diff --git a/runtime/doc/testing.txt b/runtime/doc/testing.txt
index b7825b9..53ed081 100644
--- a/runtime/doc/testing.txt
+++ b/runtime/doc/testing.txt
@@ -295,8 +295,23 @@
 
 assert_fails({cmd} [, {error} [, {msg}]])			*assert_fails()*
 		Run {cmd} and add an error message to |v:errors| if it does
-		NOT produce an error.  Also see |assert-return|.
-		When {error} is given it must match in |v:errmsg|.
+		NOT produce an error or when {error} is not found in the
+		error message.  Also see |assert-return|.
+
+		When {error} is a string it must be found literally in the
+		first reported error. Most often this will be the error code,
+		including the colon, e.g. "E123:". >
+			assert_fails('bad cmd', 'E987:')
+<
+		When {error} is a |List| with one or two strings, these are
+		used as patterns.  The first pattern is matched against the
+		first reported error: >
+			assert_fails('cmd', ['E987:.*expected bool'])
+<		The second pattern, if present, is matched against the last
+		reported error.  To only match the last error use an empty
+		string for the first error: >
+			assert_fails('cmd', ['', 'E987:'])
+<
 		Note that beeping is not considered an error, and some failing
 		commands only beep.  Use |assert_beeps()| for those.
 
diff --git a/src/evalvars.c b/src/evalvars.c
index 9cd2ec2..7066039 100644
--- a/src/evalvars.c
+++ b/src/evalvars.c
@@ -3388,7 +3388,7 @@
     int
 var_redir_start(char_u *name, int append)
 {
-    int		save_emsg;
+    int		called_emsg_before;
     int		err;
     typval_T	tv;
 
@@ -3432,8 +3432,7 @@
 
     // check if we can write to the variable: set it to or append an empty
     // string
-    save_emsg = did_emsg;
-    did_emsg = FALSE;
+    called_emsg_before = called_emsg;
     tv.v_type = VAR_STRING;
     tv.vval.v_string = (char_u *)"";
     if (append)
@@ -3441,9 +3440,7 @@
     else
 	set_var_lval(redir_lval, redir_endp, &tv, TRUE, 0, (char_u *)"=");
     clear_lval(redir_lval);
-    err = did_emsg;
-    did_emsg |= save_emsg;
-    if (err)
+    if (called_emsg > called_emsg_before)
     {
 	redir_endp = NULL;  // don't store a value, only cleanup
 	var_redir_stop();
diff --git a/src/globals.h b/src/globals.h
index 3d40cc1..5e2306b 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -220,6 +220,10 @@
 					    // expression that is skipped
 EXTERN int	emsg_severe INIT(= FALSE);  // use message of next of several
 					    // emsg() calls for throw
+// used by assert_fails()
+EXTERN int	emsg_assert_fails_used INIT(= FALSE);
+EXTERN char_u	*emsg_assert_fails_msg INIT(= NULL);
+
 EXTERN int	did_endif INIT(= FALSE);    // just had ":endif"
 #endif
 EXTERN int	did_emsg;		    // set by emsg() when the message
diff --git a/src/if_cscope.c b/src/if_cscope.c
index 89c851b..0e6f5ae 100644
--- a/src/if_cscope.c
+++ b/src/if_cscope.c
@@ -2152,7 +2152,6 @@
 		ch = getc(csinfo[i].fr_fp);
 	    if (ch == EOF)
 	    {
-		PERROR("cs_read_prompt EOF");
 		if (buf != NULL && buf[0] != NUL)
 		    (void)semsg(cs_emsg, buf);
 		else if (p_csverbose)
diff --git a/src/message.c b/src/message.c
index a26a637..76ec456 100644
--- a/src/message.c
+++ b/src/message.c
@@ -654,6 +654,9 @@
 	    return TRUE;
 	}
 
+	if (emsg_assert_fails_used && emsg_assert_fails_msg == NULL)
+	    emsg_assert_fails_msg = vim_strsave(s);
+
 	// set "v:errmsg", also when using ":silent! cmd"
 	set_vim_var_string(VV_ERRMSG, s, -1);
 #endif
diff --git a/src/testdir/test_autocmd.vim b/src/testdir/test_autocmd.vim
index 446d22b..c167ed9 100644
--- a/src/testdir/test_autocmd.vim
+++ b/src/testdir/test_autocmd.vim
@@ -168,9 +168,7 @@
     exe 'autocmd BufUnload <buffer> ' . (lastbuf + 1) . 'bwipeout!'
   augroup END
 
-  " Todo: check for E937 generated first
-  " call assert_fails('edit bb.txt', 'E937:')
-  call assert_fails('edit bb.txt', 'E517:')
+  call assert_fails('edit bb.txt', ['E937:', 'E517:'])
 
   autocmd! test_autocmd_bufunload
   augroup! test_autocmd_bufunload
@@ -1745,9 +1743,7 @@
 func Test_nocatch_wipe_all_buffers()
   " Real nasty autocommand: wipe all buffers on any event.
   au * * bwipe *
-  " Get E93 first?
-  " call assert_fails('next x', 'E93:')
-  call assert_fails('next x', 'E517:')
+  call assert_fails('next x', ['E94:', 'E517:'])
   bwipe
   au!
 endfunc
@@ -1756,7 +1752,7 @@
   if has('quickfix')
     " Nasty autocommand: wipe buffer on any event.
     au * x bwipe
-    call assert_fails('lv½ /x', 'E480')
+    call assert_fails('lv½ /x', 'E937')
     au!
   endif
 endfunc
@@ -2570,7 +2566,7 @@
   augroup END
   let save_cpo = &cpo
   set cpo+=f
-  call assert_fails('r Xfile', 'E484:')
+  call assert_fails('r Xfile', ['E812:', 'E484:'])
   call assert_equal('somefile', @%)
   let &cpo = save_cpo
   augroup TestAuCmd
diff --git a/src/testdir/test_buffer.vim b/src/testdir/test_buffer.vim
index 5981e24..c8f6c5a 100644
--- a/src/testdir/test_buffer.vim
+++ b/src/testdir/test_buffer.vim
@@ -76,7 +76,7 @@
     let caught_E90 = 1
   endtry
   call assert_equal(1, caught_E90)
-  call assert_fails('$bunload', 'E515:')
+  call assert_fails('$bunload', 'E90:')
 endfunc
 
 " Test for :buffer, :bnext, :bprevious, :brewind, :blast and :bmodified
@@ -278,7 +278,7 @@
   call assert_equal(1, &modified)
   call assert_equal('', @%)
   call feedkeys('y', 'L')
-  call assert_fails('confirm b Xfile', 'E37:')
+  call assert_fails('confirm b Xfile', ['', 'E37:'])
   call assert_equal(1, &modified)
   call assert_equal('', @%)
   call feedkeys('n', 'L')
diff --git a/src/testdir/test_cd.vim b/src/testdir/test_cd.vim
index f43f27c..bd6e3d9 100644
--- a/src/testdir/test_cd.vim
+++ b/src/testdir/test_cd.vim
@@ -4,7 +4,7 @@
 
 func Test_cd_large_path()
   " This used to crash with a heap write overflow.
-  call assert_fails('cd ' . repeat('x', 5000), 'E472:')
+  call assert_fails('cd ' . repeat('x', 5000), 'E344:')
 endfunc
 
 func Test_cd_up_and_down()
@@ -93,7 +93,7 @@
   call assert_equal('testdir', fnamemodify(getcwd(1, 1), ':t'))
 
   " Error case
-  call assert_fails("call chdir('dir-abcd')", 'E472:')
+  call assert_fails("call chdir('dir-abcd')", 'E344:')
   silent! let d = chdir("dir_abcd")
   call assert_equal("", d)
   " Should not crash
diff --git a/src/testdir/test_channel.vim b/src/testdir/test_channel.vim
index 85312ae..ae7e301 100644
--- a/src/testdir/test_channel.vim
+++ b/src/testdir/test_channel.vim
@@ -559,7 +559,7 @@
   call assert_equal(1, found)
 
   call assert_fails("call job_stop('abc')", 'E475:')
-  call assert_fails("call job_stop(job, [])", 'E474:')
+  call assert_fails("call job_stop(job, [])", 'E730:')
   call assert_fails("call job_stop(test_null_job())", 'E916:')
 
   " Try to use the job and channel where a number is expected. This is not
@@ -1641,15 +1641,15 @@
   call assert_fails("call job_start('ls', {'in_top' : -1})", 'E475:')
   call assert_fails("call job_start('ls', {'in_bot' : -1})", 'E475:')
   call assert_fails("call job_start('ls', {'channel' : -1})", 'E475:')
-  call assert_fails("call job_start('ls', {'callback' : -1})", 'E475:')
-  call assert_fails("call job_start('ls', {'out_cb' : -1})", 'E475:')
-  call assert_fails("call job_start('ls', {'err_cb' : -1})", 'E475:')
-  call assert_fails("call job_start('ls', {'close_cb' : -1})", 'E475:')
-  call assert_fails("call job_start('ls', {'exit_cb' : -1})", 'E475:')
+  call assert_fails("call job_start('ls', {'callback' : -1})", 'E921:')
+  call assert_fails("call job_start('ls', {'out_cb' : -1})", 'E921:')
+  call assert_fails("call job_start('ls', {'err_cb' : -1})", 'E921:')
+  call assert_fails("call job_start('ls', {'close_cb' : -1})", 'E921:')
+  call assert_fails("call job_start('ls', {'exit_cb' : -1})", 'E921:')
   call assert_fails("call job_start('ls', {'term_name' : []})", 'E475:')
   call assert_fails("call job_start('ls', {'term_finish' : 'run'})", 'E475:')
   call assert_fails("call job_start('ls', {'term_api' : []})", 'E475:')
-  call assert_fails("call job_start('ls', {'stoponexit' : []})", 'E475:')
+  call assert_fails("call job_start('ls', {'stoponexit' : []})", 'E730:')
   call assert_fails("call job_start('ls', {'in_io' : 'file'})", 'E920:')
   call assert_fails("call job_start('ls', {'out_io' : 'file'})", 'E920:')
   call assert_fails("call job_start('ls', {'err_io' : 'file'})", 'E920:')
diff --git a/src/testdir/test_clientserver.vim b/src/testdir/test_clientserver.vim
index 152a2e1..eb9fcb8 100644
--- a/src/testdir/test_clientserver.vim
+++ b/src/testdir/test_clientserver.vim
@@ -84,7 +84,7 @@
   call remote_send(v:servername, ":let g:testvar2 = 75\<CR>")
   call feedkeys('', 'x')
   call assert_equal(75, g:testvar2)
-  call assert_fails('let v = remote_expr(v:servername, "/2")', 'E449:')
+  call assert_fails('let v = remote_expr(v:servername, "/2")', ['E15:.*/2'])
 
   call remote_send(name, ":call server2client(expand('<client>'), 'got it')\<CR>", 'g:myserverid')
   call assert_equal('got it', g:myserverid->remote_read(2))
@@ -166,8 +166,8 @@
 
   call assert_fails('call remote_startserver([])', 'E730:')
   call assert_fails("let x = remote_peek([])", 'E730:')
-  call assert_fails("let x = remote_read('vim10')", 'E277:')
-  call assert_fails("call server2client('abc', 'xyz')", 'E258:')
+  call assert_fails("let x = remote_read('vim10')", ['E573:.*vim10'])
+  call assert_fails("call server2client('abc', 'xyz')", ['E573:.*abc'])
 endfunc
 
 " Uncomment this line to get a debugging log
diff --git a/src/testdir/test_cmdline.vim b/src/testdir/test_cmdline.vim
index eb213f1..539b782 100644
--- a/src/testdir/test_cmdline.vim
+++ b/src/testdir/test_cmdline.vim
@@ -855,7 +855,7 @@
   call assert_equal('B', getline(2))
 
   let @/ = 'apple'
-  call assert_fails('\/print', 'E486:')
+  call assert_fails('\/print', ['E486:.*apple'])
 
   bwipe!
 endfunc
@@ -972,7 +972,7 @@
   call assert_match("foo\nbar", join(log, "\n"))
   call delete('Xlog')
   call mkdir('Xdir')
-  call assert_fails('set verbosefile=Xdir', 'E474:')
+  call assert_fails('set verbosefile=Xdir', ['E484:.*Xdir', 'E474:'])
   call delete('Xdir', 'd')
 endfunc
 
@@ -1208,7 +1208,7 @@
   call assert_fails('call feedkeys("q:\<C-W>\<C-W>\<CR>", "xt")', 'E11:')
   new
   set modified
-  call assert_fails('call feedkeys("q/:qall\<CR>", "xt")', 'E162:')
+  call assert_fails('call feedkeys("q/:qall\<CR>", "xt")', ['E37:', 'E162:'])
   close!
   call feedkeys("q/:close\<CR>", "xt")
   call assert_equal(1, winnr('$'))
diff --git a/src/testdir/test_cpoptions.vim b/src/testdir/test_cpoptions.vim
index ce4e00d..02cadf4 100644
--- a/src/testdir/test_cpoptions.vim
+++ b/src/testdir/test_cpoptions.vim
@@ -104,7 +104,7 @@
   source Xfile
   call assert_equal([1, 2], g:l)
   set cpo+=C
-  call assert_fails('source Xfile', 'E10:')
+  call assert_fails('source Xfile', ['E697:', 'E10:'])
   call delete('Xfile')
   let &cpo = save_cpo
 endfunc
diff --git a/src/testdir/test_cscope.vim b/src/testdir/test_cscope.vim
index 9d12e2f..f4d4208 100644
--- a/src/testdir/test_cscope.vim
+++ b/src/testdir/test_cscope.vim
@@ -189,7 +189,7 @@
 
     " Test: 'cst' option
     set nocst
-    call assert_fails('tag TEST_COUNT', 'E426:')
+    call assert_fails('tag TEST_COUNT', 'E433:')
     set cst
     let a = execute('tag TEST_COUNT')
     call assert_match('(1 of 1): <<TEST_COUNT>> #define TEST_COUNT 50000', a)
diff --git a/src/testdir/test_excmd.vim b/src/testdir/test_excmd.vim
index 2c693e2..150e258 100644
--- a/src/testdir/test_excmd.vim
+++ b/src/testdir/test_excmd.vim
@@ -335,8 +335,8 @@
   call assert_fails('redir abc', 'E475:')
   call assert_fails('redir => 1abc', 'E474:')
   call assert_fails('redir => a b', 'E488:')
-  call assert_fails('redir => abc[1]', 'E474:')
-  let b=0zFF
+  call assert_fails('redir => abc[1]', 'E121:')
+  let b = 0zFF
   call assert_fails('redir =>> b', 'E734:')
   unlet b
 
diff --git a/src/testdir/test_expr.vim b/src/testdir/test_expr.vim
index c5dd1f3..b131543 100644
--- a/src/testdir/test_expr.vim
+++ b/src/testdir/test_expr.vim
@@ -478,7 +478,7 @@
   endif
   eval set->setmatches()
   call assert_equal(exp, getmatches())
-  call assert_fails('let m = setmatches([], [])', 'E957:')
+  call assert_fails('let m = setmatches([], [])', 'E745:')
 endfunc
 
 func Test_empty_concatenate()
diff --git a/src/testdir/test_functions.vim b/src/testdir/test_functions.vim
index 1c463f0..9aa830b 100644
--- a/src/testdir/test_functions.vim
+++ b/src/testdir/test_functions.vim
@@ -224,7 +224,7 @@
   if has('float')
     call assert_fails('call str2nr(1.2)', 'E806:')
   endif
-  call assert_fails('call str2nr(10, [])', 'E474:')
+  call assert_fails('call str2nr(10, [])', 'E745:')
 endfunc
 
 func Test_strftime()
@@ -1702,11 +1702,11 @@
   call assert_equal(4, 'abcd'->libcallnr(libc, 'strlen'))
   call assert_equal(char2nr('A'), char2nr('a')->libcallnr(libc, 'toupper'))
 
-  call assert_fails("call libcall(libc, 'Xdoesnotexist_', '')", 'E364:')
-  call assert_fails("call libcallnr(libc, 'Xdoesnotexist_', '')", 'E364:')
+  call assert_fails("call libcall(libc, 'Xdoesnotexist_', '')", ['', 'E364:'])
+  call assert_fails("call libcallnr(libc, 'Xdoesnotexist_', '')", ['', 'E364:'])
 
-  call assert_fails("call libcall('Xdoesnotexist_', 'getenv', 'HOME')", 'E364:')
-  call assert_fails("call libcallnr('Xdoesnotexist_', 'strlen', 'abcd')", 'E364:')
+  call assert_fails("call libcall('Xdoesnotexist_', 'getenv', 'HOME')", ['', 'E364:'])
+  call assert_fails("call libcallnr('Xdoesnotexist_', 'strlen', 'abcd')", ['', 'E364:'])
 endfunc
 
 sandbox function Fsandbox()
diff --git a/src/testdir/test_global.vim b/src/testdir/test_global.vim
index 38dc082..1e79ed1 100644
--- a/src/testdir/test_global.vim
+++ b/src/testdir/test_global.vim
@@ -36,7 +36,7 @@
 func Test_global_error()
   call assert_fails('g\\a', 'E10:')
   call assert_fails('g', 'E148:')
-  call assert_fails('g/\(/y', 'E476:')
+  call assert_fails('g/\(/y', 'E54:')
 endfunc
 
 " Test for printing lines using :g with different search patterns
diff --git a/src/testdir/test_json.vim b/src/testdir/test_json.vim
index 86c47ae..c3b4382 100644
--- a/src/testdir/test_json.vim
+++ b/src/testdir/test_json.vim
@@ -181,7 +181,7 @@
   call assert_fails('call json_decode("{\"n\",1}")', "E491:")
   call assert_fails('call json_decode("{-}")', "E491:")
   if has('float')
-    call assert_fails('call json_decode("{3.14:1}")', "E474:")
+    call assert_fails('call json_decode("{3.14:1}")', "E806:")
   endif
 
   call assert_fails('call json_decode("[foobar]")', "E491:")
@@ -292,25 +292,25 @@
   call assert_equal({'n': 1}, js_decode('{"n":1,}'))
   call assert_equal({'n': '1'}, js_decode("{'n':'1',}"))
 
-  call assert_fails('call js_decode("\"")', "E474:")
-  call assert_fails('call js_decode("blah")', "E474:")
-  call assert_fails('call js_decode("true blah")', "E474:")
-  call assert_fails('call js_decode("<foobar>")', "E474:")
+  call assert_fails('call js_decode("\"")', "E491:")
+  call assert_fails('call js_decode("blah")', "E491:")
+  call assert_fails('call js_decode("true blah")', "E488:")
+  call assert_fails('call js_decode("<foobar>")', "E491:")
 
-  call assert_fails('call js_decode("{")', "E474:")
-  call assert_fails('call js_decode("{foobar}")', "E474:")
-  call assert_fails('call js_decode("{\"n\",")', "E474:")
-  call assert_fails('call js_decode("{\"n\":")', "E474:")
-  call assert_fails('call js_decode("{\"n\":1")', "E474:")
-  call assert_fails('call js_decode("{\"n\":1,")', "E474:")
-  call assert_fails('call js_decode("{\"n\",1}")', "E474:")
-  call assert_fails('call js_decode("{-}")', "E474:")
+  call assert_fails('call js_decode("{")', "E491:")
+  call assert_fails('call js_decode("{foobar}")', "E491:")
+  call assert_fails('call js_decode("{\"n\",")', "E491:")
+  call assert_fails('call js_decode("{\"n\":")', "E491:")
+  call assert_fails('call js_decode("{\"n\":1")', "E491:")
+  call assert_fails('call js_decode("{\"n\":1,")', "E491:")
+  call assert_fails('call js_decode("{\"n\",1}")', "E491:")
+  call assert_fails('call js_decode("{-}")', "E491:")
 
-  call assert_fails('call js_decode("[foobar]")', "E474:")
-  call assert_fails('call js_decode("[")', "E474:")
-  call assert_fails('call js_decode("[1")', "E474:")
-  call assert_fails('call js_decode("[1,")', "E474:")
-  call assert_fails('call js_decode("[1 2]")', "E474:")
+  call assert_fails('call js_decode("[foobar]")', "E491:")
+  call assert_fails('call js_decode("[")', "E491:")
+  call assert_fails('call js_decode("[1")', "E491:")
+  call assert_fails('call js_decode("[1,")', "E491:")
+  call assert_fails('call js_decode("[1 2]")', "E491:")
 
   call assert_equal(s:varl5, js_decode(s:jsl5))
 endfunc
diff --git a/src/testdir/test_let.vim b/src/testdir/test_let.vim
index f135a2f..404fe15 100644
--- a/src/testdir/test_let.vim
+++ b/src/testdir/test_let.vim
@@ -279,7 +279,7 @@
   let l = [1, 2, 3]
   call assert_fails('let l[:] = 5', 'E709:')
 
-  call assert_fails('let x:lnum=5', 'E488:')
+  call assert_fails('let x:lnum=5', ['E121:', 'E488:'])
   call assert_fails('let v:=5', 'E461:')
   call assert_fails('let [a]', 'E474:')
   call assert_fails('let [a, b] = [', 'E697:')
diff --git a/src/testdir/test_listdict.vim b/src/testdir/test_listdict.vim
index 8a8d353..b064846 100644
--- a/src/testdir/test_listdict.vim
+++ b/src/testdir/test_listdict.vim
@@ -674,10 +674,10 @@
   endif
 
   call assert_fails('call reverse("")', 'E899:')
-  call assert_fails('call uniq([1, 2], {x, y -> []})', 'E882:')
+  call assert_fails('call uniq([1, 2], {x, y -> []})', 'E745:')
   call assert_fails("call sort([1, 2], function('min'), 1)", "E715:")
   call assert_fails("call sort([1, 2], function('invalid_func'))", "E700:")
-  call assert_fails("call sort([1, 2], function('min'))", "E702:")
+  call assert_fails("call sort([1, 2], function('min'))", "E118:")
 endfunc
 
 " reduce a list or a blob
@@ -960,7 +960,7 @@
   call assert_fails('echo d[1:2]', 'E719:')
   call assert_fails("let v = [4, 6][{-> 1}]", 'E729:')
   call assert_fails("let v = range(5)[2:[]]", 'E730:')
-  call assert_fails("let v = range(5)[2:{-> 2}(]", 'E116:')
+  call assert_fails("let v = range(5)[2:{-> 2}(]", ['E15:', 'E116:'])
   call assert_fails("let v = range(5)[2:3", 'E111:')
   call assert_fails("let l = insert([1,2,3], 4, 10)", 'E684:')
   call assert_fails("let l = insert([1,2,3], 4, -10)", 'E684:')
diff --git a/src/testdir/test_listener.vim b/src/testdir/test_listener.vim
index c1fa45e..7c69390 100644
--- a/src/testdir/test_listener.vim
+++ b/src/testdir/test_listener.vim
@@ -210,8 +210,8 @@
 
   " Invalid arguments
   call assert_fails('call listener_add([])', 'E921:')
-  call assert_fails('call listener_add("s:StoreListArgs", [])', 'E158:')
-  call assert_fails('call listener_flush([])', 'E158:')
+  call assert_fails('call listener_add("s:StoreListArgs", [])', 'E730:')
+  call assert_fails('call listener_flush([])', 'E730:')
 endfunc
 
 func s:StoreBufList(buf, start, end, added, list)
diff --git a/src/testdir/test_match.vim b/src/testdir/test_match.vim
index e34c9f2..869ad6c 100644
--- a/src/testdir/test_match.vim
+++ b/src/testdir/test_match.vim
@@ -160,7 +160,7 @@
 
 func Test_matchadd_error()
   call assert_fails("call matchadd('GroupDoesNotExist', 'X')", 'E28:')
-  call assert_fails("call matchadd('Search', '\\(')", 'E475:')
+  call assert_fails("call matchadd('Search', '\\(')", 'E54:')
   call assert_fails("call matchadd('Search', 'XXX', 1, 123, 1)", 'E715:')
   call assert_fails("call matchadd('Error', 'XXX', 1, 3)", 'E798:')
   call assert_fails("call matchadd('Error', 'XXX', 1, 0)", 'E799:')
diff --git a/src/testdir/test_menu.vim b/src/testdir/test_menu.vim
index 4fd2828..38098a1 100644
--- a/src/testdir/test_menu.vim
+++ b/src/testdir/test_menu.vim
@@ -153,7 +153,7 @@
   call assert_fails('menu Test.Foo.Bar', 'E327:')
   call assert_fails('cmenu Test.Foo', 'E328:')
   call assert_fails('emenu x Test.Foo', 'E475:')
-  call assert_fails('emenu Test.Foo.Bar', 'E334:')
+  call assert_fails('emenu Test.Foo.Bar', 'E327:')
   call assert_fails('menutranslate Test', 'E474:')
 
   silent! unmenu Foo
diff --git a/src/testdir/test_method.vim b/src/testdir/test_method.vim
index 7c0559a..0d55f2a 100644
--- a/src/testdir/test_method.vim
+++ b/src/testdir/test_method.vim
@@ -131,9 +131,9 @@
   eval [1, 2, 3]  
 	\ ->sort(
 	\ )
-  call assert_fails('eval [1, 2, 3]-> sort()', 'E260:')
+  call assert_fails('eval [1, 2, 3]-> sort()', 'E15:')
   call assert_fails('eval [1, 2, 3]->sort ()', 'E274:')
-  call assert_fails('eval [1, 2, 3]-> sort ()', 'E260:')
+  call assert_fails('eval [1, 2, 3]-> sort ()', 'E15:')
 endfunc
 
 func Test_method_lambda()
diff --git a/src/testdir/test_normal.vim b/src/testdir/test_normal.vim
index a4dc619..68aae53 100644
--- a/src/testdir/test_normal.vim
+++ b/src/testdir/test_normal.vim
@@ -1384,7 +1384,7 @@
   call setline(1, '---')
   call assert_fails('normal! ggv2lK', 'E349:')
   call setline(1, ['abc', 'xyz'])
-  call assert_fails("normal! gg2lv2h\<C-]>", 'E426:')
+  call assert_fails("normal! gg2lv2h\<C-]>", 'E433:')
   call assert_beeps("normal! ggVjK")
 
   " clean up
diff --git a/src/testdir/test_popup.vim b/src/testdir/test_popup.vim
index c7229fc..381a2c1 100644
--- a/src/testdir/test_popup.vim
+++ b/src/testdir/test_popup.vim
@@ -367,7 +367,7 @@
   setlocal completefunc=DummyCompleteTwo
   call setline(1, 'two')
   /^two
-  call assert_fails('call feedkeys("A\<C-X>\<C-U>\<C-N>\<Esc>", "x")', 'E764:')
+  call assert_fails('call feedkeys("A\<C-X>\<C-U>\<C-N>\<Esc>", "x")', 'E839:')
   call assert_notequal(winid, win_getid())
   q!
   call assert_equal(winid, win_getid())
diff --git a/src/testdir/test_python2.vim b/src/testdir/test_python2.vim
index 42fadaa..8fa7340 100644
--- a/src/testdir/test_python2.vim
+++ b/src/testdir/test_python2.vim
@@ -73,7 +73,7 @@
 
   " Try modifying a buffer with 'nomodifiable' set
   set nomodifiable
-  call assert_fails('pydo toupper(line)', 'cannot save undo information')
+  call assert_fails('pydo toupper(line)', 'E21:')
   set modifiable
 
   " Invalid command
diff --git a/src/testdir/test_python3.vim b/src/testdir/test_python3.vim
index 0082751..830fbba 100644
--- a/src/testdir/test_python3.vim
+++ b/src/testdir/test_python3.vim
@@ -90,7 +90,7 @@
 
   " Try modifying a buffer with 'nomodifiable' set
   set nomodifiable
-  call assert_fails('py3do toupper(line)', 'cannot save undo information')
+  call assert_fails('py3do toupper(line)', 'E21:')
   set modifiable
 
   " Invalid command
@@ -290,7 +290,7 @@
   call assert_equal("\nNone",          execute('py3 print(vim.eval("v:none"))'))
   call assert_equal("\nb'\\xab\\x12'", execute('py3 print(vim.eval("0zab12"))'))
 
-  call assert_fails('py3 vim.eval("1+")', 'vim.error: invalid expression')
+  call assert_fails('py3 vim.eval("1+")', 'E15: Invalid expression')
 endfunc
 
 " Test range objects, see :help python-range
@@ -305,10 +305,10 @@
   call assert_equal('3', py3eval('b[2]'))
   call assert_equal('4', py3eval('r[2]'))
 
-  call assert_fails('py3 r[3] = "x"', 'IndexError: line number out of range')
-  call assert_fails('py3 x = r[3]', 'IndexError: line number out of range')
-  call assert_fails('py3 r["a"] = "x"', 'TypeError: index must be int or slice, not str')
-  call assert_fails('py3 x = r["a"]', 'TypeError: index must be int or slice, not str')
+  call assert_fails('py3 r[3] = "x"', ['Traceback', 'IndexError: line number out of range'])
+  call assert_fails('py3 x = r[3]', ['Traceback', 'IndexError: line number out of range'])
+  call assert_fails('py3 r["a"] = "x"', ['Traceback', 'TypeError: index must be int or slice, not str'])
+  call assert_fails('py3 x = r["a"]', ['Traceback', 'TypeError: index must be int or slice, not str'])
 
   py3 del r[:]
   call assert_equal(['1', '5', '6'], getline(1, '$'))
diff --git a/src/testdir/test_quickfix.vim b/src/testdir/test_quickfix.vim
index 6d119fe..6005b8d 100644
--- a/src/testdir/test_quickfix.vim
+++ b/src/testdir/test_quickfix.vim
@@ -693,7 +693,7 @@
   " Search for non existing help string
   call assert_fails('Xhelpgrep a1b2c3', 'E480:')
   " Invalid regular expression
-  call assert_fails('Xhelpgrep \@<!', 'E480:')
+  call assert_fails('Xhelpgrep \@<!', 'E866:')
 endfunc
 
 func Test_helpgrep()
@@ -3748,8 +3748,8 @@
 
 func Test_lvimgrep_crash2()
   au BufNewFile x sfind
-  call assert_fails('lvimgrep x x', 'E480:')
-  call assert_fails('lvimgrep x x x', 'E480:')
+  call assert_fails('lvimgrep x x', 'E471:')
+  call assert_fails('lvimgrep x x x', 'E471:')
 
   au! BufNewFile
 endfunc
diff --git a/src/testdir/test_random.vim b/src/testdir/test_random.vim
index bdb7e1d..dd2044d 100644
--- a/src/testdir/test_random.vim
+++ b/src/testdir/test_random.vim
@@ -31,11 +31,11 @@
   endif
   call assert_fails('echo srand([1])', 'E745:')
   call assert_fails('echo rand("burp")', 'E475:')
-  call assert_fails('echo rand([1, 2, 3])', 'E475:')
-  call assert_fails('echo rand([[1], 2, 3, 4])', 'E475:')
-  call assert_fails('echo rand([1, [2], 3, 4])', 'E475:')
-  call assert_fails('echo rand([1, 2, [3], 4])', 'E475:')
-  call assert_fails('echo rand([1, 2, 3, [4]])', 'E475:')
+  call assert_fails('echo rand([1, 2, 3])', 'E730:')
+  call assert_fails('echo rand([[1], 2, 3, 4])', 'E730:')
+  call assert_fails('echo rand([1, [2], 3, 4])', 'E730:')
+  call assert_fails('echo rand([1, 2, [3], 4])', 'E730:')
+  call assert_fails('echo rand([1, 2, 3, [4]])', 'E730:')
 
   call test_settime(0)
 endfunc
diff --git a/src/testdir/test_regexp_latin.vim b/src/testdir/test_regexp_latin.vim
index 15ab84c..ac2b15c 100644
--- a/src/testdir/test_regexp_latin.vim
+++ b/src/testdir/test_regexp_latin.vim
@@ -83,7 +83,7 @@
   set re=2
   call assert_fails('/a**', 'E871:')
   call assert_fails('/a*\+', 'E871:')
-  call assert_fails('/a\{a}', 'E870:')
+  call assert_fails('/a\{a}', 'E554:')
   set re=0
 endfunc
 
diff --git a/src/testdir/test_search.vim b/src/testdir/test_search.vim
index e06ccaf..93b68a7 100644
--- a/src/testdir/test_search.vim
+++ b/src/testdir/test_search.vim
@@ -1494,8 +1494,8 @@
     call assert_fails(";//p", 'E35:')
     call assert_fails("??p", 'E35:')
     call assert_fails(";??p", 'E35:')
-    call assert_fails('g//p', 'E476:')
-    call assert_fails('v//p', 'E476:')
+    call assert_fails('g//p', ['E35:', 'E476:'])
+    call assert_fails('v//p', ['E35:', 'E476:'])
     call writefile(v:errors, 'Xresult')
     qall!
   [SCRIPT]
@@ -1516,8 +1516,8 @@
     call assert_fails('exe "normal /~\<CR>"', 'E33:')
     call assert_fails('exe "normal ?~\<CR>"', 'E33:')
     set regexpengine=2
-    call assert_fails('exe "normal /~\<CR>"', 'E383:')
-    call assert_fails('exe "normal ?~\<CR>"', 'E383:')
+    call assert_fails('exe "normal /~\<CR>"', ['E33:', 'E383:'])
+    call assert_fails('exe "normal ?~\<CR>"', ['E33:', 'E383:'])
     set regexpengine&
     call writefile(v:errors, 'Xresult')
     qall!
diff --git a/src/testdir/test_signs.vim b/src/testdir/test_signs.vim
index fabf581..0594ae1 100644
--- a/src/testdir/test_signs.vim
+++ b/src/testdir/test_signs.vim
@@ -458,13 +458,13 @@
   call assert_fails('call sign_place(5, "", "sign1", "@", {"lnum" : 10})',
 	      \ 'E158:')
   call assert_fails('call sign_place(5, "", "sign1", [], {"lnum" : 10})',
-	      \ 'E158:')
+	      \ 'E730:')
   call assert_fails('call sign_place(21, "", "sign1", "Xsign",
 	      \ {"lnum" : -1})', 'E474:')
   call assert_fails('call sign_place(22, "", "sign1", "Xsign",
 	      \ {"lnum" : 0})', 'E474:')
   call assert_fails('call sign_place(22, "", "sign1", "Xsign",
-	      \ {"lnum" : []})', 'E474:')
+	      \ {"lnum" : []})', 'E745:')
   call assert_equal(-1, sign_place(1, "*", "sign1", "Xsign", {"lnum" : 10}))
 
   " Tests for sign_getplaced()
@@ -1724,7 +1724,7 @@
   call assert_fails("call sign_jump(5, 'g5', 'foo')", 'E157:')
   call assert_fails('call sign_jump([], "", "foo")', 'E745:')
   call assert_fails('call sign_jump(2, [], "foo")', 'E730:')
-  call assert_fails('call sign_jump(2, "", {})', 'E158:')
+  call assert_fails('call sign_jump(2, "", {})', 'E731:')
   call assert_fails('call sign_jump(2, "", "baz")', 'E158:')
 
   sign unplace * group=*
diff --git a/src/testdir/test_spell.vim b/src/testdir/test_spell.vim
index fbd5c1a..c2de5ed 100644
--- a/src/testdir/test_spell.vim
+++ b/src/testdir/test_spell.vim
@@ -334,7 +334,7 @@
     return [[{}, {}]]
   endfunc
   set spellsuggest=expr:MySuggest3()
-  call assert_fails("call spellsuggest('baord')", 'E728:')
+  call assert_fails("call spellsuggest('baord')", 'E731:')
 
   set nospell spellsuggest&
   delfunc MySuggest
diff --git a/src/testdir/test_substitute.vim b/src/testdir/test_substitute.vim
index 40d0500..7868c90 100644
--- a/src/testdir/test_substitute.vim
+++ b/src/testdir/test_substitute.vim
@@ -235,7 +235,7 @@
 
   call assert_fails('s/FOO/bar/', 'E486:')
   call assert_fails('s/foo/bar/@', 'E488:')
-  call assert_fails('s/\(/bar/', 'E476:')
+  call assert_fails('s/\(/bar/', 'E54:')
   call assert_fails('s afooabara', 'E146:')
   call assert_fails('s\\a', 'E10:')
 
@@ -817,9 +817,9 @@
 func Test_sub_with_no_last_pat()
   let lines =<< trim [SCRIPT]
     call assert_fails('~', 'E33:')
-    call assert_fails('s//abc/g', 'E476:')
-    call assert_fails('s\/bar', 'E476:')
-    call assert_fails('s\&bar&', 'E476:')
+    call assert_fails('s//abc/g', 'E35:')
+    call assert_fails('s\/bar', 'E35:')
+    call assert_fails('s\&bar&', 'E33:')
     call writefile(v:errors, 'Xresult')
     qall!
   [SCRIPT]
diff --git a/src/testdir/test_syntax.vim b/src/testdir/test_syntax.vim
index ee9406b..2a7398f 100644
--- a/src/testdir/test_syntax.vim
+++ b/src/testdir/test_syntax.vim
@@ -348,7 +348,7 @@
   call assert_fails('syntax sync x', 'E404:')
   call assert_fails('syntax keyword Abc a[', 'E789:')
   call assert_fails('syntax keyword Abc a[bc]d', 'E890:')
-  call assert_fails('syntax cluster Abc add=A add=', 'E475:')
+  call assert_fails('syntax cluster Abc add=A add=', 'E406:')
 
   " Test for too many \z\( and unmatched \z\(
   " Not able to use assert_fails() here because both E50:/E879: and E475:
diff --git a/src/testdir/test_tagfunc.vim b/src/testdir/test_tagfunc.vim
index 97782ae..ca0d247 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', 'E426')
+  call assert_fails('tag nothing', 'E433')
   delf NullTagFunc
 
   bwipe!
diff --git a/src/testdir/test_tagjump.vim b/src/testdir/test_tagjump.vim
index e5a5768..a9890b9 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', 'E426')
+  call assert_fails('ptag does_not_exist_tag_name', 'E433')
   set tagstack&vim
 endfunc
 
@@ -345,7 +345,7 @@
         \ "Xmain.c,64",
         \ ";;;;\x7f1,0",
 	\ ], 'Xtags')
-  call assert_fails('tag foo', 'E426:')
+  call assert_fails('tag foo', 'E431:')
 
   call delete('Xtags')
   call delete('Xtags2')
diff --git a/src/testdir/test_taglist.vim b/src/testdir/test_taglist.vim
index 5252d24..f68ecb0 100644
--- a/src/testdir/test_taglist.vim
+++ b/src/testdir/test_taglist.vim
@@ -84,7 +84,7 @@
 endfunc
 
 func Test_tags_too_long()
-  call assert_fails('tag ' . repeat('x', 1020), '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 a233b2f..067fa0f 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', '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', '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))
@@ -635,7 +635,7 @@
 
 func Test_terminal_list_args()
   let buf = term_start([&shell, &shellcmdflag, 'echo "123"'])
-  call assert_fails(buf . 'bwipe', 'E517')
+  call assert_fails(buf . 'bwipe', ['E89', 'E517'])
   exe buf . 'bwipe!'
   call assert_equal("", bufname(buf))
 endfunction
@@ -981,19 +981,19 @@
   let cmd = "call term_start(0, {'curwin' : 1, 'term_finish' : 'close'})"
   call assert_fails(cmd, 'E474')
   let cmd = "call term_start('', {'term_name' : []})"
-  call assert_fails(cmd, 'E475')
+  call assert_fails(cmd, 'E730')
   let cmd = "call term_start('', {'term_finish' : 'axby'})"
   call assert_fails(cmd, 'E475')
   let cmd = "call term_start('', {'eof_chars' : []})"
-  call assert_fails(cmd, 'E475:')
+  call assert_fails(cmd, 'E730:')
   let cmd = "call term_start('', {'term_kill' : []})"
-  call assert_fails(cmd, 'E475:')
+  call assert_fails(cmd, 'E730:')
   let cmd = "call term_start('', {'tty_type' : []})"
-  call assert_fails(cmd, 'E475:')
+  call assert_fails(cmd, 'E730:')
   let cmd = "call term_start('', {'tty_type' : 'abc'})"
   call assert_fails(cmd, 'E475:')
   let cmd = "call term_start('', {'term_highlight' : []})"
-  call assert_fails(cmd, 'E475:')
+  call assert_fails(cmd, 'E730:')
   if has('gui') || has('termguicolors')
     let cmd = "call term_start('', {'ansi_colors' : 'abc'})"
     call assert_fails(cmd, 'E475:')
@@ -1242,7 +1242,7 @@
   let closedbuf = winbufnr('')
   quit
   call assert_fails("call term_dumpload('dumps/Test_popup_command_01.dump', {'bufnr': closedbuf})", 'E475:')
-  call assert_fails('call term_dumpload([])', 'E474:')
+  call assert_fails('call term_dumpload([])', 'E730:')
   call assert_fails('call term_dumpload("xabcy.dump")', 'E485:')
 
   quit
@@ -1272,7 +1272,7 @@
   call assert_equal('           bbbbbbbbbbbbbbbbbb ', getline(26)[0:29])
   quit
 
-  call assert_fails('call term_dumpdiff("X1.dump", [])', 'E474:')
+  call assert_fails('call term_dumpdiff("X1.dump", [])', 'E730:')
   call assert_fails('call term_dumpdiff("X1.dump", "X2.dump")', 'E485:')
   call writefile([], 'X1.dump')
   call assert_fails('call term_dumpdiff("X1.dump", "X2.dump")', 'E485:')
@@ -1555,7 +1555,7 @@
   call assert_equal(['hello', 123], g:called_arg2)
   call StopVimInTerminal(buf)
 
-  call assert_fails("call term_start('ls', {'term_api' : []})", 'E475:')
+  call assert_fails("call term_start('ls', {'term_api' : []})", 'E730:')
 
   unlet! g:called_bufnum2
   unlet! g:called_arg2
@@ -1761,7 +1761,7 @@
   eval buf->term_setansicolors(colors)
 
   let colors[4] = 'Invalid'
-  call assert_fails('call term_setansicolors(buf, colors)', 'E474:')
+  call assert_fails('call term_setansicolors(buf, colors)', 'E254:')
   call assert_fails('call term_setansicolors(buf, {})', 'E714:')
 
   call StopShellInTerminal(buf)
diff --git a/src/testdir/test_textprop.vim b/src/testdir/test_textprop.vim
index 5dddd16..d5f67b4 100644
--- a/src/testdir/test_textprop.vim
+++ b/src/testdir/test_textprop.vim
@@ -1214,7 +1214,7 @@
   call assert_fails('call prop_clear(1, 2, [])', 'E715:')
   call assert_fails('call prop_clear(-1, 2)', 'E16:')
   call assert_fails('call prop_find(test_null_dict())', 'E474:')
-  call assert_fails('call prop_find({"bufnr" : []})', 'E158:')
+  call assert_fails('call prop_find({"bufnr" : []})', 'E730:')
   call assert_fails('call prop_find({})', 'E968:')
   call assert_fails('call prop_find({}, "x")', 'E474:')
   call assert_fails('call prop_find({"lnum" : -2})', 'E16:')
@@ -1223,11 +1223,11 @@
   call assert_fails('call prop_remove([])', 'E474:')
   call assert_fails('call prop_remove({}, -2)', 'E16:')
   call assert_fails('call prop_remove({})', 'E968:')
-  call assert_fails('call prop_type_add([], {})', 'E474:')
+  call assert_fails('call prop_type_add([], {})', 'E730:')
   call assert_fails("call prop_type_change('long', {'xyz' : 10})", 'E971:')
-  call assert_fails("call prop_type_delete([])", 'E474:')
+  call assert_fails("call prop_type_delete([])", 'E730:')
   call assert_fails("call prop_type_delete('xyz', [])", 'E715:')
-  call assert_fails("call prop_type_get([])", 'E474:')
+  call assert_fails("call prop_type_get([])", 'E730:')
   call assert_fails("call prop_type_get('', [])", 'E474:')
   call assert_fails("call prop_type_list([])", 'E715:')
 endfunc
diff --git a/src/testdir/test_trycatch.vim b/src/testdir/test_trycatch.vim
index 68ab7fc..1f1681f 100644
--- a/src/testdir/test_trycatch.vim
+++ b/src/testdir/test_trycatch.vim
@@ -2000,7 +2000,7 @@
 func Test_try_catch_errors()
   call assert_fails('throw |', 'E471:')
   call assert_fails("throw \n ", 'E471:')
-  call assert_fails('catch abc', 'E603:')
+  call assert_fails('catch abc', 'E654:')
   call assert_fails('try | let i = 1| finally | catch | endtry', 'E604:')
   call assert_fails('finally', 'E606:')
   call assert_fails('try | finally | finally | endtry', 'E607:')
diff --git a/src/testdir/test_utf8.vim b/src/testdir/test_utf8.vim
index e83a3d0..f9f3878 100644
--- a/src/testdir/test_utf8.vim
+++ b/src/testdir/test_utf8.vim
@@ -20,7 +20,7 @@
     call assert_equal(exp[i][1], inp[i]->strchars(0))
     call assert_equal(exp[i][2], strchars(inp[i], 1))
   endfor
-  call assert_fails("let v=strchars('abc', [])", 'E474:')
+  call assert_fails("let v=strchars('abc', [])", 'E745:')
   call assert_fails("let v=strchars('abc', 2)", 'E474:')
 endfunc
 
diff --git a/src/testdir/test_vim9_disassemble.vim b/src/testdir/test_vim9_disassemble.vim
index a63779a..6cde5dd 100644
--- a/src/testdir/test_vim9_disassemble.vim
+++ b/src/testdir/test_vim9_disassemble.vim
@@ -34,8 +34,8 @@
   assert_fails('disass NotCompiled', 'E1062:')
   assert_fails('disass', 'E471:')
   assert_fails('disass [', 'E475:')
-  assert_fails('disass 234', 'E475:')
-  assert_fails('disass <XX>foo', 'E475:')
+  assert_fails('disass 234', 'E129:')
+  assert_fails('disass <XX>foo', 'E129:')
 
   let res = execute('disass s:ScriptFuncLoad')
   assert_match('<SNR>\d*_ScriptFuncLoad.*' ..
diff --git a/src/testdir/test_vim9_func.vim b/src/testdir/test_vim9_func.vim
index 77ada94..5ea2945 100644
--- a/src/testdir/test_vim9_func.vim
+++ b/src/testdir/test_vim9_func.vim
@@ -746,7 +746,7 @@
 def Test_unknown_function()
   CheckDefExecFailure([
       'let Ref: func = function("NotExist")',
-      'delfunc g:NotExist'], 'E130:')
+      'delfunc g:NotExist'], 'E700:')
 enddef
 
 def RefFunc(Ref: func(string): string): string
diff --git a/src/testdir/test_vim9_script.vim b/src/testdir/test_vim9_script.vim
index f923e14..aa0130c 100644
--- a/src/testdir/test_vim9_script.vim
+++ b/src/testdir/test_vim9_script.vim
@@ -305,7 +305,7 @@
   call CheckDefFailure(['let true = 1'], 'E1034:')
   call CheckDefFailure(['let false = 1'], 'E1034:')
 
-  call CheckDefFailure(['[a; b; c] = g:list'], 'E1001:')
+  call CheckDefFailure(['[a; b; c] = g:list'], 'E452:')
   call CheckDefExecFailure(['let a: number',
                             '[a] = test_null_list()'], 'E1093:')
   call CheckDefExecFailure(['let a: number',
@@ -897,7 +897,7 @@
   CheckScriptFailure(['vim9script', 'scriptversion 2'], 'E1040:')
   CheckScriptFailure(['export let some = 123'], 'E1042:')
   CheckScriptFailure(['import some from "./Xexport.vim"'], 'E1048:')
-  CheckScriptFailure(['vim9script', 'export let g:some'], 'E1044:')
+  CheckScriptFailure(['vim9script', 'export let g:some'], 'E1022:')
   CheckScriptFailure(['vim9script', 'export echo 134'], 'E1043:')
 
   CheckScriptFailure(['vim9script', 'let str: string', 'str = 1234'], 'E1013:')
@@ -1723,7 +1723,7 @@
       '  echo "yes"',
       'catch',
       'endtry# comment',
-      ], 'E600:')
+      ], 'E488:')
 
   CheckScriptSuccess([
       'vim9script',
diff --git a/src/testdir/test_viminfo.vim b/src/testdir/test_viminfo.vim
index 1aadf59..258b472 100644
--- a/src/testdir/test_viminfo.vim
+++ b/src/testdir/test_viminfo.vim
@@ -705,13 +705,13 @@
 
   " Too many errors in viminfo file
   call writefile(repeat(["a 123"], 15), 'Xviminfo')
-  call assert_fails('rv Xviminfo', 'E136:')
+  call assert_fails('rv Xviminfo', 'E575:')
 
   call writefile(['>'] + repeat(['@'], 10), 'Xviminfo')
-  call assert_fails('rv Xviminfo', 'E136:')
+  call assert_fails('rv Xviminfo', 'E576:')
 
   call writefile(repeat(['"@'], 15), 'Xviminfo')
-  call assert_fails('rv Xviminfo', 'E136:')
+  call assert_fails('rv Xviminfo', 'E577:')
 
   call delete('Xviminfo')
 endfunc
diff --git a/src/testdir/test_winbuf_close.vim b/src/testdir/test_winbuf_close.vim
index f4878c2..643c106 100644
--- a/src/testdir/test_winbuf_close.vim
+++ b/src/testdir/test_winbuf_close.vim
@@ -115,7 +115,7 @@
   call assert_equal('Xtest2', bufname('%'))
   quit!
   call assert_equal('Xtest3', bufname('%'))
-  call assert_fails('silent! quit!', 'E162')
+  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 aa619cd..5506dbe 100644
--- a/src/testdir/test_window_cmd.vim
+++ b/src/testdir/test_window_cmd.vim
@@ -569,7 +569,7 @@
   au * 0 vs xxx
   arg 0
   argadd
-  call assert_fails("all", "E249:")
+  call assert_fails("all", "E242:")
   au!
   bwipe xxx
   call assert_equal(&columns, winwidth(0))
diff --git a/src/testdir/test_writefile.vim b/src/testdir/test_writefile.vim
index 9106f86..5c9e4b1 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', 'E203:')
+  call assert_fails('lockmarks write', ['E32', 'E203:'])
   augroup WriteTest
     au!
   augroup END
diff --git a/src/testing.c b/src/testing.c
index 5298193..0356565 100644
--- a/src/testing.c
+++ b/src/testing.c
@@ -546,11 +546,13 @@
     garray_T	ga;
     int		save_trylevel = trylevel;
     int		called_emsg_before = called_emsg;
+    int		wrong_arg = FALSE;
 
     // trylevel must be zero for a ":throw" command to be considered failed
     trylevel = 0;
     suppress_errthrow = TRUE;
     emsg_silent = TRUE;
+    emsg_assert_fails_used = TRUE;
 
     do_cmdline_cmd(cmd);
     if (called_emsg == called_emsg_before)
@@ -565,14 +567,58 @@
     else if (argvars[1].v_type != VAR_UNKNOWN)
     {
 	char_u	buf[NUMBUFLEN];
-	char	*error = (char *)tv_get_string_buf_chk(&argvars[1], buf);
+	char_u	*expected;
+	int	error_found = FALSE;
+	char_u	*actual = emsg_assert_fails_msg == NULL ? (char_u *)"[unknown]"
+						       : emsg_assert_fails_msg;
 
-	if (error == NULL
-		  || strstr((char *)get_vim_var_str(VV_ERRMSG), error) == NULL)
+	if (argvars[1].v_type == VAR_STRING)
 	{
+	    expected = tv_get_string_buf_chk(&argvars[1], buf);
+	    error_found = expected == NULL
+			   || strstr((char *)actual, (char *)expected) == NULL;
+	}
+	else if (argvars[1].v_type == VAR_LIST)
+	{
+	    list_T	*list = argvars[1].vval.v_list;
+	    typval_T	*tv;
+
+	    if (list == NULL || list->lv_len < 1 || list->lv_len > 2)
+	    {
+		wrong_arg = TRUE;
+		goto theend;
+	    }
+	    CHECK_LIST_MATERIALIZE(list);
+	    tv = &list->lv_first->li_tv;
+	    expected = tv_get_string_buf_chk(tv, buf);
+	    if (!pattern_match(expected, actual, FALSE))
+	    {
+		error_found = TRUE;
+	    }
+	    else if (list->lv_len == 2)
+	    {
+		tv = &list->lv_u.mat.lv_last->li_tv;
+		actual = get_vim_var_str(VV_ERRMSG);
+		expected = tv_get_string_buf_chk(tv, buf);
+		if (!pattern_match(expected, actual, FALSE))
+		    error_found = TRUE;
+	    }
+	}
+	else
+	{
+	    wrong_arg = TRUE;
+	    goto theend;
+	}
+
+	if (error_found)
+	{
+	    typval_T actual_tv;
+
 	    prepare_assert_error(&ga);
+	    actual_tv.v_type = VAR_STRING;
+	    actual_tv.vval.v_string = actual;
 	    fill_assert_error(&ga, &argvars[2], NULL, &argvars[1],
-				      get_vim_var_tv(VV_ERRMSG), ASSERT_OTHER);
+						     &actual_tv, ASSERT_OTHER);
 	    ga_concat(&ga, (char_u *)": ");
 	    assert_append_cmd_or_arg(&ga, argvars, cmd);
 	    assert_error(&ga);
@@ -581,11 +627,16 @@
 	}
     }
 
+theend:
     trylevel = save_trylevel;
     suppress_errthrow = FALSE;
     emsg_silent = FALSE;
     emsg_on_display = FALSE;
+    emsg_assert_fails_used = FALSE;
+    VIM_CLEAR(emsg_assert_fails_msg);
     set_vim_var_string(VV_ERRMSG, NULL, 0);
+    if (wrong_arg)
+	emsg(_("E856: assert_fails() second argument must be a string or a list with one or two strings"));
 }
 
 /*
diff --git a/src/version.c b/src/version.c
index c15cc04..ece1006 100644
--- a/src/version.c
+++ b/src/version.c
@@ -755,6 +755,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1183,
+/**/
     1182,
 /**/
     1181,
diff --git a/src/vim9compile.c b/src/vim9compile.c
index 8905ee3..fceb481 100644
--- a/src/vim9compile.c
+++ b/src/vim9compile.c
@@ -912,7 +912,12 @@
  * - return FAIL.
  */
     static int
-need_type(type_T *actual, type_T *expected, int offset, cctx_T *cctx)
+need_type(
+	type_T	*actual,
+	type_T	*expected,
+	int	offset,
+	cctx_T	*cctx,
+	int	silent)
 {
     if (check_type(expected, actual, FALSE) == OK)
 	return OK;
@@ -921,7 +926,8 @@
 	    && !(actual->tt_type == VAR_FUNC
 		&& (actual->tt_member == &t_any || actual->tt_argcount < 0)))
     {
-	type_mismatch(expected, actual);
+	if (!silent)
+	    type_mismatch(expected, actual);
 	return FAIL;
     }
     generate_TYPECHECK(cctx, expected, offset);
@@ -1538,7 +1544,7 @@
 	    else
 		expected = ufunc->uf_va_type->tt_member;
 	    actual = ((type_T **)stack->ga_data)[stack->ga_len - argcount + i];
-	    if (need_type(actual, expected, -argcount + i, cctx) == FAIL)
+	    if (need_type(actual, expected, -argcount + i, cctx, TRUE) == FAIL)
 	    {
 		arg_type_mismatch(expected, actual, i + 1);
 		return FAIL;
@@ -4640,8 +4646,8 @@
 		emsg(_("E1096: Returning a value in a function without a return type"));
 		return NULL;
 	    }
-	    if (need_type(stack_type, cctx->ctx_ufunc->uf_ret_type, -1, cctx)
-								       == FAIL)
+	    if (need_type(stack_type, cctx->ctx_ufunc->uf_ret_type, -1,
+							  cctx, FALSE) == FAIL)
 	    return NULL;
 	}
     }
@@ -4942,7 +4948,7 @@
 		emsg(_(e_cannot_use_void));
 		goto theend;
 	    }
-	    if (need_type(stacktype, &t_list_any, -1, cctx) == FAIL)
+	    if (need_type(stacktype, &t_list_any, -1, cctx, FALSE) == FAIL)
 		goto theend;
 	    generate_CHECKLEN(cctx, semicolon ? var_count - 1 : var_count,
 								    semicolon);
@@ -5356,13 +5362,13 @@
 			    if (use_type == NULL)
 				use_type = &t_void;
 			}
-			if (need_type(stacktype, use_type, -1, cctx)
+			if (need_type(stacktype, use_type, -1, cctx, FALSE)
 								   == FAIL)
 			    goto theend;
 		    }
 		}
 		else if (*p != '=' && need_type(stacktype, member_type, -1,
-							     cctx) == FAIL)
+							  cctx, FALSE) == FAIL)
 		    goto theend;
 	    }
 	    else if (cmdidx == CMD_const)
@@ -5439,7 +5445,7 @@
 	    if (*op == '.')
 		expected = &t_string;
 	    stacktype = ((type_T **)stack->ga_data)[stack->ga_len - 1];
-	    if (need_type(stacktype, expected, -1, cctx) == FAIL)
+	    if (need_type(stacktype, expected, -1, cctx, FALSE) == FAIL)
 		goto theend;
 
 	    if (*op == '.')
@@ -6128,7 +6134,7 @@
     // Now that we know the type of "var", check that it is a list, now or at
     // runtime.
     vartype = ((type_T **)stack->ga_data)[stack->ga_len - 1];
-    if (need_type(vartype, &t_list_any, -1, cctx) == FAIL)
+    if (need_type(vartype, &t_list_any, -1, cctx, FALSE) == FAIL)
     {
 	drop_scope(cctx);
 	return NULL;