Revert "Do not allow named self in objects"

This reverts commit ecdadc9.

Author: odersky

compiler/src/dotty/tools/dotc/ast/Desugar.scala

@@ -645,7 +645,7 @@ object desugar {
         .withPos(mdef.pos.startPos)
       val ValDef(selfName, selfTpt, _) = impl.self
       val selfMods = impl.self.mods
-      if (!selfTpt.isEmpty || selfName != nme.WILDCARD) ctx.error(ObjectMayNotHaveSelfType(mdef), impl.self.pos)
+      if (!selfTpt.isEmpty) ctx.error(ObjectMayNotHaveSelfType(mdef), impl.self.pos)
       val clsSelf = ValDef(selfName, SingletonTypeTree(Ident(moduleName)), impl.self.rhs)
         .withMods(selfMods)
         .withPos(impl.self.pos orElse impl.pos.startPos)

compiler/src/dotty/tools/dotc/core/NameKinds.scala

@@ -63,7 +63,7 @@ object NameKinds {
     def infoString: String
   }
 
-  object SimpleNameKind extends NameKind(UTF8) {
+  object SimpleNameKind extends NameKind(UTF8) { self =>
     type ThisInfo = Info
     val info = new Info
     def mkString(underlying: TermName, info: ThisInfo) = unsupported("mkString")

compiler/src/dotty/tools/dotc/typer/Namer.scala

@@ -954,7 +954,13 @@ class Namer { typer: Typer =>
 
       val selfInfo =
         if (self.isEmpty) NoType
-        else if (cls.is(Module)) cls.owner.thisType.select(sourceModule)
+        else if (cls.is(Module)) {
+          val moduleType = cls.owner.thisType select sourceModule
+          if (self.name == nme.WILDCARD) moduleType
+          else recordSym(
+            ctx.newSymbol(cls, self.name, self.mods.flags, moduleType, coord = self.pos),
+            self)
+        }
         else createSymbol(self)
 
       // pre-set info, so that parent types can refer to type params

compiler/test/dotty/tools/dotc/FromTastyTests.scala

@@ -59,6 +59,9 @@ class FromTastyTests extends ParallelTesting {
         "spec-super.scala",
         "spec-sparsearray-old.scala",
         "collections_1.scala",
+
+        // Infinite compilation
+        "t3612.scala",
       )
     )
     step1.checkCompile() // Compile all files to generate the class files with tasty

scala2-library

@@ -11,7 +11,7 @@ object desugar {
   def foo1(first: Int, second: Int = 2)(third: Int = 3) = first + second
   def foo2(first: Int)(second: Int = 2)(third: Int = 3) = first + second
 
-  object caseClasses {
+  object caseClasses { self =>
     trait List[+T] {
       def head: T
       def tail: List[T]

tests/neg/i831.scala

@@ -11,7 +11,7 @@ object desugar {
   def foo1(first: Int, second: Int = 2)(third: Int = 3) = first + second
   def foo2(first: Int)(second: Int = 2)(third: Int = 3) = first + second
 
-  object caseClasses {
+  object caseClasses { self =>
     trait List[+T] {
       def head: T
       def tail: List[T]

tests/pickling/desugar.scala

@@ -0,0 +1,4 @@
+object Test { self =>
+  def a = 5
+  self.a
+}

tests/pos/desugar.scala

@@ -0,0 +1,6 @@
+trait C
+
+class Outer {
+  object O0 extends C {}
+  object O extends C { self => }
+}