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nicolasstuckinicolasstucki
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Add reflect TypeLambda.paramVariances (#17568)
Fixes #16734
2 parents 242ba21 + f86a682 commit 40cee39

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‎compiler/src/scala/quoted/runtime/impl/QuotesImpl.scala‎

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@@ -2246,6 +2246,8 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler
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extension (self: TypeLambda)
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def param(idx: Int): TypeRepr = self.newParamRef(idx)
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def paramBounds: List[TypeBounds] = self.paramInfos
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def paramVariances: List[Flags] =
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self.typeParams.map(_.paramVariance)
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end extension
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end TypeLambdaMethods
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@@ -2754,6 +2756,7 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler
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}
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def isTypeParam: Boolean = self.isTypeParam
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def paramVariance: Flags = self.paramVariance
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def signature: Signature = self.signature
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def moduleClass: Symbol = self.denot.moduleClass
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def companionClass: Symbol = self.denot.companionClass

‎library/src/scala/quoted/Quotes.scala‎

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@@ -3258,8 +3258,16 @@ trait Quotes { self: runtime.QuoteUnpickler & runtime.QuoteMatching =>
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/** Extension methods of `TypeLambda` */
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trait TypeLambdaMethods:
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extension (self: TypeLambda)
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/** Reference to the i-th parameter */
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def param(idx: Int) : TypeRepr
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/** Type bounds of the i-th parameter */
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def paramBounds: List[TypeBounds]
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/** Variance flags for the i-th parameter
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*
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* Variance flags can be one of `Flags.{Covariant, Contravariant, EmptyFlags}`.
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*/
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@experimental
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def paramVariances: List[Flags]
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end extension
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end TypeLambdaMethods
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@@ -4078,8 +4086,17 @@ trait Quotes { self: runtime.QuoteUnpickler & runtime.QuoteMatching =>
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/** Fields of a case class type -- only the ones declared in primary constructor */
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def caseFields: List[Symbol]
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/** Is this the symbol of a type parameter */
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def isTypeParam: Boolean
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/** Variance flags for of this type parameter.
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*
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* Variance flags can be one of `Flags.{Covariant, Contravariant, EmptyFlags}`.
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* If this is not the symbol of a type parameter the result is `Flags.EmptyFlags`.
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*/
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@experimental
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def paramVariance: Flags
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/** Signature of this definition */
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def signature: Signature
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‎tests/run-macros/i16734a.check‎

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@@ -0,0 +1,67 @@
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[F >: scala.Nothing <: [A >: scala.Nothing <: scala.Any] =>> scala.Any] =>> K1Inv[F]
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F
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A
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[F >: scala.Nothing <: [A >: scala.Nothing <: scala.Any] =>> scala.Any] =>> K1Cov[F]
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F
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+A
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[F >: scala.Nothing <: [A >: scala.Nothing <: scala.Any] =>> scala.Any] =>> K1Con[F]
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F
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-A
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[F >: scala.Nothing <: [A >: scala.Nothing <: scala.Any, B >: scala.Nothing <: scala.Any] =>> scala.Any] =>> K2InvInv[F]
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F
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A, B
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[F >: scala.Nothing <: [A >: scala.Nothing <: scala.Any, B >: scala.Nothing <: scala.Any] =>> scala.Any] =>> K2InvCov[F]
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F
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A, +B
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[F >: scala.Nothing <: [A >: scala.Nothing <: scala.Any, B >: scala.Nothing <: scala.Any] =>> scala.Any] =>> K2InvCon[F]
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F
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A, -B
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[F >: scala.Nothing <: [A >: scala.Nothing <: scala.Any, B >: scala.Nothing <: scala.Any] =>> scala.Any] =>> K2CovInv[F]
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F
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+A, B
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[F >: scala.Nothing <: [A >: scala.Nothing <: scala.Any, B >: scala.Nothing <: scala.Any] =>> scala.Any] =>> K2CovCov[F]
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F
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+A, +B
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[F >: scala.Nothing <: [A >: scala.Nothing <: scala.Any, B >: scala.Nothing <: scala.Any] =>> scala.Any] =>> K2CovCon[F]
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F
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+A, -B
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[F >: scala.Nothing <: [A >: scala.Nothing <: scala.Any, B >: scala.Nothing <: scala.Any] =>> scala.Any] =>> K2ConInv[F]
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F
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-A, B
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[F >: scala.Nothing <: [A >: scala.Nothing <: scala.Any, B >: scala.Nothing <: scala.Any] =>> scala.Any] =>> K2ConCov[F]
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F
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-A, +B
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[F >: scala.Nothing <: [A >: scala.Nothing <: scala.Any, B >: scala.Nothing <: scala.Any] =>> scala.Any] =>> K2ConCon[F]
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F
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-A, -B
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[G >: scala.Nothing <: [A >: scala.Nothing <: scala.Any, B >: scala.Nothing <: scala.Any, C >: scala.Nothing <: scala.Any, D >: scala.Nothing <: [X1 >: scala.Nothing <: scala.Any, Y1 >: scala.Nothing <: scala.Any, Z1 >: scala.Nothing <: scala.Any] =>> scala.Any, E >: scala.Nothing <: [X2 >: scala.Nothing <: scala.Any, Y2 >: scala.Nothing <: scala.Any, Z2 >: scala.Nothing <: scala.Any] =>> scala.Any, F >: scala.Nothing <: [X3 >: scala.Nothing <: scala.Any, Y3 >: scala.Nothing <: scala.Any, Z3 >: scala.Nothing <: scala.Any] =>> scala.Any] =>> scala.Any] =>> KFunky[G]
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G
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A, +B, -C, D, +E, -F
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X1, +Y1, -Z1
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X2, +Y2, -Z2
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X3, +Y3, -Z3
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[A >: scala.Nothing <: scala.Any, F >: scala.Nothing <: [B >: scala.Nothing <: scala.Any] =>> scala.Any] =>> F[A]
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A, +F
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B
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[A >: scala.Nothing <: scala.Any, F >: scala.Nothing <: [B >: scala.Nothing <: scala.Any] =>> scala.Any] =>> F[A]
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+A, +F
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+B
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[A >: scala.Nothing <: scala.Any, F >: scala.Nothing <: [B >: scala.Nothing <: scala.Any] =>> scala.Any] =>> F[A]
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-A, +F
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-B
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‎tests/run-macros/i16734a/Macro_1.scala‎

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import scala.quoted.*
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inline def variances[A <: AnyKind]: String =
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${variancesImpl[A]}
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def variancesImpl[A <: AnyKind: Type](using Quotes): Expr[String] =
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import quotes.reflect.*
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def loop(tpe: TypeRepr): List[String] =
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tpe match
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case tpe: TypeLambda =>
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tpe.paramNames.zip(tpe.paramVariances).map { (name, variance) =>
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if variance == Flags.Covariant then "+" + name
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else if variance == Flags.Contravariant then "-" + name
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else name
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}.mkString(", ") :: tpe.paramTypes.flatMap(loop)
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case tpe: TypeBounds =>
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loop(tpe.low) ++ loop(tpe.hi)
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case _ =>
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Nil
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val res = (Type.show[A] :: loop(TypeRepr.of[A])).mkString("", "\n", "\n")
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Expr(res)

‎tests/run-macros/i16734a/Test_2.scala‎

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trait K1Inv[F[A]]
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trait K1Cov[F[+A]]
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trait K1Con[F[-A]]
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trait K2InvInv[F[A, B]]
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trait K2InvCov[F[A, +B]]
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trait K2InvCon[F[A, -B]]
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trait K2CovInv[F[+A, B]]
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trait K2CovCov[F[+A, +B]]
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trait K2CovCon[F[+A, -B]]
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trait K2ConInv[F[-A, B]]
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trait K2ConCov[F[-A, +B]]
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trait K2ConCon[F[-A, -B]]
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trait KFunky[G[A, +B, -C, D[X1, +Y1, -Z1], +E[X2, +Y2, -Z2], -F[X3, +Y3, -Z3]]]
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@main def Test =
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println(variances[K1Inv])
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println(variances[K1Cov])
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println(variances[K1Con])
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println(variances[K2InvInv])
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println(variances[K2InvCov])
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println(variances[K2InvCon])
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println(variances[K2CovInv])
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println(variances[K2CovCov])
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println(variances[K2CovCon])
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println(variances[K2ConInv])
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println(variances[K2ConCov])
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println(variances[K2ConCon])
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println(variances[KFunky])
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println(variances[[A, F[B]] =>> F[A]])
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println(variances[[A, F[+B]] =>> F[A]])
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println(variances[[A, F[-B]] =>> F[A]])

‎tests/run-macros/i16734b.check‎

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type F1Inv
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A
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type F1Cov
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+A
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type F1Con
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-A
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type F2InvInv
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A, B
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type F2InvCov
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A, +B
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type F2InvCon
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A, -B
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type F2CovInv
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+A, B
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type F2CovCov
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+A, +B
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type F2CovCon
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+A, -B
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type F2ConInv
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-A, B
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type F2ConCov
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-A, +B
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type F2ConCon
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-A, -B
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‎tests/run-macros/i16734b/Macro_1.scala‎

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import scala.quoted.*
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inline def typeVariances[A <: AnyKind]: String =
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${variancesImpl[A]}
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def variancesImpl[A <: AnyKind: Type](using Quotes): Expr[String] =
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import quotes.reflect.*
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val TypeBounds(_, tl: TypeLambda) = TypeRepr.of[A].typeSymbol.info: @unchecked
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val variances = tl.paramNames.zip(tl.paramVariances).map { (name, variance) =>
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if variance == Flags.Covariant then "+" + name
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else if variance == Flags.Contravariant then "-" + name
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else name
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}.mkString(", ")
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Expr(TypeRepr.of[A].typeSymbol.toString() + "\n" + variances + "\n")

‎tests/run-macros/i16734b/Test_2.scala‎

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type F1Inv[A]
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type F1Cov[+A]
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type F1Con[-A]
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type F2InvInv[A, B]
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type F2InvCov[A, +B]
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type F2InvCon[A, -B]
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type F2CovInv[+A, B]
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type F2CovCov[+A, +B]
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type F2CovCon[+A, -B]
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type F2ConInv[-A, B]
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type F2ConCov[-A, +B]
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type F2ConCon[-A, -B]
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@main def Test =
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println(typeVariances[F1Inv])
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println(typeVariances[F1Cov])
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println(typeVariances[F1Con])
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println(typeVariances[F2InvInv])
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println(typeVariances[F2InvCov])
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println(typeVariances[F2InvCon])
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println(typeVariances[F2CovInv])
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println(typeVariances[F2CovCov])
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println(typeVariances[F2CovCon])
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println(typeVariances[F2ConInv])
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println(typeVariances[F2ConCov])
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println(typeVariances[F2ConCon])

‎tests/run-macros/i16734c.check‎

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class C1Inv
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A
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class C1Cov
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+A
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class C1Con
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-A
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class C2InvInv
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A, B
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class C2InvCov
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A, +B
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class C2InvCon
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A, -B
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class C2CovInv
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+A, B
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class C2CovCov
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+A, +B
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class C2CovCon
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+A, -B
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class C2ConInv
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-A, B
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class C2ConCov
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-A, +B
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class C2ConCon
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-A, -B
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‎tests/run-macros/i16734c/Macro_1.scala‎

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import scala.quoted.*
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inline def classVariances[A <: AnyKind]: String =
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${variancesImpl[A]}
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def variancesImpl[A <: AnyKind: Type](using Quotes): Expr[String] =
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import quotes.reflect.*
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val variances = TypeRepr.of[A].typeSymbol.typeMembers.filter(_.isTypeParam).map { sym =>
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if sym.paramVariance == Flags.Covariant then "+" + sym.name
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else if sym.paramVariance == Flags.Contravariant then "-" + sym.name
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else sym.name
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}
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val res = variances.mkString(TypeRepr.of[A].typeSymbol.toString + "\n", ", ", "\n")
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Expr(res)

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