Scala

What's new in this version:

Highlights of the release:
- Warn if for with many vals and overloaded map
- Support :dep ... to add library dependencies in the Scala REPL
- Upgrade to Scala.js 1.20.2.

Bump Scala CLI to v1.12.2 (was 1.11.0)
- 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

Desugaring:
- A comprehension with valdef aliases is never a candidate for map elimination

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

Experimental: Seperation Checking:
- Changes to Mutable
- Don't crash when update is used as a modifier outside cc
- Imply update only for consume methods in Mutable classes
- Decompose Mutable
- Add freeze wrapper (2)
- Make Arrays mutable types under separation checking

Experimental: Explcit Nulls:
- Relax flow typing checks on Flexible Types
- Do not expose flexible types
- Do not search contextual function type in union types in general
- Add jspecify NonNull annotation to NotNullAnnots list
- Recognize Nullable annotations in explicit nulls

Experimental: Global Initialization:
- Global object init checker gives warning when accessing an object before its super constructor finishes

Annotations:
- Accommodate adapted Scala 2 annotation value
- Harden Annotation.refersToParamOf
- Do not allow @targetName on primary constructor too

Coverage:
- Fix issues with Scala.js and coverage
- Make coverage support incremental compilation
- Improvement: Try to optimize coverage phase

Enums:
- Lint enum case in outer context

Exports:
- Preserve select of exported member in newExpr

Erasure:
- Fix isJvmAccessible to handle nested protected Java classes

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

Implicits:
- Avoid more constraints in result if trying views

Initialization:
- Skip caret when source is missing in initialization checker

JVM Backend:
- Preserve singleton types for final val aliases to Java enum constants

Linting:
- Suppression matches inlined positions
- Wshadow option recognizes Wall

Nullability:
- Record NotNullInfo for exceptional try-catch

Overloading:
- Ignore selection prototypes when typing type applications
- Fix varargs overload resolution with wildcard types
- Fix override checking for Java methods with covariant array

Parser:
- Permit new with trivial end
- Single line case lambda gets a region
- Error tree on outdent is zero extent

Pattern Matching:
- Fix false exhaustivity for GADT under separate compilation

Presentation Compiler:
- Create extension method in infer method action
- Exclude XRayModeHint for synthetics
- Fix incorrect XRay hint
- Improve multi-line code message rendering

Improvement: Allow passing -explain to the presentation compiler
- Handle inlined tree in implicit parameter inlay hints

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

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

Scaladoc:
- Allow to additional scalacOptions in Markdown code snippets

Standard Library:
- Enable capture checking on Tuple
- Update StringOps.padTo implementation
- Use String.repeat in scala.io.Source
- Ensure stability of IArray.tapEach

TASTy:
- Pickle CompactAnnotations as regular annotations
- Drop spurious applies in unpickler and inliner

Transform:
- Adjust purity of trait with lazy member

Tuples:
- Fix inconsistent typeSize calculation for TupleN vs recursive pair encodings

Typer:
- Dealias type of type constructor in typedAppliedTypeTree
- Improve TypeVar instantiation logic
- Try to instantiate TypeVars inside pt when possible
- Error instead of crash when generating trees referring to skolems
- Try to fix callee type inference in typedFunctionValue
- Fix wildcardArgOK for mixed wildcard/concrete type args

Union types:
- Dealias in isSimpleThrowable check

Value class:
- Avoid NPE when calling hashCode on a value class wrapping null

Quotes:
- Make quotes.reflect.Position.ofMacroExpansion consider -Ymagic-offset-header