deprecates resetAllAttrs and resetLocalAttrs in favor of the new API

We now have c.untypecheck, which is supposed to be a counterpart of c.typecheck
in the sense that it goes back from typed trees to untyped ones:
http://stackoverflow.com/questions/20936509/scala-macros-what-is-the-difference-between-typed-aka-typechecked-an-untyped.

Let’s hope that c.untypecheck will soon be able to solve our problems
with partially/incorrectly attributed trees emitted by macros:
https://groups.google.com/forum/#!topic/scala-internals/TtCTPlj_qcQ.

Author: xeno-by

src/compiler/scala/reflect/macros/contexts/Typers.scala

@@ -49,4 +49,6 @@ trait Typers {
   def resetAllAttrs(tree: Tree): Tree = universe.resetAllAttrs(universe.duplicateAndKeepPositions(tree))
 
   def resetLocalAttrs(tree: Tree): Tree = universe.resetLocalAttrs(universe.duplicateAndKeepPositions(tree))
+
+  def untypecheck(tree: Tree): Tree = universe.resetLocalAttrs(universe.duplicateAndKeepPositions(tree))
 }

src/compiler/scala/tools/reflect/ToolBox.scala

@@ -72,19 +72,22 @@ trait ToolBox[U <: scala.reflect.api.Universe] {
   def inferImplicitView(tree: u.Tree, from: u.Type, to: u.Type, silent: Boolean = true, withMacrosDisabled: Boolean = false, pos: u.Position = u.NoPosition): u.Tree
 
   /** Recursively resets symbols and types in a given tree.
-   *
-   *  Note that this does not revert the tree to its pre-typer shape.
-   *  For more info, read up https://issues.scala-lang.org/browse/SI-5464.
+   *  WARNING: Don't use this API, go for [[untypecheck]] instead.
    */
+  @deprecated("Use `tb.untypecheck` instead", "2.11.0")
   def resetAllAttrs(tree: u.Tree): u.Tree
 
   /** Recursively resets locally defined symbols and types in a given tree.
-   *
-   *  Note that this does not revert the tree to its pre-typer shape.
-   *  For more info, read up https://issues.scala-lang.org/browse/SI-5464.
+   *  WARNING: Don't use this API, go for [[untypecheck]] instead.
    */
+  @deprecated("Use `tb.untypecheck` instead", "2.11.0")
   def resetLocalAttrs(tree: u.Tree): u.Tree
 
+  /**
+   *  @see [[scala.reflect.macros.Typers.untypecheck]]
+   */
+  def untypecheck(tree: u.Tree): u.Tree
+
   /** .. */
   def parse(code: String): u.Tree
 

src/compiler/scala/tools/reflect/ToolBoxFactory.scala

@@ -401,6 +401,8 @@ abstract class ToolBoxFactory[U <: JavaUniverse](val u: U) { factorySelf =>
       uttree
     }
 
+    def untypecheck(tree: u.Tree): u.Tree = resetLocalAttrs(tree)
+
     def parse(code: String): u.Tree = withCompilerApi { compilerApi =>
       import compilerApi._
       if (compiler.settings.verbose) println("parsing "+code)

src/reflect/scala/reflect/macros/Typers.scala

@@ -69,18 +69,32 @@ trait Typers {
   def inferImplicitView(tree: Tree, from: Type, to: Type, silent: Boolean = true, withMacrosDisabled: Boolean = false, pos: Position = enclosingPosition): Tree
 
   /** Recursively resets symbols and types in a given tree.
-   *
-   *  Note that this does not revert the tree to its pre-typer shape.
-   *  For more info, read up https://issues.scala-lang.org/browse/SI-5464.
+   *  WARNING: Don't use this API, go for [[untypecheck]] instead.
    */
+  @deprecated("Use `c.untypecheck` instead", "2.11.0")
   def resetAllAttrs(tree: Tree): Tree
 
   /** Recursively resets locally defined symbols and types in a given tree.
-   *
-   *  Note that this does not revert the tree to its pre-typer shape.
-   *  For more info, read up https://issues.scala-lang.org/browse/SI-5464.
+   *  WARNING: Don't use this API, go for [[untypecheck]] instead.
    */
+  @deprecated("Use `c.untypecheck` instead", "2.11.0")
   def resetLocalAttrs(tree: Tree): Tree
+
+  /** In the current implementation of Scala's reflection API, untyped trees (also known as parser trees or unattributed trees)
+   *  are observationally different from typed trees (also known as typer trees, typechecked trees or attributed trees),
+   *
+   *  Usually, if some compiler API takes a tree, then both untyped and typed trees will do. However in some cases,
+   *  only untyped or only typed trees are appropriate. For example, [[eval]] only accepts untyped trees and one can only splice
+   *  typed trees inside typed trees. Therefore in the current reflection API, there is a need in functions
+   *  that go back and forth between untyped and typed trees. For this we have [[typecheck]] and `untypecheck`.
+   *
+   *  Note that `untypecheck` is currently afflicted by https://issues.scala-lang.org/browse/SI-5464,
+   *  which makes it sometimes corrupt trees so that they don't make sense anymore. Unfortunately, there's no workaround for that.
+   *  We plan to fix this issue soon, but for now please keep it in mind.
+   *
+   *  @see [[http://stackoverflow.com/questions/20936509/scala-macros-what-is-the-difference-between-typed-aka-typechecked-an-untyped]]
+   */
+  def untypecheck(tree: Tree): Tree
 }
 
 /** Indicates an error during one of the methods in [[scala.reflect.macros.Typers]].

test/files/run/idempotency-case-classes.scala

@@ -12,7 +12,7 @@ object Test extends App {
   val tb = cm.mkToolBox()
   val tcasee = tb.typecheck(casee.tree)
   println(tcasee)
-  val rtcasee = tb.resetAllAttrs(tcasee)
+  val rtcasee = tb.untypecheck(tcasee)
   try {
     println(tb.eval(rtcasee))
   } catch {

test/files/run/idempotency-extractors.scala

@@ -12,7 +12,7 @@ object Test extends App {
   val tb = cm.mkToolBox()
   val textractor = tb.typecheck(extractor.tree)
   println(textractor)
-  val rtextractor = tb.resetAllAttrs(textractor)
+  val rtextractor = tb.untypecheck(textractor)
   try {
     println(tb.eval(rtextractor))
   } catch {

test/files/run/idempotency-labels.scala

@@ -13,7 +13,7 @@ object Test extends App {
   val tb = cm.mkToolBox()
   val tlabel = tb.typecheck(label.tree)
   println(tlabel)
-  val rtlabel = tb.resetAllAttrs(tlabel)
+  val rtlabel = tb.untypecheck(tlabel)
   try {
     println(tb.eval(rtlabel))
   } catch {

test/files/run/idempotency-lazy-vals.scala

@@ -17,7 +17,7 @@ object Test extends App {
   val tb = cm.mkToolBox()
   val tlazee = tb.typecheck(lazee.tree)
   println(tlazee)
-  val rtlazee = tb.resetAllAttrs(tlazee)
+  val rtlazee = tb.untypecheck(tlazee)
   try {
     println(tb.eval(rtlazee))
   } catch {

test/files/run/idempotency-this.scala

@@ -12,7 +12,7 @@ object Test extends App {
   val tthiss = tb.typecheck(thiss.tree)
   println(tthiss)
   println(showRaw(tthiss))
-  val rtthiss = tb.resetAllAttrs(tthiss)
+  val rtthiss = tb.untypecheck(tthiss)
   try {
     println(tb.eval(rtthiss))
   } catch {

test/files/run/resetattrs-this.scala

@@ -6,6 +6,6 @@ object Test extends App {
   val tb = cm.mkToolBox()
   val tree = Select(This(cm.staticPackage("scala").moduleClass), TermName("Predef"))
   val ttree = tb.typecheck(tree)
-  val rttree = tb.resetAllAttrs(ttree)
+  val rttree = tb.untypecheck(ttree)
   println(tb.eval(rttree) == Predef)
 }