Comment by makeitdouble

> people who work on the codebase need to somehow know what to expect.

IME this is the exception more than the rule. There will be a ton of manipulations where I don't really care what the types are, just whether I can do the specific thing I want on them.

For instance you receive the data from an API and want to pass it to the appropriate validator. The type definitions are noise, and checking them is the validator's job.

Now it's nice to be able to work with stricter types where needed, ideally I'd want to switch that on and off, instead of being stuck with them everywhere.