It looks like renderPreview is broken after the wasm branch. I believe the issue is that we try to map an ASTLocation, which is really two locations a start and an end.

I started working on a fix here:
https://gist.github.com/06b35acc50732521e373bc6036304abc

[STR]

1. navigate to https://devtools-html.github.io/debugger-examples/examples/todomvc/
2. add a break point on line 34 of todo-view
3. add a todo
4. hover on a token in line 34