diff --git a/src/testdir/test_assert.vim b/src/testdir/test_assert.vim
index a3b45a1..1a18799 100644
--- a/src/testdir/test_assert.vim
+++ b/src/testdir/test_assert.vim
@@ -341,8 +341,8 @@
   call test_override('char_avail', 1)
   eval 1->test_override('redraw')
   call test_override('ALL', 0)
-  call assert_fails("call test_override('xxx', 1)", 'E475')
-  call assert_fails("call test_override('redraw', 'yes')", 'E474')
+  call assert_fails("call test_override('xxx', 1)", 'E475:')
+  call assert_fails("call test_override('redraw', 'yes')", 'E474:')
 endfunc
 
 func Test_mouse_position()
diff --git a/src/testdir/test_autocmd.vim b/src/testdir/test_autocmd.vim
index 73674a2..b7067a7 100644
--- a/src/testdir/test_autocmd.vim
+++ b/src/testdir/test_autocmd.vim
@@ -468,7 +468,7 @@
   call writefile(content, 'Xvimrc')
   call system(GetVimCommand('Xvimrc') .. ' --not-a-term --noplugins -S Session.vim -c cq')
   let errors = join(readfile('Xerrors'))
-  call assert_match('E814', errors)
+  call assert_match('E814:', errors)
 
   set swapfile
   for file in ['Session.vim', 'Xvimrc', 'Xerrors']
@@ -638,7 +638,7 @@
   " try twice, first time, shouldn't trigger because option name is invalid,
   " second time, it should trigger
   let bnum = bufnr('%')
-  call assert_fails("call setbufvar(bnum, '&l:bk', 1)", "E355")
+  call assert_fails("call setbufvar(bnum, '&l:bk', 1)", 'E355:')
   " should trigger, use correct option name
   call setbufvar(bnum, '&backup', 1)
   call assert_equal([], g:options)
@@ -1175,15 +1175,15 @@
   au OptionSet diff close
 
   call setline(1, ['buffer 1', 'line2', 'line3', 'line4'])
-  call assert_fails(':diffthis', 'E788')
+  call assert_fails(':diffthis', 'E788:')
   call assert_equal(1, &diff)
   vnew
   call setline(1, ['buffer 2', 'line 2', 'line 3', 'line4'])
-  call assert_fails(':diffthis', 'E788')
+  call assert_fails(':diffthis', 'E788:')
   call assert_equal(1, &diff)
   set diffopt-=closeoff
   bw!
-  call assert_fails(':diffoff!', 'E788')
+  call assert_fails(':diffoff!', 'E788:')
   bw!
 
   " Cleanup
@@ -1410,13 +1410,13 @@
   bdel Xtest
   e Xxx1
   " write it, will unload it and give an error msg
-  call assert_fails('w', 'E203')
+  call assert_fails('w', 'E203:')
   call assert_equal('Xxx2', bufname('%'))
   edit Xtest
   e! Xxx2
   bwipe Xtest
   " write it, will delete the buffer and give an error msg
-  call assert_fails('w', 'E203')
+  call assert_fails('w', 'E203:')
   call assert_equal('Xxx1', bufname('%'))
   au! BufWritePre
   call delete('Xxx1')
@@ -1491,7 +1491,7 @@
   au BufWriteCmd XtestA call append(line("$"), "write")
   write				" will append a line to the file
   call assert_equal('write', getline('$'))
-  call assert_fails('read XtestA', 'E484')	" should not read anything
+  call assert_fails('read XtestA', 'E484:')	" should not read anything
   call assert_equal('write', getline(4))
 
   " now we have:
@@ -1517,7 +1517,7 @@
   normal 4GA1
   4,5w XtestC			" will copy lines 4 and 5 to the end
   call assert_equal("\tabc21", getline(8))
-  call assert_fails('r XtestC', 'E484')	" should not read anything
+  call assert_fails('r XtestC', 'E484:')	" should not read anything
   call assert_equal("end of Xxx", getline(9))
 
   " now we have:
@@ -1535,7 +1535,7 @@
   au FileAppendCmd XtestD call extend(g:lines, getline(line("'["), line("']")))
   w >>XtestD			" will add lines to 'lines'
   call assert_equal(9, len(g:lines))
-  call assert_fails('$r XtestD', 'E484')	" should not read anything
+  call assert_fails('$r XtestD', 'E484:')	" should not read anything
   call assert_equal(9, line('$'))
   call assert_equal('end of Xxx', getline('$'))
 
@@ -1776,7 +1776,7 @@
   CheckFeature quickfix
   " Nasty autocommand: wipe buffer on any event.
   au * x bwipe
-  call assert_fails('lv½ /x', 'E937')
+  call assert_fails('lv½ /x', 'E937:')
   au!
 endfunc
 
diff --git a/src/testdir/test_backspace_opt.vim b/src/testdir/test_backspace_opt.vim
index 149d8a8..b7e0024 100644
--- a/src/testdir/test_backspace_opt.vim
+++ b/src/testdir/test_backspace_opt.vim
@@ -41,10 +41,10 @@
   set backspace-=eol
   call assert_equal('', &backspace)
   " Check the error
-  call assert_equal(0, match(Exec('set backspace=ABC'), '.*E474'))
-  call assert_equal(0, match(Exec('set backspace+=def'), '.*E474'))
+  call assert_equal(0, match(Exec('set backspace=ABC'), '.*E474:'))
+  call assert_equal(0, match(Exec('set backspace+=def'), '.*E474:'))
   " NOTE: Vim doesn't check following error...
-  "call assert_equal(0, match(Exec('set backspace-=ghi'), '.*E474'))
+  "call assert_equal(0, match(Exec('set backspace-=ghi'), '.*E474:'))
 
   " Check backwards compatibility with version 5.4 and earlier
   set backspace=0
@@ -55,8 +55,8 @@
   call assert_equal('2', &backspace)
   set backspace=3
   call assert_equal('3', &backspace)
-  call assert_false(match(Exec('set backspace=4'), '.*E474'))
-  call assert_false(match(Exec('set backspace=10'), '.*E474'))
+  call assert_false(match(Exec('set backspace=4'), '.*E474:'))
+  call assert_false(match(Exec('set backspace=10'), '.*E474:'))
 
   " Cleared when 'compatible' is set
   set compatible
diff --git a/src/testdir/test_channel.vim b/src/testdir/test_channel.vim
index 065e8b4..6fa7e3b 100644
--- a/src/testdir/test_channel.vim
+++ b/src/testdir/test_channel.vim
@@ -163,11 +163,11 @@
   eval handle->ch_setoptions({'callback': 's:NotUsed'})
   call ch_setoptions(handle, {'timeout': 1111})
   call ch_setoptions(handle, {'mode': 'json'})
-  call assert_fails("call ch_setoptions(handle, {'waittime': 111})", "E475")
+  call assert_fails("call ch_setoptions(handle, {'waittime': 111})", 'E475:')
   call ch_setoptions(handle, {'callback': ''})
   call ch_setoptions(handle, {'drop': 'never'})
   call ch_setoptions(handle, {'drop': 'auto'})
-  call assert_fails("call ch_setoptions(handle, {'drop': 'bad'})", "E475")
+  call assert_fails("call ch_setoptions(handle, {'drop': 'bad'})", 'E475:')
   call assert_equal(0, ch_setoptions(handle, test_null_dict()))
   call assert_equal(0, ch_setoptions(test_null_channel(), {'drop' : 'never'}))
 
diff --git a/src/testdir/test_clientserver.vim b/src/testdir/test_clientserver.vim
index ab80bd2..7a75055 100644
--- a/src/testdir/test_clientserver.vim
+++ b/src/testdir/test_clientserver.vim
@@ -70,7 +70,7 @@
     call WaitForAssert({-> assert_equal('maybe', remote_expr(name, "testvar", "", 2))})
   endif
 
-  call assert_fails('call remote_send("XXX", ":let testvar = ''yes''\<CR>")', 'E241')
+  call assert_fails('call remote_send("XXX", ":let testvar = ''yes''\<CR>")', 'E241:')
 
   " Expression evaluated locally.
   if v:servername == ''
diff --git a/src/testdir/test_cmdline.vim b/src/testdir/test_cmdline.vim
index 6ebfa31..628db67 100644
--- a/src/testdir/test_cmdline.vim
+++ b/src/testdir/test_cmdline.vim
@@ -843,7 +843,7 @@
   f %<
   call assert_equal('foo-B', expand('%'))
   new
-  call assert_fails('f #<', 'E95')
+  call assert_fails('f #<', 'E95:')
   bw!
   f foo-B.txt
   f %<-A
diff --git a/src/testdir/test_const.vim b/src/testdir/test_const.vim
index 107e250..5eb2f69 100644
--- a/src/testdir/test_const.vim
+++ b/src/testdir/test_const.vim
@@ -207,9 +207,9 @@
 func Test_lockvar()
   let x = 'hello'
   lockvar x
-  call assert_fails('let x = "there"', 'E741')
+  call assert_fails('let x = "there"', 'E741:')
   if 0 | unlockvar x | endif
-  call assert_fails('let x = "there"', 'E741')
+  call assert_fails('let x = "there"', 'E741:')
   unlockvar x
   let x = 'there'
 
diff --git a/src/testdir/test_cscope.vim b/src/testdir/test_cscope.vim
index f4d4208..9ffe956 100644
--- a/src/testdir/test_cscope.vim
+++ b/src/testdir/test_cscope.vim
@@ -31,9 +31,9 @@
     catch
       call assert_report('exception thrown')
     endtry
-    call assert_fails('cscope add', 'E560')
-    call assert_fails('cscope add Xcscope.out', 'E568')
-    call assert_fails('cscope add doesnotexist.out', 'E563')
+    call assert_fails('cscope add', 'E560:')
+    call assert_fails('cscope add Xcscope.out', 'E568:')
+    call assert_fails('cscope add doesnotexist.out', 'E563:')
     if has('unix')
       call assert_fails('cscope add /dev/null', 'E564:')
     endif
diff --git a/src/testdir/test_eval_stuff.vim b/src/testdir/test_eval_stuff.vim
index 1490ffb..316fb42 100644
--- a/src/testdir/test_eval_stuff.vim
+++ b/src/testdir/test_eval_stuff.vim
@@ -35,12 +35,12 @@
   endtry
   " 'p' doesn't suppress real errors
   call writefile([], 'Xfile')
-  call assert_fails('call mkdir("Xfile", "p")', 'E739')
+  call assert_fails('call mkdir("Xfile", "p")', 'E739:')
   call delete('Xfile')
   call delete('Xmkdir', 'rf')
   call assert_equal(0, mkdir(test_null_string()))
-  call assert_fails('call mkdir([])', 'E730')
-  call assert_fails('call mkdir("abc", [], [])', 'E745')
+  call assert_fails('call mkdir([])', 'E730:')
+  call assert_fails('call mkdir("abc", [], [])', 'E745:')
 endfunc
 
 func Test_line_continuation()
diff --git a/src/testdir/test_functions.vim b/src/testdir/test_functions.vim
index 70dc339..7ff9b7a 100644
--- a/src/testdir/test_functions.vim
+++ b/src/testdir/test_functions.vim
@@ -2025,7 +2025,7 @@
   exe "lang collate" collate
 
   " 5) Errors
-  call assert_fails('call readdir(dir, 1, 1)', 'E715')
+  call assert_fails('call readdir(dir, 1, 1)', 'E715:')
   call assert_fails('call readdir(dir, 1, #{sorta: 1})')
   call assert_fails('call readdirex(dir, 1, #{sorta: 1})')
 
diff --git a/src/testdir/test_global.vim b/src/testdir/test_global.vim
index ee4808c..4a01be4 100644
--- a/src/testdir/test_global.vim
+++ b/src/testdir/test_global.vim
@@ -29,7 +29,7 @@
 func Test_nested_global()
   new
   call setline(1, ['nothing', 'found', 'found bad', 'bad'])
-  call assert_fails('g/found/3v/bad/s/^/++/', 'E147')
+  call assert_fails('g/found/3v/bad/s/^/++/', 'E147:')
   g/found/v/bad/s/^/++/
   call assert_equal(['nothing', '++found', 'found bad', 'bad'], getline(1, 4))
   bwipe!
diff --git a/src/testdir/test_gui.vim b/src/testdir/test_gui.vim
index c01a290..64537ac 100644
--- a/src/testdir/test_gui.vim
+++ b/src/testdir/test_gui.vim
@@ -525,7 +525,7 @@
         set guifontset=-*-notexist-*
         call assert_report("'set guifontset=-*-notexist-*' should have failed")
       catch
-        call assert_exception('E598')
+        call assert_exception('E598:')
       endtry
       " Set it to an invalid value brutally for preparation.
       let &guifontset = '-*-notexist-*'
diff --git a/src/testdir/test_hlsearch.vim b/src/testdir/test_hlsearch.vim
index 58e1d8c..db54ed4 100644
--- a/src/testdir/test_hlsearch.vim
+++ b/src/testdir/test_hlsearch.vim
@@ -28,7 +28,7 @@
   set nohls
   exe "normal! /\<CR>" | redraw
   call assert_notequal(r1, screenattr(1,1))
-  call assert_fails('let v:hlsearch=[]', 'E745')
+  call assert_fails('let v:hlsearch=[]', 'E745:')
   call garbagecollect(1)
   call getchar(1)
   enew!
diff --git a/src/testdir/test_lambda.vim b/src/testdir/test_lambda.vim
index b43ef52..aa73462 100644
--- a/src/testdir/test_lambda.vim
+++ b/src/testdir/test_lambda.vim
@@ -308,7 +308,7 @@
 
 func Test_lambda_error()
   " This was causing a crash
-  call assert_fails('ec{@{->{d->()()', 'E15')
+  call assert_fails('ec{@{->{d->()()', 'E15:')
 endfunc
 
 func Test_closure_error()
diff --git a/src/testdir/test_let.vim b/src/testdir/test_let.vim
index 017b2a4..6dc36ea 100644
--- a/src/testdir/test_let.vim
+++ b/src/testdir/test_let.vim
@@ -250,23 +250,23 @@
     let &t_k1 = old_t_k1
   endif
 
-  call assert_fails('let x = &t_xx', 'E113')
+  call assert_fails('let x = &t_xx', 'E113:')
   let &t_xx = "yes"
   call assert_equal("yes", &t_xx)
   let &t_xx = ""
-  call assert_fails('let x = &t_xx', 'E113')
+  call assert_fails('let x = &t_xx', 'E113:')
 endfunc
 
 func Test_let_option_error()
   let _w = &tw
   let &tw = 80
-  call assert_fails('let &tw .= 1', 'E734')
+  call assert_fails('let &tw .= 1', 'E734:')
   call assert_equal(80, &tw)
   let &tw = _w
 
   let _w = &fillchars
   let &fillchars = "vert:|"
-  call assert_fails('let &fillchars += "diff:-"', 'E734')
+  call assert_fails('let &fillchars += "diff:-"', 'E734:')
   call assert_equal("vert:|", &fillchars)
   let &fillchars = _w
 endfunc
diff --git a/src/testdir/test_listdict.vim b/src/testdir/test_listdict.vim
index 563c79f..8db7b3f 100644
--- a/src/testdir/test_listdict.vim
+++ b/src/testdir/test_listdict.vim
@@ -67,7 +67,7 @@
 
   " removing items out of range: silently skip items that don't exist
   let l = [0, 1, 2, 3]
-  call assert_fails('unlet l[2:1]', 'E684')
+  call assert_fails('unlet l[2:1]', 'E684:')
   let l = [0, 1, 2, 3]
   unlet l[2:2]
   call assert_equal([0, 1, 3], l)
@@ -81,7 +81,7 @@
   unlet l[2:5]
   call assert_equal([0, 1], l)
   let l = [0, 1, 2, 3]
-  call assert_fails('unlet l[-1:2]', 'E684')
+  call assert_fails('unlet l[-1:2]', 'E684:')
   let l = [0, 1, 2, 3]
   unlet l[-2:2]
   call assert_equal([0, 1, 3], l)
@@ -104,8 +104,8 @@
   let l = [0, 1, 2, 3]
   let [va, vb] = l[2:3]
   call assert_equal([2, 3], [va, vb])
-  call assert_fails('let [va, vb] = l', 'E687')
-  call assert_fails('let [va, vb] = l[1:1]', 'E688')
+  call assert_fails('let [va, vb] = l', 'E687:')
+  call assert_fails('let [va, vb] = l[1:1]', 'E688:')
 endfunc
 
 " test for range assign
@@ -186,7 +186,7 @@
 
   call extend(d, {3:33, 1:99})
   call extend(d, {'b':'bbb', 'c':'ccc'}, "keep")
-  call assert_fails("call extend(d, {3:333,4:444}, 'error')", 'E737')
+  call assert_fails("call extend(d, {3:333,4:444}, 'error')", 'E737:')
   call assert_equal({'c': 'ccc', '1': 99, 'b': [1, 2, function('strlen')], '3': 33, '-1': {'a': 1}}, d)
   call filter(d, 'v:key =~ ''[ac391]''')
   call assert_equal({'c': 'ccc', '1': 99, '3': 33, '-1': {'a': 1}}, d)
@@ -343,7 +343,7 @@
   let l = [4, d, 6]
   let d[3] = l
   let dc = deepcopy(d)
-  call assert_fails('call deepcopy(d, 1)', 'E698')
+  call assert_fails('call deepcopy(d, 1)', 'E698:')
   let l2 = [0, l, l, 3]
   let l[1] = l2
   let l3 = deepcopy(l2)
@@ -522,7 +522,7 @@
   unlet! d
   let d = {'a': 99, 'b': 100}
   lockvar 1 d
-  call assert_fails('unlet d.a', 'E741')
+  call assert_fails('unlet d.a', 'E741:')
 endfunc
 
 " unlet after lock on dict item
@@ -557,7 +557,7 @@
   unlet! d
   let d = {'a': 99, 'b': 100}
   lockvar d.a
-  call assert_fails("call extend(d, {'a' : 123})", 'E741')
+  call assert_fails("call extend(d, {'a' : 123})", 'E741:')
   call assert_equal({'a': 99, 'b': 100}, d)
 endfunc
 
@@ -572,7 +572,7 @@
 
 " No remove() of write-protected scope-level variable
 func Tfunc1(this_is_a_long_parameter_name)
-  call assert_fails("call remove(a:, 'this_is_a_long_parameter_name')", 'E742')
+  call assert_fails("call remove(a:, 'this_is_a_long_parameter_name')", 'E742:')
 endfunc
 func Test_dict_scope_var_remove()
   call Tfunc1('testval')
@@ -580,11 +580,11 @@
 
 " No extend() of write-protected scope-level variable
 func Test_dict_scope_var_extend()
-  call assert_fails("call extend(a:, {'this_is_a_long_parameter_name': 1234})", 'E742')
+  call assert_fails("call extend(a:, {'this_is_a_long_parameter_name': 1234})", 'E742:')
 endfunc
 
 func Tfunc2(this_is_a_long_parameter_name)
-  call assert_fails("call extend(a:, {'this_is_a_long_parameter_name': 1234})", 'E742')
+  call assert_fails("call extend(a:, {'this_is_a_long_parameter_name': 1234})", 'E742:')
 endfunc
 func Test_dict_scope_var_extend_overwrite()
   call Tfunc2('testval')
@@ -862,7 +862,7 @@
 
   let cmd = s:gen_cmd('let x:foo = 1', a:x)
   if a:fixed
-    call assert_fails(cmd, 'E461')
+    call assert_fails(cmd, 'E461:')
   else
     exe cmd
     exe s:gen_cmd('call assert_equal(1, x:foo)', a:x)
@@ -870,7 +870,7 @@
 
   let cmd = s:gen_cmd('let x:["bar"] = 2', a:x)
   if a:fixed
-    call assert_fails(cmd, 'E461')
+    call assert_fails(cmd, 'E461:')
   else
     exe cmd
     exe s:gen_cmd('call assert_equal(2, x:bar)', a:x)
@@ -878,7 +878,7 @@
 
   let cmd = s:gen_cmd('call extend(x:, {"baz": 3})', a:x)
   if a:fixed
-    call assert_fails(cmd, 'E742')
+    call assert_fails(cmd, 'E742:')
   else
     exe cmd
     exe s:gen_cmd('call assert_equal(3, x:baz)', a:x)
@@ -886,11 +886,11 @@
 
   if a:fixed
     if a:x ==# 'a'
-      call assert_fails('unlet a:x', 'E795')
-      call assert_fails('call remove(a:, "x")', 'E742')
+      call assert_fails('unlet a:x', 'E795:')
+      call assert_fails('call remove(a:, "x")', 'E742:')
     elseif a:x ==# 'v'
-      call assert_fails('unlet v:count', 'E795')
-      call assert_fails('call remove(v:, "count")', 'E742')
+      call assert_fails('unlet v:count', 'E795:')
+      call assert_fails('call remove(v:, "count")', 'E742:')
     endif
   else
     exe s:gen_cmd('unlet x:foo', a:x)
diff --git a/src/testdir/test_move.vim b/src/testdir/test_move.vim
index 8c40369..98c7665 100644
--- a/src/testdir/test_move.vim
+++ b/src/testdir/test_move.vim
@@ -33,8 +33,8 @@
   call assert_true(&modified)
   set nomodified
 
-  call assert_fails('1,2move 1', 'E134')
-  call assert_fails('2,3move 2', 'E134')
+  call assert_fails('1,2move 1', 'E134:')
+  call assert_fails('2,3move 2', 'E134:')
   call assert_fails("move -100", 'E16:')
   call assert_fails("move +100", 'E16:')
   call assert_fails('move', 'E16:')
diff --git a/src/testdir/test_normal.vim b/src/testdir/test_normal.vim
index 58c9ece..76f4dd6 100644
--- a/src/testdir/test_normal.vim
+++ b/src/testdir/test_normal.vim
@@ -1265,8 +1265,8 @@
   " Edit a fresh file and wipe the buffer list so that there is no alternate
   " file present.  Next, check for the expected command failures.
   edit Xfoo | %bw
-  call assert_fails(':buffer #', 'E86')
-  call assert_fails(':execute "normal! \<C-^>"', 'E23')
+  call assert_fails(':buffer #', 'E86:')
+  call assert_fails(':execute "normal! \<C-^>"', 'E23:')
   call assert_fails("normal i\<C-R>#", 'E23:')
 
   " Test for the expected behavior when switching between two named buffers.
@@ -1942,8 +1942,8 @@
   " there is only one change in the changelist
   " currently, when we setup the window
   call assert_equal(2, line('.'))
-  call assert_fails(':norm! g;', 'E662')
-  call assert_fails(':norm! g,', 'E663')
+  call assert_fails(':norm! g;', 'E662:')
+  call assert_fails(':norm! g,', 'E663:')
   let &ul=&ul
   call append('$', ['a', 'b', 'c', 'd'])
   let &ul=&ul
@@ -2466,10 +2466,10 @@
   " unfortunately, without a gui, we can't really test much here,
   " so simply test that ~p fails (which uses the drop register)
   new
-  call assert_fails(':norm! "~p', 'E353')
+  call assert_fails(':norm! "~p', 'E353:')
   call assert_equal([],  getreg('~', 1, 1))
   " the ~ register is read only
-  call assert_fails(':let @~="1"', 'E354')
+  call assert_fails(':let @~="1"', 'E354:')
   bw!
 endfunc
 
@@ -2510,7 +2510,7 @@
   new
   exe "norm! \<c-w>c"
   call assert_equal(1, winnr('$'))
-  call assert_fails(":norm! \<c-w>c", "E444")
+  call assert_fails(":norm! \<c-w>c", 'E444:')
 endfunc
 
 func Test_normal49_counts()
@@ -2531,7 +2531,7 @@
     "call feedkeys("\<c-^>", 'tm')
 
     " should also fail with E11
-    call assert_fails(":wincmd p", 'E11')
+    call assert_fails(":wincmd p", 'E11:')
     " return from commandline window
     call feedkeys("\<cr>")
   endfunc
@@ -2560,7 +2560,7 @@
   new Xreadonly.log
   setl ro
   au FileChangedRO <buffer> :call feedkeys("\<c-^>", 'tix')
-  call assert_fails(":norm! Af", 'E788')
+  call assert_fails(":norm! Af", 'E788:')
   call assert_equal(['foo'], getline(1,'$'))
   call assert_equal('Xreadonly.log', bufname(''))
 
@@ -2701,7 +2701,7 @@
 func Test_nv_hat_count()
   %bwipeout!
   let l:nr = bufnr('%') + 1
-  call assert_fails(':execute "normal! ' . l:nr . '\<C-^>"', 'E92')
+  call assert_fails(':execute "normal! ' . l:nr . '\<C-^>"', 'E92:')
 
   edit Xfoo
   let l:foo_nr = bufnr('Xfoo')
diff --git a/src/testdir/test_popupwin.vim b/src/testdir/test_popupwin.vim
index ec4898f..a92dc25 100644
--- a/src/testdir/test_popupwin.vim
+++ b/src/testdir/test_popupwin.vim
@@ -976,11 +976,11 @@
 func Test_win_execute_closing_curwin()
   split
   let winid = popup_create('some text', {})
-  call assert_fails('call win_execute(winid, winnr() .. "close")', 'E994')
+  call assert_fails('call win_execute(winid, winnr() .. "close")', 'E994:')
   call popup_clear()
 
   let winid = popup_create('some text', {})
-  call assert_fails('call win_execute(winid, printf("normal! :\<C-u>call popup_close(%d)\<CR>", winid))', 'E994')
+  call assert_fails('call win_execute(winid, printf("normal! :\<C-u>call popup_close(%d)\<CR>", winid))', 'E994:')
   call popup_clear()
 endfunc
 
diff --git a/src/testdir/test_put.vim b/src/testdir/test_put.vim
index 6741af1..3d4c5e7 100644
--- a/src/testdir/test_put.vim
+++ b/src/testdir/test_put.vim
@@ -60,16 +60,16 @@
   setlocal nomodifiable
 
   normal! yy
-  call assert_fails(':put', 'E21')
-  call assert_fails(':put!', 'E21')
-  call assert_fails(':normal! p', 'E21')
-  call assert_fails(':normal! gp', 'E21')
-  call assert_fails(':normal! P', 'E21')
-  call assert_fails(':normal! gP', 'E21')
+  call assert_fails(':put', 'E21:')
+  call assert_fails(':put!', 'E21:')
+  call assert_fails(':normal! p', 'E21:')
+  call assert_fails(':normal! gp', 'E21:')
+  call assert_fails(':normal! P', 'E21:')
+  call assert_fails(':normal! gP', 'E21:')
 
   if has('mouse')
     set mouse=n
-    call assert_fails('execute "normal! \<MiddleMouse>"', 'E21')
+    call assert_fails('execute "normal! \<MiddleMouse>"', 'E21:')
     set mouse&
   endif
 
diff --git a/src/testdir/test_quickfix.vim b/src/testdir/test_quickfix.vim
index 1faf02d..2fbbd14 100644
--- a/src/testdir/test_quickfix.vim
+++ b/src/testdir/test_quickfix.vim
@@ -359,7 +359,7 @@
 	\ l[1].lnum == 800 && l[1].col == 15 && l[1].text ==# 'Line 800')
 
   " Test with a non existent file
-  call assert_fails('Xfile non_existent_file', 'E40')
+  call assert_fails('Xfile non_existent_file', 'E40:')
 
   " Run cfile/lfile from a modified buffer
   enew!
@@ -502,8 +502,8 @@
 
   Xfirst
   call assert_fails('-5Xcc', 'E16:')
-  call assert_fails('Xprev', 'E553')
-  call assert_fails('Xpfile', 'E553')
+  call assert_fails('Xprev', 'E553:')
+  call assert_fails('Xpfile', 'E553:')
   Xnfile
   call assert_equal('Xqftestfile2', @%)
   call assert_equal(10, line('.'))
@@ -526,8 +526,8 @@
   Xprev
   call assert_equal('Xqftestfile2', @%)
   call assert_equal(11, line('.'))
-  call assert_fails('Xnext', 'E553')
-  call assert_fails('Xnfile', 'E553')
+  call assert_fails('Xnext', 'E553:')
+  call assert_fails('Xnfile', 'E553:')
   " To process the range using quickfix list entries, directly use the
   " quickfix commands (don't use the user defined commands)
   if a:cchar == 'c'
@@ -2174,8 +2174,8 @@
   endif
 
   " Invalid arguments
-  call assert_fails('call g:Xgetlist([])', 'E715')
-  call assert_fails('call g:Xsetlist([], "a", [])', 'E715')
+  call assert_fails('call g:Xgetlist([])', 'E715:')
+  call assert_fails('call g:Xsetlist([], "a", [])', 'E715:')
   let s = g:Xsetlist([], 'a', {'abc':1})
   call assert_equal(-1, s)
 
@@ -2978,7 +2978,7 @@
 func Test_cclose_from_copen()
     augroup QF_Test
 	au!
-        au FileType qf :call assert_fails(':cclose', 'E788')
+        au FileType qf :call assert_fails(':cclose', 'E788:')
     augroup END
     copen
     augroup QF_Test
@@ -2993,7 +2993,7 @@
   call test_override('starting', 1)
   augroup QF_Test
     au!
-    au FileType qf :call assert_fails(':cclose', 'E788')
+    au FileType qf :call assert_fails(':cclose', 'E788:')
   augroup END
   copen
   augroup QF_Test
@@ -3021,7 +3021,7 @@
   " Fails with argument.
   augroup QF_Test
     au!
-    au FileType qf call assert_fails(':file foo', 'E788')
+    au FileType qf call assert_fails(':file foo', 'E788:')
   augroup END
   copen
   augroup QF_Test
@@ -3702,7 +3702,7 @@
 func Test_lfile_crash()
   sp Xtest
   au QuickFixCmdPre * bw
-  call assert_fails('lfile', 'E40')
+  call assert_fails('lfile', 'E40:')
   au! QuickFixCmdPre
 endfunc
 
@@ -4235,7 +4235,7 @@
   call g:Xsetlist([])
   Xopen
   let l:win_count = winnr('$')
-  call assert_fails('execute "normal! \<C-W>\<CR>"', 'E42')
+  call assert_fails('execute "normal! \<C-W>\<CR>"', 'E42:')
   call assert_equal(l:win_count, winnr('$'))
   Xclose
 endfunc
diff --git a/src/testdir/test_rename.vim b/src/testdir/test_rename.vim
index 664a247..53fa3ff 100644
--- a/src/testdir/test_rename.vim
+++ b/src/testdir/test_rename.vim
@@ -113,8 +113,8 @@
   " Can't rename to en empty file name.
   call assert_notequal(0, rename('Xrenamefile', ''))
 
-  call assert_fails('call rename("Xrenamefile", [])', 'E730')
-  call assert_fails('call rename(0z, "Xrenamefile")', 'E976')
+  call assert_fails('call rename("Xrenamefile", [])', 'E730:')
+  call assert_fails('call rename(0z, "Xrenamefile")', 'E976:')
 
   call delete('Xrenamefile')
 endfunc
diff --git a/src/testdir/test_search.vim b/src/testdir/test_search.vim
index 9769fb2..ca06c34 100644
--- a/src/testdir/test_search.vim
+++ b/src/testdir/test_search.vim
@@ -266,7 +266,7 @@
   " In that case Vim should return "E35 no previous regular expression",
   " but it looks like Vim still sees /foo and therefore the test fails.
   " Therefore, disabling this test
-  "call assert_fails(feedkeys("/foo\<c-w>\<cr>", 'tx'), 'E35')
+  "call assert_fails(feedkeys("/foo\<c-w>\<cr>", 'tx'), 'E35:')
   "call assert_equal({'lnum': 1, 'leftcol': 0, 'col': 0, 'topfill': 0, 'topline': 1, 'coladd': 0, 'skipcol': 0, 'curswant': 0}, winsaveview())
 
   " clean up
@@ -470,7 +470,7 @@
   call feedkeys(":%smagic/the.e/xxx\<cr>", 'tx')
   call assert_equal('  2 xxx', getline('.'))
   undo
-  call assert_fails(":%snomagic/the.e/xxx\<cr>", 'E486')
+  call assert_fails(":%snomagic/the.e/xxx\<cr>", 'E486:')
   "
   call feedkeys(":%snomagic/the\\.e/xxx\<cr>", 'tx')
   call assert_equal('  2 xxx', getline('.'))
@@ -1278,8 +1278,8 @@
 func Test_search_sentence()
   new
   " this used to cause a crash
-  call assert_fails("/\\%')", 'E486')
-  call assert_fails("/", 'E486')
+  call assert_fails("/\\%')", 'E486:')
+  call assert_fails("/", 'E486:')
   /\%'(
   /
 endfunc
diff --git a/src/testdir/test_signs.vim b/src/testdir/test_signs.vim
index 3ee2b49..738eebf 100644
--- a/src/testdir/test_signs.vim
+++ b/src/testdir/test_signs.vim
@@ -1994,7 +1994,7 @@
   call assert_fails('call sign_unplacelist([[]])', "E715:")
   call assert_fails('call sign_unplacelist(["abc"])', "E715:")
   call assert_fails('call sign_unplacelist([100])', "E715:")
-  call assert_fails("call sign_unplacelist([{'id' : -1}])", 'E474')
+  call assert_fails("call sign_unplacelist([{'id' : -1}])", 'E474:')
 
   call assert_equal([0, 0, 0, 0],
 	      \ sign_undefine(['sign1', 'sign2', 'sign3', 'sign4']))
diff --git a/src/testdir/test_substitute.vim b/src/testdir/test_substitute.vim
index 7868c90..61c9cb3 100644
--- a/src/testdir/test_substitute.vim
+++ b/src/testdir/test_substitute.vim
@@ -449,7 +449,7 @@
 
    " 20 arguments plus one is too many
    let Replacer = function('SubReplacer20', repeat(['foo'], 20))
-   call assert_fails("call substitute('123', '2', Replacer, 'g')", 'E118')
+   call assert_fails("call substitute('123', '2', Replacer, 'g')", 'E118:')
 endfunc
 
 " Tests for *sub-replace-special* and *sub-replace-expression* on :substitute.
@@ -632,7 +632,7 @@
   call Run_SubCmd_Tests(tests)
 
   exe "normal oQ\nQ\<Esc>k"
-  call assert_fails('s/Q[^\n]Q/\=submatch(0)."foobar"/', 'E486')
+  call assert_fails('s/Q[^\n]Q/\=submatch(0)."foobar"/', 'E486:')
   enew!
 endfunc
 
diff --git a/src/testdir/test_syntax.vim b/src/testdir/test_syntax.vim
index 96d0f1a..cd06892 100644
--- a/src/testdir/test_syntax.vim
+++ b/src/testdir/test_syntax.vim
@@ -107,7 +107,7 @@
   call assert_notmatch('.* cppNumber*', a)
   call assert_notmatch('[1-9]', a)
 
-  call assert_fails('syntime abc', 'E475')
+  call assert_fails('syntime abc', 'E475:')
 
   syntax clear
   let a = execute('syntime report')
@@ -718,8 +718,8 @@
   syntax on
   set foldmethod=syntax
 
-  call assert_fails('syn foldlevel start start', 'E390')
-  call assert_fails('syn foldlevel not_an_option', 'E390')
+  call assert_fails('syn foldlevel start start', 'E390:')
+  call assert_fails('syn foldlevel not_an_option', 'E390:')
 
   set foldlevel=1
 
diff --git a/src/testdir/test_tagfunc.vim b/src/testdir/test_tagfunc.vim
index ca0d247..54c9e50 100644
--- a/src/testdir/test_tagfunc.vim
+++ b/src/testdir/test_tagfunc.vim
@@ -73,7 +73,7 @@
     return v:null
   endfunc
   set tags= tfu=NullTagFunc
-  call assert_fails('tag nothing', 'E433')
+  call assert_fails('tag nothing', 'E433:')
   delf NullTagFunc
 
   bwipe!
diff --git a/src/testdir/test_tagjump.vim b/src/testdir/test_tagjump.vim
index 3d2feb7..ab4841f 100644
--- a/src/testdir/test_tagjump.vim
+++ b/src/testdir/test_tagjump.vim
@@ -8,7 +8,7 @@
   CheckFeature quickfix
 
   set notagstack
-  call assert_fails('ptag does_not_exist_tag_name', 'E433')
+  call assert_fails('ptag does_not_exist_tag_name', 'E433:')
   set tagstack&vim
 endfunc
 
@@ -365,10 +365,10 @@
   " Error cases
   call assert_equal({}, gettagstack(100))
   call assert_equal(-1, settagstack(100, {'items' : []}))
-  call assert_fails('call settagstack(1, [1, 10])', 'E715')
-  call assert_fails("call settagstack(1, {'items' : 10})", 'E714')
-  call assert_fails("call settagstack(1, {'items' : []}, 10)", 'E928')
-  call assert_fails("call settagstack(1, {'items' : []}, 'b')", 'E962')
+  call assert_fails('call settagstack(1, [1, 10])', 'E715:')
+  call assert_fails("call settagstack(1, {'items' : 10})", 'E714:')
+  call assert_fails("call settagstack(1, {'items' : []}, 10)", 'E928:')
+  call assert_fails("call settagstack(1, {'items' : []}, 'b')", 'E962:')
   call assert_equal(-1, settagstack(0, test_null_dict()))
 
   set tags=Xtags
@@ -565,7 +565,7 @@
   let old_vbs = &verbose
   set verbose=5
   " ":tjump" should give "tag not found" not "Format error in tags file"
-  call assert_fails('tj /foo', 'E426')
+  call assert_fails('tj /foo', 'E426:')
   try
     tj /foo
   catch /^Vim\%((\a\+)\)\=:E431/
@@ -577,7 +577,7 @@
   call writefile([
 	\ '123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567	django/contrib/admin/templates/admin/edit_inline/stacked.html	16;"	j	line:16	language:HTML'
 	\ ], 'Xtags')
-  call assert_fails('tj /foo', 'E426')
+  call assert_fails('tj /foo', 'E426:')
   try
     tj /foo
   catch /^Vim\%((\a\+)\)\=:E431/
diff --git a/src/testdir/test_taglist.vim b/src/testdir/test_taglist.vim
index 63520be..58ad565 100644
--- a/src/testdir/test_taglist.vim
+++ b/src/testdir/test_taglist.vim
@@ -83,7 +83,7 @@
 endfunc
 
 func Test_tags_too_long()
-  call assert_fails('tag ' . repeat('x', 1020), ['E433', 'E426'])
+  call assert_fails('tag ' . repeat('x', 1020), ['E433:', 'E426:'])
   tags
 endfunc
 
diff --git a/src/testdir/test_terminal.vim b/src/testdir/test_terminal.vim
index 17eba9c..fbb725c 100644
--- a/src/testdir/test_terminal.vim
+++ b/src/testdir/test_terminal.vim
@@ -65,7 +65,7 @@
 
   setlocal modifiable
   exe "normal Axxx\<Esc>"
-  call assert_fails(buf . 'bwipe', ['E89:', 'E517'])
+  call assert_fails(buf . 'bwipe', ['E89:', 'E517:'])
   undo
 
   exe buf . 'bwipe'
@@ -89,7 +89,7 @@
 
 func Test_terminal_wipe_buffer()
   let buf = Run_shell_in_terminal({})
-  call assert_fails(buf . 'bwipe', ['E89', 'E517'])
+  call assert_fails(buf . 'bwipe', ['E89:', 'E517:'])
   exe buf . 'bwipe!'
   call WaitForAssert({-> assert_equal('dead', job_status(g:job))})
   call assert_equal("", bufname(buf))
@@ -648,7 +648,7 @@
 
 func Test_terminal_list_args()
   let buf = term_start([&shell, &shellcmdflag, 'echo "123"'])
-  call assert_fails(buf . 'bwipe', ['E89', 'E517'])
+  call assert_fails(buf . 'bwipe', ['E89:', 'E517:'])
   exe buf . 'bwipe!'
   call assert_equal("", bufname(buf))
 endfunction
@@ -892,7 +892,7 @@
 
 func Test_terminal_wqall()
   let buf = Run_shell_in_terminal({})
-  call assert_fails('wqall', 'E948')
+  call assert_fails('wqall', 'E948:')
   call StopShellInTerminal(buf)
   call TermWait(buf)
   exe buf . 'bwipe'
@@ -993,17 +993,17 @@
 
 func Test_terminal_term_start_empty_command()
   let cmd = "call term_start('', {'curwin' : 1, 'term_finish' : 'close'})"
-  call assert_fails(cmd, 'E474')
+  call assert_fails(cmd, 'E474:')
   let cmd = "call term_start('', {'curwin' : 1, 'term_finish' : 'close'})"
-  call assert_fails(cmd, 'E474')
+  call assert_fails(cmd, 'E474:')
   let cmd = "call term_start({}, {'curwin' : 1, 'term_finish' : 'close'})"
-  call assert_fails(cmd, 'E474')
+  call assert_fails(cmd, 'E474:')
   let cmd = "call term_start(0, {'curwin' : 1, 'term_finish' : 'close'})"
-  call assert_fails(cmd, 'E474')
+  call assert_fails(cmd, 'E474:')
   let cmd = "call term_start('', {'term_name' : []})"
-  call assert_fails(cmd, 'E730')
+  call assert_fails(cmd, 'E730:')
   let cmd = "call term_start('', {'term_finish' : 'axby'})"
-  call assert_fails(cmd, 'E475')
+  call assert_fails(cmd, 'E475:')
   let cmd = "call term_start('', {'eof_chars' : []})"
   call assert_fails(cmd, 'E730:')
   let cmd = "call term_start('', {'term_kill' : []})"
diff --git a/src/testdir/test_terminal2.vim b/src/testdir/test_terminal2.vim
index f9f221b..a99818b 100644
--- a/src/testdir/test_terminal2.vim
+++ b/src/testdir/test_terminal2.vim
@@ -36,9 +36,9 @@
   call StopVimInTerminal(buf)
   call delete('Xwinsize')
 
-  call assert_fails('set termwinsize=40', 'E474')
-  call assert_fails('set termwinsize=10+40', 'E474')
-  call assert_fails('set termwinsize=abc', 'E474')
+  call assert_fails('set termwinsize=40', 'E474:')
+  call assert_fails('set termwinsize=10+40', 'E474:')
+  call assert_fails('set termwinsize=abc', 'E474:')
 
   set termwinsize=
 endfunc
diff --git a/src/testdir/test_textprop.vim b/src/testdir/test_textprop.vim
index bacb288..012b3eb 100644
--- a/src/testdir/test_textprop.vim
+++ b/src/testdir/test_textprop.vim
@@ -314,8 +314,8 @@
   unlet props[3]
   call assert_equal(props, prop_list(1))
 
-  call assert_fails("call prop_remove({'id': 11, 'both': 1})", 'E860')
-  call assert_fails("call prop_remove({'type': 'three', 'both': 1})", 'E860')
+  call assert_fails("call prop_remove({'id': 11, 'both': 1})", 'E860:')
+  call assert_fails("call prop_remove({'type': 'three', 'both': 1})", 'E860:')
 
   call DeletePropTypes()
   bwipe!
diff --git a/src/testdir/test_timers.vim b/src/testdir/test_timers.vim
index 829e94b..47e2699 100644
--- a/src/testdir/test_timers.vim
+++ b/src/testdir/test_timers.vim
@@ -422,7 +422,7 @@
 endfunc
 
 func Test_timer_invalid_callback()
-  call assert_fails('call timer_start(0, "0")', 'E921')
+  call assert_fails('call timer_start(0, "0")', 'E921:')
 endfunc
 
 func Test_timer_changing_function_list()
@@ -442,7 +442,7 @@
   call term_sendkeys(buf, ":fu\<CR>")
   call WaitForAssert({-> assert_match('-- More --', term_getline(buf, 10))})
   call term_sendkeys(buf, "G")
-  call WaitForAssert({-> assert_match('E454', term_getline(buf, 9))})
+  call WaitForAssert({-> assert_match('E454:', term_getline(buf, 9))})
   call term_sendkeys(buf, "\<Esc>")
 
   call StopVimInTerminal(buf)
diff --git a/src/testdir/test_true_false.vim b/src/testdir/test_true_false.vim
index 37b0997..2071f5e 100644
--- a/src/testdir/test_true_false.vim
+++ b/src/testdir/test_true_false.vim
@@ -40,11 +40,11 @@
     call assert_true(false, 'one in string is true')
   endif
 
-  call assert_fails('if [1]', 'E745')
-  call assert_fails('if {1: 1}', 'E728')
-  call assert_fails('if function("string")', 'E703')
+  call assert_fails('if [1]', 'E745:')
+  call assert_fails('if {1: 1}', 'E728:')
+  call assert_fails('if function("string")', 'E703:')
   if has('float')
-    call assert_fails('if 1.3")', 'E805')
+    call assert_fails('if 1.3")', 'E805:')
   endif
 endfunc
 
diff --git a/src/testdir/test_user_func.vim b/src/testdir/test_user_func.vim
index d4d149c..ed07d99 100644
--- a/src/testdir/test_user_func.vim
+++ b/src/testdir/test_user_func.vim
@@ -88,7 +88,7 @@
 
   " Try to overwrite a function in the global (g:) scope
   call assert_equal(3, max([1, 2, 3]))
-  call assert_fails("call extend(g:, {'max': function('min')})", 'E704')
+  call assert_fails("call extend(g:, {'max': function('min')})", 'E704:')
   call assert_equal(3, max([1, 2, 3]))
 
   " Try to overwrite an user defined function with a function reference
@@ -131,7 +131,7 @@
   if has('float')
     call assert_equal(1.0, Log(10))
     call assert_equal(log(10), Log(10, exp(1)))
-    call assert_fails("call Log(1,2,3)", 'E118')
+    call assert_fails("call Log(1,2,3)", 'E118:')
   endif
 
   let res = Args(1)
@@ -149,8 +149,8 @@
   call assert_equal(res.optional, 2)
   call assert_equal(res['0'], 1)
 
-  call assert_fails("call MakeBadFunc()", 'E989')
-  call assert_fails("fu F(a=1 ,) | endf", 'E475')
+  call assert_fails("call MakeBadFunc()", 'E989:')
+  call assert_fails("fu F(a=1 ,) | endf", 'E475:')
 
   let d = Args2(7, v:none, 9)
   call assert_equal([7, 2, 9], [d.a, d.b, d.c])
diff --git a/src/testdir/test_vim9_func.vim b/src/testdir/test_vim9_func.vim
index 3e21730..828dbba 100644
--- a/src/testdir/test_vim9_func.vim
+++ b/src/testdir/test_vim9_func.vim
@@ -523,7 +523,7 @@
 
 def Test_error_in_nested_function()
   # Error in called function requires unwinding the call stack.
-  assert_fails('call FuncWithForwardCall()', 'E1096')
+  assert_fails('call FuncWithForwardCall()', 'E1096:')
 enddef
 
 def Test_return_type_wrong()
@@ -735,8 +735,8 @@
     CallGoneSoon()
   END
   writefile(lines, 'XToDelFunc')
-  assert_fails('so XToDelFunc', 'E933')
-  assert_fails('so XToDelFunc', 'E933')
+  assert_fails('so XToDelFunc', 'E933:')
+  assert_fails('so XToDelFunc', 'E933:')
 
   delete('XToDelFunc')
 enddef
diff --git a/src/testdir/test_vim9_script.vim b/src/testdir/test_vim9_script.vim
index 8ebcc28..ed7648e 100644
--- a/src/testdir/test_vim9_script.vim
+++ b/src/testdir/test_vim9_script.vim
@@ -1575,8 +1575,8 @@
   CheckScriptFailure(['vim9script', 'let str: string', 'str = 1234'], 'E1012:')
   CheckScriptFailure(['vim9script', 'const str = "asdf"', 'str = "xxx"'], 'E46:')
 
-  assert_fails('vim9script', 'E1038')
-  assert_fails('export something', 'E1043')
+  assert_fails('vim9script', 'E1038:')
+  assert_fails('export something', 'E1043:')
 enddef
 
 func Test_import_fails_without_script()
diff --git a/src/testdir/test_vimscript.vim b/src/testdir/test_vimscript.vim
index f17e908..8c93199 100644
--- a/src/testdir/test_vimscript.vim
+++ b/src/testdir/test_vimscript.vim
@@ -95,7 +95,7 @@
     call T1_G()
   catch
     " Catch missing :endif
-    call assert_true(v:exception =~ 'E171')
+    call assert_true(v:exception =~ 'E171:')
     Xpath 'x'
   endtry
   Xpath 'G'
@@ -125,7 +125,7 @@
     ExecAsScript T1_G
   catch
     " Catch missing :endif
-    call assert_true(v:exception =~ 'E171')
+    call assert_true(v:exception =~ 'E171:')
     Xpath 'x'
   endtry
   Xpath 'G'
@@ -7022,8 +7022,8 @@
       call assert_equal(10.5, x)
       let x /= 2.5
       call assert_equal(4.2, x)
-      call assert_fails('let x %= 0.5', 'E734')
-      call assert_fails('let x .= "f"', 'E734')
+      call assert_fails('let x %= 0.5', 'E734:')
+      call assert_fails('let x .= "f"', 'E734:')
       let x = !3.14
       call assert_equal(0.0, x)
 
@@ -7044,11 +7044,11 @@
 
     " Test for environment variable
     let $FOO = 1
-    call assert_fails('let $FOO += 1', 'E734')
-    call assert_fails('let $FOO -= 1', 'E734')
-    call assert_fails('let $FOO *= 1', 'E734')
-    call assert_fails('let $FOO /= 1', 'E734')
-    call assert_fails('let $FOO %= 1', 'E734')
+    call assert_fails('let $FOO += 1', 'E734:')
+    call assert_fails('let $FOO -= 1', 'E734:')
+    call assert_fails('let $FOO *= 1', 'E734:')
+    call assert_fails('let $FOO /= 1', 'E734:')
+    call assert_fails('let $FOO %= 1', 'E734:')
     let $FOO .= 's'
     call assert_equal('1s', $FOO)
     unlet $FOO
@@ -7065,16 +7065,16 @@
     call assert_equal(6, &scrolljump)
     let &scrolljump %= 5
     call assert_equal(1, &scrolljump)
-    call assert_fails('let &scrolljump .= "j"', 'E734')
+    call assert_fails('let &scrolljump .= "j"', 'E734:')
     set scrolljump&vim
 
     " Test for register
     let @/ = 1
-    call assert_fails('let @/ += 1', 'E734')
-    call assert_fails('let @/ -= 1', 'E734')
-    call assert_fails('let @/ *= 1', 'E734')
-    call assert_fails('let @/ /= 1', 'E734')
-    call assert_fails('let @/ %= 1', 'E734')
+    call assert_fails('let @/ += 1', 'E734:')
+    call assert_fails('let @/ -= 1', 'E734:')
+    call assert_fails('let @/ *= 1', 'E734:')
+    call assert_fails('let @/ /= 1', 'E734:')
+    call assert_fails('let @/ %= 1', 'E734:')
     let @/ .= 's'
     call assert_equal('1s', @/)
     let @/ = ''
@@ -7083,8 +7083,8 @@
 func Test_unlet_env()
   let $TESTVAR = 'yes'
   call assert_equal('yes', $TESTVAR)
-  call assert_fails('lockvar $TESTVAR', 'E940')
-  call assert_fails('unlockvar $TESTVAR', 'E940')
+  call assert_fails('lockvar $TESTVAR', 'E940:')
+  call assert_fails('unlockvar $TESTVAR', 'E940:')
   call assert_equal('yes', $TESTVAR)
   if 0
     unlet $TESTVAR
@@ -7339,8 +7339,8 @@
 " Test for errors in converting to float from various types         {{{1
 func Test_float_conversion_errors()
   if has('float')
-    call assert_fails('let x = 4.0 % 2.0', 'E804')
-    call assert_fails('echo 1.1[0]', 'E806')
+    call assert_fails('let x = 4.0 % 2.0', 'E804:')
+    call assert_fails('echo 1.1[0]', 'E806:')
     call assert_fails('echo sort([function("min"), 1], "f")', 'E891:')
     call assert_fails('echo 3.2 == "vim"', 'E892:')
     call assert_fails('echo sort([[], 1], "f")', 'E893:')
diff --git a/src/testdir/test_winbar.vim b/src/testdir/test_winbar.vim
index 86066af..3412ce5 100644
--- a/src/testdir/test_winbar.vim
+++ b/src/testdir/test_winbar.vim
@@ -18,7 +18,7 @@
   call assert_equal(12, g:did_cont)
 
   wincmd w
-  call assert_fails('emenu WinBar.Next', 'E334')
+  call assert_fails('emenu WinBar.Next', 'E334:')
   wincmd p
 
   aunmenu WinBar.Next
diff --git a/src/testdir/test_winbuf_close.vim b/src/testdir/test_winbuf_close.vim
index 3f67e88..1d3e357 100644
--- a/src/testdir/test_winbuf_close.vim
+++ b/src/testdir/test_winbuf_close.vim
@@ -27,7 +27,7 @@
   " test for failing :rew when hidden not set
   set nohidden
   call setline(1, 'testtext 2 2')
-  call assert_fails('rewind', 'E37')
+  call assert_fails('rewind', 'E37:')
   call assert_equal('Xtest2', bufname('%'))
   call assert_equal('testtext 2 2', getline(1))
 
@@ -66,7 +66,7 @@
 
   " test ":edit" failing in modified buffer when 'hidden' not set
   call setline(1, 'testtext 3 3')
-  call assert_fails('edit Xtest1', 'E37')
+  call assert_fails('edit Xtest1', 'E37:')
   call assert_equal('Xtest3', bufname('%'))
   call assert_equal('testtext 3 3', getline(1))
 
@@ -80,7 +80,7 @@
   split Xtest3
   set nohidden
   call setline(1, 'testtext 3 3 3')
-  call assert_fails('close', 'E37')
+  call assert_fails('close', 'E37:')
   call assert_equal('Xtest3', bufname('%'))
   call assert_equal('testtext 3 3 3', getline(1))
 
@@ -115,7 +115,7 @@
   call assert_equal('Xtest2', bufname('%'))
   quit!
   call assert_equal('Xtest3', bufname('%'))
-  call assert_fails('silent! quit!', 'E37')
+  call assert_fails('silent! quit!', 'E37:')
   call assert_equal('Xtest1', bufname('%'))
 
   call delete('Xtest1')
diff --git a/src/testdir/test_window_cmd.vim b/src/testdir/test_window_cmd.vim
index 88141a9..a4b4f53 100644
--- a/src/testdir/test_window_cmd.vim
+++ b/src/testdir/test_window_cmd.vim
@@ -121,7 +121,7 @@
 
   " Test for failure when the alternate buffer/file no longer exists.
   edit Xfoo | %bw
-  call assert_fails(':wincmd ^', 'E23')
+  call assert_fails(':wincmd ^', 'E23:')
 
   " Test for the expected behavior when we have two named buffers.
   edit Xfoo | edit Xbar
@@ -154,9 +154,9 @@
 
   %bwipeout
   let l:nr = bufnr('%') + 1
-  call assert_fails(':execute "normal! ' . l:nr . '\<C-W>\<C-^>"', 'E92')
-  call assert_fails(':' . l:nr . 'wincmd ^', 'E16')
-  call assert_fails(':0wincmd ^', 'E16')
+  call assert_fails(':execute "normal! ' . l:nr . '\<C-W>\<C-^>"', 'E92:')
+  call assert_fails(':' . l:nr . 'wincmd ^', 'E16:')
+  call assert_fails(':0wincmd ^', 'E16:')
 
   edit Xfoo | edit Xbar | edit Xbaz
   let l:foo_nr = bufnr('Xfoo')
diff --git a/src/testdir/test_writefile.vim b/src/testdir/test_writefile.vim
index a1cf686..c858b75 100644
--- a/src/testdir/test_writefile.vim
+++ b/src/testdir/test_writefile.vim
@@ -310,7 +310,7 @@
     autocmd BufWritePre Xfile enew | write
   augroup END
   e Xfile
-  call assert_fails('lockmarks write', ['E32', 'E203:'])
+  call assert_fails('lockmarks write', ['E32:', 'E203:'])
   augroup WriteTest
     au!
   augroup END
diff --git a/src/version.c b/src/version.c
index 111405f..7058d62 100644
--- a/src/version.c
+++ b/src/version.c
@@ -755,6 +755,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1593,
+/**/
     1592,
 /**/
     1591,