clarify: all trait vals receive accessors

those that wouldn't are synthesized later anyway -- right?

Author: adriaanm

src/compiler/scala/tools/nsc/typechecker/Namers.scala

@@ -117,10 +117,14 @@ trait Namers extends MethodSynthesis {
     }
 
     // All lazy vals need accessors, including those owned by terms (e.g., in method) or private[this] in a class
-    def deriveAccessors(vd: ValDef) = vd.mods.isLazy || (owner.isClass && deriveAccessorsInClass(vd))
+    def deriveAccessors(vd: ValDef) = (vd.mods.isLazy ||
+         owner.isTrait && { assert(!(vd.name startsWith nme.OUTER) && !isEnumConstant(vd), s"deriveAccessors invar fail for $vd"); true }
+      || (owner.isClass && deriveAccessorsInClass(vd))
+    )
+
 
     private def deriveAccessorsInClass(vd: ValDef) =
-      (!vd.mods.isPrivateLocal || owner.isTrait) && // note, private[this] lazy vals do get accessors -- see outer disjunction of deriveAccessors
+      !vd.mods.isPrivateLocal && // note, private[this] lazy vals do get accessors -- see outer disjunction of deriveAccessors
       !(vd.name startsWith nme.OUTER) && // outer accessors are added later, in explicitouter
       !isEnumConstant(vd)                // enums can only occur in classes, so only check here