Question: Should `tslib` be a dependency or a dev dependency?

[Matt Henkes]

I noticed tslib was added as a dependency. I'm not super familiar with typescript but it seemed to stick out as the only non dev dependency and it seems like it's only used in internal typescript.
https://github.com/benjamn/ast-types/blob/master/package.json#L40

Added here:
03d6467

[Ben Newman]

Definitely a non-dev dependency, as it provides a runtime library for TypeScript-generated code!