fix when no enclosingClass can be found (#1239)

In certain situations no enclosingClass can be found, quick fix is to just return then.

src/Macro.php

@@ -98,6 +98,9 @@ class Macro extends Method
             $enclosingClass = $this->method->getClosureScopeClass();
         }
 
+        if (!$enclosingClass) {
+            return;
+        }
         /** @var \ReflectionMethod $enclosingMethod */
         $enclosingMethod = Collection::make($enclosingClass->getMethods())
             ->first(function (\ReflectionMethod $method) {