Merge pull request #10868 from xuwei-k/explicit-implicit-types

add explicit type annotations for public implicit val and def

core/play/src/main/scala/controllers/Execution.scala

@@ -4,7 +4,7 @@
 
 package play.api.controllers {
   sealed trait TrampolineContextProvider {
-    implicit def trampoline = play.core.Execution.Implicits.trampoline
+    implicit def trampoline: play.api.libs.streams.Execution.trampoline.type = play.core.Execution.Implicits.trampoline
   }
 }
 

core/play/src/main/scala/play/api/Logger.scala

@@ -367,7 +367,7 @@ trait LowPriorityMarkerContextImplicits {
    * no implicit MarkerContext is found in local scope (meaning there is nothing defined
    * through import or "implicit val").
    */
-  implicit val NoMarker = MarkerContext(null)
+  implicit val NoMarker: MarkerContext = MarkerContext(null)
 
   /**
    * Enables conversion from a marker to a MarkerContext:

core/play/src/main/scala/play/api/http/MediaRange.scala

@@ -145,7 +145,7 @@ object MediaRange {
    * Then compare the sub media type.  If they are the same, the one with the more parameters has a higher priority.
    * Otherwise the least specific has the lower priority, otherwise they have the same priority.
    */
-  implicit val ordering = new Ordering[play.api.http.MediaRange] {
+  implicit val ordering: Ordering[play.api.http.MediaRange] = new Ordering[play.api.http.MediaRange] {
     def compareQValues(x: Option[BigDecimal], y: Option[BigDecimal]) = {
       if (x.isEmpty && y.isEmpty) 0
       else if (x.isEmpty) 1

core/play/src/main/scala/play/api/mvc/Binders.scala

@@ -333,7 +333,7 @@ object QueryStringBindable {
   /**
    * QueryString binder for String.
    */
-  implicit def bindableString = new QueryStringBindable[String] {
+  implicit def bindableString: QueryStringBindable[String] = new QueryStringBindable[String] {
     def bind(key: String, params: Map[String, Seq[String]]) =
       params.get(key).flatMap(_.headOption).map(Right(_))
     // No need to URL decode from query string since netty already does that

core/play/src/main/scala/play/api/mvc/Results.scala

@@ -463,7 +463,7 @@ object Codec {
   /**
    * Codec for UTF-8
    */
-  implicit val utf_8 = javaSupported("utf-8")
+  implicit val utf_8: Codec = javaSupported("utf-8")
 
   /**
    * Codec for ISO-8859-1

core/play/src/main/scala/play/core/Execution.scala

@@ -8,6 +8,6 @@ private[play] object Execution {
   def trampoline = play.api.libs.streams.Execution.trampoline
 
   object Implicits {
-    implicit def trampoline = Execution.trampoline
+    implicit def trampoline: play.api.libs.streams.Execution.trampoline.type = Execution.trampoline
   }
 }

core/play/src/main/scala/play/core/routing/ReverseRouteContext.scala

@@ -17,5 +17,5 @@ package play.core.routing
 case class ReverseRouteContext(fixedParams: Map[String, Any])
 
 object ReverseRouteContext {
-  implicit val empty = ReverseRouteContext(Map())
+  implicit val empty: ReverseRouteContext = ReverseRouteContext(Map())
 }

testkit/play-specs2/src/main/scala/play/api/test/Specs.scala

@@ -5,6 +5,7 @@
 package play.api.test
 
 import akka.annotation.ApiMayChange
+import akka.stream.Materializer
 import org.openqa.selenium.WebDriver
 import org.specs2.execute.AsResult
 import org.specs2.execute.Result
@@ -52,8 +53,8 @@ abstract class WithApplication(val app: Application = GuiceApplicationBuilder().
     this(builder(GuiceApplicationBuilder()).build())
   }
 
-  implicit def implicitApp          = app
-  implicit def implicitMaterializer = app.materializer
+  implicit def implicitApp: Application           = app
+  implicit def implicitMaterializer: Materializer = app.materializer
   override def around[T: AsResult](t: => T): Result = {
     Helpers.running(app)(AsResult.effectively(t))
   }
@@ -73,9 +74,9 @@ abstract class WithServer(
     val serverProvider: Option[ServerProvider] = None
 ) extends Around
     with Scope {
-  implicit def implicitMaterializer = app.materializer
-  implicit def implicitApp          = app
-  implicit def implicitPort: Port   = port
+  implicit def implicitMaterializer: Materializer = app.materializer
+  implicit def implicitApp: Application           = app
+  implicit def implicitPort: Port                 = port
 
   override def around[T: AsResult](t: => T): Result =
     Helpers.running(TestServer(port = port, application = app, serverProvider = serverProvider))(

testkit/play-test/src/main/scala/play/api/test/Helpers.scala

@@ -220,7 +220,7 @@ trait DefaultAwaitTimeout {
    * check for the event immediately rather than using using NegativeTimeout.
    */
   case class NegativeTimeout(t: Timeout)
-  implicit val defaultNegativeTimeout = NegativeTimeout(200.millis)
+  implicit val defaultNegativeTimeout: NegativeTimeout = NegativeTimeout(200.millis)
 }
 
 trait FutureAwaits {

transport/server/play-netty-server/src/main/scala/play/core/server/NettyServer.scala

@@ -397,7 +397,7 @@ class NettyServerProvider extends ServerProvider {
 object NettyServer extends ServerFromRouter {
   private val logger = Logger(this.getClass)
 
-  implicit val provider = new NettyServerProvider
+  implicit val provider: NettyServerProvider = new NettyServerProvider
 
   def main(args: Array[String]): Unit = {
     System.err.println(