diff --git a/format_test.go b/format_test.go
index 781892b..15fd7d8 100644
--- a/format_test.go
+++ b/format_test.go
@@ -27,12 +27,11 @@ func TestFormatNew(t *testing.T) {
 		"%+v",
 		"error\n" +
 			"github.com/pkg/errors.TestFormatNew\n" +
-			"\t.+/github.com/pkg/errors/format_test.go:25",
+			"\t.+/github.com/pkg/errors/format_test.go:26",
 	}, {
 		New("error"),
 		"%q",
 		`"error"`,
-		"\t.+/github.com/pkg/errors/format_test.go:26",
 	}}
 
 	for i, tt := range tests {
@@ -58,7 +57,7 @@ func TestFormatErrorf(t *testing.T) {
 		"%+v",
 		"error\n" +
 			"github.com/pkg/errors.TestFormatErrorf\n" +
-			"\t.+/github.com/pkg/errors/format_test.go:55",
+			"\t.+/github.com/pkg/errors/format_test.go:56",
 	}}
 
 	for i, tt := range tests {
@@ -84,7 +83,7 @@ func TestFormatWrap(t *testing.T) {
 		"%+v",
 		"error\n" +
 			"github.com/pkg/errors.TestFormatWrap\n" +
-			"\t.+/github.com/pkg/errors/format_test.go:81",
+			"\t.+/github.com/pkg/errors/format_test.go:82",
 	}, {
 		Wrap(io.EOF, "error"),
 		"%s",
@@ -99,14 +98,14 @@ func TestFormatWrap(t *testing.T) {
 		"EOF\n" +
 			"error\n" +
 			"github.com/pkg/errors.TestFormatWrap\n" +
-			"\t.+/github.com/pkg/errors/format_test.go:95",
+			"\t.+/github.com/pkg/errors/format_test.go:96",
 	}, {
 		Wrap(Wrap(io.EOF, "error1"), "error2"),
 		"%+v",
 		"EOF\n" +
 			"error1\n" +
 			"github.com/pkg/errors.TestFormatWrap\n" +
-			"\t.+/github.com/pkg/errors/format_test.go:102\n",
+			"\t.+/github.com/pkg/errors/format_test.go:103\n",
 	}, {
 		Wrap(New("error with space"), "context"),
 		"%q",
@@ -137,7 +136,7 @@ func TestFormatWrapf(t *testing.T) {
 		"EOF\n" +
 			"error2\n" +
 			"github.com/pkg/errors.TestFormatWrapf\n" +
-			"\t.+/github.com/pkg/errors/format_test.go:133",
+			"\t.+/github.com/pkg/errors/format_test.go:134",
 	}, {
 		Wrapf(New("error"), "error%d", 2),
 		"%s",
@@ -151,7 +150,7 @@ func TestFormatWrapf(t *testing.T) {
 		"%+v",
 		"error\n" +
 			"github.com/pkg/errors.TestFormatWrapf\n" +
-			"\t.+/github.com/pkg/errors/format_test.go:148",
+			"\t.+/github.com/pkg/errors/format_test.go:149",
 	}}
 
 	for i, tt := range tests {
@@ -177,7 +176,7 @@ func TestFormatWithStack(t *testing.T) {
 		"%+v",
 		[]string{"EOF",
 			"github.com/pkg/errors.TestFormatWithStack\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:171"},
+				"\t.+/github.com/pkg/errors/format_test.go:175"},
 	}, {
 		WithStack(New("error")),
 		"%s",
@@ -191,36 +190,36 @@ func TestFormatWithStack(t *testing.T) {
 		"%+v",
 		[]string{"error",
 			"github.com/pkg/errors.TestFormatWithStack\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:185",
+				"\t.+/github.com/pkg/errors/format_test.go:189",
 			"github.com/pkg/errors.TestFormatWithStack\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:185"},
+				"\t.+/github.com/pkg/errors/format_test.go:189"},
 	}, {
 		WithStack(WithStack(io.EOF)),
 		"%+v",
 		[]string{"EOF",
 			"github.com/pkg/errors.TestFormatWithStack\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:193",
+				"\t.+/github.com/pkg/errors/format_test.go:197",
 			"github.com/pkg/errors.TestFormatWithStack\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:193"},
+				"\t.+/github.com/pkg/errors/format_test.go:197"},
 	}, {
 		WithStack(WithStack(Wrapf(io.EOF, "message"))),
 		"%+v",
 		[]string{"EOF",
 			"message",
 			"github.com/pkg/errors.TestFormatWithStack\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:201",
+				"\t.+/github.com/pkg/errors/format_test.go:205",
 			"github.com/pkg/errors.TestFormatWithStack\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:201",
+				"\t.+/github.com/pkg/errors/format_test.go:205",
 			"github.com/pkg/errors.TestFormatWithStack\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:201"},
+				"\t.+/github.com/pkg/errors/format_test.go:205"},
 	}, {
 		WithStack(Errorf("error%d", 1)),
 		"%+v",
 		[]string{"error1",
 			"github.com/pkg/errors.TestFormatWithStack\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:212",
+				"\t.+/github.com/pkg/errors/format_test.go:216",
 			"github.com/pkg/errors.TestFormatWithStack\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:212"},
+				"\t.+/github.com/pkg/errors/format_test.go:216"},
 	}}
 
 	for i, tt := range tests {
@@ -247,7 +246,7 @@ func TestFormatWithMessage(t *testing.T) {
 		[]string{
 			"error",
 			"github.com/pkg/errors.TestFormatWithMessage\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:240",
+				"\t.+/github.com/pkg/errors/format_test.go:244",
 			"error2"},
 	}, {
 		WithMessage(io.EOF, "addition1"),
@@ -274,13 +273,13 @@ func TestFormatWithMessage(t *testing.T) {
 		"%+v",
 		[]string{"EOF", "error1", "error2",
 			"github.com/pkg/errors.TestFormatWithMessage\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:268"},
+				"\t.+/github.com/pkg/errors/format_test.go:272"},
 	}, {
 		WithMessage(Errorf("error%d", 1), "error2"),
 		"%+v",
 		[]string{"error1",
 			"github.com/pkg/errors.TestFormatWithMessage\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:274",
+				"\t.+/github.com/pkg/errors/format_test.go:278",
 			"error2"},
 	}, {
 		WithMessage(WithStack(io.EOF), "error"),
@@ -288,7 +287,7 @@ func TestFormatWithMessage(t *testing.T) {
 		[]string{
 			"EOF",
 			"github.com/pkg/errors.TestFormatWithMessage\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:281",
+				"\t.+/github.com/pkg/errors/format_test.go:285",
 			"error"},
 	}, {
 		WithMessage(Wrap(WithStack(io.EOF), "inside-error"), "outside-error"),
@@ -296,10 +295,10 @@ func TestFormatWithMessage(t *testing.T) {
 		[]string{
 			"EOF",
 			"github.com/pkg/errors.TestFormatWithMessage\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:289",
+				"\t.+/github.com/pkg/errors/format_test.go:293",
 			"inside-error",
 			"github.com/pkg/errors.TestFormatWithMessage\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:289",
+				"\t.+/github.com/pkg/errors/format_test.go:293",
 			"outside-error"},
 	}}
 
@@ -316,11 +315,11 @@ func TestFormatGeneric(t *testing.T) {
 		{New("new-error"), []string{
 			"new-error",
 			"github.com/pkg/errors.TestFormatGeneric\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:311"},
+				"\t.+/github.com/pkg/errors/format_test.go:315"},
 		}, {Errorf("errorf-error"), []string{
 			"errorf-error",
 			"github.com/pkg/errors.TestFormatGeneric\n" +
-				"\t.+/github.com/pkg/errors/format_test.go:315"},
+				"\t.+/github.com/pkg/errors/format_test.go:319"},
 		}, {errors.New("errors-new-error"), []string{
 			"errors-new-error"},
 		},
@@ -334,21 +333,21 @@ func TestFormatGeneric(t *testing.T) {
 			func(err error) error { return WithStack(err) },
 			[]string{
 				"github.com/pkg/errors.(func·002|TestFormatGeneric.func2)\n\t" +
-					".+/github.com/pkg/errors/format_test.go:329",
+					".+/github.com/pkg/errors/format_test.go:333",
 			},
 		}, {
 			func(err error) error { return Wrap(err, "wrap-error") },
 			[]string{
 				"wrap-error",
 				"github.com/pkg/errors.(func·003|TestFormatGeneric.func3)\n\t" +
-					".+/github.com/pkg/errors/format_test.go:335",
+					".+/github.com/pkg/errors/format_test.go:339",
 			},
 		}, {
 			func(err error) error { return Wrapf(err, "wrapf-error%d", 1) },
 			[]string{
 				"wrapf-error1",
 				"github.com/pkg/errors.(func·004|TestFormatGeneric.func4)\n\t" +
-					".+/github.com/pkg/errors/format_test.go:342",
+					".+/github.com/pkg/errors/format_test.go:346",
 			},
 		},
 	}