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generic-data v0.9.0.0 Release Notes

    • 👌 Improved definition of gfoldMap, gtraverse, and sequenceA. The optimized Core of Traversable instances eliminates all GHC.Generic instance boilerplate. In many cases, it is identical to the result of GHC's DeriveFoldable and DeriveTraversable extensions (note: this was already not a problem for gfmap).

    It's worth noting that there are currently issues with inlining which prevent optimizations that generic-data would ideally rely on.

    + The biggest issue is that GHC will not even inline the `to` and `from`
  methods of the `Generic` instance it derives for large types (this shows
  up at around 5 constructors and 10 fields, which is indeed not really
  big). This will be fixed by a patch for GHC (WIP):
  https://gitlab.haskell.org/ghc/ghc/-/merge_requests/2965

+ There appear to be some more inlining issues beyond that (issue #40).