Make non-existent compiler options emit warnings instead of failing

Author: felixmulder

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

@@ -104,6 +104,9 @@ object CompilerCommand extends DotClass {
       else ""
     }
 
+    // Print all warnings encountered during arguments parsing
+    summary.warnings.foreach(ctx.warning(_))
+
     if (summary.errors.nonEmpty) {
       summary.errors foreach (ctx.error(_))
       ctx.echo("  dotc -help  gives more information")

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

@@ -144,7 +144,7 @@ object PathResolver {
     }
     else {
       implicit val ctx = (new ContextBase).initialCtx
-      val ArgsSummary(sstate, rest, errors) =
+      val ArgsSummary(sstate, rest, errors, warnings) =
         ctx.settings.processArguments(args.toList, true)
       errors.foreach(println)
       val pr = new PathResolver()(ctx.fresh.setSettings(sstate))

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

@@ -26,8 +26,6 @@ class ScalaSettings extends Settings.SettingGroup {
   val explain = BooleanSetting("-explain", "Explain errors in more detail.")
   val feature = BooleanSetting("-feature", "Emit warning and location for usages of features that should be imported explicitly.")
   val help = BooleanSetting("-help", "Print a synopsis of standard options")
-  // FIXME: `-nowarn` is not used in the compiler, but sbt passes this as an option
-  val nowarn = BooleanSetting("-nowarn", "Generate no warnings.")
   val color = ChoiceSetting("-color", "mode", "Colored output", List("always", "never"/*, "auto"*/), "always"/* "auto"*/)
   val target = ChoiceSetting("-target", "target", "Target platform for object files. All JVM 1.5 targets are deprecated.",
     List("jvm-1.5", "jvm-1.5-fjbg", "jvm-1.5-asm", "jvm-1.6", "jvm-1.7", "jvm-1.8", "msil"), "jvm-1.8")

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

@@ -44,10 +44,14 @@ object Settings {
   case class ArgsSummary(
     sstate: SettingsState,
     arguments: List[String],
-    errors: List[String]) {
+    errors: List[String],
+    warnings: List[String]) {
 
     def fail(msg: String) =
-      ArgsSummary(sstate, arguments, errors :+ msg)
+      ArgsSummary(sstate, arguments.tail, errors :+ msg, warnings)
+
+    def warn(msg: String) =
+      ArgsSummary(sstate, arguments.tail, errors, warnings :+ msg)
   }
 
   case class Setting[T: ClassTag] private[Settings] (
@@ -106,11 +110,11 @@ object Settings {
       }
 
     def tryToSet(state: ArgsSummary): ArgsSummary = {
-      val ArgsSummary(sstate, arg :: args, errors) = state
+      val ArgsSummary(sstate, arg :: args, errors, warnings) = state
       def update(value: Any, args: List[String]) =
-        ArgsSummary(updateIn(sstate, value), args, errors)
+        ArgsSummary(updateIn(sstate, value), args, errors, warnings)
       def fail(msg: String, args: List[String]) =
-        ArgsSummary(sstate, args, errors :+ msg)
+        ArgsSummary(sstate, args, errors :+ msg, warnings)
       def missingArg =
         fail(s"missing argument for option $name", args)
       def doSet(argRest: String) = ((implicitly[ClassTag[T]], args): @unchecked) match {
@@ -206,7 +210,7 @@ object Settings {
      *  to get their arguments.
      */
     protected def processArguments(state: ArgsSummary, processAll: Boolean, skipped: List[String]): ArgsSummary = {
-      def stateWithArgs(args: List[String]) = ArgsSummary(state.sstate, args, state.errors)
+      def stateWithArgs(args: List[String]) = ArgsSummary(state.sstate, args, state.errors, state.warnings)
       state.arguments match {
         case Nil =>
           checkDependencies(stateWithArgs(skipped))
@@ -219,7 +223,7 @@ object Settings {
               if (state1 ne state) processArguments(state1, processAll, skipped)
               else loop(settings1)
             case Nil =>
-              state.fail(s"bad option: '$x'")
+              processArguments(state.warn(s"bad option '$x' was ignored"), processAll, skipped)
           }
           loop(allSettings.toList)
         case arg :: args =>
@@ -229,7 +233,7 @@ object Settings {
     }
 
     def processArguments(arguments: List[String], processAll: Boolean)(implicit ctx: Context): ArgsSummary =
-      processArguments(ArgsSummary(ctx.sstate, arguments, Nil), processAll, Nil)
+      processArguments(ArgsSummary(ctx.sstate, arguments, Nil, Nil), processAll, Nil)
 
     def publish[T](settingf: Int => Setting[T]): Setting[T] = {
       val setting = settingf(_allSettings.length)

compiler/test/dotc/tests.scala

@@ -180,8 +180,6 @@ class tests extends CompilerTest {
 
   val negCustomArgs = negDir + "customArgs/"
 
-  @Test def neg_cli_error = compileFile(negCustomArgs, "cliError", List("-thisOptionDoesNotExist"))
-
   @Test def neg_typers() = compileFile(negCustomArgs, "typers")(allowDoubleBindings)
   @Test def neg_overrideClass = compileFile(negCustomArgs, "overrideClass", scala2mode)
   @Test def neg_autoTupling = compileFile(negCustomArgs, "autoTuplingTest", args = "-language:noAutoTupling" :: Nil)