This is the first milestone (pre-)release of 0.18.0. It is not binary compatible with 0.17.0 and may not be binary compatible with 0.18.0 final. It is published for Scala 2.13 and 3.1, as well as Scala.js 1.7.

Notable Changes: support for Scala 3!

A big round of applause for @cquiroz for his multi-month, multi-PR effort to cross-compile spire for Scala 3, including porting "unportable" macros. A heroic effort, which culminated in #1067.

Various other infrastructure PRs, code, benchmarks, and reviews were contributed by @danicheg, @pinguinson, @vasilmkd, @bishabosha, and @larsrh. Much thanks to all of you!

Performance

Scala 3 does not support specialization for type parameters, so code relying on this feature takes a severe performance hit. Otherwise, benchmarks suggest that performance on Scala 3 roughly matches Scala 2.

The complete benchmark suite run for 2.13 vs 3 is available here: https://github.com/typelevel/spire/pull/1067#issuecomment-939369626.

Migration guide

• parentheses: these are now omitted for 0-arity (empty-parens) methods with no side-effects.
• cfor macros: replaced by fastFor in Scala 3 and deprecated in Scala 2. The cfor macro has complex semantics in certain edge cases. The new fastFor macro in Scala 3 simplifies those semantics. A fastFor reference implementation is provided in Scala 2 with semantics matching the Scala 3 macro. Performance-sensitive code should continue using cfor on Scala 2.
• Checked macros: very nearly ported in whole (!), except for tryOrReturn which can be replaced with try / catch and return.
• Literals: all ported to Scala 3, except radix literals.

Deprecated and/or unported features

UnboundSyntax and Machinist macros, Fpf, and Auto macros. Some of these could be ported in a later release, but don't count on it!

Full Changelog: https://github.com/typelevel/spire/compare/v0.17.0...v0.18.0-M1