Allow toplevel implicits

Author: odersky

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

@@ -960,7 +960,8 @@ object desugar {
   def packageDef(pdef: PackageDef)(implicit ctx: Context): PackageDef = {
     def needsObject(stat: Tree) = stat match {
       case _: ValDef | _: PatDef | _: DefDef => true
-      case stat: TypeDef => !stat.isClassDef
+      case stat: ModuleDef => stat.mods.is(Implicit)
+      case stat: TypeDef => !stat.isClassDef || stat.mods.is(Implicit)
       case _ => false
     }
     val (nestedStats, topStats) = pdef.stats.partition(needsObject)

tests/run/toplevel-implicits.check

@@ -0,0 +1,2 @@
+(C(),C())
+(a D,a D)

tests/run/toplevel-implicits/Test_2.scala

@@ -0,0 +1,11 @@
+object Test extends App {
+  import implicits._
+
+  val c = new C
+  val c2 = c.pair(c)
+  println(c2)
+
+  val d = new D
+  val d2 = d.pair(d)
+  println(d2)
+}

tests/run/toplevel-implicits/defs_1.scala

@@ -0,0 +1,15 @@
+package implicits
+
+case class C()
+
+implicit object Cops {
+  def (x: C) pair (y: C) = (x, y)
+}
+
+class D {
+  override def toString = "a D"
+}
+
+implicit class Ddeco(x: D) {
+  def pair(y: D) = (x, y)
+}