Pre-GHC-Proposal: Instantiate backpack signatures when importing

[ChShersh]

I remember this message by @mpickering about Backpack:

Deprecating Language Features

From my perspective the two features which incur large maintenance burden on my day-to-day work are safe haskell and backpack. For each developer their list will be different, I mostly work on driver related code so regularly my work gets stalled on fixing an assumption or misimplementation in the backpack code. This does lead to frustration but also a low level of confidence that the backpack implementation is robust for serious use.

In my understanding, if a feature is barely used but causes major pain for GHC developers, it should be ripped off.

Haskell doesn’t need a kitchen-sink of all possible features. Haskell needs a good Product Manager.