diff --git a/mercurial/util.py b/mercurial/util.py
--- a/mercurial/util.py
+++ b/mercurial/util.py
@@ -1953,7 +1953,7 @@ def matchdate(date):
         except ValueError:
             raise Abort(_("invalid day spec: %s") % date[1:])
         if days < 0:
-            raise Abort(_('%s must be nonnegative (see "hg help dates")')
+            raise Abort(_("%s must be nonnegative (see 'hg help dates')")
                 % date[1:])
         when = makedate()[0] - days * 3600 * 24
         return lambda x: x >= when
diff --git a/tests/test-parse-date.t b/tests/test-parse-date.t
--- a/tests/test-parse-date.t
+++ b/tests/test-parse-date.t
@@ -102,7 +102,7 @@ Normal range
 Negative range
 
   $ hg log -d "--2"
-  abort: -2 must be nonnegative (see "hg help dates")
+  abort: -2 must be nonnegative (see 'hg help dates')
   [255]
 
 Whitespace only