When storing previous url we should use current_url() to ensure we ge…

…t baseURL paths and any query vars. Fixes #2378

system/CodeIgniter.php

@@ -373,7 +373,7 @@ protected function handleRequest(RouteCollectionInterface $routes = null, $cache
 
 		// Save our current URI as the previous URI in the session
 		// for safer, more accurate use with `previous_url()` helper function.
-		$this->storePreviousURL($this->request->uri ?? $uri);
+		$this->storePreviousURL((string)current_url(true));
 
 		unset($uri);