Merge pull request #8008 from dotty-staging/fix-7991

Fix #7991: don't set JavaDefined for Dotty Enum module class

Author: anatoliykmetyuk

compiler/src/dotty/tools/dotc/Compiler.scala

@@ -58,8 +58,8 @@ class Compiler {
          new CheckReentrant,         // Internal use only: Check that compiled program has no data races involving global vars
          new ElimPackagePrefixes,    // Eliminate references to package prefixes in Select nodes
          new CookComments,           // Cook the comments: expand variables, doc, etc.
-         new CompleteJavaEnums) ::   // Fill in constructors for Java enums
-    List(new CheckStatic,            // Check restrictions that apply to @static members
+         new CheckStatic) ::         // Check restrictions that apply to @static members
+    List(new CompleteJavaEnums,      // Fill in constructors for Java enums
          new ElimRepeated,           // Rewrite vararg parameters and arguments
          new ExpandSAMs,             // Expand single abstract method closures to anonymous classes
          new ProtectedAccessors,     // Add accessors for protected members

compiler/src/dotty/tools/dotc/core/classfile/ClassfileConstants.scala

@@ -343,6 +343,7 @@ object ClassfileConstants {
       case JAVA_ACC_FINAL      => Final
       case JAVA_ACC_SYNTHETIC  => Synthetic
       case JAVA_ACC_STATIC     => JavaStatic
+      case JAVA_ACC_ENUM       => Enum
       case JAVA_ACC_ABSTRACT   => if (isClass) Abstract else Deferred
       case JAVA_ACC_INTERFACE  => PureInterfaceCreationFlags | JavaDefined
       case _                   => EmptyFlags

compiler/src/dotty/tools/dotc/core/classfile/ClassfileParser.scala

@@ -200,12 +200,10 @@ class ClassfileParser(
         sym.markAbsent()
       }
 
-    // eager load java enum definitions for exhaustivity check of pattern match
+    // eager load enum definitions for exhaustivity check of pattern match
     if (isEnum) {
       instanceScope.toList.map(_.ensureCompleted())
       staticScope.toList.map(_.ensureCompleted())
-      classRoot.setFlag(Flags.JavaEnumTrait)
-      moduleRoot.setFlag(Flags.JavaEnumTrait)
     }
 
     result

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

@@ -110,11 +110,20 @@ class CompleteJavaEnums extends MiniPhase with InfoTransformer { thisPhase =>
     else tree
   }
 
-  override def transformValDef(tree: ValDef)(implicit ctx: Context): ValDef = {
-    val sym = tree.symbol
-    if ((sym.isAllOf(EnumValue) || sym.name == nme.DOLLAR_VALUES) && sym.owner.linkedClass.derivesFromJavaEnum)
-      sym.addAnnotation(Annotations.Annotation(defn.ScalaStaticAnnot))
-    tree
+  /** Return a list of forwarders for enum values defined in the companion object
+   *  for java interop.
+   */
+  private def addedEnumForwarders(clazz: Symbol)(implicit ctx: Context): List[ValDef] = {
+    val moduleCls = clazz.companionClass
+    val moduleRef = ref(clazz.companionModule)
+
+    val enums = moduleCls.info.decls.filter(member => member.isAllOf(EnumValue))
+    for { enumValue <- enums }
+    yield {
+      val fieldSym = ctx.newSymbol(clazz, enumValue.name.asTermName, EnumValue | JavaStatic, enumValue.info)
+      fieldSym.addAnnotation(Annotations.Annotation(defn.ScalaStaticAnnot))
+      ValDef(fieldSym, moduleRef.select(enumValue))
+    }
   }
 
   /** 1. If this is an enum class, add $name and $ordinal parameters to its
@@ -143,9 +152,10 @@ class CompleteJavaEnums extends MiniPhase with InfoTransformer { thisPhase =>
       val (params, rest) = decomposeTemplateBody(templ.body)
       val addedDefs = addedParams(cls, ParamAccessor)
       val addedSyms = addedDefs.map(_.symbol.entered)
+      val addedForwarders = addedEnumForwarders(cls)
       cpy.Template(templ)(
         parents = addEnumConstrArgs(defn.JavaEnumClass, templ.parents, addedSyms.map(ref)),
-        body = params ++ addedDefs ++ rest)
+        body = params ++ addedDefs ++ addedForwarders ++ rest)
     }
     else if (cls.isAnonymousClass && cls.owner.isAllOf(EnumCase) && cls.owner.owner.linkedClass.derivesFromJavaEnum) {
       def rhsOf(name: TermName) =

compiler/test-resources/repl/i7410

@@ -0,0 +1,4 @@
+scala> enum E { case A, B, C }
+// defined class E
+scala> E.A
+val res0: E = A

tests/run/i6664/Bomb_1.scala

@@ -0,0 +1,4 @@
+enum Bomb
+{
+    case Kaboom
+}

tests/run/i6664/Detonator_2.scala

@@ -0,0 +1,5 @@
+object Test
+{
+    def boom: Unit = Bomb.valueOf("Kaboom")
+    def main(args: Array[String]): Unit = println("ok!")
+}

tests/run/i6664b/Bomb_1.scala

@@ -0,0 +1,4 @@
+enum Bomb extends java.lang.Enum[Bomb]
+{
+    case Kaboom
+}

tests/run/i6664b/Detonator_2.scala

@@ -0,0 +1,4 @@
+object Test
+{
+    def main(args: Array[String]): Unit = println(Bomb.Kaboom)
+}

tests/run/i6677/Enum_1.scala

@@ -0,0 +1,3 @@
+enum Foo[A] {
+  case Bar extends Foo[Int]
+}