Warn about unused values/declarations

[garyb]

• Unused values declared in a let or where
• Unused declarations in modules that have explicit export lists - the warnings can apply to any declaration that is private to the module and unreachable by the exports, not just members.
  • Normal value declarations
  • foreign import value declarations
  • Type synonym declarations
  • Normal data declarations
  • foreign import data declarations
  • Type class declarations
• Unused names introduced in binders

[paf31]

👍

[paf31]

Moving to Backlog.

[garyb]

I'd like to do this for 0.9 actually.

[paf31]

Sounds good.