Notable Changes

Language & Syntax

• Type-Safe Pattern Matching (doc)
  • Fix #2578 Part 1: Tighten type checking of pattern bindings #6389
  • Fix #2578: (part 2) Make for-generators filter only if prefixed with case #6448
• Make given clauses come last #6513
• Add @infix annotation #5975 (doc)

Type System Improvements

• Fix #6199: Use a skolemized prefix in asSeenFrom when needed #6454
• Fix #6385: Don't instantiate hk type constructors too early #6467
• Skolem based gadt constraints #5736
• Fix #6288: Allow Singletons in Unions #6299

Scala 2 and Cats code support

• Fix #6484: Properly unpickle some Scala 2 type lambdas #6494
• Fix #6242: package objects leak members from Any and Object #6498

Compiler Development

• Full bootstrap: Use Dotty as the reference compiler #5923

Contributors

Thank you to all the contributors who made this release possible 🎉

According to git shortlog -sn --no-merges 0.14.0-RC1..0.15.0-RC1 these are:

   191  Martin Odersky
   112  Nicolas Stucki
    29  Guillaume Martres
    25  Olivier Blanvillain
    21  Aleksander Boruch-Gruszecki
    17  Anatolii Kmetiuk
    10  Miles Sabin
     9  Liu Fengyun
     8  Aggelos Biboudis
     8  Jentsch
     5  Sébastien Doeraene
     2  Anatolii
     1  Fengyun Liu
     1  Olivier ROLAND
     1  phderome

Reporting Bugs

If you encounter a bug, please open an issue! 🙏