diff --git a/src/evalfunc.c b/src/evalfunc.c
index e69f293..619abba 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -495,7 +495,7 @@
     {"assert_equal",	2, 3, FEARG_2,	  ret_number,	f_assert_equal},
     {"assert_equalfile", 2, 3, FEARG_1,	  ret_number,	f_assert_equalfile},
     {"assert_exception", 1, 2, 0,	  ret_number,	f_assert_exception},
-    {"assert_fails",	1, 4, FEARG_1,	  ret_number,	f_assert_fails},
+    {"assert_fails",	1, 5, FEARG_1,	  ret_number,	f_assert_fails},
     {"assert_false",	1, 2, FEARG_1,	  ret_number,	f_assert_false},
     {"assert_inrange",	3, 4, FEARG_3,	  ret_number,	f_assert_inrange},
     {"assert_match",	2, 3, FEARG_2,	  ret_number,	f_assert_match},
diff --git a/src/globals.h b/src/globals.h
index 6434190..337c068 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -224,6 +224,7 @@
 EXTERN int	emsg_assert_fails_used INIT(= FALSE);
 EXTERN char_u	*emsg_assert_fails_msg INIT(= NULL);
 EXTERN long	emsg_assert_fails_lnum INIT(= 0);
+EXTERN char_u	*emsg_assert_fails_context INIT(= NULL);
 
 EXTERN int	did_endif INIT(= FALSE);    // just had ":endif"
 #endif
diff --git a/src/message.c b/src/message.c
index 38e6959..a9851ef 100644
--- a/src/message.c
+++ b/src/message.c
@@ -658,6 +658,9 @@
 	{
 	    emsg_assert_fails_msg = vim_strsave(s);
 	    emsg_assert_fails_lnum = SOURCING_LNUM;
+	    vim_free(emsg_assert_fails_context);
+	    emsg_assert_fails_context = vim_strsave(
+			 SOURCING_NAME == NULL ? (char_u *)"" : SOURCING_NAME);
 	}
 
 	// set "v:errmsg", also when using ":silent! cmd"
diff --git a/src/testdir/test_vim9_func.vim b/src/testdir/test_vim9_func.vim
index 4efb48e..bf81bbe 100644
--- a/src/testdir/test_vim9_func.vim
+++ b/src/testdir/test_vim9_func.vim
@@ -30,7 +30,7 @@
 def Test_return_something()
   assert_equal('string', ReturnString())
   assert_equal(123, ReturnNumber())
-  assert_fails('ReturnGlobal()', 'E1029: Expected number but got string')
+  assert_fails('ReturnGlobal()', 'E1029: Expected number but got string', '', 1, 'ReturnGlobal')
 enddef
 
 def Test_missing_return()
@@ -112,7 +112,7 @@
 def Test_call_default_args()
   assert_equal('string', MyDefaultArgs())
   assert_equal('one', MyDefaultArgs('one'))
-  assert_fails('MyDefaultArgs("one", "two")', 'E118:')
+  assert_fails('MyDefaultArgs("one", "two")', 'E118:', '', 3, 'Test_call_default_args')
 
   assert_equal('test', MyDefaultSecond('test'))
   assert_equal('test', MyDefaultSecond('test', true))
@@ -139,7 +139,7 @@
 func Test_call_default_args_from_func()
   call assert_equal('string', MyDefaultArgs())
   call assert_equal('one', MyDefaultArgs('one'))
-  call assert_fails('call MyDefaultArgs("one", "two")', 'E118:')
+  call assert_fails('call MyDefaultArgs("one", "two")', 'E118:', '', 3, 'Test_call_default_args_from_func')
 endfunc
 
 def Test_nested_global_function()
@@ -245,7 +245,7 @@
 enddef
 
 def Test_call_def_varargs()
-  assert_fails('MyDefVarargs()', 'E119:')
+  assert_fails('MyDefVarargs()', 'E119:', '', 1, 'Test_call_def_varargs')
   assert_equal('one,foo', MyDefVarargs('one'))
   assert_equal('one,two', MyDefVarargs('one', 'two'))
   assert_equal('one,two,three', MyDefVarargs('one', 'two', 'three'))
@@ -362,7 +362,7 @@
 
 def Test_using_var_as_arg()
   writefile(['def Func(x: number)',  'let x = 234', 'enddef', 'defcompile'], 'Xdef')
-  assert_fails('so Xdef', 'E1006:')
+  assert_fails('so Xdef', 'E1006:', '', 1, 'Func')
   delete('Xdef')
 enddef
 
@@ -388,7 +388,7 @@
 
 def Test_call_func_defined_later()
   assert_equal('one', g:DefinedLater('one'))
-  assert_fails('NotDefined("one")', 'E117:')
+  assert_fails('NotDefined("one")', 'E117:', '', 2, 'Test_call_func_defined_later')
 enddef
 
 func DefinedLater(arg)
@@ -397,8 +397,8 @@
 
 def Test_call_funcref()
   assert_equal(3, g:SomeFunc('abc'))
-  assert_fails('NotAFunc()', 'E117:') # comment after call
-  assert_fails('g:NotAFunc()', 'E117:')
+  assert_fails('NotAFunc()', 'E117:', '', 2, 'Test_call_funcref') # comment after call
+  assert_fails('g:NotAFunc()', 'E117:', '', 3, 'Test_call_funcref')
 
   let lines =<< trim END
     vim9script
@@ -524,7 +524,7 @@
 
 def Test_error_in_nested_function()
   # Error in called function requires unwinding the call stack.
-  assert_fails('FuncWithForwardCall()', 'E1096:')
+  assert_fails('FuncWithForwardCall()', 'E1096:', 1, 'FuncWithForwardCall')
 enddef
 
 def Test_return_type_wrong()
@@ -705,7 +705,7 @@
     defcompile
   END
   writefile(lines, 'Xcall_const.vim')
-  assert_fails('source Xcall_const.vim', 'E46:')
+  assert_fails('source Xcall_const.vim', 'E46:', '', 1, 'MyFunc')
   delete('Xcall_const.vim')
 enddef
 
@@ -736,8 +736,8 @@
     CallGoneSoon()
   END
   writefile(lines, 'XToDelFunc')
-  assert_fails('so XToDelFunc', 'E933:')
-  assert_fails('so XToDelFunc', 'E933:')
+  assert_fails('so XToDelFunc', 'E933:', '', 1, 'CallGoneSoon')
+  assert_fails('so XToDelFunc', 'E933:', '', 1, 'CallGoneSoon')
 
   delete('XToDelFunc')
 enddef
@@ -748,7 +748,7 @@
   writefile(['def Func1(): string',  'return "Func1"', 'enddef'], 'Xdef')
   so Xdef
   writefile(['def! Func0(): string', 'enddef', 'defcompile'], 'Xdef')
-  assert_fails('so Xdef', 'E1027:')
+  assert_fails('so Xdef', 'E1027:', '', 1, 'Func0')
   writefile(['def Func2(): string',  'return "Func2"', 'enddef'], 'Xdef')
   so Xdef
   delete('Xdef')
@@ -824,7 +824,7 @@
     defcompile
   END
   call writefile(l, 'Xinvalidarg')
-  call assert_fails('so Xinvalidarg', 'E118:')
+  call assert_fails('so Xinvalidarg', 'E118:', '', 1, 'FArgErr')
   let l =<< trim END
     def! FArgErr(): float
       return ceil()
@@ -832,7 +832,7 @@
     defcompile
   END
   call writefile(l, 'Xinvalidarg')
-  call assert_fails('so Xinvalidarg', 'E119:')
+  call assert_fails('so Xinvalidarg', 'E119:', '', 1, 'FArgErr')
   call delete('Xinvalidarg')
 endfunc
 
diff --git a/src/testing.c b/src/testing.c
index ed2d511..5f7858d 100644
--- a/src/testing.c
+++ b/src/testing.c
@@ -573,7 +573,7 @@
 	char_u	buf[NUMBUFLEN];
 	char_u	*expected;
 	int	error_found = FALSE;
-	int	lnum_error_found = FALSE;
+	int	error_found_index = 1;
 	char_u	*actual = emsg_assert_fails_msg == NULL ? (char_u *)"[unknown]"
 						       : emsg_assert_fails_msg;
 
@@ -616,12 +616,22 @@
 	}
 
 	if (!error_found && argvars[2].v_type != VAR_UNKNOWN
-		&& argvars[3].v_type == VAR_NUMBER
-		&& argvars[3].vval.v_number >= 0
-		&& argvars[3].vval.v_number != emsg_assert_fails_lnum)
+		&& argvars[3].v_type == VAR_NUMBER)
 	{
-	    error_found = TRUE;
-	    lnum_error_found = TRUE;
+	    if (argvars[3].vval.v_number >= 0
+		&& argvars[3].vval.v_number != emsg_assert_fails_lnum)
+	    {
+		error_found = TRUE;
+		error_found_index = 3;
+	    }
+	    if (!error_found && argvars[4].v_type == VAR_STRING
+		    && argvars[4].vval.v_string != NULL
+		    && !pattern_match(argvars[4].vval.v_string,
+					     emsg_assert_fails_context, FALSE))
+	    {
+		error_found = TRUE;
+		error_found_index = 4;
+	    }
 	}
 
 	if (error_found)
@@ -629,19 +639,23 @@
 	    typval_T actual_tv;
 
 	    prepare_assert_error(&ga);
-	    if (lnum_error_found)
+	    if (error_found_index == 3)
 	    {
 		actual_tv.v_type = VAR_NUMBER;
 		actual_tv.vval.v_number = emsg_assert_fails_lnum;
 	    }
+	    else if (error_found_index == 4)
+	    {
+		actual_tv.v_type = VAR_STRING;
+		actual_tv.vval.v_string = emsg_assert_fails_context;
+	    }
 	    else
 	    {
 		actual_tv.v_type = VAR_STRING;
 		actual_tv.vval.v_string = actual;
 	    }
 	    fill_assert_error(&ga, &argvars[2], NULL,
-		    &argvars[lnum_error_found ? 3 : 1],
-						     &actual_tv, ASSERT_OTHER);
+			&argvars[error_found_index], &actual_tv, ASSERT_OTHER);
 	    ga_concat(&ga, (char_u *)": ");
 	    assert_append_cmd_or_arg(&ga, argvars, cmd);
 	    assert_error(&ga);
diff --git a/src/version.c b/src/version.c
index b07e2a8..39dbe0f 100644
--- a/src/version.c
+++ b/src/version.c
@@ -755,6 +755,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1631,
+/**/
     1630,
 /**/
     1629,