E603 - No renderer for slide IR

Cause

A slide's source loaded into an IR type for which no renderer is registered. With the built-in SlideIR this only surfaces if a custom IR class was registered without a paired renderer.

Example

A custom IR registered via register_ir with no corresponding register_renderer call.

How to fix

This is an internal scrolly bug for built-in IRs. For custom IRs, register a renderer that matches your IR class via register_renderer.