We need AST transform tests

[taras]

I've been experimenting with inline let and it behaves unpredictably. There could be something wrong with the AST transform code. We need to add node tests for it.

[rwjblue]

They will just be super brittle. We need to focus on testing the things we care about, which in this case is whatever thing at runtime that you noticed was wrong.

[mmun]

Do you have an example? The AST transform is fairly straightforward and only touches stable parts of the AST so I would be surprised if it broken in any version. It seems more likely that helper runtime code is malfunctioning.