Scala

Highlights of the release

• Stabilize new lazy vals #16614
• Experimental Macro annotations #16392 #16454 #16534
• Fix stability check for inline parameters #15511
• Make fewerBraces a standard feature #16297
• Add new front-end phase for unused entities and add support for unused imports #16157
• Implement -Wvalue-discard warning #15975
• Introduce boundary/break control abstraction. #16612

Other changes and fixes

Annotations

• Support use-site meta-annotations #16445

Desugaring

• Reuse typed prefix for applyDynamic and applyDynamicNamed #16552
• Fix object selftype match error #16441

Erasure

• Dealias before checking for outer references in types #16525
• Fix generic signature for type params bounded by primitive #16442
• Avoid EmptyScope.cloneScope crashing, eg on missing references #16314

GADTs

• Inline GADT state restoring in TypeComparer #16564
• Add extension/conversion to GADT selection healing #16638
• Split out immutable GadtConstraint #16602
• Avoid bidirectional GADT typebounds from fullBounds #15683

Incremental compilation

• Unpickle arguments of parent constructors in Templates lazily #16688

Initialization

• Fix #16438: Supply dummy args for erroneous parent call in init check #16448

Inline

• Dealias in ConstantValue, for inline if cond #16652
• Set Span for top level annotations generated in PostTyper #16378
• Interpolate any type vars from comparing against SelectionProto #16348
• Handle binding of beta reduced inlined lambdas #16377
• Do not add dummy RHS to abstract inline methods #16510
• Warn on inline given aliases with functions as RHS #16499
• Support inline overrides in value classes #16523

Java interop

• Represent Java annotations as interfaces so they can be extended, and disallow various misuses of them #16260

Linting

• Fix -Wunused:import registering constructor instead of its owner (also fix false positive for enum) #16661
• Fix #16675 : -Wunused false positive on case class generated method, due to flags used to distinguish case accessors. #16683
• Fix #16682: CheckUnused missed some used symbols #16690
• Fix "-Wunused: False positive on parameterless enum member" #16927
• Register usage of symbols in non-inferred type trees in CheckUnused #16939
• Traverse annotations instead of just registering in -Wunused #16956
• Ignore parameter of accessors in -Wunused #16957
• Ignore parameter of accessors in -Wunused #16957
• Improve override detection in CheckUnused #16965
• WUnused: Fix unused warning in synthetic symbols #17020
• Fix WUnused with idents in derived code #17095
• WUnused: Fix for symbols with synthetic names and unused transparent inlines #17061
• Skip extension method params in WUnused #17178
• Fix wunused false positive when deriving alias type #17157
• Fix WUnused for accessible symbols that are renamed #17177
• Fix WUnused false positive in for #17176
• Make CheckUnused run both after Typer and Inlining #17206
• Disable WUnused for params of non-private defs #17223
• Wunused: Check if symbol exists before isValidMemberDef check #17316
• Wunused: Include import selector bounds in unused checks #17323
• Fix compiler crash in WUnused #17340

Opaque Types

• Delay opaque alias checking until PostTyper #16644

Overloading

• Handle context function arguments in overloading resolution #16511

Parser

• Improve support for Unicode supplementary characters in identifiers and string interpolation (as in Scala 2) #16278
• Require indent after colon at EOL #16466
• Help givens return refined types #16293

Pattern Matching

• Tweak AvoidMap's derivedSelect #16563
• Space: Use RHS of & when refining subtypes #16573
• Freeze constraints in a condition check of maximiseType #16526
• Restrict syntax of typed patterns #16150
• Test case to show that #16252 works with transparent #16262
• Support inline unapplySeq and with leading given parameters #16358
• Handle sealed prefixes in exh checking #16621
• Detect irrefutable quoted patterns #16674
• Patmat: Use less type variables in prefix inference #16827

Pickling

• Allow case classes with up to 254 parameters #16501
• Correctly unpickle Scala 2 private case classes in traits #16519

Polyfunctions

• Fix #9996: Crash with function accepting polymorphic function type with singleton result #16327

Quotes

• Remove contents of inline methods #16345
• Fix errors in explicit type annotations in inline match cases #16257
• Handle macro annotation suspends and crashes #16509
• Fix macro annotations spliceOwner #16513
• Fix HK quoted pattern type variables #16907

REPL

• REPL: Fix crash when printing instances of value classes #16393
• Attempt to fix completion crash #16267
• Fix REPL shadowing bug #16389
• Open up for extensibility #16276
• Don't crash if completions throw #16687

Reflection

• Fix reflect typeMembers to return all members #15033
• Deprecate reflect Flags.Static #16568

Reporting

• Suppress follow-on errors for erroneous import qualifiers #16658
• Fix order in which errors are reported for assignment to val #16660
• Fix class name in error message #16635
• Make refined type printing more source compatible #16303
• Add error hint on local inline def used in quotes #16572
• Fix Text wrapping #16277
• Fix #16680 by registering Ident not containing a symbol #16689
• Fix the non-miniphase tree traverser #16684
• Just warn on type ascription on a pattern #17454

Scala-JS

• Fix #14289: Accept Ident refs to js.native in native member rhs. #16185

Scaladoc

• Added jpath check to `ClassLi...