Revert old behaviour of -Xlint

Author: rochala

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

@@ -356,7 +356,7 @@ private sealed trait XSettings:
   val XmacroSettings: Setting[List[String]] = MultiStringSetting(AdvancedSetting, "Xmacro-settings", "setting1,setting2,..settingN", "List of settings which exposed to the macros")
 
   // Deprecated
-  val Xlint: Setting[List[ChoiceWithHelp[String]]] = MultiChoiceHelpSetting(
+  val Xlint: Setting[List[ChoiceWithHelp[String]]] = UncompleteMultiChoiceHelpSetting(
     AdvancedSetting,
     name = "Xlint",
     helpArg = "advanced warning",
@@ -367,7 +367,7 @@ private sealed trait XSettings:
       ChoiceWithHelp("type-parameter-shadow", "Warn when a type parameter shadows a type already in the scope"),
     ),
     default = Nil,
-    deprecation = Some(Deprecation("Use -Wshadow to enable shadowing lints.", "-Wshadow"))
+    deprecation = Some(Deprecation("Use -Wshadow to enable shadowing lints.", "-Wshadow")),
   )
 
 end XSettings

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

@@ -375,6 +375,9 @@ object Settings:
     def MultiChoiceHelpSetting(category: SettingCategory, name: String, helpArg: String, descr: String, choices: List[ChoiceWithHelp[String]], default: List[ChoiceWithHelp[String]], aliases: List[String] = Nil, deprecation: Option[Deprecation] = None): Setting[List[ChoiceWithHelp[String]]] =
       publish(Setting(category, prependName(name), descr, default, helpArg, Some(choices), aliases = aliases, deprecation = deprecation))
 
+    def UncompleteMultiChoiceHelpSetting(category: SettingCategory, name: String, helpArg: String, descr: String, choices: List[ChoiceWithHelp[String]], default: List[ChoiceWithHelp[String]], aliases: List[String] = Nil, deprecation: Option[Deprecation] = None): Setting[List[ChoiceWithHelp[String]]] =
+      publish(Setting(category, prependName(name), descr, default, helpArg, Some(choices), aliases = aliases, deprecation = deprecation, ignoreInvalidArgs = true))
+
     def IntSetting(category: SettingCategory, name: String, descr: String, default: Int, aliases: List[String] = Nil, deprecation: Option[Deprecation] = None): Setting[Int] =
       publish(Setting(category, prependName(name), descr, default, aliases = aliases, deprecation = deprecation))