Add deprecation message to -{Y, X, W, ...} compiler flag

Author: rochala

compiler/src/dotty/tools/dotc/config/CliCommand.scala

@@ -60,7 +60,8 @@ trait CliCommand:
       def defaultValue = s.default match
         case _: Int | _: String => s.default.toString
         case _ => ""
-      val info = List(shortHelp(s), if defaultValue.nonEmpty then s"Default $defaultValue" else "", if s.legalChoices.nonEmpty then s"Choices : ${s.legalChoices}" else "")
+      val deprecationMessage = s.deprecation.map(d => s"Option deprecated.\n${d.msg}").getOrElse("")
+      val info = List(deprecationMessage, shortHelp(s), if defaultValue.nonEmpty then s"Default $defaultValue" else "", if s.legalChoices.nonEmpty then s"Choices : ${s.legalChoices}" else "")
       (s.name, info.filter(_.nonEmpty).mkString("\n"))
     end help