establishes scala.reflect.api#internal

Reflection API exhibits a tension inherent to experimental things:
on the one hand we want it to grow into a beautiful and robust API,
but on the other hand we have to deal with immaturity of underlying mechanisms
by providing not very pretty solutions to enable important use cases.

In Scala 2.10, which was our first stab at reflection API, we didn't
have a systematic approach to dealing with this tension, sometimes exposing
too much of internals (e.g. Symbol.deSkolemize) and sometimes exposing
too little (e.g. there's still no facility to change owners, to do typing
transformations, etc). This resulted in certain confusion with some internal
APIs living among public ones, scaring the newcomers, and some internal APIs
only available via casting, which requires intimate knowledge of the
compiler and breaks compatibility guarantees.

This led to creation of the `internal` API module for the reflection API,
which provides advanced APIs necessary for macros that push boundaries
of the state of the art, clearly demarcating them from the more or less
straightforward rest and providing compatibility guarantees on par with
the rest of the reflection API.

This commit does break source compatibility with reflection API in 2.10,
but the next commit is going to introduce a strategy of dealing with that.

10 files changed, 45 insertions, 47 deletions

diff --git a/src/compiler/scala/reflect/macros/contexts/Evals.scala b/src/compiler/scala/reflect/macros/contexts/Evals.scala
index 180a998c39..a715af986c 100644
--- a/src/compiler/scala/reflect/macros/contexts/Evals.scala
+++ b/src/compiler/scala/reflect/macros/contexts/Evals.scala
@@ -9,7 +9,7 @@ trait Evals {
 
   private lazy val evalMirror = ru.runtimeMirror(universe.analyzer.defaultMacroClassloader)
   private lazy val evalToolBox = evalMirror.mkToolBox()
-  private lazy val evalImporter = ru.mkImporter(universe).asInstanceOf[ru.Importer { val from: universe.type }]
+  private lazy val evalImporter = ru.internal.createImporter(universe).asInstanceOf[ru.Importer { val from: universe.type }]
 
   def eval[T](expr: Expr[T]): T = {
     expr.tree match {
diff --git a/src/compiler/scala/reflect/reify/codegen/GenTypes.scala b/src/compiler/scala/reflect/reify/codegen/GenTypes.scala
index a90a3a338b..a6b69e239f 100644
--- a/src/compiler/scala/reflect/reify/codegen/GenTypes.scala
+++ b/src/compiler/scala/reflect/reify/codegen/GenTypes.scala
@@ -45,21 +45,21 @@ trait GenTypes {
       case tpe @ ThisType(clazz) if clazz.isModuleClass && clazz.isStatic =>
         val module = reify(clazz.sourceModule)
         val moduleClass = Select(Select(module, nme.asModule), nme.moduleClass)
-        mirrorFactoryCall(nme.ThisType, moduleClass)
-      case tpe @ ThisType(_) =>
-        reifyProduct(tpe)
+        mirrorBuildCall(nme.ThisType, moduleClass)
+      case tpe @ ThisType(sym) =>
+        reifyBuildCall(nme.ThisType, sym)
       case tpe @ SuperType(thistpe, supertpe) =>
-        reifyProduct(tpe)
+        reifyBuildCall(nme.SuperType, thistpe, supertpe)
       case tpe @ SingleType(pre, sym) =>
-        reifyProduct(tpe)
+        reifyBuildCall(nme.SingleType, pre, sym)
       case tpe @ ConstantType(value) =>
-        mirrorFactoryCall(nme.ConstantType, reifyProduct(value))
+        mirrorBuildCall(nme.ConstantType, reifyProduct(value))
       case tpe @ TypeRef(pre, sym, args) =>
-        reifyProduct(tpe)
+        reifyBuildCall(nme.TypeRef, pre, sym, args)
       case tpe @ TypeBounds(lo, hi) =>
-        reifyProduct(tpe)
+        reifyBuildCall(nme.TypeBounds, lo, hi)
       case tpe @ NullaryMethodType(restpe) =>
-        reifyProduct(tpe)
+        reifyBuildCall(nme.NullaryMethodType, restpe)
       case tpe @ AnnotatedType(anns, underlying) =>
         reifyAnnotatedType(tpe)
       case _ =>
@@ -119,7 +119,8 @@ trait GenTypes {
             // todo. write a test for this
             if (ReflectRuntimeUniverse == NoSymbol) CannotConvertManifestToTagWithoutScalaReflect(tpe, manifestInScope)
             val cm = typer.typed(Ident(ReflectRuntimeCurrentMirror))
-            val tagTree = gen.mkMethodCall(ReflectRuntimeUniverse, nme.manifestToTypeTag, List(tpe), List(cm, manifestInScope))
+            val internal = gen.mkAttributedSelect(gen.mkAttributedRef(ReflectRuntimeUniverse), UniverseInternal)
+            val tagTree = gen.mkMethodCall(Select(internal, nme.manifestToTypeTag), List(tpe), List(cm, manifestInScope))
             Select(Apply(Select(tagTree, nme.in), List(Ident(nme.MIRROR_SHORT))), nme.tpe)
           case _ =>
             EmptyTree
@@ -157,13 +158,13 @@ trait GenTypes {
    */
   private def reifySemiConcreteTypeMember(tpe: Type): Tree = tpe match {
     case tpe @ TypeRef(pre @ SingleType(prepre, presym), sym, args) if sym.isAbstractType && !sym.isExistential =>
-      mirrorFactoryCall(nme.TypeRef, reify(pre), mirrorBuildCall(nme.selectType, reify(sym.owner), reify(sym.name.toString)), reify(args))
+      mirrorBuildCall(nme.TypeRef, reify(pre), mirrorBuildCall(nme.selectType, reify(sym.owner), reify(sym.name.toString)), reify(args))
   }
 
   /** Reify an annotated type, i.e. the one that makes us deal with AnnotationInfos */
   private def reifyAnnotatedType(tpe: AnnotatedType): Tree = {
     val AnnotatedType(anns, underlying) = tpe
-    mirrorFactoryCall(nme.AnnotatedType, mkList(anns map reifyAnnotationInfo), reify(underlying))
+    mirrorBuildCall(nme.AnnotatedType, mkList(anns map reifyAnnotationInfo), reify(underlying))
   }
 
   /** Reify a tough type, i.e. the one that leads to creation of auxiliary symbols */
@@ -172,25 +173,25 @@ trait GenTypes {
 
     def reifyScope(scope: Scope): Tree = {
       scope foreach reifySymDef
-      mirrorCall(nme.newScopeWith, scope.toList map reify: _*)
+      mirrorBuildCall(nme.newScopeWith, scope.toList map reify: _*)
     }
 
     tpe match {
       case tpe @ RefinedType(parents, decls) =>
         reifySymDef(tpe.typeSymbol)
-        mirrorFactoryCall(tpe, reify(parents), reifyScope(decls), reify(tpe.typeSymbol))
+        mirrorBuildCall(nme.RefinedType, reify(parents), reifyScope(decls), reify(tpe.typeSymbol))
       case tpe @ ExistentialType(tparams, underlying) =>
         tparams foreach reifySymDef
-        mirrorFactoryCall(tpe, reify(tparams), reify(underlying))
+        reifyBuildCall(nme.ExistentialType, tparams, underlying)
       case tpe @ ClassInfoType(parents, decls, clazz) =>
         reifySymDef(clazz)
-        mirrorFactoryCall(tpe, reify(parents), reifyScope(decls), reify(tpe.typeSymbol))
+        mirrorBuildCall(nme.ClassInfoType, reify(parents), reifyScope(decls), reify(tpe.typeSymbol))
       case tpe @ MethodType(params, restpe) =>
         params foreach reifySymDef
-        mirrorFactoryCall(tpe, reify(params), reify(restpe))
+        reifyBuildCall(nme.MethodType, params, restpe)
       case tpe @ PolyType(tparams, underlying) =>
         tparams foreach reifySymDef
-        mirrorFactoryCall(tpe, reify(tparams), reify(underlying))
+        reifyBuildCall(nme.PolyType, tparams, underlying)
       case _ =>
         throw new Error("internal error: %s (%s) is not supported".format(tpe, tpe.kind))
     }
diff --git a/src/compiler/scala/reflect/reify/utils/Extractors.scala b/src/compiler/scala/reflect/reify/utils/Extractors.scala
index d052127956..cfc42e31a9 100644
--- a/src/compiler/scala/reflect/reify/utils/Extractors.scala
+++ b/src/compiler/scala/reflect/reify/utils/Extractors.scala
@@ -183,12 +183,12 @@ trait Extractors {
       tree match {
         case
           ValDef(_, name, _, Apply(
-            Select(Select(uref1 @ Ident(_), build1), freeTermFactory),
+            Select(Select(Select(uref1 @ Ident(_), internal1), rs1), freeTermFactory),
             _ :+
-            ApplyCall(Select(Select(uref2 @ Ident(_), build2), flagsRepr), List(Literal(Constant(flags: Long)))) :+
+            ApplyCall(Select(Select(Select(uref2 @ Ident(_), internal2), rs2), flagsRepr), List(Literal(Constant(flags: Long)))) :+
             Literal(Constant(origin: String))))
-        if uref1.name == nme.UNIVERSE_SHORT && build1 == nme.build && acceptFreeTermFactory(freeTermFactory) &&
-           uref2.name == nme.UNIVERSE_SHORT && build2 == nme.build && flagsRepr == nme.FlagsRepr =>
+        if uref1.name == nme.UNIVERSE_SHORT && internal1 == nme.internal && rs1 == nme.reificationSupport && acceptFreeTermFactory(freeTermFactory) &&
+           uref2.name == nme.UNIVERSE_SHORT && internal2 == nme.internal && rs2 == nme.reificationSupport && flagsRepr == nme.FlagsRepr =>
           Some((uref1, name, reifyBinding(tree), flags, origin))
         case _ =>
           None
@@ -201,8 +201,8 @@ trait Extractors {
 
   object FreeRef {
     def unapply(tree: Tree): Option[(Tree, TermName)] = tree match {
-      case Apply(Select(Select(uref @ Ident(_), build), ident), List(Ident(name: TermName)))
-      if build == nme.build && ident == nme.Ident && name.startsWith(nme.REIFY_FREE_PREFIX) =>
+      case Apply(Select(Select(Select(uref @ Ident(_), internal), rs), ident), List(Ident(name: TermName)))
+      if internal == nme.internal && rs == nme.reificationSupport && ident == nme.Ident && name.startsWith(nme.REIFY_FREE_PREFIX) =>
         Some((uref, name))
       case _ =>
         None
@@ -213,15 +213,15 @@ trait Extractors {
     def unapply(tree: Tree): Option[(Tree, TermName, Long, Boolean)] = tree match {
       case
         ValDef(_, name, _, Apply(
-          Select(Select(uref1 @ Ident(_), build1), newNestedSymbol),
+          Select(Select(Select(uref1 @ Ident(_), internal1), rs1), newNestedSymbol),
           List(
             _,
             _,
             _,
-            ApplyCall(Select(Select(uref2 @ Ident(_), build2), flagsRepr), List(Literal(Constant(flags: Long)))),
+            ApplyCall(Select(Select(Select(uref2 @ Ident(_), internal2), rs2), flagsRepr), List(Literal(Constant(flags: Long)))),
             Literal(Constant(isClass: Boolean)))))
-      if uref1.name == nme.UNIVERSE_SHORT && build1 == nme.build && newNestedSymbol == nme.newNestedSymbol &&
-         uref2.name == nme.UNIVERSE_SHORT && build2 == nme.build && flagsRepr == nme.FlagsRepr =>
+      if uref1.name == nme.UNIVERSE_SHORT && internal1 == nme.internal && rs1 == nme.reificationSupport && newNestedSymbol == nme.newNestedSymbol &&
+         uref2.name == nme.UNIVERSE_SHORT && internal2 == nme.internal && rs2 == nme.reificationSupport && flagsRepr == nme.FlagsRepr =>
         Some((uref1, name, flags, isClass))
       case _ =>
         None
diff --git a/src/compiler/scala/reflect/reify/utils/NodePrinters.scala b/src/compiler/scala/reflect/reify/utils/NodePrinters.scala
index e37b861461..3b91d28360 100644
--- a/src/compiler/scala/reflect/reify/utils/NodePrinters.scala
+++ b/src/compiler/scala/reflect/reify/utils/NodePrinters.scala
@@ -32,7 +32,7 @@ trait NodePrinters {
         s = "List\\[List\\[.*?\\].*?\\]".r.replaceAllIn(s, "List")
         s = "List\\[.*?\\]".r.replaceAllIn(s, "List")
         s = s.replace("immutable.this.Nil", "List()")
-        s = """build\.FlagsRepr\((\d+)[lL]\)""".r.replaceAllIn(s, m => {
+        s = """internal\.reificationSupport\.FlagsRepr\((\d+)[lL]\)""".r.replaceAllIn(s, m => {
           flagsAreUsed = true
           show(m.group(1).toLong)
         })
@@ -76,7 +76,6 @@ trait NodePrinters {
       if (mirrorIsUsed) printout += mirror.replace("Mirror[", "scala.reflect.api.Mirror[").trim
       val imports = scala.collection.mutable.ListBuffer[String]()
       imports += nme.UNIVERSE_SHORT.toString
-      // if (buildIsUsed) imports += nme.build
       if (mirrorIsUsed) imports += nme.MIRROR_SHORT.toString
       if (flagsAreUsed) imports += nme.Flag.toString
       printout += s"""import ${imports map (_ + "._") mkString ", "}"""
diff --git a/src/compiler/scala/tools/nsc/Global.scala b/src/compiler/scala/tools/nsc/Global.scala
index 5ce0238b3b..03b76ed99e 100644
--- a/src/compiler/scala/tools/nsc/Global.scala
+++ b/src/compiler/scala/tools/nsc/Global.scala
@@ -34,6 +34,7 @@ import backend.jvm.GenASM
 import backend.opt.{ Inliners, InlineExceptionHandlers, ConstantOptimization, ClosureElimination, DeadCodeElimination }
 import backend.icode.analysis._
 import scala.language.postfixOps
+import scala.tools.nsc.ast.{TreeGen => AstTreeGen}
 
 class Global(var currentSettings: Settings, var reporter: Reporter)
     extends SymbolTable
@@ -105,13 +106,10 @@ class Global(var currentSettings: Settings, var reporter: Reporter)
 
   // sub-components --------------------------------------------------
 
-  /** Generate ASTs */
-  type TreeGen = scala.tools.nsc.ast.TreeGen
-
   /** Tree generation, usually based on existing symbols. */
   override object gen extends {
     val global: Global.this.type = Global.this
-  } with TreeGen {
+  } with AstTreeGen {
     def mkAttributedCast(tree: Tree, pt: Type): Tree =
       typer.typed(mkCast(tree, pt))
   }
diff --git a/src/compiler/scala/tools/nsc/typechecker/Implicits.scala b/src/compiler/scala/tools/nsc/typechecker/Implicits.scala
index d3b5564f60..2bb874a8aa 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Implicits.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Implicits.scala
@@ -1271,7 +1271,8 @@ trait Implicits {
             return SearchFailure
           }
           val cm = typed(Ident(ReflectRuntimeCurrentMirror))
-          val interop = gen.mkMethodCall(ReflectRuntimeUniverse, nme.typeTagToManifest, List(tp), List(cm, tagInScope))
+          val internal = gen.mkAttributedSelect(gen.mkAttributedRef(ReflectRuntimeUniverse), UniverseInternal)
+          val interop = gen.mkMethodCall(Select(internal, nme.typeTagToManifest), List(tp), List(cm, tagInScope))
           wrapResult(interop)
         }
       } else {
diff --git a/src/compiler/scala/tools/reflect/StdTags.scala b/src/compiler/scala/tools/reflect/StdTags.scala
index 5c53c81e8b..ee352c5e02 100644
--- a/src/compiler/scala/tools/reflect/StdTags.scala
+++ b/src/compiler/scala/tools/reflect/StdTags.scala
@@ -18,8 +18,7 @@ trait StdTags {
       new TypeCreator {
         def apply[U <: ApiUniverse with Singleton](m: Mirror[U]): U # Type = {
           val u = m.universe
-          val pre = u.ThisType(m.staticPackage("scala.collection.immutable").moduleClass.asInstanceOf[u.Symbol])
-          u.TypeRef(pre, u.definitions.ListClass, List(u.definitions.StringClass.toTypeConstructor))
+          u.appliedType(u.definitions.ListClass.toType, List(u.definitions.StringClass.toType))
         }
       })
 
diff --git a/src/compiler/scala/tools/reflect/ToolBoxFactory.scala b/src/compiler/scala/tools/reflect/ToolBoxFactory.scala
index b43b4653eb..ce6382bec8 100644
--- a/src/compiler/scala/tools/reflect/ToolBoxFactory.scala
+++ b/src/compiler/scala/tools/reflect/ToolBoxFactory.scala
@@ -217,7 +217,7 @@ abstract class ToolBoxFactory[U <: JavaUniverse](val u: U) { factorySelf =>
           val (expr, freeTerms) = extractFreeTerms(expr0, wrapFreeTermRefs = true)
 
           val (obj, _) = rootMirror.EmptyPackageClass.newModuleAndClassSymbol(
-            nextWrapperModuleName())
+            nextWrapperModuleName(), NoPosition, NoFlags)
 
           val minfo = ClassInfoType(List(ObjectTpe), newScope, obj.moduleClass)
           obj.moduleClass setInfo minfo
diff --git a/src/compiler/scala/tools/reflect/quasiquotes/Holes.scala b/src/compiler/scala/tools/reflect/quasiquotes/Holes.scala
index 2027d43264..c2f1bf430d 100644
--- a/src/compiler/scala/tools/reflect/quasiquotes/Holes.scala
+++ b/src/compiler/scala/tools/reflect/quasiquotes/Holes.scala
@@ -120,8 +120,8 @@ trait Holes { self: Quasiquotes =>
     }
 
     private def toStats(tree: Tree): Tree =
-      // q"$u.build.toStats($tree)"
-      Apply(Select(Select(u, nme.build), nme.toStats), tree :: Nil)
+      // q"$u.internal.reificationSupport.toStats($tree)"
+      Apply(Select(Select(Select(u, nme.internal), nme.reificationSupport), nme.toStats), tree :: Nil)
 
     private def toList(tree: Tree, tpe: Type): Tree =
       if (isListType(tpe)) tree
@@ -234,10 +234,10 @@ trait Holes { self: Quasiquotes =>
         }
         val lifter = inferUnliftable(tpe)
         assert(helperName.isTermName)
-        // q"val $name: $u.build.${helperName.toTypeName} = $u.build.$helperName($lifter)"
+        // q"val $name: $u.internal.reificationSupport.${helperName.toTypeName} = $u.internal.reificationSupport.$helperName($lifter)"
         ValDef(NoMods, name,
-          AppliedTypeTree(Select(Select(u, nme.build), helperName.toTypeName), List(TypeTree(tpe))),
-          Apply(Select(Select(u, nme.build), helperName), lifter :: Nil))
+          AppliedTypeTree(Select(Select(Select(u, nme.internal), nme.reificationSupport), helperName.toTypeName), List(TypeTree(tpe))),
+          Apply(Select(Select(Select(u, nme.internal), nme.reificationSupport), helperName), lifter :: Nil))
       }
   }
 }
diff --git a/src/compiler/scala/tools/reflect/quasiquotes/Reifiers.scala b/src/compiler/scala/tools/reflect/quasiquotes/Reifiers.scala
index 017e966f63..9078228314 100644
--- a/src/compiler/scala/tools/reflect/quasiquotes/Reifiers.scala
+++ b/src/compiler/scala/tools/reflect/quasiquotes/Reifiers.scala
@@ -64,9 +64,9 @@ trait Reifiers { self: Quasiquotes =>
             val FreshName(prefix) = origname
             val nameTypeName = if (origname.isTermName) tpnme.TermName else tpnme.TypeName
             val freshName = if (origname.isTermName) nme.freshTermName else nme.freshTypeName
-            // q"val ${names.head}: $u.$nameTypeName = $u.build.$freshName($prefix)"
+            // q"val ${names.head}: $u.$nameTypeName = $u.internal.reificationSupport.$freshName($prefix)"
             ValDef(NoMods, names.head, Select(u, nameTypeName),
-              Apply(Select(Select(u, nme.build), freshName), Literal(Constant(prefix)) :: Nil))
+              Apply(Select(Select(Select(u, nme.internal), nme.reificationSupport), freshName), Literal(Constant(prefix)) :: Nil))
         }.toList
         // q"..$freshdefs; $tree"
         SyntacticBlock(freshdefs :+ tree)
@@ -358,7 +358,7 @@ trait Reifiers { self: Quasiquotes =>
       Apply(Select(universe, name), args.toList)
 
     override def mirrorBuildCall(name: TermName, args: Tree*): Tree =
-      Apply(Select(Select(universe, nme.build), name), args.toList)
+      Apply(Select(Select(Select(universe, nme.internal), nme.reificationSupport), name), args.toList)
 
     override def scalaFactoryCall(name: String, args: Tree*): Tree =
       call("scala." + name, args: _*)