[Scala 3] implicit def/val → given

MIGRATION.md

@@ -54,6 +54,31 @@ the bottom of this file. Restoration ships incrementally per feature area.
   compiles).
 - `enum` was renamed to `e` at one call site in `GenKeyCodec` (`enum` is reserved in Scala 3).
 - `@targetName` annotation added to `CloseableIterator` overloaded methods.
+- `implicit val/def` typeclass instances rewritten to `given` across `serialization`, `cbor`,
+  `meta`, `misc`, `tuples` (slice 3.3). Named-import callers that referenced these by name
+  (e.g. `GenCodec.bseqCodec`, `GenKeyCodec.IntKeyCodec`, `TypeString.codec`) must switch to
+  `summon[GenCodec[BSeq[T]]]` or use `import X.given` for given-import semantics. Anonymous
+  `given T = …` preferred for canonical instances per fork pattern.
+- Named-import compatibility shims: `@deprecated def NAME: T = summon[T]` aliases added in
+  `BoxingUnboxing` (`BooleanBoxing` … `DoubleBoxing`, `BooleanUnboxing` … `DoubleUnboxing`)
+  and `GenKeyCodec` (`BooleanKeyCodec` … `BytesKeyCodec`) so downstream callers using
+  `GenKeyCodec.IntKeyCodec`-style named lookup keep compiling. Each shim emits a deprecation
+  warning pointing to `summon[T]`. Mirrors `BsonGenCodecs` source-compat layer from fork
+  commit `8f70be80`.
+- `OptArg.argToOptArg` PRESERVED as `implicit def` — polymorphic `Conversion[A, OptArg[A]]`
+  would generate a clashing JVM erasure bridge (both `A` and the `OptArg` value class erase to
+  `Object`). Verbatim explanatory comment from fork `39c047eb` retained inline.
+- `GenRef.fun2GenRef` PRESERVED as `implicit def` (currently a `???` Phase-2 stub; Phase 4
+  feature-port will restore the macro-splice body; macro-splice-over-inline-arg rationale per
+  fork `ebffde26` documented as preservation rule).
+- `RunNowEC.Implicits.executionContext` / `RunInQueueEC.Implicits.executionContext` PRESERVED
+  as `implicit val` — the wildcard-import-into-`Implicits`-object idiom is the public API
+  (`import RunNowEC.Implicits._`). Converting to `given` would silently stop providing the EC
+  to wildcard-import callers (givens require `import X.given`).
+- `(implicit X: T)` parameter lists left in place across slice-3.1 extension-shim sites
+  (`SharedExtensions.implicit def *Ops`, jiop, jsiop, `Components.autoComponent`, etc.). Those
+  are conversion shims for `implicit class` value-class wrappers and are being rewritten to
+  `extension` blocks in slice 3.1 (PR #868), which deletes the conversion entirely.
 
 ### mongo
 
@@ -63,10 +88,33 @@ the bottom of this file. Restoration ships incrementally per feature area.
   Scala 3 forbids type projections on non-concrete prefixes). Public-API signature change.
 - `BsonValueOutput.write` / `BsonValueInput.read` call sites require explicit `using` keyword.
 - `MongoPolyDataCompanion` / `TypedMapFormat` / `TypedMapRefOps` widened from `K[_]` / `D[_]` to `K[Any]` / `D[Any]`.
+- `(implicit X: T)` parameter lists rewritten to `(using X: T)` across 19 mongo files in
+  slice 3.3 (BsonCodec, BsonRef, DocKey, Filter, GenCodecProvider, BsonRefIterable*, Sorting,
+  MongoOps, TextSearchLanguage, DataTypeDsl, MongoEntityCompanion, MongoIndex,
+  MongoPolyDataCompanion, MongoRef, MongoUpdateOperator, ProjectionZippers, QueryOperatorsDsl,
+  TypedMongoCollection). Source-compat: positional call sites unchanged (Scala 3 accepts both
+  syntaxes); named-arg call sites must update from `foo(x = …)` to `foo(using x = …)`.
+- `BsonGenCodecs` rewritten per fork `8f70be80`: trait uses `export BsonGenCodecs.given`,
+  object holds anonymous `given GenCodec[X] = …` declarations + `@deprecated def name: T = summon`
+  shims for source-compat with named-import callers (`BsonGenCodecs.objectIdCodec`, etc.).
+- `MongoFormat.codec` / `MongoAdtFormat.codec`/`dataClassTag` are now `given` in trait
+  declarations; consumers using `import meta.format._` to bring `codec`/`dataClassTag` into
+  implicit scope must switch to `import meta.format.{given, _}` for given-import semantics
+  (already applied internally in `TypedMongoCollection.mkNativeCollection`).
+- `KeyGetter.bsonRefKeyGetter` / `docKeyKeyGetter` rewritten from `implicit object … extends T`
+  to `given X: T with { … }`. Source-compat: positional resolution unchanged; `import X._`
+  callers must switch to `import X.given`.
 
 ### hocon
 
 - `SealedEnumCompanion.values` override now `lazy val` (see core notes).
+- `HoconGenCodecs` codec instances (`ConfigCodec`, `FiniteDurationCodec`, `JavaDurationCodec`,
+  `PeriodCodec`, `SizeInBytesCodec`, `ClassKeyCodec`, `ClassCodec`) rewritten from
+  `implicit final val` to `given` (slice 3.3). Same named-import caveat as the core entry
+  applies.
+- `ConfigObjectCompanion.codec` instance and `DefaultConfigCompanion` macro-instance
+  parameter rewritten to `using`.
+- `HTree.HIncludeQualifier` / `HStringSyntax` constructor implicit param rewritten to `using`.
 
 ## 4. Binary-compat breaks
 

benchmark/jvm/src/main/scala/com/avsystem/commons/ser/GenCodecBenchmarks.scala

@@ -18,13 +18,13 @@ class GenCodecBenchmarks {
 
   @Benchmark
   def cleanSomeWriting: String = {
-    implicit val cleanCodec: GenCodec[Option[String]] = GenCodecBenchmarks.cleanOptionCodec[String]
+    given cleanCodec: GenCodec[Option[String]] = GenCodecBenchmarks.cleanOptionCodec[String]
     JsonStringOutput.write(GenCodecBenchmarks.somes)
   }
 
   @Benchmark
   def cleanNoneWriting: String = {
-    implicit val cleanCodec: GenCodec[Option[String]] = GenCodecBenchmarks.cleanOptionCodec[String]
+    given cleanCodec: GenCodec[Option[String]] = GenCodecBenchmarks.cleanOptionCodec[String]
     JsonStringOutput.write(GenCodecBenchmarks.nones)
   }
 
@@ -34,7 +34,7 @@ class GenCodecBenchmarks {
 }
 
 object GenCodecBenchmarks {
-  implicit def cleanOptionCodec[T: GenCodec]: GenCodec[Option[T]] =
+  given cleanOptionCodec[T: GenCodec]: GenCodec[Option[T]] =
     GenCodec.create[Option[T]](
       i => if (i.readNull()) None else Some(GenCodec.read[T](i)),
       (o, vo) =>

benchmark/jvm/src/main/scala/com/avsystem/commons/ser/StreamInputOutputBenchmark.scala

@@ -11,8 +11,8 @@ case class Toplevel(int: Int, nested: Nested, str: String)
 case class Nested(list: List[Int], int: Int)
 
 object Toplevel {
-  implicit val nestedCodec: GenCodec[Nested] = GenCodec.materialize[Nested]
-  implicit val codec: GenCodec[Toplevel] = GenCodec.materialize[Toplevel]
+  given nestedCodec: GenCodec[Nested] = GenCodec.materialize[Nested]
+  given codec: GenCodec[Toplevel] = GenCodec.materialize[Toplevel]
 }
 
 @Warmup(iterations = 10)

core/js/src/main/scala/com/avsystem/commons/serialization/nativejs/NativeFormatOptions.scala

@@ -6,7 +6,7 @@ import com.avsystem.commons.misc.{AbstractValueEnum, AbstractValueEnumCompanion,
 /** Specifies format used by `NativeJsonOutput.writeLong` / `NativeJsonInput.readLong` to represent [[Long]]. JS does
   * not support 64-bit representation.
   */
-final class NativeLongFormat(implicit ctx: EnumCtx) extends AbstractValueEnum
+final class NativeLongFormat(using ctx: EnumCtx) extends AbstractValueEnum
 object NativeLongFormat extends AbstractValueEnumCompanion[NativeLongFormat] {
   final val RawString: Value = new NativeLongFormat
   final val JsNumber: Value = new NativeLongFormat
@@ -16,7 +16,7 @@ object NativeLongFormat extends AbstractValueEnumCompanion[NativeLongFormat] {
 /** Specifies format used by `NativeJsonOutput.writeTimestamp` / `NativeJsonInput.readTimestamp` to represent
   * timestamps.
   */
-final class NativeDateFormat(implicit ctx: EnumCtx) extends AbstractValueEnum
+final class NativeDateFormat(using ctx: EnumCtx) extends AbstractValueEnum
 object NativeDateFormat extends AbstractValueEnumCompanion[NativeDateFormat] {
   final val RawString: Value = new NativeDateFormat
   final val JsNumber: Value = new NativeDateFormat
@@ -27,7 +27,7 @@ object NativeDateFormat extends AbstractValueEnumCompanion[NativeDateFormat] {
   *
   * Note that [[scala.scalajs.js.JSON.stringify]] does not know how to serialize a BigInt and throws an error
   */
-final class NativeBigIntFormat(implicit ctx: EnumCtx) extends AbstractValueEnum
+final class NativeBigIntFormat(using ctx: EnumCtx) extends AbstractValueEnum
 object NativeBigIntFormat extends AbstractValueEnumCompanion[NativeBigIntFormat] {
   final val RawString: Value = new NativeBigIntFormat
   final val JsBigInt: Value = new NativeBigIntFormat

core/jvm/src/main/scala/com/avsystem/commons/concurrent/BlockingUtils.scala

@@ -15,7 +15,7 @@ abstract class BlockingUtils {
 
   /** Default scheduler used to run `Task`s and `Observable`s. This scheduler is not meant for blocking code.
     */
-  implicit def scheduler: Scheduler
+  given scheduler: Scheduler
 
   /** Scheduler used for running blocking code.
     */
@@ -71,6 +71,6 @@ abstract class BlockingUtils {
 }
 
 object DefaultBlocking extends BlockingUtils {
-  implicit def scheduler: Scheduler = Scheduler.global
+  given scheduler: Scheduler = Scheduler.global
   lazy val ioScheduler: Scheduler = Scheduler.io()
 }

core/jvm/src/main/scala/com/avsystem/commons/concurrent/ObservableBlockingIterator.scala

@@ -19,7 +19,7 @@ class ObservableBlockingIterator[T](
   timeout: Long,
   unit: TimeUnit,
   bufferSize: Int,
-)(implicit val scheduler: Scheduler
+)(using val scheduler: Scheduler
 ) extends CloseableIterator[T]
     with Subscriber[T] {
 

core/src/main/scala/com/avsystem/commons/concurrent/executionContexts.scala

@@ -67,13 +67,13 @@ class RunInQueueEC extends ExecutionContextExecutor {
 }
 
 trait HasExecutionContext {
-  protected implicit def executionContext: ExecutionContext
+  protected given executionContext: ExecutionContext
 }
 
 trait HasRunNowEC extends HasExecutionContext {
-  protected implicit final def executionContext: ExecutionContext = RunNowEC
+  protected implicit val executionContext: ExecutionContext = RunNowEC
 }
 
 trait HasRunInQueueEC extends HasExecutionContext {
-  protected implicit final def executionContext: ExecutionContext = RunInQueueEC
+  protected implicit val executionContext: ExecutionContext = RunInQueueEC
 }

core/src/main/scala/com/avsystem/commons/di/Component.scala

@@ -34,7 +34,7 @@ object ComponentInfo {
     )
 
   @compileTimeOnly("implicit ComponentInfo is only available inside code passed to component/singleton macro")
-  implicit def info: ComponentInfo = sys.error("stub")
+  given info: ComponentInfo = sys.error("stub")
 }
 
 /** Represents a lazily initialized component in a dependency injection setting. The name "component" indicates that the

core/src/main/scala/com/avsystem/commons/di/Components.scala

@@ -43,11 +43,12 @@ trait Components extends ComponentsLowPrio {
   // avoids divergent implicit expansion involving `inject`
   // this is not strictly necessary but makes compiler error messages nicer
   // i.e. the compiler will emit "could not find implicit value" instead of "divergent implicit expansion"
-  implicit def ambiguousArbitraryComponent1[T]: Component[T] = null
-  implicit def ambiguousArbitraryComponent2[T]: Component[T] = null
+  given ambiguousArbitraryComponent1[T]: Component[T] = null
+  given ambiguousArbitraryComponent2[T]: Component[T] = null
 
   // TODO[scala3-port]: autoComponent (Scala 2 macro def) (L)
-  implicit def autoComponent[T](definition: => T)(implicit sourceInfo: SourceInfo): AutoComponent[T] = ???
+  // Kept as `implicit def`: macro-stubbed and takes a by-name parameter, which a non-inline `given Conversion` cannot carry.
+  implicit def autoComponent[T](definition: => T)(using sourceInfo: SourceInfo): AutoComponent[T] = ???
 
   // TODO[scala3-port]: optEmptyComponent (depends on stubbed singleton macro) (S)
   protected def optEmptyComponent: Component[Opt[Nothing]] = ???
@@ -65,5 +66,5 @@ trait ComponentsLowPrio {
   @compileTimeOnly(
     "implicit Component[T] => implicit T inference only works inside code passed to component/singleton macro"
   )
-  implicit def inject[T](implicit component: Component[T]): T = sys.error("stub")
+  given inject[T](using component: Component[T]): T = sys.error("stub")
 }

core/src/main/scala/com/avsystem/commons/meta/MacroInstances.scala

@@ -45,5 +45,5 @@ object MacroInstances {
   final class materializeWith(prefix: Any, materializer: String = "materialize") extends StaticAnnotation
 
   // TODO[scala3-port]: materialize (Scala 2 macro def) (L)
-  implicit def materialize[Implicits, Instances]: MacroInstances[Implicits, Instances] = ???
+  given materialize[Implicits, Instances]: MacroInstances[Implicits, Instances] = ???
 }

core/src/main/scala/com/avsystem/commons/meta/MetadataCompanion.scala

@@ -13,9 +13,9 @@ import scala.annotation.implicitNotFound
   *   metadata class constructor
   */
 trait MetadataCompanion[M[_]] {
-  final def apply[Real](implicit metadata: M[Real]): M[Real] = metadata
+  final def apply[Real](using metadata: M[Real]): M[Real] = metadata
 
-  implicit final def fromFallback[Real](implicit fallback: Fallback[M[Real]]): M[Real] = fallback.value
+  given fromFallback[Real](using fallback: Fallback[M[Real]]): M[Real] = fallback.value
 
   final class Lazy[Real](metadata: => M[Real]) {
     lazy val value: M[Real] = metadata
@@ -25,10 +25,10 @@ trait MetadataCompanion[M[_]] {
 
     // macro effectively turns `metadata` param into by-name param (implicit params by themselves cannot be by-name)
     // TODO[scala3-port]: lazyMetadata (Scala 2 macro def) (L)
-    implicit def lazyMetadata[Real](implicit metadata: M[Real]): Lazy[Real] = ???
+    given lazyMetadata[Real](using metadata: M[Real]): Lazy[Real] = ???
 
     @implicitNotFound("#{forNotLazy}")
-    implicit def notFound[T](implicit forNotLazy: ImplicitNotFound[M[T]]): ImplicitNotFound[Lazy[T]] =
+    given notFound[T](using forNotLazy: ImplicitNotFound[M[T]]): ImplicitNotFound[Lazy[T]] =
       ImplicitNotFound()
   }
 }
@@ -44,9 +44,9 @@ trait MetadataCompanion[M[_]] {
   */
 // cannot share code with MetadataCompanion because of binary compatibility problems, must copy
 trait BoundedMetadataCompanion[Hi, Lo <: Hi, M[_ >: Lo <: Hi]] {
-  final def apply[Real >: Lo <: Hi](implicit metadata: M[Real]): M[Real] = metadata
+  final def apply[Real >: Lo <: Hi](using metadata: M[Real]): M[Real] = metadata
 
-  implicit final def fromFallback[Real >: Lo <: Hi](implicit fallback: Fallback[M[Real]]): M[Real] = fallback.value
+  given fromFallback[Real >: Lo <: Hi](using fallback: Fallback[M[Real]]): M[Real] = fallback.value
 
   final class Lazy[Real >: Lo <: Hi](metadata: => M[Real]) {
     lazy val value: M[Real] = metadata
@@ -56,10 +56,10 @@ trait BoundedMetadataCompanion[Hi, Lo <: Hi, M[_ >: Lo <: Hi]] {
 
     // macro effectively turns `metadata` param into by-name param (implicit params by themselves cannot be by-name)
     // TODO[scala3-port]: lazyMetadata (bounded) (Scala 2 macro def) (L)
-    implicit def lazyMetadata[Real >: Lo <: Hi](implicit metadata: M[Real]): Lazy[Real] = ???
+    given lazyMetadata[Real >: Lo <: Hi](using metadata: M[Real]): Lazy[Real] = ???
 
     @implicitNotFound("#{forNotLazy}")
-    implicit def notFound[T >: Lo <: Hi](implicit forNotLazy: ImplicitNotFound[M[T]]): ImplicitNotFound[Lazy[T]] =
+    given notFound[T >: Lo <: Hi](using forNotLazy: ImplicitNotFound[M[T]]): ImplicitNotFound[Lazy[T]] =
       ImplicitNotFound()
   }
 }

core/src/main/scala/com/avsystem/commons/meta/OptionLike.scala

@@ -53,19 +53,19 @@ final class OptionLikeImpl[O, A](
 object OptionLike {
   type Aux[O, V] = OptionLike[O] { type Value = V }
 
-  implicit def optionOptionLike[A]: BaseOptionLike[Option[A], A] =
+  given optionOptionLike[A]: BaseOptionLike[Option[A], A] =
     new OptionLikeImpl(None, Some(_), _.isDefined, _.get, ignoreNulls = true)
 
-  implicit def optOptionLike[A]: BaseOptionLike[Opt[A], A] =
+  given optOptionLike[A]: BaseOptionLike[Opt[A], A] =
     new OptionLikeImpl(Opt.Empty, Opt.some, _.isDefined, _.get, ignoreNulls = true)
 
-  implicit def optRefOptionLike[A >: Null]: BaseOptionLike[OptRef[A], A] =
+  given optRefOptionLike[A >: Null]: BaseOptionLike[OptRef[A], A] =
     new OptionLikeImpl(OptRef.Empty, OptRef.some, _.isDefined, _.get, ignoreNulls = true)
 
-  implicit def optArgOptionLike[A]: BaseOptionLike[OptArg[A], A] =
+  given optArgOptionLike[A]: BaseOptionLike[OptArg[A], A] =
     new OptionLikeImpl(OptArg.Empty, OptArg.some, _.isDefined, _.get, ignoreNulls = true)
 
-  implicit def nOptOptionLike[A]: BaseOptionLike[NOpt[A], A] =
+  given nOptOptionLike[A]: BaseOptionLike[NOpt[A], A] =
     new OptionLikeImpl(NOpt.Empty, NOpt.some, _.isDefined, _.get, ignoreNulls = false)
 }
 
@@ -82,8 +82,6 @@ object AutoOptionalParam {
 }
 
 trait AutoOptionalParams {
-  implicit def allAutoOptionalParams[T](
-    implicit optionLike: OptionLike[T]
-  ): AutoOptionalParam[T] = AutoOptionalParam[T]
+  given allAutoOptionalParams[T](using optionLike: OptionLike[T]): AutoOptionalParam[T] = AutoOptionalParam[T]
 }
 object AutoOptionalParams extends AutoOptionalParams

core/src/main/scala/com/avsystem/commons/misc/AnnotationOf.scala

@@ -10,7 +10,7 @@ import scala.annotation.implicitNotFound
 case class AnnotationOf[A, T](annot: A) extends AnyVal
 object AnnotationOf {
   // TODO[scala3-port]: AnnotationOf.materialize (Scala 2 macro def) (L)
-  implicit def materialize[A, T]: AnnotationOf[A, T] = ???
+  given materialize[A, T]: AnnotationOf[A, T] = ???
 }
 
 /** A typeclass which captures a possible annotation of type `A` applied on a class/trait/object associated with type
@@ -20,7 +20,7 @@ object AnnotationOf {
 case class OptAnnotationOf[A, T](annotOpt: Opt[A])
 object OptAnnotationOf {
   // TODO[scala3-port]: OptAnnotationOf.materialize (Scala 2 macro def) (L)
-  implicit def materialize[A, T]: OptAnnotationOf[A, T] = ???
+  given materialize[A, T]: OptAnnotationOf[A, T] = ???
 }
 
 /** A typeclass which captures all annotations of type `A` applied on a class/trait/object associated with type `T`.
@@ -29,7 +29,7 @@ object OptAnnotationOf {
 case class AnnotationsOf[A, T](annots: List[A]) extends AnyVal
 object AnnotationsOf {
   // TODO[scala3-port]: AnnotationsOf.materialize (Scala 2 macro def) (L)
-  implicit def materialize[A, T]: AnnotationsOf[A, T] = ???
+  given materialize[A, T]: AnnotationsOf[A, T] = ???
 }
 
 /** A typeclass which serves as an evidence that an annotation of type `A` is applied on a class/trait/object associated
@@ -44,7 +44,7 @@ object HasAnnotation {
   def create[A, T]: HasAnnotation[A, T] = reusable.asInstanceOf[HasAnnotation[A, T]]
 
   // TODO[scala3-port]: HasAnnotation.materialize (Scala 2 macro def) (L)
-  implicit def materialize[A, T]: HasAnnotation[A, T] = ???
+  given materialize[A, T]: HasAnnotation[A, T] = ???
 }
 
 /** A typeclass which may be used in an implicit constructor parameter of an abstract class. Captures an annotation of
@@ -67,7 +67,7 @@ object HasAnnotation {
 case class SelfAnnotation[A](annot: A) extends AnyVal
 object SelfAnnotation {
   // TODO[scala3-port]: SelfAnnotation.materialize (Scala 2 macro def) (L)
-  implicit def materialize[A]: SelfAnnotation[A] = ???
+  given materialize[A]: SelfAnnotation[A] = ???
 }
 
 /** A typeclass which may be used in an implicit constructor parameter of an abstract class. Captures a possible
@@ -90,7 +90,7 @@ object SelfAnnotation {
 case class SelfOptAnnotation[A](annotOpt: Opt[A])
 object SelfOptAnnotation {
   // TODO[scala3-port]: SelfOptAnnotation.materialize (Scala 2 macro def) (L)
-  implicit def materialize[A]: SelfOptAnnotation[A] = ???
+  given materialize[A]: SelfOptAnnotation[A] = ???
 }
 
 /** A typeclass which may be used in an implicit constructor parameter of an abstract class. Captures all annotations of
@@ -112,5 +112,5 @@ object SelfOptAnnotation {
 case class SelfAnnotations[A](annots: List[A]) extends AnyVal
 object SelfAnnotations {
   // TODO[scala3-port]: SelfAnnotations.materialize (Scala 2 macro def) (L)
-  implicit def materialize[A]: SelfAnnotations[A] = ???
+  given materialize[A]: SelfAnnotations[A] = ???
 }

core/src/main/scala/com/avsystem/commons/misc/ApplierUnapplier.scala

@@ -11,7 +11,7 @@ trait Applier[T] {
 }
 object Applier {
   // TODO[scala3-port]: Applier.materialize (Scala 2 macro def) (L)
-  implicit def materialize[T]: Applier[T] = ???
+  given materialize[T]: Applier[T] = ???
 }
 
 /** Typeclass which captures case class `unapply`/`unapplySeq` method in a raw form that returns untyped sequence of
@@ -23,7 +23,7 @@ trait Unapplier[T] {
 }
 object Unapplier {
   // TODO[scala3-port]: Unapplier.materialize (Scala 2 macro def) (L)
-  implicit def materialize[T]: Unapplier[T] = ???
+  given materialize[T]: Unapplier[T] = ???
 }
 
 class ProductUnapplier[T <: Product] extends Unapplier[T] {
@@ -35,5 +35,5 @@ abstract class ProductApplierUnapplier[T <: Product] extends ProductUnapplier[T]
 trait ApplierUnapplier[T] extends Applier[T] with Unapplier[T]
 object ApplierUnapplier {
   // TODO[scala3-port]: ApplierUnapplier.materialize (Scala 2 macro def) (L)
-  implicit def materialize[T]: ApplierUnapplier[T] = ???
+  given materialize[T]: ApplierUnapplier[T] = ???
 }