Scala 3.8 nightlies regressions tracker

[WojciechMazur]

The tracker issue for remaining Scala 3.8-nightlies regressions introduced (or discovered) since 3.7.3
For build logs see https://virtuslab.github.io/community-build3/2025/09/13/3.8.0-rc1-bin-20250912-c4c48e3-nightly.html
For instructions how to reproduce / build locally see: https://gist.github.com/WojciechMazur/3f5691e064f96b28fc1d465c5782a92a

Help wanted with minimisation of issues

scaladoc - Java annotated class (all Scala versions)

• disneystreaming/weaver-test From tasty compilation fails when referencing methods missing from the JDK #16709 (comment)

cannot reduce summonFrom with

• funktionalio/pillars
• gvolpe/trading

typer (miscellaneous problems)

• getkyo/kyo
• typelevel/fs2
• zio/zio-schema Regression in zio/zio-schema for typer/implicit resolution #24007
• kasiamarek/tyre-scala
• paoloboni/binance-scala-client
• pityka/relational3
• scala/scala-parallel-collections (fix: update parent type of ParSeqLike scala-parallel-collections#308)
• taig/geojson

orphan parameter reference: TermParamRef(t)

• guntiso/mojoz

is not a lergal path since it is not a concreate type

• trace4cats/trace4cats-opentelemetry
• hagay3/skuber
• thoughtworksinc/dsl.scala
• leanovate/play-mockws

macros changed behaviour

• kacperfkorban/guinep Incorrect does not take parameters error when using quotes reflection #23969
• kitlangton/neotype Regression: inferred types with @retains cause previous macro implementations to crash #24006

unresolved symbols when pickling

• natural-transformation/korolev
• sangria-graphql/sangria

Infix syntax: value compose is not a member of () => S => cats.Id[S]

• sagifogel/proptics
• scalatest/scalatest ## similar not the same

Not found: typeCheckErrors

• kevin-lee/refined4s Wunused: False positive for compiletime.testing.typeCheckErrors #23967

Conflciting definitions / erasure

• swaldman/conveniences Union type triggers conflictings definitions after erasure but normal generic argument does not #23882

Reported

Implicit resolution under -Yexplcit-nulls

• broij/zarrow -Yexplicit-nulls breaks givens resolution when depending on libraries without this flag #23935
• com-lihaoyi/mill-moduledefs -Yexplicit-nulls breaks obtaining quoted.Type #23937

MatchError FlexibleType

• bishabosha/enhanced-string-interpolator -Yexplicit-nulls breaks enums #23933
• earogov/ordset -Yexplicit-nulls breaks anonymous sealed class implementations #23936
• evolution-gaming/derivation
• facsimile/facsimile
• guidoschmidt17/zio-pgcopy
• kuceramartin/tyqu
• scalacenter/tasty-mima
• scalacenter/tasty-query
• shuwariafrica/doobie-util
• shuwariafrica/version
• tabdulradi/happypath
• tabdulradi/nullable
• tofu-tf/cherry
• zero-deps/proto
• marcinzh/turbolift
• stg-tud/bismuth

assertion: should not flexily HKLambda

• fehu/opentracing-scala -Yexplicit-nulls failing assertion for flexify HKTypeLambda #23939 / Crash with FlexibleTypes when nullifying classes with Higher-kinded Type Parameters #23908
• japgolly/univeq

[jchyb]

I'll try to minimise macros changed behavior and Not found: typeCheckErrors tomorrow (I might be able to do more later on, but I'll notify here to avoid duplicate work).

[hamzaremmal]

Upstream PR to fix scala/scala-parallel-collection: scala/scala-parallel-collections#308