[v4] Infinite loop with duplicate inferred type names

[kinglozzer]

Given two classes with an inferred type name of Page, e.g:

• https://github.com/bigfork/silverstripe-recipe/blob/master/app/src/bootstrap.php
• https://github.com/bigfork/silverstripe-recipe/blob/master/app/src/Model/Page.php

If typeMapping is not set up, an error should be thrown as per #421. However this doesn’t happen, instead an infinite loop occurs when running a dev/build.