Fix issue where first slug was duplicated on fallback routes

Author: ivanvermeyen

src/Middleware/SetLocale.php

@@ -51,6 +51,10 @@ protected function getLocaleFromFallbackRoute(\Illuminate\Http\Request $request)
             return $omittedLocale;
         }
 
+        if ( ! $localeIsSupported) {
+            return null;
+        }
+
         return $locale;
     }
 

tests/Unit/Macros/LocalizedUrlMacroTest.php

@@ -463,7 +463,7 @@ public function it_returns_a_localized_url_for_a_non_localized_fallback_route_if
                 'en' => Route::localizedUrl('en'),
                 'nl' => Route::localizedUrl('nl'),
             ], 404);
-        })->name('404');
+        })->middleware(SetLocale::class)->name('404');
 
         $response = $this->call('GET', '/non/existing/route');
         $response->assertNotFound();