Fix WUnused with indents in derived code

Author: szymon-rd

compiler/src/dotty/tools/dotc/transform/CheckUnused.scala

@@ -15,19 +15,15 @@ import dotty.tools.dotc.reporting.Message
 import dotty.tools.dotc.typer.ImportInfo
 import dotty.tools.dotc.util.Property
 import dotty.tools.dotc.core.Mode
-import dotty.tools.dotc.core.Types.TypeTraverser
-import dotty.tools.dotc.core.Types.Type
-import dotty.tools.dotc.core.Types.AnnotatedType
+import dotty.tools.dotc.core.Types.{AnnotatedType, ConstantType, NameFilter, NoType, TermRef, Type, TypeTraverser}
 import dotty.tools.dotc.core.Flags.flagsString
 import dotty.tools.dotc.core.Flags
 import dotty.tools.dotc.core.Names.Name
 import dotty.tools.dotc.transform.MegaPhase.MiniPhase
 import dotty.tools.dotc.core.Annotations
 import dotty.tools.dotc.core.Definitions
-import dotty.tools.dotc.core.Types.ConstantType
 import dotty.tools.dotc.core.NameKinds.WildcardParamName
-import dotty.tools.dotc.core.Types.TermRef
-import dotty.tools.dotc.core.Types.NameFilter
+import dotty.tools.dotc.core.Symbols.Symbol
 
 
 
@@ -81,6 +77,12 @@ class CheckUnused extends MiniPhase:
 
   override def prepareForIdent(tree: tpd.Ident)(using Context): Context =
     if tree.symbol.exists then
+      val prefixes = LazyList.iterate(tree.typeOpt.normalizedPrefix)(_.normalizedPrefix).takeWhile(_ != NoType)
+      for {
+        prefix <- prefixes
+      } {
+        unusedDataApply(_.registerUsed(prefix.classSymbol, None))
+      }
       unusedDataApply(_.registerUsed(tree.symbol, Some(tree.name)))
     else if tree.hasType then
       unusedDataApply(_.registerUsed(tree.tpe.classSymbol, Some(tree.name)))
@@ -407,7 +409,6 @@ object CheckUnused:
       val kept = used.filterNot { t =>
         val (sym, isAccessible, optName) = t
         // keep the symbol for outer scope, if it matches **no** import
-
         // This is the first matching wildcard selector
         var selWildCard: Option[ImportSelector] = None
 

tests/neg-custom-args/fatal-warnings/i15503i.scala

@@ -78,13 +78,13 @@ package foo.test.companionprivate:
 package foo.test.i16678:
   def foo(func: Int => String, value: Int): String = func(value) // OK
 
-  def run = 
+  def run =
     println(foo(number => number.toString, value = 5)) // OK
     println(foo(number => "<number>", value = 5)) // error
     println(foo(func = number => "<number>", value = 5)) // error
     println(foo(func = number => number.toString, value = 5)) // OK
     println(foo(func = _.toString, value = 5)) // OK
-    
+
 package foo.test.possibleclasses:
   case class AllCaseClass(
     k: Int, // OK
@@ -93,7 +93,7 @@ package foo.test.possibleclasses:
     s: Int, // error /* But not these */
     val t: Int, // OK
     private val z: Int // error
-  )       
+  )
 
   case class AllCaseUsed(
     k: Int, // OK
@@ -113,7 +113,7 @@ package foo.test.possibleclasses:
     s: Int, // error
     val t: Int, // OK
     private val z: Int // error
-  )      
+  )
 
   class AllUsed(
     k: Int, // OK
@@ -124,10 +124,61 @@ package foo.test.possibleclasses:
     private val z: Int // OK
   ) {
     def a = k + y + s + t + z
-  } 
+  }
 
 package foo.test.from.i16675:
   case class PositiveNumber private (i: Int) // OK
   object PositiveNumber:
-    def make(i: Int): Option[PositiveNumber] = //OK 
+    def make(i: Int): Option[PositiveNumber] = //OK
       Option.when(i >= 0)(PositiveNumber(i)) // OK
+
+package foo.test.i16822:
+  enum ExampleEnum {
+    case Build(context: String) // OK
+    case List // OK
+  }
+
+  def demo = {
+    val x = ExampleEnum.List // OK
+    println(x) // OK
+  }
+
+package foo.test.i16877:
+  import scala.collection.immutable.HashMap // OK
+  import scala.annotation.StaticAnnotation // OK
+
+  class ExampleAnnotation(val a: Object) extends StaticAnnotation // OK
+
+  @ExampleAnnotation(new HashMap()) // OK
+  class Test //OK
+
+package foo.test.i16926:
+  def hello(): Unit =
+    for {
+      i <- (0 to 10).toList
+      (a, b) = "hello" -> "world" // OK
+    } yield println(s"$a $b")
+
+package foo.test.i16925:
+  def hello =
+    for {
+      i <- 1 to 2 if true
+      _ = println(i) // OK
+    } yield ()
+
+package foo.test.i16679:
+  object myPackage:
+    trait CaseClassName[A]:
+      def name: String
+    object CaseClassName:
+      trait CaseClassByStringName[A] extends CaseClassName[A]
+      import scala.deriving.Mirror
+      object CaseClassByStringName:
+        inline final def derived[A](using inline A: Mirror.Of[A]): CaseClassByStringName[A] =
+          new CaseClassByStringName[A]:
+            def name: String = A.toString
+
+  object secondPackage:
+    import myPackage.CaseClassName // OK
+    case class CoolClass(i: Int) derives CaseClassName.CaseClassByStringName
+    println(summon[CaseClassName[CoolClass]].name)