lean4-htt/releases_drafts/hashmap.md

• The Lean module has switched from Lean.HashMap and Lean.HashSet to Std.HashMap and Std.HashSet. Lean.HashMap and Lean.HashSet are now deprecated and will be removed in a future release. Users of Lean APIs that interact with hash maps, for example Lean.Environment.const2ModIdx, might encounter minor breakage due to the following breaking changes from Lean.HashMap to Std.HashMap:
  • query functions use the term get instead of find,
  • the notation map[key] no longer returns an optional value but expects a proof that the key is present in the map instead. The previous behavior is available via the map[key]? notation.