Update to drupal 8.0.0-rc1. For more information, see https://www.drupal.org/node/2582663

vendor/symfony/routing/Tests/Fixtures/validpattern.yml

@@ -0,0 +1,13 @@
+blog_show:
+    path:         /blog/{slug}
+    defaults:     { _controller: "MyBundle:Blog:show" }
+    host:         "{locale}.example.com"
+    requirements: { 'locale': '\w+' }
+    methods:      ['GET','POST','put','OpTiOnS']
+    schemes:      ['https']
+    condition:    'context.getMethod() == "GET"'
+    options:
+        compiler_class: RouteCompiler
+
+blog_show_inherited:
+    path:      /blog/{slug}