release/0.5.19

What's changed

• upgrade now allows library authors to repurpose names for a different definition, without breaking any downstream users. That is, you can rename a definition, then add a new definition with the original name but new behavior, without forcing library users to update to the new definition when they upgrade. #4720
• Fixes an annoying issue where record types weren't being printed as records (reported and fixed by @runarorama)
• Improves speed of merge via a faster ancestry check to find the LCA.
• Greatly improves the error message when the scratch file fails to even parse.
• Improves error messages and type inference for match statements (now, if the type of the overall match is known, that information is pushed down into the branches of the match, which behaves more nicely)

We've also made improvements and fixes to the new just-in-time native compiler, though the feature is still not quite ready for general use.

All PRs since last release

• Update release-steps.md by @aryairani in #4739
• tweak: make upgrade not touch things that exist in new dep by @mitchellwrosen in #4720
• updated third-party-facing Slack to Discord refs by @kylegoetz in #4743
• Fix a variable capture issue during let floating by @dolio in #4756
• Fix field accessors not showing up in view in some cases by @runarorama in #4752
• Allow tuning sync config with env vars by @ChrisPenner in #4767
• Vastly speed up ancestry check by not re-crawling duplicate histories. by @ChrisPenner in #4753
• Rework racket based runtime/compilation by @dolio in #4675
• Push type checking through match statements by @dolio in #4768
• fix default path for unison-runtime by @aryairani in #4774
• YAML: try changing ormolu commit conditions by @aryairani in #4775
• Create ormolu.yaml by @aryairani in #4776
• Minor JIT fixes by @dolio in #4779
• Fix builtin link reflection in jit by @dolio in #4785
• Better error messages for generic parser failures by @ChrisPenner in #4788
• fix condition on ormolu manual workflow by @aryairani in #4778
• autoformat aryairani-patch-4 by @github-actions in #4784

New Contributors

• @github-actions made their first contribution in #4784

Full Changelog: release/0.5.18...release/0.5.19