term and type reftrees are now reified uniformly

Top-level (i.e. owned by a package) => Ident(symbol)
Nested (i.e. owned by an object or a package object) => Select(owner, symbol)
Inner (i.e. owned by a static class) => selectTerm/selectType(owner, name)
Non-locatable (i.e. everything else) => see GenTrees.scala for more details

Changes w.r.t the previous approaches:
  * Top-level refs are no longer reified as Select(This(package), symbol).
    Proposed reification scheme is as resistant to resetAttrs as previous one,
    but is at the same time much shorter.
  * Refs to definitions from package objects are no longer Ident(symbol).
    Otherwise reflective compilation of things like `_ :: _` fails.
  * Contents of Predef._ and scala._ are no longer treated specially.
    This increases the size of reificode, but is more hygienic.

1 files changed, 11 insertions, 9 deletions

diff --git a/test/files/run/showraw_tree_types_ids.check b/test/files/run/showraw_tree_types_ids.check
index 92ee45a1e6..fccb81d8df 100644
--- a/test/files/run/showraw_tree_types_ids.check
+++ b/test/files/run/showraw_tree_types_ids.check
@@ -1,10 +1,12 @@
-Apply[1](Select[2](New[1](TypeTree[1]().setOriginal(AppliedTypeTree(Ident[3](scala.collection.immutable.HashMap#<id>), List(TypeTree[4]().setOriginal(Ident[4](newTypeName("String")#<id>)), TypeTree[4]().setOriginal(Ident[4](newTypeName("String")#<id>)))))), nme.CONSTRUCTOR#<id>), List())
-[1] TypeRef(ThisType(scala.collection.immutable#<id>), scala.collection.immutable.HashMap#<id>, List(TypeRef(ThisType(scala.Predef#<id>), newTypeName("String")#<id>, List()), TypeRef(ThisType(scala.Predef#<id>), newTypeName("String")#<id>, List())))
-[2] MethodType(List(), TypeRef(ThisType(scala.collection.immutable#<id>), scala.collection.immutable.HashMap#<id>, List(TypeRef(ThisType(scala.Predef#<id>), newTypeName("String")#<id>, List()), TypeRef(ThisType(scala.Predef#<id>), newTypeName("String")#<id>, List()))))
+Apply[1](Select[2](New[1](TypeTree[1]().setOriginal(AppliedTypeTree(Ident[3](scala.collection.immutable.HashMap#<id>), List(TypeTree[4]().setOriginal(Select[4](Ident[5](scala.Predef#<id>), newTypeName("String")#<id>)), TypeTree[4]().setOriginal(Select[4](Ident[5](scala.Predef#<id>), newTypeName("String")#<id>)))))), nme.CONSTRUCTOR#<id>), List())
+[1] TypeRef(ThisType(scala.collection.immutable#<id>), scala.collection.immutable.HashMap#<id>, List(TypeRef(SingleType(ThisType(scala#<id>), scala.Predef#<id>), newTypeName("String")#<id>, List()), TypeRef(SingleType(ThisType(scala#<id>), scala.Predef#<id>), newTypeName("String")#<id>, List())))
+[2] MethodType(List(), TypeRef(ThisType(scala.collection.immutable#<id>), scala.collection.immutable.HashMap#<id>, List(TypeRef(SingleType(ThisType(scala#<id>), scala.Predef#<id>), newTypeName("String")#<id>, List()), TypeRef(SingleType(ThisType(scala#<id>), scala.Predef#<id>), newTypeName("String")#<id>, List()))))
 [3] TypeRef(ThisType(scala.collection.immutable#<id>), scala.collection.immutable.HashMap#<id>, List())
-[4] TypeRef(ThisType(scala.Predef#<id>), newTypeName("String")#<id>, List())
-Apply[5](Select[6](New[5](TypeTree[5]().setOriginal(AppliedTypeTree(Ident[7](scala.collection.mutable.HashMap#<id>), List(TypeTree[4]().setOriginal(Ident[4](newTypeName("String")#<id>)), TypeTree[4]().setOriginal(Ident[4](newTypeName("String")#<id>)))))), nme.CONSTRUCTOR#<id>), List())
-[4] TypeRef(ThisType(scala.Predef#<id>), newTypeName("String")#<id>, List())
-[5] TypeRef(ThisType(scala.collection.mutable#<id>), scala.collection.mutable.HashMap#<id>, List(TypeRef(ThisType(scala.Predef#<id>), newTypeName("String")#<id>, List()), TypeRef(ThisType(scala.Predef#<id>), newTypeName("String")#<id>, List())))
-[6] MethodType(List(), TypeRef(ThisType(scala.collection.mutable#<id>), scala.collection.mutable.HashMap#<id>, List(TypeRef(ThisType(scala.Predef#<id>), newTypeName("String")#<id>, List()), TypeRef(ThisType(scala.Predef#<id>), newTypeName("String")#<id>, List()))))
-[7] TypeRef(ThisType(scala.collection.mutable#<id>), scala.collection.mutable.HashMap#<id>, List())
+[4] TypeRef(SingleType(ThisType(scala#<id>), scala.Predef#<id>), newTypeName("String")#<id>, List())
+[5] SingleType(ThisType(scala#<id>), scala.Predef#<id>)
+Apply[6](Select[7](New[6](TypeTree[6]().setOriginal(AppliedTypeTree(Ident[8](scala.collection.mutable.HashMap#<id>), List(TypeTree[4]().setOriginal(Select[4](Ident[5](scala.Predef#<id>), newTypeName("String")#<id>)), TypeTree[4]().setOriginal(Select[4](Ident[5](scala.Predef#<id>), newTypeName("String")#<id>)))))), nme.CONSTRUCTOR#<id>), List())
+[4] TypeRef(SingleType(ThisType(scala#<id>), scala.Predef#<id>), newTypeName("String")#<id>, List())
+[5] SingleType(ThisType(scala#<id>), scala.Predef#<id>)
+[6] TypeRef(ThisType(scala.collection.mutable#<id>), scala.collection.mutable.HashMap#<id>, List(TypeRef(SingleType(ThisType(scala#<id>), scala.Predef#<id>), newTypeName("String")#<id>, List()), TypeRef(SingleType(ThisType(scala#<id>), scala.Predef#<id>), newTypeName("String")#<id>, List())))
+[7] MethodType(List(), TypeRef(ThisType(scala.collection.mutable#<id>), scala.collection.mutable.HashMap#<id>, List(TypeRef(SingleType(ThisType(scala#<id>), scala.Predef#<id>), newTypeName("String")#<id>, List()), TypeRef(SingleType(ThisType(scala#<id>), scala.Predef#<id>), newTypeName("String")#<id>, List()))))
+[8] TypeRef(ThisType(scala.collection.mutable#<id>), scala.collection.mutable.HashMap#<id>, List())