diff --git a/contrib/synthrepo.py b/contrib/synthrepo.py
--- a/contrib/synthrepo.py
+++ b/contrib/synthrepo.py
@@ -54,6 +54,7 @@ from mercurial.node import (
 )
 from mercurial import (
     context,
+    diffutil,
     error,
     hg,
     patch,
@@ -62,7 +63,6 @@ from mercurial import (
 )
 from mercurial.utils import (
     dateutil,
-    diffutil,
 )
 
 # Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
diff --git a/mercurial/utils/diffutil.py b/mercurial/diffutil.py
rename from mercurial/utils/diffutil.py
rename to mercurial/diffutil.py
--- a/mercurial/utils/diffutil.py
+++ b/mercurial/diffutil.py
@@ -9,9 +9,9 @@
 
 from __future__ import absolute_import
 
-from ..i18n import _
+from .i18n import _
 
-from .. import (
+from . import (
     mdiff,
     pycompat,
 )
diff --git a/mercurial/hgweb/webutil.py b/mercurial/hgweb/webutil.py
--- a/mercurial/hgweb/webutil.py
+++ b/mercurial/hgweb/webutil.py
@@ -25,6 +25,7 @@ from .common import (
 
 from .. import (
     context,
+    diffutil,
     error,
     match,
     mdiff,
@@ -41,7 +42,6 @@ from .. import (
 )
 
 from ..utils import (
-    diffutil,
     stringutil,
 )
 
diff --git a/mercurial/obsutil.py b/mercurial/obsutil.py
--- a/mercurial/obsutil.py
+++ b/mercurial/obsutil.py
@@ -11,13 +11,13 @@ import re
 
 from .i18n import _
 from . import (
+    diffutil,
     node as nodemod,
     phases,
     util,
 )
 from .utils import (
     dateutil,
-    diffutil,
 )
 
 ### obsolescence marker flag
diff --git a/mercurial/patch.py b/mercurial/patch.py
--- a/mercurial/patch.py
+++ b/mercurial/patch.py
@@ -28,6 +28,7 @@ from .node import (
 from . import (
     copies,
     diffhelper,
+    diffutil,
     encoding,
     error,
     mail,
@@ -41,7 +42,6 @@ from . import (
 )
 from .utils import (
     dateutil,
-    diffutil,
     procutil,
     stringutil,
 )
diff --git a/mercurial/revset.py b/mercurial/revset.py
--- a/mercurial/revset.py
+++ b/mercurial/revset.py
@@ -13,6 +13,7 @@ from .i18n import _
 from . import (
     dagop,
     destutil,
+    diffutil,
     encoding,
     error,
     hbisect,
@@ -33,7 +34,6 @@ from . import (
 )
 from .utils import (
     dateutil,
-    diffutil,
     stringutil,
 )
 
diff --git a/mercurial/templatekw.py b/mercurial/templatekw.py
--- a/mercurial/templatekw.py
+++ b/mercurial/templatekw.py
@@ -14,6 +14,7 @@ from .node import (
 )
 
 from . import (
+    diffutil,
     encoding,
     error,
     hbisect,
@@ -27,7 +28,6 @@ from . import (
     util,
 )
 from .utils import (
-    diffutil,
     stringutil,
 )
 
diff --git a/tests/test-context.py b/tests/test-context.py
--- a/tests/test-context.py
+++ b/tests/test-context.py
@@ -5,12 +5,12 @@ import sys
 from mercurial.node import hex
 from mercurial import (
     context,
+    diffutil,
     encoding,
     hg,
     scmutil,
     ui as uimod,
 )
-from mercurial.utils import diffutil
 
 print_ = print
 def print(*args, **kwargs):