(lnum, 12))
+ call assert_equal(screenattr(lnum, 1), screenattr(lnum, 16))
+
+ quit!
+endfunction