Highlights of the release

• Warn if for with many vals and overloaded map #25090
• Support :dep ... to add library dependencies in the Scala REPL #24131
• Upgrade to Scala.js 1.20.2. #24898
• Bump Scala CLI to v1.12.2 (was 1.11.0) #25217:
• New aliases for RC and nightly Scala versions
• Detailed changelog available in scala-cli release notes for versions: v1.12.0, v1.12.1 and v1.12.2

Other changes and fixes

Context Functions

• Inferred Contextual params are less nameable #24381

Desugaring

• A comprehension with valdef aliases is never a candidate for map elimination. #23448

Experimental: Capture Checking

• Capture Checking of Lazy Vals #24261
• Represent read-only with a classifier #24295
• Fix typing closure blocks where result type refers to a closure parameter. #24299
• Systematically recompute denotations when needed in rechecker phases #24302
• Ensure that read-only methods don't use exclusive capabilities #24311
• Handle capture parameters in dcs #24328
• Don't prematurely force info of fields with inferred types #24336
• Disallow fresh caps from parameter bounds in results #24541
• Avoid box failures and better diagnosis if they come back #24546
• Freshen all explicit arguments of type applications #24354
• Optimize and harden isCaptureChecking tests #24439
• Add Unscoped classifier #24470
• Optimization: Introduce CompactAnnotation #24679

Experimental: Seperation Checking

• Changes to Mutable #24352
• Don't crash when update is used as a modifier outside cc #24378
• Imply update only for consume methods in Mutable classes #24383
• Decompose Mutable #24495
• Add freeze wrapper (2) #24518
• Make Arrays mutable types under separation checking #24649

Experimental: Explcit Nulls

• Relax flow typing checks on Flexible Types #24278
• Do not expose flexible types #24292
• Do not search contextual function type in union types in general #24393
• Add jspecify NonNull annotation to NotNullAnnots list #24487
• Recognize Nullable annotations in explicit nulls #25237

Experimental: Global Initialization

• Global object init checker gives warning when accessing an object before its super constructor finishes #24349

Annotations

• Accommodate adapted Scala 2 annotation value #17516
• Harden Annotation.refersToParamOf #24647
• Do not allow @targetName on primary constructor too #24682

Coverage

• Fix issues with Scala.js and coverage #24769
• Make coverage support incremental compilation #24773
• Improvement: Try to optimize coverage phase #24925

Enums

• Lint enum case in outer context #24652

Exports

• Preserve select of exported member in newExpr #24570

Erasure

• Fix isJvmAccessible to handle nested protected Java classes #24625

Inline

• Allow references to erased values in types #24421
• Cast inline call results to result type, not method type #25111
• Fix "Compiler crash when calling another file's inline def that uses a private constructor" #24941

Implicits

• Avoid more constraints in result if trying views #24369

Initialization

• Skip caret when source is missing in initialization checker #23926

JVM Backend

• Preserve singleton types for final val aliases to Java enum constants #24980

Linting

• Suppression matches inlined positions #24092
• Wshadow option recognizes Wall #24469

Nullability

• Record NotNullInfo for exceptional try-catch #24320

Overloading

• Ignore selection prototypes when typing type applications #24489
• Fix varargs overload resolution with wildcard types #24669
• Fix override checking for Java methods with covariant array #24408

Parser

• Permit new with trivial end #24331
• Single line case lambda gets a region #24497
• Error tree on outdent is zero extent #23796

Pattern Matching

• Fix false exhaustivity for GADT under separate compilation #23966

Presentation Compiler

• Create extension method in infer method action #24721
• Exclude XRayModeHint for synthetics #24722
• Fix incorrect XRay hint #24738
• Improve multi-line code message rendering #24723
• Improvement: Allow passing -explain to the presentation compiler #24740
• Handle inlined tree in implicit parameter inlay hints #24762

REPL

• Improve REPL code, echo and exception highlighting with pprint and fansi #24298
• Replace REPL signal handling with raw mode jline terminal to make Ctrl-C handling work when REPL is a child process #24842
• Fix "Colon as operator part at beginning of line in REPL" #24942
• Fix "REPL dependency on scala-parallel-collections doesn't work" #25064
• Fix "Still can't use scala-parallel-collections in REPL via :dep" #25092

Reporting

• Addendum when apply error involves default arg #21133
• Forward reference error includes line numbers #22534
• Improve error messages for scope extrusion errors #24318
• Use a better span for an anonymous class #24640
• Add ErrorMessageID to -Winfer-union warnings (#25073) #25249

Scaladoc

• Allow to additional scalacOptions in Markdown code snippets #24755

Standard Library

• Enable capture checking on Tuple #24345
• Update StringOps.padTo implementation #24575
• Use String.repeat in scala.io.Source #24594
• Ensure stability of IArray.tapEach #24727

TASTy

• Pickle CompactAnnotations as regular annotations #25213
• Drop spurious applies in unpickler and inliner #25201

Transform

• Adjust purity of trait with lazy member #23788

Tuples

• Fix inconsistent typeSize calculation for TupleN vs recursive pair encodings #24743

Typer

• Dealias type of type constructor in typedAppliedTypeTree #24522
• Improve TypeVar instantiation logic #24697
• Try to instantiate TypeVars inside pt when possible #24231
• Error instead of crash when generating trees referring to skolems #24380
• Try to fix callee type inference in typedFunctionValue #24732
• Fix wildcardArgOK for mixed wildcard/concrete type args #25001

Union types

• Dealias in isSimpleThrowable check #24744

Value class

• Avoid NPE when calling hashCode on a value class wrapping null #25110

Quotes

• Make quotes.reflect.Position.ofMacroExpansion consider -Ymagic-offset-header #24301

Contributors

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

According to git shortlog -sn --no-merges 3.8.1..3.8.2 these are:

   103  Martin Odersky
    93  Hamza Remmal
    79  Wojciech Mazur
    36  Som Snytt
    27  noti0na1
    16  Rikito Taniguchi
     9  Li Haoyi
     8  Matt Bovel
     8  Oliver Bračevac
     7  Kenji Yoshida
     7  Natsu Kagami
     7  Tomasz Godzik
     7  Yichen Xu
     6  Jan Chyb
     6  Piotr Chabelski
     5  Zieliński Patryk
     5  dependabot[bot]
     4  HarrisL2
     4  Lukas Rytz
     3  Jamie Thompson
     2  Chua Chee Seng
     2  Fengyun Liu
     2  Guillaume Martres
     2  Lluc Santamaria Riba
     2  Sébastien Doeraene
     1  Alex1005a
     1  Bill Venners
     1  Emil Ejbyfeldt
     1  EnzeXing
     1  Evgeny Vereshchagin
     1  Jeon Yoonjae
     1  Lorenzo Gabriele
     1  Seth Tisue
     1  matsu-chara
     1  rjolly
     1  zielinsky