scala · szeiger · Sep 9, 2019 · Aug 19, 2019
diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
@@ -2436,9 +2436,6 @@ trait Typers extends Adaptations with Tags with TypersTracking with PatternTyper
           case _                                        => ()
         }
 
-      if (tdef.symbol.isDeferred && tdef.symbol.info.isHigherKinded)
-        checkFeature(tdef.pos, currentRun.runDefinitions.HigherKindsFeature)
-
       treeCopy.TypeDef(tdef, typedMods, tdef.name, tparams1, rhs1) setType NoType
     }
 

diff --git a/src/library/scala/language.scala b/src/library/scala/language.scala
@@ -148,6 +148,7 @@ object language {
    *
    *  @group production
    */
+  @deprecated("higherKinds no longer needs to be imported explicitly", "2.13.1")
   implicit lazy val higherKinds: higherKinds = languageFeature.higherKinds
 
   /** Where this feature is enabled, existential types that cannot be expressed as wildcard

diff --git a/src/library/scala/languageFeature.scala b/src/library/scala/languageFeature.scala
@@ -32,6 +32,7 @@ object languageFeature {
   sealed trait implicitConversions
   object implicitConversions extends implicitConversions
 
+  @deprecated("scala.language.higherKinds no longer needs to be imported explicitly", "2.13.1")
   @meta.languageFeature("higher-kinded type", enableRequired = false)
   sealed trait higherKinds
   object higherKinds extends higherKinds

diff --git a/src/reflect/scala/reflect/internal/Definitions.scala b/src/reflect/scala/reflect/internal/Definitions.scala
@@ -1705,7 +1705,10 @@ trait Definitions extends api.StandardDefinitions {
       lazy val PostfixOpsFeature          = getLanguageFeature("postfixOps")
       lazy val ReflectiveCallsFeature     = getLanguageFeature("reflectiveCalls")
       lazy val ImplicitConversionsFeature = getLanguageFeature("implicitConversions")
+
+      @deprecated("scala.language.higherKinds no longer needs to be imported explicitly", "2.13.1")
       lazy val HigherKindsFeature         = getLanguageFeature("higherKinds")
+
       lazy val ExistentialsFeature        = getLanguageFeature("existentials")
 
       lazy val ApiUniverseReify = ApiUniverseClass.map(sym => getDeclIfDefined(sym, nme.reify))

diff --git a/test/files/neg/t2462b.check b/test/files/neg/t2462b.check
@@ -14,7 +14,6 @@ t2462b.scala:21: warning: Invalid implicitNotFound message for value i:
 The type parameters XX, ZZ, Nix referenced in the message of the @implicitNotFound annotation are not in scope.
     def m[S](implicit @implicitNotFound("${X} ${Y} ${ Z } ${R} ${S} -- ${XX} ${ZZ} ${ Nix }") i: Int) = ???
                                                                                               ^
-warning: there were two feature warnings; re-run with -feature for details
 error: No warnings can be incurred under -Werror.
-5 warnings found
+four warnings found
 one error found
diff --git a/test/files/neg/t8736-c.check b/test/files/neg/t8736-c.check
diff --git a/test/files/neg/t8736-c.scala b/test/files/neg/t8736-c.scala
diff --git a/test/files/pos/higherKinds.flags b/test/files/pos/higherKinds.flags
@@ -0,0 +1 @@
+-feature -Xfatal-warnings
diff --git a/test/files/pos/higherKinds.scala b/test/files/pos/higherKinds.scala
@@ -0,0 +1,4 @@
+object Test {
+  type F[A] <: List[A]
+  def foo[G[X] <: List[X]](x: F[Int]): F[Int] = x
+}
diff --git a/test/files/pos/t10623.scala b/test/files/pos/t10623.scala
@@ -1,7 +1,6 @@
 
 // scalac: -Xfatal-warnings -Xlint:unused
 //
-import language.higherKinds
 
 object `package` {
   def refl[A]: A Is A = ???

diff --git a/test/files/run/inferred-type-constructors-hou.check b/test/files/run/inferred-type-constructors-hou.check
@@ -1,4 +1,3 @@
-warning: there were two feature warnings; re-run with -feature for details
                 p.Iterable[Int]
                 p.Set[Int]
                 p.Seq[Int]

diff --git a/test/files/run/inferred-type-constructors.check b/test/files/run/inferred-type-constructors.check
@@ -1,4 +1,3 @@
-warning: there were two feature warnings; re-run with -feature for details
                 p.Iterable[Int]
                 p.Set[Int]
                 p.Seq[Int]

diff --git a/test/files/run/t7319.check b/test/files/run/t7319.check
@@ -11,7 +11,6 @@ warning: there was one feature warning; for details, enable `:setting -feature'
 ma1: [A](a: A)M[A]
 
 scala> def convert[F[X <: F[X]]](builder: F[_ <: F[_]]) = 0
-warning: there was one feature warning; for details, enable `:setting -feature' or `:replay -feature'
 convert: [F[X <: F[X]]](builder: F[_ <: F[_]])Int
 
 scala> convert(Some[Int](0))