Yes it adds a lot of complexity on the tokenization level (and others), potentially requiring some form of contextual tokenization. Scala originally supported

Yes it adds a lot of complexity on the tokenization level (and others), potentially requiring some form of contextual tokenization. Scala originally supported "inline" XML but moved it into some form of compiler plugin you can opt-in to as just having it enabled had drawbacks even if you don't use any XML... (I don't remember the exact drawbacks anymore).