Add various scala warning options to mill build

We had a number of scala warning options set in the sbt build,
add these to the mill build.

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>

build.sbt

@@ -52,7 +52,19 @@ scalacOptions ++= scalacOptionsVersion(scalaVersion.value)
 
 javacOptions ++= javacOptionsVersion(scalaVersion.value)
 
-scalacOptions ++= Seq("-unchecked", "-deprecation", "-language:reflectiveCalls", "-feature")
-scalacOptions ++= Seq("-Ywarn-value-discard", "-Ywarn-dead-code", "-Ywarn-unused")
+scalacOptions ++= Seq(
+  "-unchecked",
+  "-deprecation",
+  "-language:reflectiveCalls",
+  "-feature",
+  "-Xlint",
+  "-Ywarn-value-discard",
+  "-Ywarn-dead-code",
+  "-Ywarn-unused",
+  "-Ywarn-unused-import",
+  "-Ywarn-numeric-widen",
+  "-Xfuture",
+  "-Yno-adapted-args"
+)
 
 libraryDependencies += "edu.berkeley.cs" %% "chiseltest" % "0.2-SNAPSHOT"

build.sc

@@ -48,4 +48,16 @@ object chiselwatt extends CrossSbtModule with HasChisel3 with HasChiselTests wit
   override def millSourcePath = super.millSourcePath
   def crossScalaVersion = "2.12.10"
   def mainClass = Some("CoreObj")
+  def scalacOptions = super.scalacOptions() ++ Seq(
+    "-language:reflectiveCalls",
+    "-feature",
+    "-Xlint",
+    "-Ywarn-value-discard",
+    "-Ywarn-dead-code",
+    "-Ywarn-unused",
+    "-Ywarn-unused-import",
+    "-Ywarn-numeric-widen",
+    "-Xfuture",
+    "-Yno-adapted-args"
+  )
 }