do not use empty() without write-context

views/html/users/login.tpl

@@ -0,0 +1,18 @@
+<h1><?=_('Users')?></h1>
+
+<h2><?=_('Login')?></h2>
+<?php if($failed) : ?>
+<p class="invalid"><?=_('Login failed')?>.</p>
+<?php endif ?>
+<form method="post" action="<?=$linker->link(array(), 2)?>" class="logreg">
+	<fieldset>
+		<label for="username"><?=_('Username')?>:</label>
+		<input name="username" type="text" placeholder="<?=_('Username')?>" value="<?=$username?>" required="required" autofocus="autofocus" /><br />
+		<label for="password"><?=_('Password')?>:</label>
+		<input name="password" type="password" placeholder="<?=_('Password')?>" required="required" /><br />
+	</fieldset>
+	<?php if(!empty($referrer)) : ?>
+	<input type="hidden" name="referrer" value="<?=$referrer?>" />
+	<?php endif ?>
+	<input type="submit" name="login" value="<?=_('Login')?>" />
+</form>