lib/PublicInbox/ViewDiff.pm | 4 ++--

diff --git a/lib/PublicInbox/ViewDiff.pm b/lib/PublicInbox/ViewDiff.pm
index 2074e12fffbd01a5deb6ffd955849e7aaafd185d..fbdc5b951e73e691bf2d37f445da1977efd8decf 100644
--- a/lib/PublicInbox/ViewDiff.pm
+++ b/lib/PublicInbox/ViewDiff.pm
@@ -133,8 +133,8 @@ 				$dctx = {
 					Q => "?b=".uri_escape_utf8($pb, UNSAFE),
 				};
 				if ($pa ne $pb) {
-					$dctx->{Q} .=
-					     "&a=".uri_escape_utf8($pa, UNSAFE);
+					$dctx->{Q} .= '&a='.
+						uri_escape_utf8($pa, UNSAFE);
 				}
 				anchor1($dst, $ctx, $linkify, $pb, $s) and next;
 			}