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.
• 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!

Algebra v2.8.0

Several typeclasses that originated in Spire were ported to Algebra in its v2.7.0 release. While updating in https://github.com/typelevel/spire/pull/1115 we removed the following typeclasses from Spire and replaced them with type aliases pointing to the Algebra implementations.

• GCDRing
• EuclideanRing
• DivisionRing
• Signed / SignedAdditiveCMonoid/ SignedAdditiveAbGroup
• TruncatedDivision / TruncatedDivisionCRing
• Field

Note that in Algebra Signed no longer extends Order. So in many places an additional Order constraint has to be added where previously Signed was sufficient.

User-facing PRs

• Dotty by @cquiroz in https://github.com/typelevel/spire/pull/1067
• Drop support for scala 2.12 by @cquiroz in https://github.com/typelevel/spire/pull/978
• Updated version info on microsite by @pinguinson in https://github.com/typelevel/spire/pull/1046
• Deprecate NoImplicit in favor of NotGiven by @cquiroz in https://github.com/typelevel/spire/pull/1098
• Improve docs by @i10416 in https://github.com/typelevel/spire/pull/1095
• rename traversable to iterable by @i10416 in https://github.com/typelevel/spire/pull/1107
• hygiene macros by @i10416 in https://github.com/typelevel/spire/pull/1109
• Update to algebra 2.7.0 by @armanbilge in https://github.com/typelevel/spire/pull/1115
• ensure fastForInline does not make closures by @bishabosha in https://github.com/typelevel/spire/pull/1111
• Don't assume NRoot[Real] is perfect by @kschwarz1116 in https://github.com/typelevel/spire/pull/1173
• Cross-build for Native by @armanbilge in https://github.com/typelevel/spire/pull/1180
• Add allButCats syntax by @armanbilge in https://github.com/typelevel/spire/pull/1181

Behind-the-scenes

• Switch to github actions by @cquiroz in https://github.com/typelevel/spire/pull/956
• Switch to github actions by @larsrh in https://github.com/typelevel/spire/pull/963
• Switch to munit by @cquiroz in https://github.com/typelevel/spire/pull/968
• Fewer warnings by @cquiroz in https://github.com/typelevel/spire/pull/974
• scalafmt by @cquiroz in https://github.com/typelevel/spire/pull/982
• Type ascriptions by @cquiroz in https://github.com/typelevel/spire/pull/1027
• Update sbt and libs by @cquiroz in https://github.com/typelevel/spire/pull/1029
• Use the new cross-project builder command by @danicheg in https://github.com/typelevel/spire/pull/1048
• Migrate on mdoc by @danicheg in https://github.com/typelevel/spire/pull/1047
• Rename master to main by @danicheg in https://github.com/typelevel/spire/pull/1045
• Use new SBT syntax in CI pipeline by @danicheg in https://github.com/typelevel/spire/pull/1062
• Replace cfor with fastFor by @armanbilge in https://github.com/typelevel/spire/pull/1077
• Dotty diff minimizing by @armanbilge in https://github.com/typelevel/spire/pull/1079
• Use sbt-ci-release by @cquiroz in https://github.com/typelevel/spire/pull/1081
• Update bundle by @armanbilge in https://github.com/typelevel/spire/pull/1082
• Set the version scheme by @cquiroz in https://github.com/typelevel/spire/pull/1085
• Remove version.sbt by @cquiroz in https://github.com/typelevel/spire/pull/1087
• Update scalafmt to 3.0.6 by @armanbilge, @cquiroz in https://github.com/typelevel/spire/pull/1084
• fix publish workflow by @i10416 in https://github.com/typelevel/spire/pull/1078
• Fix ci by @i10416 in https://github.com/typelevel/spire/pull/1093
• Show previousStableVersion on site if snapshot by @armanbilge in https://github.com/typelevel/spire/pull/1094
• Remove some unreachable code by @cquiroz in https://github.com/typelevel/spire/pull/1099
• Test on jdk-17 by @cquiroz in https://github.com/typelevel/spire/pull/1100
• migrate caliper to jmh by @i10416 in https://github.com/typelevel/spire/pull/1122
• Rename fastFor back to cfor by @armanbilge in https://github.com/typelevel/spire/pull/1137
• Migrate to sbt-typelevel by @armanbilge in https://github.com/typelevel/spire/pull/1138
• Migrate to sbt-typelevel-site by @armanbilge in https://github.com/typelevel/spire/pull/1142
• update benchmarks by @i10416 in https://github.com/typelevel/spire/pull/1128
• Remove unused sbt plugins by @armanbilge in https://github.com/typelevel/spire/pull/1161
• format headers with brackets properly by @kschwarz1116 in https://github.com/typelevel/spire/pull/1175
• Reduce min tests for native in various scalacheck suites by @armanbilge in https://github.com/typelevel/spire/pull/1182

New Contributors

• @danicheg made their first contribution in https://github.com/typelevel/spire/pull/1048
• @pinguinson made their first contribution in https://github.com/typelevel/spire/pull/1046
• @armanbilge made their first contribution in https://github.com/typelevel/spire/pull/1077
• @i10416 made their first contribution in https://github.com/typelevel/spire/pull/1078
• @bishabosha made their first contribution in https://github.com/typelevel/spire/pull/1111
• @kschwarz1116 made their first contribution in https://github.com/typelevel/spire/pull/1173
• @typelevel-steward made their first contribution in https://github.com/typelevel/spire/pull/1177

Thank you wonderful contributors!!

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