(...)
$this->getOutput() ->setPageTitle( wfMsg( 'abusefilter-examine' ) ) ->addWikiMsg( 'abusefilter-examine-intro' );
vs
$out = $this->getOutput(); $out->setPageTitle( wfMsg( 'abusefilter-examine' ) ); $out->addWikiMsg( 'abusefilter-examine-intro' );
And if $out was indeed null, just the line number would point out which object was, instead of needing to test the whole chain.