identify the code that is relying on ApplicativeDo

[mitchellwrosen]

I noticed we have ApplicativeDo enabled as a default extension in many packages. This is very odd - it's a rather ad-hoc extension that rewrites your do-blocks to use applicative operators where it can, with some hacky hard-coded rules. I think it should just be enabled in the small number of modules that want to opt in for whatever reason.

So I tried removing it, but the context.verifyClosedTerm.report-all-free-vars test failed!

You can run it with:

stack build --test unison-parser-typechecker --test-arguments context.verifyClosedTerm.report-all-free-vars

I think we should identify the Applicative in our codebase that is relying on some do-block being rewritten to use applicative operators, rewrite it to use those operators explicitly, then stop using ApplicativeDo (if not everywhere, then at least as a default extension)