Highlights of the release

• Add sources of synthetic classes to sources jar #20904

Other changes and fixes

Annotations

• Preventing compilation of a @tailrec method when it does not rewrite, but an inner method does #20143
• #20145 - bugfix when a return tailrec is called inside a val def. #20652

Backend

• Fix EnclosingMethod for lifted anonfun #20558
• Emit switch bytecode when matching unions of a switchable type #20411
• Fix deterministically adding additional interfaces #20593
• Emit generatedNonLocalClass in backend when callback is not enabled #21186

Documentation

• Avoid jpath in example #20775
• Chore: Fix doc link in clauseInterleaving docstring #20590
• Chore: fix doc link in namedTuples docstring #20770

Erasure

• Don't re-balance AndTypes arising from supertypes #20400

GADTs

• Harden GADT constraint handling to survive illegal F-bounds #20325

Inferencing

• Adapt toInstantiate in interpolateTypeVars to consider #20399 #20426

Infrastructure

• Update addToBackportingProject.scala #20461
• Simple scripts to run non-bootstrapped compiler after 'sbt buildQuick' #19894
• Bump from 3.4.0 to 3.5.0-RC1 for MiMA #20404
• Set reference version to 3.5.0-RC4 #21175
• Bring back windows performance improvements #20423
• Bump scalacenter/sbt-dependency-submission from 2 to 3 #20440
• Fix incorrect paths to sha256 check sum files in release workflow #20709
• Bump VirtusLab/scala-cli-setup from 1.3.2 to 1.4.0 #20906

Inline

• Mark genSJSIR as disabled (rather than non-runnable) when no -scalajs. #20815
• Map over refs of ImportTypes in TypeMap #20837

Initialization

• More principled filtering of abstract values in initialization check #20548

Match Types

• TryCompiletimeConstantFold in disjointnessBoundary #20168

Pattern Matching

• Fix #20372: Check pattern match exhaustivity in inlined code #20403

Presentation Compiler

• Add pattern completion for unapply contexts #20274
• Bugfix: Exclude newer LSP4j, which is built on JDK 11 #20771
• Chore: Bump mtags to latest stable #20442
• Weekly metals backport #20542
• Port pc find references from metals #20544

Quotes

• Add regression test for issue 20309 #20387

REPL

• Only consider methods with 0 parameters in valueOf #20543

Reflection

• Fix erasure crash for Inlined rhs of a context function closure #20398
• Fix #20458: do not expose ClassInfo in quotes reflect widenTermRefByName #20468

Reporting

• Fix error message on setter with wrong type #20444
• Add a specific error message for local final defs #20557
• Explain unresolvable references better #20477
• Add error code to diagnostics about unused code #19780
• Better error diagnostics for illegal match cases #20905

Runner

• Bump scala-cli to 1.4.1 + drop old cli management #21234
• Bump scala-cli to 1.4.3 #21338

Scaladoc

• Fix handling of right associative extension methods across scaladoc and printers #20467

Specification

• Add binary lits to syntax summaries #19551

Settings

• Enhance help message for language flag #20247
• Accept legacy language features #20454
• Set default source version to 3.5 #20435

Tooling

• Improve source positions emited for synthetic unit in if-conditions #20431
• Adjust the API name entry for nested classes #20279
• Fix declaring product of straight-to-jar compilation #20592

Transform

• Correct Java signature for value classes appearing in type arguments #20463

Typer

• Retry constraint.replace after constraint.updateEntry #20399
• Add special handling for comparisons with Singleton types #20474
• Reinstantiate restriction to transparent inline methods #20371
• Add regression test for #20288 fixed in #20527 #20857
• Fix isEffectivelySingleton #20486
• Fall back to direct subtype comparison at the end in dropIfSuper and dropIfSub #20523
• Mark AppliedType cachedSuper valid Nowhere when using provisional args #20527
• Fix healAmbiguous to compareAlternatives with disambiguate = true #21372

Experimentqal Changes

Capture Checking

• Fix soundness hole of forgotten reach capabilities #20524
• Drop @capability annotations #20396
• Fix symbol reference retrivial for scala.caps.Caps #20493
• Refactor adaptBoxed #20525
• Fix error related to reaches when using scala2-library-cc-tasty #20528

Named tuples

• Make NamedTuple.Empty an alias to NamedTuple #20502
• Move NamedTuple methods to separate scope. re-export #20504
• WidenDealias before extracting namedTupleElementTypes #20505
• Improve type inference for literal named tuples #20497
• Fix issue #20267 with regression test #20506
• Only set AppliedType#validSuper after AppliedType#cachedSuper #20553
• Fix NamedTuple selection on an unstable prefix #20455
• Allow apply adaptation on Selectable with Fields #20489

Contributors

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

According to git shortlog -sn --no-merges 3.5.0..3.5.1 these are:

    82  Martin Odersky
    29  Wojciech Mazur
    22  Hamza REMMAL
    16  Jamie Thompson
    15  Eugene Flesselle
    14  Hamza Remmal
    13  noti0na1
     9  Katarzyna Marek
     7  Fengyun Liu
     7  Jan Chyb
     6  Dale Wijnand
     6  Guillaume Martres
     5  Som Snytt
     4  dependabot[bot]
     3  Adrien Piquerez
     3  Derek Wickern
     3  Matt Bovel
     3  OlegYch
     2  Florian3k
     2  Kacper Korban
     2  Lucy Martin
     2  Paweł Marks
     2  Tomasz Godzik
     1  Arnout Engelen
     1  Eugene Yokota
     1  João Ferreira
     1  Kasper Kondzielski
     1  Lucas Nouguier
     1  Lukas Rytz
     1  Mikołaj Fornal
     1  Nafer Sanabria
     1  Natsu Kagami
     1  Seth Tisue
     1  Sébastien Doeraene