Release highlights

• Add support for local coverage on and off with // $COVERAGE-OFF$ and // $COVERAGE-ON$ #24486
• Deprecate for removal -print-lines compiler setting #25330
• Add safe mode capture checking extension #25307
• Port the Scala2 JVM backend optimizer #25165

Other changes and fixes

Desugaring

• Fix [#24997]: Avoid unnecessary CHECKCAST in untupled function parameters #25085

Documentation

• Fix little errors in the API documentation #25241
• CC Language Reference: Rename cap to any/fresh #25057

Enums

• Deprecate override class, improve checks #24828
• Fix Java enum forwarders to pull from companion on initialization #24361

Experimental: Capture Checking

• Rename caps.cap to caps.any #24923
• Track global capabilities #24883
• Treat local mutable vars as capabilities #24815
• Fix Crashes when Capture-set Parameters Conflict with Terms #25029
• Replace "cannot be included in" by "cannot flow into" in error messages #25155
• CC: Add field captures to self-type constraints #24984
• Add uses clauses for templates #24857
• Drop special code paths for objects #24881
• Do not consider generated getters to be update def #24906
• Under cc, mark inferred type arguments to inline methods with an @inferred annotation #25175
• Handle call-by-name types in bad locations under cc #25154
• Fixes for global capabilities #25123
• Warn if reach capability in result will likely cause leakage #24860
• Make <fluid> decorations replace existing capture sets #25012
• Make TypeMaps in Setup work correctly for fresh #24985
• For a limited time, also recognize caps.cap #25076
• Fix closure typing #25014
• Map class capture sets via as-seen-from with prefix of created types #24830
• Drop SafeMode attribute in Tasty #25357
• Fix @assumeSafe addition in safe mode #25364
• Disallow @assumeSafe under safe mode #25462

Experimental: Modularity

• Fix nested desugaring of applied constructor types #25288

Exports

• Add ctor proxies before exports #24884

Inline

• Make containsOuterRefsAnywhere follow aliases #25214
• Find annotation args in inline expansion #24895
• Also substitute symbols in case bindings symbols #24849

JDK

• Skip over JEP 445 compact compilation units #23247
• Handle MissingType during Erasure phase #24817

JVM Backend

• Simplify JVM interface list emission, remove a mini-phase #25203
• Don't generate bridge methods for inaccessible Java package-private methods #25166
• Revise isLocalToCompilationUnit #24856
• Enforce JVM UTF-8 string limits in the backend #25300
• Fix class super-call invokespecial owner #25437

Linting

• Extension check handles hiBound of opaque type #25172
• Distrust tree pos for patvar lint #25043
• Move second CheckUnused after pattern matcher #25114
• Unused lint ignores args to ctor of enclosing class #24768
• Check inline expansion for exclusion #23019

Metaprogramming

• Fix: Fix incremental compilation of (some unquoted) macros #24969

Named Tuples

• Don't try checking for ambiguous single-element tuples when in types #24910
• Fix "NamedTuple type in match is parsed as named pattern" #24929
• Fix "Named pattern matching doesn't work in val statements or for generators" #24928
• Fix false exhaustivity warning for pattern returning NamedTuple #23362

Overloading

• Prefer non-extension to extension #24943

Parser

• Check seen for TypeParamRef in TypeSizeAccumulator #25264
• End of new expr never shrinks #25253
• Use toVector for XML literal sequences #23221

Pattern Matching

• Emit unchecked warnings for trait patterns #24962

Presentation Compiler

• Bugfix: inline value false-positive shadowing with lambda params #25140
• Test hover on backticked identifiers with whitespace #25142
• Inlining interpolated variables #25144
• Bugfix: treat self types as parent types #25167
• Feat(pc): add closing labels inlay hints #25178
• Coursier dependency imports should have lexicographic ordering #21592
• Bugfix: Fix various minor presentation compiler issues #25256
• Fix negative activeParameter in signature help #24945
• Closes [#7532]: Parameter hints not working for functions #23854
• Fix opaque types displayed as Nothing & Any in hover and signature help #24921

REPL

• Skip module-info.class files during REPL tab-completion #24838
• Fix REPL usage of macros loaded via :dep and :jar #25312
• Make REPL type echo-ing use partially qualified names where made possible by imports #24850
• Force REPL to not evaluate LazyList #25444

Reporting

• Check -Werror on summarize #25096
• Fixes [#24233]: Remove misleading JDK compatibility hint for TASTy errors #25171
• Ignore resetting if preferPrevious #24991
• Enhance WInferUnion to not warn propagated explicit union types #25280
• Improve diagnostic message for unnecessary trailing underscore in eta-expansion #25285
• More descriptive "not found" message when type/term exists with the expected term/type name #24959
• Warn on Scala 2 auto-apply if loosely nullary #24811
• Fix printing references to nested objects #25086
• Add error note for type mismatch involving blocks without last expression #25181
• Drop -print-lines option #24905
• Don't suggest invisible members of root imports #24999

Runner

• Bump Scala CLI to v1.12.3 (was v1.12.2) #25365
• Bump Scala CLI to 1.12.4 (was 1.12.3) #25434

Rewrites

• Accommodate ArrowAssoc in infix named arg migration #25255

Scaladoc

• Init MacroClassLoader in scaladoc #25141
• Scaladoc Overload Method Link Fix #25156
• Fix duplicate member entries in Scaladoc generation #24712
• Scaladoc Tests for CC #25277
• Skip generation of API pages when building reference docs #25153
• Docs: Enforce links checks in the generated docs #25425

Scala.js

• Fix issues in presentation compiler when using Scala JS #25450
• Fix issues with Scala JS and the presentation compiler #25550

Settings

• Don't enable compact annotations under 2.13. #25419

Standard Library

• Remove incorrect equals implementations from ArrayBuilder #25205
• Use StringBuilder intead of StringBuffer in Regex #24576
• Update StringOps.* implementation #24786

TASTy format

• Don't absolutize sources outside of the sourceroot in TASTy #25429

Tooling

• Fix behavior of -Ydump-sbt-inc #25125

Typer

• Never widen constant type on selector type in matches #25197
• Preserve insertion order when balancing And/OrType #25361
• Improve ref check of constructors #24342

Quotes

• Fix [#25208]: handle AndType(TermRef, TypeRef) in TreeUnpickler path trees #25209

Contributors

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

According to git shortlog -sn --no-merges 3.8.2..3.8.3 these are:

    92  Martin Odersky
    68  Solal Pirelli
    65  Wojciech Mazur
    27  Som Snytt
    13  Tomasz Godzik
    11  Li Haoyi
     9  Kenji Yoshida
     9  Oliver Bračevac
     8  Rikito Taniguchi
     7  dependabot[bot]
     5  Jakub Warchoł
     4  Emil Ejbyfeldt
     4  Hamza Remmal
     4  Zieliński Patryk
     4  noti0na1
     3  Binayak Das
     3  Lukas Rytz
     3  Matt Bovel
     3  Piotr Chabelski
     2  Chua Chee Seng
     2  Eugene Yokota
     2  Jamie Thompson
     2  Jędrzej Rochala
     2  Natsu Kagami
     2  Oscar Boykin
     2  P. Oscar Boykin
     2  Sébastien Doeraene
     1  Anatolii Kmetiuk
     1  Aviral Garg
     1  Bbn08
     1  Bill Venners
     1  Eric Ventor
     1  Jentsch
     1  Jeon Yoonjae
     1  Krrish Biswas
     1  Matt Dziuban
     1  Merlin Hughes
     1  Philippus Baalman
     1  Vadim Chelyshov