Compute PureInterface flag after pickling.

ElimLocals becomes a slightly less trivial transform: NormalizeFlags.
It also computes PureInterface flag, thus relieving Namer and Unpickler
from doing the same in two different ways. Besides, the computation in
Namer/TreeInfo was flawed because it did not take into account that
nested non-static classes are not allowed in an interface (only static
classes are, but these would not be members of the interface in the Scala
sense).

1 files changed, 3 insertions, 8 deletions

diff --git a/src/dotty/tools/dotc/ast/TreeInfo.scala b/src/dotty/tools/dotc/ast/TreeInfo.scala
index 5338297e8..0abd25f51 100644
--- a/src/dotty/tools/dotc/ast/TreeInfo.scala
+++ b/src/dotty/tools/dotc/ast/TreeInfo.scala
@@ -24,19 +24,14 @@ trait TreeInfo[T >: Untyped <: Type] { self: Trees.Instance[T] =>
     case _ => false
   }
 
-  /** Is tree legal as a member definition of an interface?
+  /** Does tree contain an initialization part when seen as a member of a class or trait?
    */
-  def isPureInterfaceMember(tree: Tree): Boolean = unsplice(tree) match {
+  def isNoInitMember(tree: Tree): Boolean = unsplice(tree) match {
     case EmptyTree | Import(_, _) | TypeDef(_, _) => true
-    case defn: ValOrDefDef => defn.unforcedRhs == EmptyTree
+    case tree: ValDef => tree.unforcedRhs == EmptyTree
     case _ => false
   }
 
-  /** Is tree legal as a member definition of a no-init trait?
-   */
-  def isNoInitMember(tree: Tree): Boolean =
-    isPureInterfaceMember(tree) || unsplice(tree).isInstanceOf[DefDef]
-
   def isOpAssign(tree: Tree) = unsplice(tree) match {
     case Apply(fn, _ :: Nil) =>
       unsplice(fn) match {