Add capture checking to scala.util

Author: natsukagami

library/src/scala/util/FromDigits.scala

@@ -3,6 +3,7 @@ import scala.math.{BigInt}
 import quoted.*
 import annotation.internal.sharable
 
+import language.experimental.captureChecking
 
 /** A type class for types that admit numeric literals.
  */

library/src/scala/util/NotGiven.scala

@@ -1,5 +1,7 @@
 package scala.util
 
+import language.experimental.captureChecking
+
 /** A special class used to implement negation in implicit search.
  *
  *  Consider the problem of using implicit `i1` for a query type `D` if an implicit

library/src/scala/util/TupledFunction.scala

@@ -1,5 +1,7 @@
 package scala.util
 
+import language.experimental.captureChecking
+
 import scala.annotation.implicitNotFound
 import scala.annotation.experimental
 
@@ -16,7 +18,7 @@ sealed trait TupledFunction[F, G]:
 
 @experimental
 private[scala] object TupledFunction:
-  def apply[F, G](tupledImpl: F => G, untupledImpl: G => F): TupledFunction[F, G] =
+  def apply[F, G](tupledImpl: F => G, untupledImpl: G => F): TupledFunction[F, G]^{tupledImpl, untupledImpl} =
     new TupledFunction[F, G]:
       def tupled(f: F): G = tupledImpl(f)
       def untupled(g: G): F = untupledImpl(g)

project/Build.scala

@@ -1080,6 +1080,7 @@ object Build {
       // NOTE: Do not use `sourceDirectories` since `sources` are currently pinned until `3.8.0`
       "-sourcepath", (Compile / sources).value.map(_.getCanonicalPath).distinct.mkString(File.pathSeparator),
       "-Yexplicit-nulls",
+      "-explain",
     ),
     (Compile / doc / scalacOptions) ++= ScaladocConfigs.DefaultGenerationSettings.value.settings,
     (Compile / packageSrc / mappings) ++= {