Regression in CheckUnused leads to compiler crash

[WojciechMazur]

The regression can be observed in multiple OpenCB projects:

Project	Version	Build URL	Notes
johnspade/tgbot-utils	0.8.1	Open CB logs	reproducer below
kaizen-solutions/virgil	1.2.2	Open CB logs
kirill5k/mongo4cats	0.7.11	Open CB logs
kubukoz/smithy-playground	0.8.0	Open CB logs
lichess-org/scalachess	HEAD	Open CB logs
scalacenter/course-management-tools	2.0.22	Open CB logs
scalacenter/scalafix	0.14.0	Open CB logs
softwaremill/ox	0.5.8	Open CB logs
softwaremill/tapir	1.11.13	Open CB logs
tofu-tf/tofu	0.13.6	Open CB logs
typelevel/kittens	3.4.0	Open CB logs
zio/zio-lambda	1.0.5	Open CB logs
kitlangton/neotype	0.3.10 -> 0.3.11	Open CB logs

Compiler version

Last good release: 3.7.0-RC1-bin-20250127-89c20f8-NIGHTLY
First bad release: 3.7.0-RC1-bin-20250128-9cb97ec-NIGHTLY

Bisect failed, can be coused by any:
a5d9e25
c65d45d
6c2c5c5

Reproducer code

Needs minimization

package ru.johnspade.tgbot.callbackdata

import ru.johnspade.tgbot.callbackdata.named.MagnoliaRowEncoder
import ru.johnspade.csv3s.codecs.*
import ru.johnspade.csv3s.codecs.instances.given

sealed trait TestCallbackData

final case class BuyIcecream(flavor: String) extends TestCallbackData
case object SayHello                         extends TestCallbackData

object TestCallbackData:
  given encoder: RowEncoder[TestCallbackData] = MagnoliaRowEncoder.derived

Output (click arrow to expand)

 unhandled exception while running checkUnusedPostInlining on /Users/wmazur/projects/scala/community-build3/repo/tgbot-callback-data/src/test/scala/ru/johnspade/tgbot/callbackdata/TestCallbackData.scala

  An unhandled exception was thrown in the compiler.
  Please file a crash report here:
  https://github.com/scala/scala3/issues/new/choose
  For non-enriched exceptions, compile with -Xno-enrich-error-messages.


     while compiling: /Users/wmazur/projects/scala/community-build3/repo/tgbot-callback-data/src/test/scala/ru/johnspade/tgbot/callbackdata/TestCallbackData.scala
        during phase: checkUnusedPostInlining
                mode: Mode(ImplicitsEnabled)
     library version: version 2.13.16
    compiler version: version 3.7.0-RC1-bin-20250131-590691b-NIGHTLY-git-590691b
            settings: -Wnonunit-statement true -Wunused List(implicits, explicits, imports, locals, params, privates) -Wvalue-discard true -Xkind-projector "" -bootclasspath /Users/wmazur/Library/Caches/Coursier/v1/https/repo1.maven.org/maven2/org/scala-lang/scala3-library_3/3.7.0-RC1-bin-20250131-590691b-NIGHTLY/scala3-library_3-3.7.0-RC1-bin-20250131-590691b-NIGHTLY.jar:/Users/wmazur/Library/Caches/Coursier/v1/https/repo1.maven.org/maven2/org/scala-lang/scala-library/2.13.16/scala-library-2.13.16.jar -classpath /Users/wmazur/projects/scala/community-build3/repo/tgbot-callback-data/target/scala-3.7.0-RC1-bin-20250131-590691b-NIGHTLY/test-classes:/Users/wmazur/projects/scala/community-build3/repo/tgbot-callback-data/target/scala-3.7.0-RC1-bin-20250131-590691b-NIGHTLY/classes:/Users/wmazur/Library/Caches/Coursier/v1/https/repo1.maven.org/maven2/com/softwaremill/magnolia1_3/magnolia_3/1.3.7/magnolia_3-1.3.7.jar:/Users/wmazur/Library/Caches/Coursier/v1/https/repo1.maven.org/maven2/ru/johnspade/csv3s_3/0.1.4/csv3s_3-0.1.4.jar:/Users/wmazur/Library/Caches/Coursier/v1/https/repo1.maven.org/maven2/dev/zio/zio-test_3/2.1.3/zio-test_3-2.1.3.jar:/Users/wmazur/Library/Caches/Coursier/v1/https/repo1.maven.org/maven2/dev/zio/zio-test-sbt_3/2.1.3/zio-test-sbt_3-2.1.3.jar:/Users/wmazur/Library/Caches/Coursier/v1/https/repo1.maven.org/maven2/org/typelevel/cats-core_3/2.12.0/cats-core_3-2.12.0.jar:/Users/wmazur/Library/Caches/Coursier/v1/https/repo1.maven.org/maven2/dev/zio/zio_3/2.1.3/zio_3-2.1.3.jar:/Users/wmazur/Library/Caches/Coursier/v1/https/repo1.maven.org/maven2/dev/zio/zio-parser_3/0.1.10/zio-parser_3-0.1.10.jar:/Users/wmazur/Library/Caches/Coursier/v1/https/repo1.maven.org/maven2/dev/zio/zio-streams_3/2.1.3/zio-streams_3-2.1.3.jar:/Users/wmazur/Library/Caches/Coursier/v1/https/repo1.maven.org/maven2/org/portable-scala/portable-scala-reflect_2.13/1.1.2/portable-scala-reflect_2.13-1.1.2.jar:/Users/wmazur/Library/Caches/Coursier/v1/https/repo1.maven.org/maven2/org/scala-sbt/test-interface/1.0/test-interface-1.0.jar:/Users/wmazur/Library/Caches/Coursier/v1/https/repo1.maven.org/maven2/org/typelevel/cats-kernel_3/2.12.0/cats-kernel_3-2.12.0.jar:/Users/wmazur/Library/Caches/Coursier/v1/https/repo1.maven.org/maven2/dev/zio/zio-internal-macros_3/2.1.3/zio-internal-macros_3-2.1.3.jar:/Users/wmazur/Library/Caches/Coursier/v1/https/repo1.maven.org/maven2/dev/zio/zio-stacktracer_3/2.1.3/zio-stacktracer_3-2.1.3.jar:/Users/wmazur/Library/Caches/Coursier/v1/https/repo1.maven.org/maven2/dev/zio/izumi-reflect_3/2.3.8/izumi-reflect_3-2.3.8.jar:/Users/wmazur/Library/Caches/Coursier/v1/https/repo1.maven.org/maven2/dev/zio/izumi-reflect-thirdparty-boopickle-shaded_3/2.3.8/izumi-reflect-thirdparty-boopickle-shaded_3-2.3.8.jar -d /Users/wmazur/projects/scala/community-build3/repo/tgbot-callback-data/target/scala-3.7.0-RC1-bin-20250131-590691b-NIGHTLY/test-classes -deprecation true -encoding utf8 -feature true -language List(experimental.macros, implicitConversions)

[error] ## Exception when compiling 2 sources to /Users/wmazur/projects/scala/community-build3/repo/tgbot-callback-data/target/scala-3.7.0-RC1-bin-20250131-590691b-NIGHTLY/test-classes
[error] java.lang.AssertionError: assertion failed
[error] scala.runtime.Scala3RunTime$.assertFailed(Scala3RunTime.scala:11)
[error] dotty.tools.dotc.util.Spans$Span$.start$extension(Spans.scala:45)
[error] dotty.tools.dotc.transform.CheckUnused$.isZeroExtentSynthetic(CheckUnused.scala:905)
[error] dotty.tools.dotc.transform.CheckUnused.transformIdent(CheckUnused.scala:58)
[error] dotty.tools.dotc.transform.CheckUnused.transformIdent(CheckUnused.scala:53)
[error] dotty.tools.dotc.transform.MegaPhase.goIdent(MegaPhase.scala:621)
[error] dotty.tools.dotc.transform.MegaPhase.transformNamed$1(MegaPhase.scala:240)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:452)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:332)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.transformNamed$1(MegaPhase.scala:244)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:452)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:295)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase$MiniPhase.transformAllDeep(MegaPhase.scala:125)
[error] dotty.tools.dotc.transform.CheckUnused.transformTypeTree(CheckUnused.scala:125)
[error] dotty.tools.dotc.transform.CheckUnused.transformTypeTree(CheckUnused.scala:123)
[error] dotty.tools.dotc.transform.MegaPhase.goTypeTree(MegaPhase.scala:966)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:301)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:338)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.transformNamed$1(MegaPhase.scala:244)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:452)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:319)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.loop$3(MegaPhase.scala:486)
[error] dotty.tools.dotc.transform.MegaPhase.transformTrees(MegaPhase.scala:486)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:296)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.loop$3(MegaPhase.scala:486)
[error] dotty.tools.dotc.transform.MegaPhase.transformTrees(MegaPhase.scala:486)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:296)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:295)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.mapDefDef$1(MegaPhase.scala:265)
[error] dotty.tools.dotc.transform.MegaPhase.transformNamed$1(MegaPhase.scala:268)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:452)
[error] dotty.tools.dotc.transform.MegaPhase.loop$2(MegaPhase.scala:471)
[error] dotty.tools.dotc.transform.MegaPhase.transformBlock(MegaPhase.scala:476)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:315)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:337)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:411)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:337)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.loop$3(MegaPhase.scala:486)
[error] dotty.tools.dotc.transform.MegaPhase.transformTrees(MegaPhase.scala:486)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:296)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:295)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.mapValDef$1(MegaPhase.scala:251)
[error] dotty.tools.dotc.transform.MegaPhase.transformNamed$1(MegaPhase.scala:256)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:452)
[error] dotty.tools.dotc.transform.MegaPhase.loop$2(MegaPhase.scala:471)
[error] dotty.tools.dotc.transform.MegaPhase.transformBlock(MegaPhase.scala:476)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:315)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:337)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:450)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:411)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.loop$3(MegaPhase.scala:486)
[error] dotty.tools.dotc.transform.MegaPhase.transformTrees(MegaPhase.scala:486)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:296)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:337)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:411)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.loop$2$$anonfun$1(MegaPhase.scala:474)
[error] dotty.tools.dotc.transform.MegaPhase.loop$2(MegaPhase.scala:476)
[error] dotty.tools.dotc.transform.MegaPhase.transformBlock(MegaPhase.scala:476)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:315)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:337)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:411)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:337)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:450)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:411)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.loop$3(MegaPhase.scala:486)
[error] dotty.tools.dotc.transform.MegaPhase.transformTrees(MegaPhase.scala:486)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:296)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.loop$3(MegaPhase.scala:486)
[error] dotty.tools.dotc.transform.MegaPhase.transformTrees(MegaPhase.scala:486)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:296)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.loop$3(MegaPhase.scala:486)
[error] dotty.tools.dotc.transform.MegaPhase.transformTrees(MegaPhase.scala:486)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:363)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:337)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.loop$3(MegaPhase.scala:486)
[error] dotty.tools.dotc.transform.MegaPhase.transformTrees(MegaPhase.scala:486)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:296)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.mapValDef$1(MegaPhase.scala:251)
[error] dotty.tools.dotc.transform.MegaPhase.transformNamed$1(MegaPhase.scala:256)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:452)
[error] dotty.tools.dotc.transform.MegaPhase.loop$2(MegaPhase.scala:471)
[error] dotty.tools.dotc.transform.MegaPhase.transformBlock(MegaPhase.scala:476)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:315)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:411)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:337)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.loop$3(MegaPhase.scala:486)
[error] dotty.tools.dotc.transform.MegaPhase.transformTrees(MegaPhase.scala:486)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:296)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:295)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.loop$3(MegaPhase.scala:486)
[error] dotty.tools.dotc.transform.MegaPhase.transformTrees(MegaPhase.scala:486)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:296)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:337)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:450)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:411)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.loop$3(MegaPhase.scala:486)
[error] dotty.tools.dotc.transform.MegaPhase.transformTrees(MegaPhase.scala:486)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:296)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:337)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:411)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.loop$2$$anonfun$1(MegaPhase.scala:474)
[error] dotty.tools.dotc.transform.MegaPhase.loop$2(MegaPhase.scala:476)
[error] dotty.tools.dotc.transform.MegaPhase.transformBlock(MegaPhase.scala:476)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:315)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:337)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:411)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:337)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:450)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:411)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.mapValDef$1(MegaPhase.scala:251)
[error] dotty.tools.dotc.transform.MegaPhase.transformNamed$1(MegaPhase.scala:256)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:452)
[error] dotty.tools.dotc.transform.MegaPhase.loop$1(MegaPhase.scala:465)
[error] dotty.tools.dotc.transform.MegaPhase.transformStats(MegaPhase.scala:465)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:376)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.transformNamed$1(MegaPhase.scala:272)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:452)
[error] dotty.tools.dotc.transform.MegaPhase.loop$1(MegaPhase.scala:465)
[error] dotty.tools.dotc.transform.MegaPhase.transformStats(MegaPhase.scala:465)
[error] dotty.tools.dotc.transform.MegaPhase.mapPackage$1(MegaPhase.scala:396)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:399)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnit(MegaPhase.scala:481)
[error] dotty.tools.dotc.transform.MegaPhase.run(MegaPhase.scala:493)
[error] dotty.tools.dotc.transform.MegaPhase$MiniPhase.run(MegaPhase.scala:138)
[error] dotty.tools.dotc.core.Phases$Phase.runOn$$anonfun$1(Phases.scala:383)
[error] scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
[error] scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
[error] scala.collection.immutable.List.foreach(List.scala:334)
[error] dotty.tools.dotc.core.Phases$Phase.runOn(Phases.scala:376)
[error] dotty.tools.dotc.Run.runPhases$1$$anonfun$1(Run.scala:345)
[error] scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
[error] scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
[error] scala.collection.ArrayOps$.foreach$extension(ArrayOps.scala:1324)
[error] dotty.tools.dotc.Run.runPhases$1(Run.scala:338)
[error] dotty.tools.dotc.Run.compileUnits$$anonfun$1(Run.scala:385)
[error] dotty.tools.dotc.Run.compileUnits$$anonfun$adapted$1(Run.scala:397)
[error] dotty.tools.dotc.util.Stats$.maybeMonitored(Stats.scala:69)
[error] dotty.tools.dotc.Run.compileUnits(Run.scala:397)
[error] dotty.tools.dotc.Run.compileSources(Run.scala:284)
[error] dotty.tools.dotc.Run.compile(Run.scala:269)
[error] dotty.tools.dotc.Driver.doCompile(Driver.scala:37)
[error] dotty.tools.xsbt.CompilerBridgeDriver.run(CompilerBridgeDriver.java:141)
[error] dotty.tools.xsbt.CompilerBridge.run(CompilerBridge.java:22)
[error] sbt.internal.inc.AnalyzingCompiler.compile(AnalyzingCompiler.scala:91)
[error] sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$7(MixedAnalyzingCompiler.scala:193)
[error] scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
[error] sbt.internal.inc.MixedAnalyzingCompiler.timed(MixedAnalyzingCompiler.scala:248)
[error] sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$4(MixedAnalyzingCompiler.scala:183)
[error] sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$4$adapted(MixedAnalyzingCompiler.scala:163)
[error] sbt.internal.inc.JarUtils$.withPreviousJar(JarUtils.scala:239)
[error] sbt.internal.inc.MixedAnalyzingCompiler.compileScala$1(MixedAnalyzingCompiler.scala:163)
[error] sbt.internal.inc.MixedAnalyzingCompiler.compile(MixedAnalyzingCompiler.scala:211)
[error] sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileInternal$1(IncrementalCompilerImpl.scala:534)
[error] sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileInternal$1$adapted(IncrementalCompilerImpl.scala:534)
[error] sbt.internal.inc.Incremental$.$anonfun$apply$5(Incremental.scala:180)
[error] sbt.internal.inc.Incremental$.$anonfun$apply$5$adapted(Incremental.scala:178)
[error] sbt.internal.inc.Incremental$$anon$2.run(Incremental.scala:464)
[error] sbt.internal.inc.IncrementalCommon$CycleState.next(IncrementalCommon.scala:116)
[error] sbt.internal.inc.IncrementalCommon$$anon$1.next(IncrementalCommon.scala:56)
[error] sbt.internal.inc.IncrementalCommon$$anon$1.next(IncrementalCommon.scala:52)
[error] sbt.internal.inc.IncrementalCommon.cycle(IncrementalCommon.scala:263)
[error] sbt.internal.inc.Incremental$.$anonfun$incrementalCompile$8(Incremental.scala:419)
[error] sbt.internal.inc.Incremental$.withClassfileManager(Incremental.scala:506)
[error] sbt.internal.inc.Incremental$.incrementalCompile(Incremental.scala:406)
[error] sbt.internal.inc.Incremental$.apply(Incremental.scala:172)
[error] sbt.internal.inc.IncrementalCompilerImpl.compileInternal(IncrementalCompilerImpl.scala:534)
[error] sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileIncrementally$1(IncrementalCompilerImpl.scala:488)
[error] sbt.internal.inc.IncrementalCompilerImpl.handleCompilationError(IncrementalCompilerImpl.scala:332)
[error] sbt.internal.inc.IncrementalCompilerImpl.compileIncrementally(IncrementalCompilerImpl.scala:425)
[error] sbt.internal.inc.IncrementalCompilerImpl.compile(IncrementalCompilerImpl.scala:137)
[error] sbt.Defaults$.compileIncrementalTaskImpl(Defaults.scala:2371)
[error] sbt.Defaults$.$anonfun$compileIncrementalTask$2(Defaults.scala:2321)
[error] sbt.internal.server.BspCompileTask$.$anonfun$compute$1(BspCompileTask.scala:31)
[error] sbt.internal.io.Retry$.apply(Retry.scala:47)
[error] sbt.internal.io.Retry$.apply(Retry.scala:29)
[error] sbt.internal.io.Retry$.apply(Retry.scala:24)
[error] sbt.internal.server.BspCompileTask$.compute(BspCompileTask.scala:31)
[error] sbt.Defaults$.$anonfun$compileIncrementalTask$1(Defaults.scala:2319)
[error] scala.Function1.$anonfun$compose$1(Function1.scala:49)
[error] sbt.internal.util.$tilde$greater.$anonfun$$u2219$1(TypeFunctions.scala:63)
[error] sbt.std.Transform$$anon$4.work(Transform.scala:69)
[error] sbt.Execute.$anonfun$submit$2(Execute.scala:283)
[error] sbt.internal.util.ErrorHandling$.wideConvert(ErrorHandling.scala:24)
[error] sbt.Execute.work(Execute.scala:292)
[error] sbt.Execute.$anonfun$submit$1(Execute.scala:283)
[error] sbt.ConcurrentRestrictions$$anon$4.$anonfun$submitValid$1(ConcurrentRestrictions.scala:265)
[error] sbt.CompletionService$$anon$2.call(CompletionService.scala:65)
[error] java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
[error] java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:539)
[error] java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
[error] java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
[error] java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
[error] java.base/java.lang.Thread.run(Thread.java:833)
[error]            

[som-snytt]

Besides the position error, there is an error because of incompatible removal of "choice":

Error:  invalid choice(s) for -Wunused: unsafe-warn-patvars

Probably "top-level" options only warn if wrong, but a "choice" is a hard error. Then it's necessary for the choice to have a deprecation cycle, if that is technically feasible.

(Same for strict-no-implicit-warn, which is still supported, but which was also a work-around.)

(Both "work-around" options probably should have been -Y.)

[som-snytt]

NoSpan.isSynthetic, but it's not permitted to take its components start/point/end but note that pointDelta does not assert.

def isZeroExtentSynthetic: Boolean = pos.span.isSynthetic && pos.span.start == pos.span.end

should use span.isZeroExtent, which checks exists.

CheckUnused should be audited for similar usages, since it tests isSynthetic for some trees, and unused patvars relies on positions, converting to synthetic for purposes of comparison. A test for isSynthetic probably always intends "is synthetic and exists".

It is a separate question whether an Ident should have NoSpan instead of a useful synthetic span.

withStart is not validated, as the assert is commented out at fromOffsets, noticed at scala/scala#10989 (comment)

I don't see span combinators resulting in NoSpan from an existing span.

[som-snytt]

tgbot-utils works with the fix.

The unpositioned tree is unchecked in the expansion of TestCallbackData. There are two, in ordinalBody and also from a magnolia method.

Not all trees in SyntheticMembers are granted a span, such as in ordinalBody

Match(param.annotated(New(defn.UncheckedAnnot.typeRef, Nil)), cases)

but a trivial test did not demonstrate that.

The inlined stack in CheckUnused shows Magnolia's paramsFromMaps (as an enclosing Inlined), so maybe the elaboration of unsafeCast is involved.

NoSpan for Ident unchecked (class unchecked) [Stack(Apply(TypeApply(Ident(paramsFromMaps),List(TypeTree[HKTypeLambda(List(T), List(TypeBounds(TypeRef(TermRef(ThisType(TypeRef(NoPrefix,module class <root>)),object scala),Nothing),TypeRef(TermRef(ThisType(TypeRef(NoPrefix,module class <root>)),object scala),Any))), AppliedType(TypeRef(TermRef(TermRef(ThisType(TypeRef(NoPrefix,module class csv3s)),object codecs),types$package),RowEncoder),List(TypeParamRef(T))))], TypeTree[TypeRef(ThisType(TypeRef(NoPrefix,module class callbackdata)),class BuyIcecream)],

[info]                                                         def unsafeCast(any: Any)
[info]                                                           : Option[String] =
[info]                                                           Option.when[String](
[info]                                                             any.==(null).||(
[info]                                                               (any:
[info]
[info]                                                                   (any : Any)
[info]                                                                     @unchecked
[info]
[info]                                                               ).isInstanceOf[
[info]                                                                 String]
[info]                                                             )
[info]                                                           )(
[info]                                                             any.asInstanceOf[
[info]                                                               String]
[info]                                                           )

object TestCallbackData:
  given encoder: RowEncoder[TestCallbackData] = MagnoliaRowEncoder.derived
  given decoder: RowDecoder[TestCallbackData] = MagnoliaRowDecoder.derived
  def decode(csv: String) =
    val row = parseRow(csv).left.map(e => new RuntimeException(e.toString)).valueOr(throw _)
    decoder.decode(row)

For reference:

[info]     type MirroredMonoType = ru.johnspade.tgbot.callbackdata.TestCallbackData
[info]     def ordinal(
[info]       x$0: ru.johnspade.tgbot.callbackdata.TestCallbackData.MirroredMonoType):
[info]       Int =
[info]       x$0:
[info]
[info]           (x$0 :
[info]             ru.johnspade.tgbot.callbackdata.TestCallbackData.MirroredMonoType)
[info]             @unchecked
[info]
[info]        match
[info]         {
[info]           case _:ru.johnspade.tgbot.callbackdata.BuyIcecream => 0
[info]           case _:ru.johnspade.tgbot.callbackdata.SayHello.type => 1
[info]         }

[WojciechMazur]

I'll start the OpenCB to test other projects to check if it fixes them as well

[som-snytt]

scalachess passes but reports some other ident as spanless, so presumably it's something about inlining.

NoSpan for Ident $_lazy_implicit_$3 (val $_lazy_implicit_$3) [Stack(Apply(TypeApply(Ident(summonAsArray0),List(TypeTree[AppliedType(TypeRef(TermRef(ThisType(TypeRef(NoPrefix,module class <root>)),object scala),*:),List(AppliedType(TypeRef(TermRef(TermRef(TermRef(ThisType(TypeRef(NoPrefix,module class cats)),object derived),Derived$package),Derived),type Or),

Worth adding that it's amazing that I can bump scala version locally and projects just compile (without rebuilding dependencies).

[WojciechMazur]

I'll start the OpenCB to test other projects to check if it fixes them as well

When testing using 4e39163 I've not observed any new regressions, all of the previously failing projects are now compiling

[som-snytt]

I confirmed that tgbot-utils and neotype pass when Magnolia is built with 3.3.5. My previous remark suggests it's not only about annotations, so I'll try again with scalachess.

(TIL lazy val is InsufficientMatingMaterial.)