Backported changes

• Revert #26579 and #25126 for binary compatibility #26813
• Preserve GADT constraints until PatternMatcher #26805
• Ignore @throws annotation on non-methods #26802
• Box bounded arguments of HKT result types in Java generic signatures #26787
• Fix issue with reading legal java cyclic signatures #26775
• Bail out of patDef opt for .runtimeChecked, not only @unchecked #26774
• Do not emit Java generic signatures for trait private val setters #26633
• Desugaring: avoid patdef optimization for lazy vals #26770
• Scaladoc: Fix variable expansion #26730

Contributors

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

According to git shortlog -sn --no-merges 3.9.0-RC6..3.9.0-RC6 these are:

     7	Wojciech Mazur
     6	Patryk Zieliński
     4	Solal Pirelli
     2	Jan Chyb
     1	Rikito Taniguchi

Backported changes

• Bump Scala CLI to v1.16.0 #26703
• Fix stale baseTypeCache after synthetic Product.Mirror parents added #26714
• Ignore coverage probes in unused update analysis #26711
• Fix crash when unapply returns a Boolean-deriving opaque type #26658
• Emit inline info attribute #26650
• Fix false unused-var warning on self-assignment reads (#26620) #26635
• Stop hiding errors in GenericSignatureVisitor #26632
• Emit a super init call for primitives on the JVM #26630
• Preserve qualifier purity through compiler-generated casts #26579
• Fix regression #26153 (in dotty-cps-async) use typer skolems as inline proxy's type #26563
• Fix a couple issues related to erased value types #26213
• Scaladoc: Remove jquery and hanging javascript assets. #22014
• Scaladoc: add fallback lookup from nearest package #26661
• Fix Scaladoc top package order to be alphabetical #26653
• Fixes #26013: Wrap with->& rewrite in parens for typed patterns #26016
• Make Option.orNull public in binary #26751

Contributors

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

According to git shortlog -sn --no-merges 3.9.0-RC4..3.9.0-RC5 these are:

     8	Wojciech Mazur
     4	Rikito Taniguchi
     4	Solal Pirelli
     1	Anatolii Kmetiuk
     1	Jack Koenig
     1	Mathias
     1	Oron Port
     1	Piotr Chabelski

Backported changes

• Fix generic signatures for inherited inner classes #26549
• Fix regression #26374: generic signatures of mixed-in trait setters #26542
• Fix regression #26550: revert isPrimitiveValueType change #26565
• Skip unresolved annotation trees (during TASTy loading) #26520

Contributors

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

According to git shortlog -sn --no-merges 3.9.0-RC3..3.9.0-RC4 these are:

     4  Rikito Taniguchi
     2  Wojciech Mazur

Backported changes

• Reliably decide whether to generate static forwarders #26510
• REPL: attempt to detect user overridden toString for Product #26451
• Add missing directives-parser artifacts to the released artifacts #26516

Contributors

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

According to git shortlog -sn --no-merges 3.9.0-RC2..3.9.0-RC3 these are:

     4  Jamie Thompson
     4  Wojciech Mazur
     2  Solal Pirelli
     1  Arnout Engelen

Backported changes

• Upgrade to Scala.js 1.22.0. #26389
• Stop using custom fonts for Scaladoc #26393
• Bump Scala CLI to 1.15.0 (was 1.14.0) and coursier to 2.1.25-M26 (was 2.1.25-M25) #26432
• Vendor REPL dependencies #26433
• Deprecate JPath use in Quotes #26446
• Migrate Scala CLI's using directive parser to a compiler module #26449
• Refactor directives-parser #26461
• Minor using directives parser improvements #26460
• Scaladoc snippets: fix Show all lines & Scastie popup theme bugs #26165
• Do not warn on dollars in Java names #26303
• Don't skip generic signature for constructors with generic using parameters #26302
• Don't eliminate var used by anonfun #26360
• Erase more aliases of Unit as result type to void. #26252
• Reset dirty unimported state after findRef #26412
• Fix :help regressions #26301
• Fix generic signature of trait val setter #26374
• Fixes #25754: Preserve apply result type after beta reducing through opaque proxies #25988
• Fix memberType for constructor params #25669
• Fix #25866: match-alias subtyping and wildcard appliedTo #25981

Contributors

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

According to git shortlog -sn --no-merges 3.9.0-RC1..3.9.0-RC2 these are:

    10	Solal Pirelli
     7	Wojciech Mazur
     6	Piotr Chabelski
     3	Sébastien Doeraene
     1	Jamie Thompson
     1	Oliver Bračevac
     1	Oron Port
     1	Som Snytt
     1	Zieliński Patryk

Highlights of the release

• Support for JDK 26 #24430
• Multiple coverage improvement to make it on par with Scala 2 support including
  // $COVERAGE-OFF$ and // $COVERAGE-ON$ markers.
• New @uncheckedOverride annotation for definitions that may override.
  #24545
• Trap Ctrl-C in the REPL: if no command is running clear the prompt, if some
  command is running ask for confirmation before exiting.
  #24127
• Numerous linting and presentation compiler improvements and fixes.
• New '-Yfuture-lazy-vals' options that allows to compile with new lazy val
  implementation compatible with all JDK 9+
  #637

Other changes and fixes

Access modifiers

• Check protected parent constructor accesses only occurs in child constructors
  #25511
• Fix protected constructor access
  #25523

Annotations

• Improve ref check of constructors
  #24342
• Also copy param annots at mixin
  #24916
• Named arg may be deprecatedName
  #21588
• Fix: emit deprecation warnings when a symbol is annotated by a deprecated
  annotation #23906
• Fix #20063: Java leading annotation parsing
  #25503
• Accommodate adapted Scala 2 annotation value
  #17516
• Regression test for #3403 #25521
• Fix: do not allow @targetName on primary constructor too
  #24682
• Add @uncheckedOverride annotation for definitions that may override
  #24545

Backend

• Chore: add regression test for #4528
  #24663
• Cast inline call results to result type, not method type
  #25111
• Regression tests for #25 #25536
• Enforce JVM UTF-8 string limits in the backend
  #25300
• Do not simplify isInstanceOf if unrelated types might be subtypes at run-time
  #25535
• Adjust purity of trait with lazy member
  #23788
• Use Objects.equals in translating ==
  #25314
• Fix generic signatures for mixin forwarders conflicting type parameter names
  #24567
• No mixin forwarder when ancestor is sealed
  #23482
• Simplify JVM interface list emission, remove a mini-phase
  #25203
• Chore: optimize lazy val with power of two
  #22428
• Fix infinite loop with bad section ends in TastyHeaderUnpickler
  #25676
• Fix TastyPrinter's JAR-walking logic to include subdirectories
  #25678

Classpath

• Skip module-info.class files during REPL tab-completion
  #24838
• Fix for #22461 Empty ClassPath attribute in one or more classpath jars causes
  crash #22462

Coverage

• Make coverage more similar to the one in Scala 2
  #23722
• Fix #25555: Preserve singleton precision during scoverage lifting
  #25556
• Fixes #25482: Ensure package transformation properly handles language imports
  in InstrumentCoverage #25546
• Bugfix: Fix issues with Scala JS and coverage
  #24769
• Make coverage support incremental compilation
  #24773
• Add support for local coverage on and off with // $COVERAGE-OFF$ and
  // $COVERAGE-ON$ #24486
• Improvement: Try to optimize coverage phase
  #24925
• Scoverage: do not instrument erased values
  #25298

Default parameters

• Fix named arguments evaluation order with by-name parameters
  #25161

Documentation

• Docs: Enforce links checks in the generated docs
  #25425
• Improve the contributing guide
  #25384
• Extend copyright into 2026
  #24927
• Update README: This is Scala 3
  #25424
• Explain implicit vs default args
  #25311
• Fix some scaladoc in compiler
  #24166
• Docs: fix task name for scaladoc/testOnly
  #23678
• Replace internal tab char in comment in Synthesizer.scala
  #23691

Enums

• Fix Java enum forwarders to pull from companion on initialization
  #24361
• Make enum apply ascriptions inferred types
  #25562

Exports

• Fix: look at the underlying of a TermRef for a getter
  #24565

Extension Methods

• Accept using right associative parameters
  #24766
• Add ctor proxies before exports
  #24884
• Fix pkg obj prefix of opaque tp ext meth
  #21527
• Better handling of illegal trees in extension
  #25368
• Fix LiftToAnchors for higher-kinded type applications
  #23672
• Prevent crash when extension not found
  #18830

GADTs

• Also trust TypeTest when there is a Bind
  #24568

Implicits

• Only check seen for LazyRef for TypeSizeAccumulator
  #20459
• Chore: add regression test for #8581
  #24666
• Fix "Regression in zio/zio-schema for typer/implicit resolution"
  #24156
• Fix implicit scope liftToAnchors for parameter lower bounds
  #23679

Inference

• Tweak type for tryParameterless
  #24716

Initialization

• Refine parameter adaptation logic for arrays
  #23591

Infrastructure

• Tweak tests to not fail under jdk 25
  #25148
• Bump actions/upload-artifact from 6 to 7
  #25423
• Bump actions/download-artifact from 7 to 8
  #25420
• Bump VirtusLab/scala-cli-setup from 1.12.2 to 1.12.3
  #25422
• Bump coursier/cache-action from 7 to 8
  #25220
• Bump actions/upload-artifact from 5 to 6
  #24758
• Bump actions/download-artifact from 6 to 7
  #24759
• Bump actions/checkout from 5 to 6
  #24517
• Bump actions/upload-artifact from 4 to 5
  #24268
• Bump actions/download-artifact from 5 to 6
  #24271
• Bump actions/download-artifact from 4 to 5
  #23711
• Bump actions/checkout from 4 to 5
  #23710
• Chore: bump sbt to 1.11.5 #23805
• Chore(deps): bump actions/setup-java from 4 to 5
  #23812
• Chore: Use numberOfWorkers instead
  #24338
• Improvement: Additional way of defining ENABLE_BSP_ALL_PROJECTS
  #24122
• Formatting: Format presentation-compiler with scalafmt
  #24977
• Ensure mistakes in CI inputs are caught early
  #25677

Inline

• Chore: add regression test for #22575
  #25337
• Ensure the inline match scrutinee type conforms to the recalculated type
  #24988
• Make containsOuterRefsAnywhere follow aliases
  #25214
• Find annotation args in inline expansion
  #24895
• Chore: add regression test for #10343
  #24668
• Improve the test for creating protected method accessors fo...

Highlights of the release

• Long Term Support
• Make into type and modifier stable #26184
• Remove automatic collection of entry points #25215
• Scaladoc: support expectations in snippets #25713
• Restore Automatic-Module-Name in standard library's manifest #26218

Other changes and fixes

Annotations

• Unify annotation handling for thread-safe & -unsafe lazy vals #24907

Backend

• Use IndexOutOfBoundsException constructor with Int #24764
• Emit acceptable Java generic signatures for HKTs #25540
• Unwrap refined types for Java generic signatures #25626
• Fix Java signatures for arrays of value classes #25631
• Fix Java generic signatures for context functions #25632
• Handle HKT bounds in Java generic signatures #25744
• Emit nested module classes as static inner classes #26137

Constructors

• Lambda-owned param ref in ctor incurs no field #23286

Coverage

• Fix #25624: Scoverage and separation checking failures #25625
• Scoverage: do not instrument methods that have too large bodies #25629
• Scoverage & CC interaction: exempt CC nested symbols from @experimental check #25687
• Coverage + Experimental nested match cases interaction fix #25913
• Scoverage: fix broken warnings related to tail recursion and infinite loop detection #25941
• Scoverage: correctly detect curried constructor applications #26048
• Scoverage: correctly lift wildcard and singleton types #26049
• Scoverage: refrain from lifting closures for capture calculus compatibility #26067
• Scoverage: fix lifted type computation for parameterless methods #26069
• Scoverage: Fix coverage parameterless select qualifier casts #26087

Documentation

• Sys, concurrent, runtime (1): fill in missing @PARAM, @tparam, and @return tags in Scaladoc comments #25371
• Collection mutable (2): fill in missing @PARAM, @tparam, and @return tags in Scaladoc comments #25372
• Collection immutable (3): fill in missing @PARAM, @tparam, and @return tags in Scaladoc comments #25373
• Collection core (4): fill in missing @PARAM, @tparam, and @return tags in Scaladoc comments #25374
• Numeric types (5): fill in missing @PARAM, @tparam, and @return tags in Scaladoc comments #25375
• Array, IArray, Predef, Option (6): fill in missing @PARAM, @tparam, and @return tags in Scaladoc comments #25376
• Math (7): fill in missing @PARAM, @tparam, and @return tags in Scaladoc comments #25377
• Quoted, compiletime (8): fill in missing @PARAM, @tparam, and @return tags in Scaladoc comments #25378
• Jdk (9): fill in missing @PARAM, @tparam, and @return tags in Scaladoc comments #25379
• Util, io, ref (10): fill in missing @PARAM, @tparam, and @return tags in Scaladoc comments #25380
• Improve sizeCompare doc #25696
• Function, Tuple, Product (12): fill in missing @PARAM, @tparam, and @return tags in Scaladoc comments (V2) #25996
• Improve Scaladoc for Tuple#map #26060
• Fixed broken URL links. #26064
• Enable sc:compile for stdlib package scala.annotation #25836
• Enable sc:compile for stdlib package scala.beans #25837
• Enable sc:compile for stdlib package scala.collection #25838
• Enable sc:compile for stdlib package scala.collection.convert #25839
• Fix secondary constructor capture checking #25841
• Enable sc:compile for stdlib package scala.collection.generic #25845
• Enable sc:compile for stdlib package scala.collection.immutable #25855
• Enable sc:compile for stdlib package scala.collection.mutable #25860
• Enable sc:compile for stdlib package scala.collection.compat #25861
• Enable sc:compile for stdlib package scala.compiletime #25862
• Enable sc:compile for stdlib package scala.concurrent #25867
• Enable sc:compile for stdlib package scala.io #25868
• Enable sc:compile for stdlib package scala.jdk #25870
• Enable sc:compile for stdlib package scala.math #25878
• Enable sc:compile for stdlib package scala.quoted #25912
• Enable sc:compile for stdlib package scala.reflect #25915

Enums

• Adjust error on bad enum #23080
• Preserve Java enum semantics for explicit java.lang.Enum inheritance #25658

Erasure

• Preserve erased flags on synthetic context-function parameters #25751
• Fix #24653: Erase aliases of Unit as result type to void. #26192

Expression Compiler

• Fix expression evaluation in debugger under -old-syntax #26096

Extension Methods

• Fix: #24765 SAM conversion for extension method from self-based types #25637

Implicits

• Fixes #24914 Treat equivalent candidates as divergent in implicit search #25910
• Disallow implicit conversion to AnyRef again. #26210

Incremental Compilation

• Support zinc invalidation for type arguments in macro calls #23900
• Ignore annotations no longer on the classpath in ExtractAPI #25889
• Fixes #21383 enable Mode.ReadPositions when reading annotation trees #25911

Inline

• [OpenCB Project Fix] Fixes #26015: Start of NoSpan in adaptToArgs fallBack #26017

Lambda Lift

• Fixes #25943: Track super-calls as call edges in LambdaLift #26029

Linting

• Improve unused check of variable in assignment body #24685
• Warn about dollars in names of definitions unless backticked #24690
• Use precise type for x in case x @ (_: A, _: B), take 2 #26161

Opaque Types

• Fix crash on invalid opaque type in package #26118

Parser

• Fix span of xml literal #15635
• Warn if name of empty template has trailing colon #23907
• Warn dubious negative literal syntax #24163
• Fix "Compiler crashes when illegal signature of applyDynamic is used " #24974
• Check ascription in valdef pattern #25597
• Parse Java annotations on wildcard type arguments #26187

Pattern Matching

• Make sealed abstract java classes exhaustive checkable #25788

Pickling

• Fixes #25801: Handle TypeDefs in ensureHasSym #26011

Presentation Compiler

• Bugfix: Fix issue with empty name throwing exceptions #25752
• Improvement: improve perfomance of the presentation compiler #25769
• Bugfix: Don't add square braces in context bounds #25798
• Bugfix: Show hover on derives clause [#25804](#2...

Highlights of the release

• Allow :help syntax for all settings #26052
• feature: Add logical package parsing for sourcepath #25446
• Upgrade Scala CLI to 1.14.0
  • https://github.com/VirtusLab/scala-cli/releases/tag/v1.12.5
    • --cross support for run, package and doc sub-commands (experimental)
    • Global --offline config key
    • Local .m2 in publish local (experimental)
  • https://github.com/VirtusLab/scala-cli/releases/tag/v1.13.0
    • Support for Scala.js 1.21.0
    • Ammonite REPL deprecated & scheduled for removal
    • java-test-runner for pure Java tests
    • GraalVM native-image packaging: packaging.graalvmJvmId and packaging.graalvmArgs
  • https://github.com/VirtusLab/scala-cli/releases/tag/v1.14.0
    • Support for .test.java
    • A toggle to turn auto-IDE-setup off

Other changes and fixes

Annotations

• Also copy param annots at mixin #24916
• Named arg may be deprecatedName #21588
• Use dealiasKeepRefiningAnnots in AvoidMap #25609

Backend

• Do not simplify isInstanceOf if unrelated types might be subtypes at run-time #25535
• Port more Scala2 tests + some mixin improvements #25573
• Use Objects.equals in translating == #25314

Compiler Phases

• Harden Period creation and use of Run/PhaseId #25484
• Make Phase.run protected #25366

Context Functions

• Fix crash when processing path dependent context functions using HKTs #25530

Coverage

• Fix #25555: Preserve singleton precision during scoverage lifting #25556
• Fixes #25482: Ensure package transformation properly handles language imports in InstrumentCoverage #25546
• Scoverage: do not instrument erased values. #25298

Default parameters

• Fix named arguments evaluation order with by-name parameters #25161
• Typer: remove by-name lifting and replace default-getter args with fresh syms #25502

Documentation

• Error mentions bad _1 selector #25616
• Document Scala compiler error codes #24734
• Fix capture checking doc links in language.scala #25498
• Docs: apply snippet compiler on new types reference docs #19513
• Remove outdated comment in value classes #25428
• Update IsIterable scaladoc #24692

Enums

• Make enum apply ascriptions inferred types #25562

Extension Methods

• Accept using right associative parameters #24766
• Better handling of illegal trees in extension #25368

GADTs

• Also trust TypeTest when there is a Bind #24568

Implicits

• Deprecation when inferring implicit from non-accessible companion #25516
• Fix missing deprecation warning for implicit in non-accessible companion #25608
• Update migration message #25627

Inline

• Ensure the inline match scrutinee type conforms to the recalculated type #24988
• Do not update Symbol defTrees when retyping after Inlining #23870
• Inlines: decide sealing against original target, while using widened type as cast destination #25448
• Do not generate access proxies for locally defined protected defs #25056
• Avoid useless scrutinee proxy vals in inline match reduction #25279
• Improve the test for creating protected method accessors for inlines #25865

Linting

• Match apply in PolyFunction for override #25505
• Value discard checks inline call for exemption #25554
• Introduce error message ids for shadow warnings #25101
• Warn if for with many vals and overloaded map #25090

Match Types

• Restore MatchTypeNoCases warning with correct source position #25470

Named Tuples

• Fix Ycheck crash from singleton tuple selects after specialization #25331
• Fix #23621: make named tuples exhaustive checkable #25267

Nullability

• Patch to allow interop with XMLBuilder and -Yexplicit-nulls #25221
• Be honest about the nullability of ConsoleReporter.reader and SourcePosition.outer. #25561

Opaque Types

• Treat synthetic casts as pure #25126

Overloading

• Pretype args before skipping clause of overloaded application #23012

Parser

• Fix #20063: Java leading annotation parsing #25503
• Observe outdent also for type cases and type blocks in quotes #25519
• Fix: import resolution for Java #25537
• Fix #25456: parser crash on polymorphic context bound #25623
• Accept primitive.class in annotations #25363
• InCase has indent width of case #25295
• Don't automatically insert OUTDENT before COMMA #25501
• Add "did you mean to use parentheses/a block" when finding a complex expression on the RHS of an infix operator #25099
• Pat var must be isVarPattern #25701
• Don't pop outermost region when skipping #25738
• Context bound always has a span #25809
• Don't lookahead from interpolation #25834

Pattern Matching

• Clean desugaring of simple tuple assignments #25010
• Extend caching in the space engine beyond local context #23483
• Prevent from getting children in case of non-sealed private #25359
• Use MatchCaseUnreachable #24829
• Fix wrong exhaustive check with sequence wildcard on case class with custom unapply #24260
• Try expanding case class to the product of its fields #25454
• Fix false-positive pat mat unreachable case warning #25978

Positions

• Preserve span of this during statification of trait constructors #25354

Presentation Compiler

• Improvement: Add fallbacks in non critical places for presentation compiler #25483
• Improvement: Use method type if it's available #25641
• Bugfix: Fix wrong type in InferredType code action #25469
• Fix & feat: improvements in selection ranges #25290
• Fix: ignore implicit apply for signature help #25294
• Bugfix: remove stale top-level symbols between runs #25317
• feature: Improve the logical sources provider #26079

Quotes

• Fix crashing for context bound type variables in quoted patterns #25286
• Remove redundant mapOver in fixThisTypeModuleClassReferences #25440
• Improve LambdaTypes handling in Quotes reflect memberType #25786

Reflection

• Fix Select.copy in reflect API losing DerivedName for default getters #25269
• Do not expose ClassInfo in memberType in reflect API #24922

Reporting

• Force conditional warnings when configured #25552
• Suppressions before finalize #25576
• Use dollar-free...

Backported fixes

• Backport: Retry backporting #23665
  (#910)
• Backport "Do not overwrite the supertype of non-trait super in Erasure" to 3.3
  LTS (#909)
• Backport "feature: Improve the logical sources provider" to 3.3 LTS
  (#908)
• Backport "feature: Add logical package parsing for sourcepath" to 3.3 LTS
  (#907)
• Backport "Don't lookahead from interpolation" to 3.3 LTS
  (#905)
• Backport "Fix infinite loop with bad section ends in TastyHeaderUnpickler" to
  3.3 LTS (#904)
• Backport "Context bound always has a span" to 3.3 LTS
  (#903)
• Backport "Parse HTML properly in Scaladoc" to 3.3 LTS
  (#902)
• Backport "Don't pop outermost region when skipping" to 3.3 LTS
  (#901)
• Backport "Fix TastyPrinter's JAR-walking logic to include subdirectories" to
  3.3 LTS (#900)
• Backport "Ensure mistakes in CI inputs are caught early" to 3.3 LTS
  (#899)
• Backport "Delete dead code in io/Path" to 3.3 LTS
  (#898)

Contributors

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

According to git shortlog -sn --no-merges 3.3.8-RC1..3.3.8-RC2 these are:

    16  Tomasz Godzik
     2  Solal Pirelli
     2  Som Snytt

Backported PRs

• Bump Scala CLI to v1.14.0 (was v1.13.0) #26065
• Bump coursier to 2.1.25-M25 (was 2.1.25-M24) #26057
• Allow :help syntax for all settings #26052
• feature: Improve the logical sources provider #26079
• Add ErrorMessageID to -Winfer-union warnings (#25073) #25249
• Warn if for with many vals and overloaded map #25090
• Recognize Nullable annotations in explicit nulls #25237
• Fix false-positive pat mat unreachable case warning #25978
• Make type arguments to default methods InferredTypeTrees #25852
• Do not overwrite the supertype of non-trait super in Erasure #26081
• Move process parse exceptions to sys.error instead of a custom exception #25675
• Ensure mistakes in CI inputs are caught early #25677
• Fix TastyPrinter's JAR-walking logic to include subdirectories #25678
• Don't pop outermost region when skipping #25738
• Parse HTML properly in Scaladoc #25681
• Context bound always has a span #25809
• Fix infinite loop with bad section ends in TastyHeaderUnpickler #25676
• Don't lookahead from interpolation #25834

Contributors

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

According to git shortlog -sn --no-merges 3.8.4-RC2..3.8.4-RC3 these are:

     8	Solal Pirelli
     4	Wojciech Mazur
     3	Som Snytt
     2	Piotr Chabelski
     1	Martin Odersky
     1	Tomasz Godzik