Address reviewers comments

Author: odersky

src/dotty/tools/dotc/parsing/JavaParsers.scala

@@ -605,11 +605,8 @@ object JavaParsers {
           makeTemplate(List(), statics, List(), false)).withMods((cdef.mods & (Flags.AccessFlags | Flags.JavaDefined)).toTermFlags)
       }
 
-    private def wild     = Ident(nme.WILDCARD)
-    private def wildList = List(wild) // OPT This list is shared for performance.
-
     def importCompanionObject(cdef: TypeDef): Tree =
-      Import(Ident(cdef.name.toTermName).withPos(NoPosition), wildList)
+      Import(Ident(cdef.name.toTermName).withPos(NoPosition), Ident(nme.WILDCARD) :: Nil)
 
     // Importing the companion object members cannot be done uncritically: see
     // ticket #2377 wherein a class contains two static inner classes, each of which

src/dotty/tools/dotc/parsing/Parsers.scala

@@ -59,18 +59,28 @@ object Parsers {
 
     /* ------------- POSITIONS ------------------------------------------- */
 
+    /** Positions tree.
+     *  If `t` does not have a position yet, set its position to the given one.
+     */
+    def atPos[T <: Positioned](pos: Position)(t: T): T =
+      if (t.pos.isSourceDerived) t else t.withPos(pos)
+
     def atPos[T <: Positioned](start: Offset, point: Offset, end: Offset)(t: T): T =
       atPos(Position(start, end, point))(t)
 
+    /** If the last read offset is strictly greater than `start`, position tree
+     *  to position spanning from `start` to last read offset, with given point.
+     *  If the last offset is less than or equal to start, the tree `t` did not
+     *  consume any source for its construction. In this case, don't position it yet,
+     *  but wait for its position to be determined by `setChildPositions` when the
+     *  parent node is positioned.
+     */
     def atPos[T <: Positioned](start: Offset, point: Offset)(t: T): T =
       if (in.lastOffset > start) atPos(start, point, in.lastOffset)(t) else t
 
     def atPos[T <: Positioned](start: Offset)(t: T): T =
       atPos(start, start)(t)
 
-    def atPos[T <: Positioned](pos: Position)(t: T): T =
-      if (t.pos.isSourceDerived) t else t.withPos(pos)
-
     def nameStart: Offset =
       if (in.token == BACKQUOTED_IDENT) in.offset + 1 else in.offset