make internal implementation of universe.build less restrictive

1. Use protected instead of private to avoid needless lock-in

2. Use BuildImpl field type to expose non-protected members to the
   compiler (user-facing side in the reflection api stays the same)

1 files changed, 16 insertions, 26 deletions

diff --git a/src/reflect/scala/reflect/internal/BuildUtils.scala b/src/reflect/scala/reflect/internal/BuildUtils.scala
index 9d111e8852..004c4aa40b 100644
--- a/src/reflect/scala/reflect/internal/BuildUtils.scala
+++ b/src/reflect/scala/reflect/internal/BuildUtils.scala
@@ -9,7 +9,6 @@ trait BuildUtils { self: SymbolTable =>
   import definitions.{TupleClass, FunctionClass, ScalaPackage, UnitClass}
 
   class BuildImpl extends BuildApi {
-
     def selectType(owner: Symbol, name: String): TypeSymbol =
       select(owner, newTypeName(name)).asType
 
@@ -19,7 +18,7 @@ trait BuildUtils { self: SymbolTable =>
       else result
     }
 
-    private def select(owner: Symbol, name: Name): Symbol = {
+    protected def select(owner: Symbol, name: Name): Symbol = {
       val result = owner.info decl name
       if (result ne NoSymbol) result
       else
@@ -135,7 +134,7 @@ trait BuildUtils { self: SymbolTable =>
 
     def withFreshTypeName[T](prefix: String)(f: TypeName => T): T = f(freshTypeName(prefix))
 
-    private implicit def fresh: FreshNameCreator = self.currentFreshNameCreator
+    protected implicit def fresh: FreshNameCreator = self.currentFreshNameCreator
 
     object FlagsRepr extends FlagsReprExtractor {
       def apply(bits: Long): FlagSet = bits
@@ -175,7 +174,8 @@ trait BuildUtils { self: SymbolTable =>
       }
     }
 
-    private object UnCtor {
+    // recover constructor contents generated by gen.mkTemplate
+    protected object UnCtor {
       def unapply(tree: Tree): Option[(Modifiers, List[List[ValDef]], List[Tree])] = tree match {
         case DefDef(mods, nme.MIXIN_CONSTRUCTOR, _, _, _, Block(lvdefs, _)) =>
           Some((mods | Flag.TRAIT, Nil, lvdefs))
@@ -185,7 +185,8 @@ trait BuildUtils { self: SymbolTable =>
       }
     }
 
-    private object UnMkTemplate {
+    // undo gen.mkTemplate
+    protected object UnMkTemplate {
       def unapply(templ: Template): Option[(List[Tree], ValDef, Modifiers, List[List[ValDef]], List[Tree], List[Tree])] = {
         val Template(parents, selfType, tbody) = templ
         def result(ctorMods: Modifiers, vparamss: List[List[ValDef]], edefs: List[Tree], body: List[Tree]) =
@@ -297,8 +298,8 @@ trait BuildUtils { self: SymbolTable =>
       }
     }
 
-    private trait ScalaMemberRef {
-      val symbols: Seq[Symbol]
+    // match references to `scala.$name`
+    protected class ScalaMemberRef(symbols: Seq[Symbol]) {
       def result(name: Name): Option[Symbol] =
         symbols.collect { case sym if sym.name == name => sym }.headOption
       def unapply(tree: Tree): Option[Symbol] = tree match {
@@ -311,18 +312,10 @@ trait BuildUtils { self: SymbolTable =>
         case _ => None
       }
     }
-    private object TupleClassRef extends ScalaMemberRef {
-      val symbols = TupleClass.seq
-    }
-    private object TupleCompanionRef extends ScalaMemberRef {
-      val symbols = TupleClass.seq.map { _.companionModule }
-    }
-    private object UnitClassRef extends ScalaMemberRef {
-      val symbols = Seq(UnitClass)
-    }
-    private object FunctionClassRef extends ScalaMemberRef {
-      val symbols = FunctionClass.seq
-    }
+    protected object TupleClassRef extends ScalaMemberRef(TupleClass.seq)
+    protected object TupleCompanionRef extends ScalaMemberRef(TupleClass.seq.map { _.companionModule })
+    protected object UnitClassRef extends ScalaMemberRef(Seq(UnitClass))
+    protected object FunctionClassRef extends ScalaMemberRef(FunctionClass.seq)
 
     object SyntacticTuple extends SyntacticTupleExtractor {
       def apply(args: List[Tree]): Tree = {
@@ -419,9 +412,7 @@ trait BuildUtils { self: SymbolTable =>
       }
     }
 
-    trait SyntacticValDefBase extends SyntacticValDefExtractor {
-      val isMutable: Boolean
-
+    protected class SyntacticValDefBase(isMutable: Boolean) extends SyntacticValDefExtractor {
       def apply(mods: Modifiers, name: TermName, tpt: Tree, rhs: Tree) = {
         val mods1 = if (isMutable) mods | MUTABLE else mods
         ValDef(mods1, name, tpt, rhs)
@@ -434,9 +425,8 @@ trait BuildUtils { self: SymbolTable =>
           None
       }
     }
-
-    object SyntacticValDef extends SyntacticValDefBase { val isMutable = false }
-    object SyntacticVarDef extends SyntacticValDefBase { val isMutable = true }
+    object SyntacticValDef extends SyntacticValDefBase(isMutable = false)
+    object SyntacticVarDef extends SyntacticValDefBase(isMutable = true)
 
     object SyntacticAssign extends SyntacticAssignExtractor {
       def apply(lhs: Tree, rhs: Tree): Tree = gen.mkAssign(lhs, rhs)
@@ -449,5 +439,5 @@ trait BuildUtils { self: SymbolTable =>
     }
   }
 
-  val build: BuildApi = new BuildImpl
+  val build: BuildImpl = new BuildImpl
 }