patch 8.1.0141: :cexpr no longer jumps to the first error

Problem:    :cexpr no longer jumps to the first error.
Solution:   Use the quickfix list identifier. (Yegappan Lakshmanan,
            closes #3092)

src/testdir/test_quickfix.vim

@@ -3363,13 +3363,124 @@ func Test_lbuffer_with_bwipe()
   augroup END
 endfunc
 
-func Test_setloclist_in_aucmd()
+" Test for an autocmd freeing the quickfix/location list when cexpr/lexpr is
+" running
+func Xexpr_acmd_freelist(cchar)
+  call s:setup_commands(a:cchar)
+
   " This was using freed memory.
   augroup nasty
-    au * * call setloclist(0, [], 'f')
+    au * * call g:Xsetlist([], 'f')
   augroup END
-  lexpr "x"
+  Xexpr "x"
   augroup nasty
     au!
   augroup END
 endfunc
+
+func Test_cexpr_acmd_freelist()
+  call Xexpr_acmd_freelist('c')
+  call Xexpr_acmd_freelist('l')
+endfunc
+
+" Test for commands that create a new quickfix/location list and jump to the
+" first error automatically.
+func Xjumpto_first_error_test(cchar)
+  call s:setup_commands(a:cchar)
+
+  call s:create_test_file('Xtestfile1')
+  call s:create_test_file('Xtestfile2')
+  let l = ['Xtestfile1:2:Line2', 'Xtestfile2:4:Line4']
+
+  " Test for cexpr/lexpr
+  enew
+  Xexpr l
+  call assert_equal('Xtestfile1', bufname(''))
+  call assert_equal(2, line('.'))
+
+  " Test for cfile/lfile
+  enew
+  call writefile(l, 'Xerr')
+  Xfile Xerr
+  call assert_equal('Xtestfile1', bufname(''))
+  call assert_equal(2, line('.'))
+
+  " Test for cbuffer/lbuffer
+  edit Xerr
+  Xbuffer
+  call assert_equal('Xtestfile1', bufname(''))
+  call assert_equal(2, line('.'))
+
+  call delete('Xerr')
+  call delete('Xtestfile1')
+  call delete('Xtestfile2')
+endfunc
+
+func Test_jumpto_first_error()
+  call Xjumpto_first_error_test('c')
+  call Xjumpto_first_error_test('l')
+endfunc
+
+" Test for a quickfix autocmd changing the quickfix/location list before
+" jumping to the first error in the new list.
+func Xautocmd_changelist(cchar)
+  call s:setup_commands(a:cchar)
+
+  " Test for cfile/lfile
+  call s:create_test_file('Xtestfile1')
+  call s:create_test_file('Xtestfile2')
+  Xexpr 'Xtestfile1:2:Line2'
+  autocmd QuickFixCmdPost * Xolder
+  call writefile(['Xtestfile2:4:Line4'], 'Xerr')
+  Xfile Xerr
+  call assert_equal('Xtestfile2', bufname(''))
+  call assert_equal(4, line('.'))
+  autocmd! QuickFixCmdPost
+
+  " Test for cbuffer/lbuffer
+  call g:Xsetlist([], 'f')
+  Xexpr 'Xtestfile1:2:Line2'
+  autocmd QuickFixCmdPost * Xolder
+  call writefile(['Xtestfile2:4:Line4'], 'Xerr')
+  edit Xerr
+  Xbuffer
+  call assert_equal('Xtestfile2', bufname(''))
+  call assert_equal(4, line('.'))
+  autocmd! QuickFixCmdPost
+
+  " Test for cexpr/lexpr
+  call g:Xsetlist([], 'f')
+  Xexpr 'Xtestfile1:2:Line2'
+  autocmd QuickFixCmdPost * Xolder
+  Xexpr 'Xtestfile2:4:Line4'
+  call assert_equal('Xtestfile2', bufname(''))
+  call assert_equal(4, line('.'))
+  autocmd! QuickFixCmdPost
+
+  " Test for grep/lgrep
+  call g:Xsetlist([], 'f')
+  Xexpr 'Xtestfile1:2:Line2'
+  autocmd QuickFixCmdPost * Xolder
+  silent Xgrep Line5 Xtestfile2
+  call assert_equal('Xtestfile2', bufname(''))
+  call assert_equal(5, line('.'))
+  autocmd! QuickFixCmdPost
+
+  " Test for vimgrep/lvimgrep
+  call g:Xsetlist([], 'f')
+  Xexpr 'Xtestfile1:2:Line2'
+  autocmd QuickFixCmdPost * Xolder
+  silent Xvimgrep Line5 Xtestfile2
+  call assert_equal('Xtestfile2', bufname(''))
+  call assert_equal(5, line('.'))
+  autocmd! QuickFixCmdPost
+
+  call delete('Xerr')
+  call delete('Xtestfile1')
+  call delete('Xtestfile2')
+endfunc
+
+func Test_autocmd_changelist()
+  call Xautocmd_changelist('c')
+  call Xautocmd_changelist('l')
+endfunc