diff --git a/build.sbt b/build.sbt
index 9a07324dd..2d5976cea 100644
--- a/build.sbt
+++ b/build.sbt
@@ -14,15 +14,6 @@ def commonSettings: Seq[Setting[_]] = Seq(
   testOptions += Tests.Argument(TestFrameworks.ScalaCheck, "-w", "1"),
   javacOptions in compile ++= Seq("-Xlint", "-Xlint:-serial"),
   crossScalaVersions := Seq(scala211, scala212),
-  scalacOptions := {
-    val old = scalacOptions.value
-    scalaVersion.value match {
-      case sv if sv.startsWith("2.10") =>
-        old diff List("-Xfuture", "-Ywarn-unused", "-Ywarn-unused-import")
-      case sv if sv.startsWith("2.11") => old ++ List("-Ywarn-unused", "-Ywarn-unused-import")
-      case _                           => old ++ List("-Ywarn-unused", "-Ywarn-unused-import", "-YdisableFlatCpCaching")
-    }
-  },
   scalacOptions in console in Compile -= "-Ywarn-unused-import",
   scalacOptions in console in Test -= "-Ywarn-unused-import",
   publishArtifact in Compile := true,
@@ -110,8 +101,13 @@ lazy val utilLogging = (project in internalPath / "util-logging")
     crossScalaVersions := Seq(scala210, scala211, scala212),
     name := "Util Logging",
     libraryDependencies ++=
-      Seq(jline, log4jApi, log4jCore, disruptor, sjsonnewScalaJson.value, scalaReflect.value),
+      Seq(jline, log4jApi, log4jCore, disruptor, sjsonnewScalaJson.value, scalaReflect.value,
+        compilerPlugin(silencerPlugin), silencerLib),
     libraryDependencies ++= Seq(scalaCheck, scalaTest),
+    Compile / scalacOptions ++= (scalaVersion.value match {
+      case v if v.startsWith("2.12.") => List("-Ywarn-unused:-locals,-explicits,-privates")
+      case _                          => List()
+    }),
     sourceManaged in (Compile, generateContrabands) := baseDirectory.value / "src" / "main" / "contraband-scala",
     contrabandFormatsForType in generateContrabands in Compile := { tpe =>
       val old = (contrabandFormatsForType in generateContrabands in Compile).value
diff --git a/internal/util-logging/src/main/scala/sbt/internal/util/FilterLogger.scala b/internal/util-logging/src/main/scala/sbt/internal/util/FilterLogger.scala
index d52901c7b..03bc1e862 100644
--- a/internal/util-logging/src/main/scala/sbt/internal/util/FilterLogger.scala
+++ b/internal/util-logging/src/main/scala/sbt/internal/util/FilterLogger.scala
@@ -4,13 +4,14 @@
 package sbt.internal.util
 
 import sbt.util._
+import com.github.ghik.silencer.silent
 
 /**
  * A filter logger is used to delegate messages but not the logging level to another logger.  This means
  * that messages are logged at the higher of the two levels set by this logger and its delegate.
  */
 class FilterLogger(delegate: AbstractLogger) extends BasicLogger {
-  override lazy val ansiCodesSupported = delegate.ansiCodesSupported
+  @silent override lazy val ansiCodesSupported = delegate.ansiCodesSupported
   def trace(t: => Throwable): Unit = {
     if (traceEnabled)
       delegate.trace(t)
diff --git a/internal/util-logging/src/main/scala/sbt/internal/util/FullLogger.scala b/internal/util-logging/src/main/scala/sbt/internal/util/FullLogger.scala
index c3ad40442..60478d3b9 100644
--- a/internal/util-logging/src/main/scala/sbt/internal/util/FullLogger.scala
+++ b/internal/util-logging/src/main/scala/sbt/internal/util/FullLogger.scala
@@ -4,11 +4,12 @@
 package sbt.internal.util
 
 import sbt.util._
+import com.github.ghik.silencer.silent
 
 /** Promotes the simple Logger interface to the full AbstractLogger interface. */
 class FullLogger(delegate: Logger) extends BasicLogger {
   @deprecated("No longer used.", "1.0.0")
-  override val ansiCodesSupported: Boolean = delegate.ansiCodesSupported
+  @silent override val ansiCodesSupported: Boolean = delegate.ansiCodesSupported
 
   def trace(t: => Throwable): Unit = {
     if (traceEnabled)
diff --git a/internal/util-logging/src/main/scala/sbt/internal/util/MultiLogger.scala b/internal/util-logging/src/main/scala/sbt/internal/util/MultiLogger.scala
index 2d12a1b2f..a3eb9948e 100644
--- a/internal/util-logging/src/main/scala/sbt/internal/util/MultiLogger.scala
+++ b/internal/util-logging/src/main/scala/sbt/internal/util/MultiLogger.scala
@@ -4,13 +4,14 @@
 package sbt.internal.util
 
 import sbt.util._
+import com.github.ghik.silencer.silent
 
 // note that setting the logging level on this logger has no effect on its behavior, only
 //   on the behavior of the delegates.
 class MultiLogger(delegates: List[AbstractLogger]) extends BasicLogger {
   @deprecated("No longer used.", "1.0.0")
   override lazy val ansiCodesSupported = delegates exists supported
-  private[this] def supported = (_: AbstractLogger).ansiCodesSupported
+  @silent private[this] def supported = (_: AbstractLogger).ansiCodesSupported
 
   override def setLevel(newLevel: Level.Value): Unit = {
     super.setLevel(newLevel)
diff --git a/internal/util-position/src/main/scala/sbt/internal/util/Positions.scala b/internal/util-position/src/main/scala/sbt/internal/util/Positions.scala
index ca3626db1..47c5bc16b 100644
--- a/internal/util-position/src/main/scala/sbt/internal/util/Positions.scala
+++ b/internal/util-position/src/main/scala/sbt/internal/util/Positions.scala
@@ -1,5 +1,7 @@
 package sbt.internal.util
 
+import scala.language.experimental.macros
+
 sealed trait SourcePosition
 
 sealed trait FilePosition extends SourcePosition {
@@ -22,7 +24,6 @@ final case class RangePosition(path: String, range: LineRange) extends FilePosit
 object SourcePosition {
 
   /** Creates a SourcePosition by using the enclosing position of the invocation of this method.
-   * @see [[scala.reflect.macros.Enclosures#enclosingPosition]]
    * @return SourcePosition
    */
   def fromEnclosing(): SourcePosition = macro SourcePositionMacro.fromEnclosingImpl
diff --git a/project/Dependencies.scala b/project/Dependencies.scala
index 806cbe65b..6d51c107f 100644
--- a/project/Dependencies.scala
+++ b/project/Dependencies.scala
@@ -7,7 +7,7 @@ object Dependencies {
   val scala211 = "2.11.12"
   val scala212 = "2.12.6"
 
-  private val ioVersion = "1.2.0"
+  private val ioVersion = "1.2.1"
 
   private val sbtIO = "org.scala-sbt" %% "io" % ioVersion
 
@@ -58,4 +58,6 @@ object Dependencies {
   val log4jApi = "org.apache.logging.log4j" % "log4j-api" % log4jVersion
   val log4jCore = "org.apache.logging.log4j" % "log4j-core" % log4jVersion
   val disruptor = "com.lmax" % "disruptor" % "3.3.6"
+  val silencerPlugin = "com.github.ghik" %% "silencer-plugin" % "1.2"
+  val silencerLib = "com.github.ghik" %% "silencer-lib" % "1.2" % Provided
 }
diff --git a/project/build.properties b/project/build.properties
index 5620cc502..0cd8b0798 100644
--- a/project/build.properties
+++ b/project/build.properties
@@ -1 +1 @@
-sbt.version=1.2.1
+sbt.version=1.2.3
diff --git a/project/plugins.sbt b/project/plugins.sbt
index e1c769a77..c064ea157 100644
--- a/project/plugins.sbt
+++ b/project/plugins.sbt
@@ -1,3 +1,3 @@
-addSbtPlugin("org.scala-sbt" % "sbt-houserules" % "0.3.7")
-addSbtPlugin("org.scala-sbt" % "sbt-contraband" % "0.4.0")
+addSbtPlugin("org.scala-sbt" % "sbt-houserules" % "0.3.8")
+addSbtPlugin("org.scala-sbt" % "sbt-contraband" % "0.4.1")
 addSbtPlugin("com.lightbend" % "sbt-whitesource" % "0.1.9")
diff --git a/util-cache/src/main/scala/sbt/util/FileInfo.scala b/util-cache/src/main/scala/sbt/util/FileInfo.scala
index bef3d6bfd..1fc605a3d 100644
--- a/util-cache/src/main/scala/sbt/util/FileInfo.scala
+++ b/util-cache/src/main/scala/sbt/util/FileInfo.scala
@@ -4,7 +4,6 @@
 package sbt.util
 
 import java.io.File
-import java.io.FileNotFoundException
 import scala.util.control.NonFatal
 import sbt.io.{ Hash, IO }
 import sjsonnew.{ Builder, JsonFormat, Unbuilder, deserializationError }
diff --git a/util-cache/src/test/scala/CacheSpec.scala b/util-cache/src/test/scala/CacheSpec.scala
index ad51d7ff5..138e6218b 100644
--- a/util-cache/src/test/scala/CacheSpec.scala
+++ b/util-cache/src/test/scala/CacheSpec.scala
@@ -46,7 +46,7 @@ class CacheSpec extends FlatSpec {
         }
 
         cache(store)("someKey") match {
-          case Hit(read) => assert(read === value)
+          case Hit(read) => assert(read === value); ()
           case Miss(_)   => fail
         }
     }
@@ -63,7 +63,7 @@ class CacheSpec extends FlatSpec {
         }
 
         cache(store)(key) match {
-          case Hit(read) => assert(read === value)
+          case Hit(read) => assert(read === value); ()
           case Miss(_)   => fail
         }
     }
diff --git a/util-cache/src/test/scala/SingletonCacheSpec.scala b/util-cache/src/test/scala/SingletonCacheSpec.scala
index d22e10f2d..5c812f8d1 100644
--- a/util-cache/src/test/scala/SingletonCacheSpec.scala
+++ b/util-cache/src/test/scala/SingletonCacheSpec.scala
@@ -69,7 +69,7 @@ class SingletonCacheSpec extends FlatSpec {
         cache.write(store, value)
         val read = cache.read(store)
 
-        assert(read === value)
+        assert(read === value); ()
     }
   }
 
@@ -80,7 +80,7 @@ class SingletonCacheSpec extends FlatSpec {
         cache.write(store, value)
         val read = cache.read(store)
 
-        assert(read === value)
+        assert(read === value); ()
     }
   }