Delete redundantly warning for list options

Author: som-snytt

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

@@ -254,28 +254,26 @@ object Settings:
 
       def setMultivalue(arg: String, args: List[String]) =
         val split = arg.split(",").toList
-        // check whether a value was previously set
-        def checkRedundant(actual: List[String]) =
-          if changed then
-            var dangers: List[String] = Nil
-            val current = valueIn(sstate).asInstanceOf[List[String]]
-            for value <- split if current.contains(value) do
-              dangers :+= s"Setting $name set to $value redundantly"
-            dangers.foldLeft(update(current ++ actual, arg, args))((sum, w) => sum.warn(w))
-          else
-            update(actual, arg, args)
+        def setOrUpdate(actual: List[String]) =
+          val updated =
+            if changed then
+              val current = valueIn(sstate).asInstanceOf[List[String]]
+              current ++ actual
+            else
+              actual
+          update(updated, arg, args)
         choices match
         case Some(choices) =>
           split.partition(choices.contains) match
-          case (_, Nil) => checkRedundant(split)
+          case (_, Nil) => setOrUpdate(split)
           case (valid, invalid) =>
             legacyChoices match
             case Some(legacyChoices) =>
               invalid.filterNot(legacyChoices.contains) match
-              case Nil => checkRedundant(valid) // silently ignore legacy choices
+              case Nil => setOrUpdate(valid) // silently ignore legacy choices
               case invalid => invalidChoices(invalid)
             case none => invalidChoices(invalid)
-        case none => checkRedundant(split)
+        case none => setOrUpdate(split)
 
       def matches: Boolean =
         val name = arg.takeWhile(_ != ':')

compiler/test/dotty/tools/dotc/config/ScalaSettingsTests.scala

@@ -58,7 +58,7 @@ class ScalaSettingsTests:
     assertTrue("Has the feature", set.contains("implicitConversions"))
     assertTrue("Has the feature", set.contains("dynamics"))
 
-  @Test def `Warn if multistring element is supplied multiply`: Unit =
+  @Test def `Don't warn if multistring element is supplied multiply`: Unit =
     class SUT extends SettingGroup:
       val language: Setting[List[String]] = MultiStringSetting(RootSetting, "language", "feature", "Enable one or more language features.")
     val sut  = SUT()
@@ -67,7 +67,7 @@ class ScalaSettingsTests:
     val res  = sut.processArguments(sumy, processAll = true, skipped = Nil)
     val set  = sut.language.valueIn(res.sstate)
     assertEquals(3, args.length)
-    assertEquals("Must warn", 1, res.warnings.length)
+    assertTrue("Mustn't warn", res.warnings.isEmpty)
     assertTrue("No errors!", res.errors.isEmpty)
     assertTrue("Has the feature", set.contains("implicitConversions"))
     assertTrue("Has the feature", set.contains("dynamics"))

tests/neg/no-patches.check

@@ -1,4 +1,3 @@
-Flag -Yno-stdlib-patches set repeatedly
 -- Error: tests/neg/no-patches.scala:3:23 ------------------------------------------------------------------------------
 3 |val _ = scala.language.`3.4` // error: we do not patch `scala.language`
   |        ^^^^^^^^^^^^^^^^^^^^