Task macro cleanup

* use normal TypeTree constructor
* remove unnecessary 'with Singleton' in macro utility
* integrate changes suggested by @xeno-by
* add refVar back and call asTypeConstructor instead of asType to refer to a type variable

util/appmacro/ContextUtil.scala

@@ -14,7 +14,7 @@ object ContextUtil {
 /** Utility methods for macros.  Several methods assume that the context's universe is a full compiler (`scala.tools.nsc.Global`).
 * This is not thread safe due to the underlying Context and related data structures not being thread safe.
 * Use `ContextUtil[c.type](c)` to construct. */
-final class ContextUtil[C <: Context with Singleton](val ctx: C) 
+final class ContextUtil[C <: Context](val ctx: C) 
 {
 		import ctx.universe.{Apply=>ApplyTree,_}
 
@@ -31,13 +31,11 @@ final class ContextUtil[C <: Context with Singleton](val ctx: C)
 	* (The current implementation uses Context.fresh, which increments*/
 	def freshTermName(prefix: String) = newTermName(ctx.fresh("$" + prefix))
 
-	def typeTree(tpe: Type) = TypeTree().setType(tpe)
-
 	/** Constructs a new, local ValDef with the given Type, a unique name, 
 	* the same position as `sym`, and an empty implementation (no rhs). */
 	def freshValDef(tpe: Type, sym: Symbol): ValDef =
 	{
-		val vd = localValDef(typeTree(tpe), EmptyTree)
+		val vd = localValDef(TypeTree(tpe), EmptyTree)
 		vd setPos getPos(sym)
 		vd
 	}
@@ -54,10 +52,10 @@ final class ContextUtil[C <: Context with Singleton](val ctx: C)
 	}
 
 	/** Creates a new, synthetic type variable with the specified `owner`. */
-	def newTypeVariable(owner: Symbol): Symbol =
+	def newTypeVariable(owner: Symbol, prefix: String = "T0"): TypeSymbol =
 	{
 		val global: Global = ctx.universe.asInstanceOf[Global]
-		owner.asInstanceOf[global.Symbol].newSyntheticTypeParam().asInstanceOf[ctx.universe.Symbol]
+		owner.asInstanceOf[global.Symbol].newSyntheticTypeParam(prefix, 0L).asInstanceOf[ctx.universe.TypeSymbol]
 	}
 	/** The type representing the type constructor `[X] X` */
 	val idTC: Type =
@@ -65,28 +63,27 @@ final class ContextUtil[C <: Context with Singleton](val ctx: C)
 		val tvar = newTypeVariable(NoSymbol)
 		polyType(tvar :: Nil, refVar(tvar))
 	}
+	/** A Type that references the given type variable. */
+	def refVar(variable: TypeSymbol): Type = variable.asTypeConstructor
 	/** Constructs a new, synthetic type variable that is a type constructor. For example, in type Y[L[x]], L is such a type variable. */
-	def newTCVariable(owner: Symbol): Symbol =
+	def newTCVariable(owner: Symbol): TypeSymbol =
 	{
-		val global: Global = ctx.universe.asInstanceOf[Global]
-		val tc = owner.asInstanceOf[global.Symbol].newSyntheticTypeParam()
-		val arg = tc.newSyntheticTypeParam("x", 0L)
-		tc.setInfo(global.PolyType(arg :: Nil, global.TypeBounds.empty)).asInstanceOf[ctx.universe.Symbol]
+		val tc = newTypeVariable(owner)
+		val arg = newTypeVariable(tc, "x")
+		tc.setTypeSignature(PolyType(arg :: Nil, emptyTypeBounds))
+		tc
 	}
+	def emptyTypeBounds: TypeBounds = TypeBounds(definitions.NothingClass.asType, definitions.AnyClass.asType)
+
 	/** Returns the Symbol that references the statically accessible singleton `i`. */
 	def singleton[T <: AnyRef with Singleton](i: T)(implicit it: ctx.TypeTag[i.type]): Symbol =
 		it.tpe match {
 			case SingleType(_, sym) if !sym.isFreeTerm && sym.isStatic => sym
 			case x => error("Instance must be static (was " + x + ").")
 		}
-	/** Constructs a Type that references the given type variable. */
-	def refVar(variable: Symbol): Type = typeRef(NoPrefix, variable, Nil)
 
 	/** Returns the symbol for the non-private method named `name` for the class/module `obj`. */
-	def method(obj: Symbol, name: String): Symbol = {
-		val global: Global = ctx.universe.asInstanceOf[Global]
-		obj.asInstanceOf[global.Symbol].info.nonPrivateMember(global.newTermName(name)).asInstanceOf[ctx.universe.Symbol]
-	}
+	def method(obj: Symbol, name: String): Symbol = obj.typeSignature.nonPrivateMember(newTermName(name))
 
 	/** Returns a Type representing the type constructor tcp.<name>.  For example, given
 	*  `object Demo { type M[x] = List[x] }`, the call `extractTC(Demo, "M")` will return a type representing

util/appmacro/Instance.scala

@@ -84,10 +84,6 @@ object Instance
 		implicit tt: c.TypeTag[T], mt: c.TypeTag[i.M[T]], it: c.TypeTag[i.type]): c.Expr[i.M[T]] =
 	{
 			import c.universe.{Apply=>ApplyTree,_}
-
-			import scala.tools.nsc.Global
-			// Used to access compiler methods not yet exposed via the reflection/macro APIs
-		val global: Global = c.universe.asInstanceOf[Global]
 		
 		val util = ContextUtil[c.type](c)
 		val mTC: Type = util.extractTC(i, InstanceTCName)
@@ -113,19 +109,9 @@ object Instance
 
 		// constructs a ValDef with a parameter modifier, a unique name, with the provided Type and with an empty rhs
 		def freshMethodParameter(tpe: Type): ValDef =
-			ValDef(parameterModifiers, freshTermName("p"), typeTree(tpe), EmptyTree)
+			ValDef(parameterModifiers, freshTermName("p"), TypeTree(tpe), EmptyTree)
 
 		def freshTermName(prefix: String) = newTermName(c.fresh("$" + prefix))
-		def typeTree(tpe: Type) = TypeTree().setType(tpe)
-
-		// constructs a function that applies f to each subtree of the input tree
-		def visitor(f: Tree => Unit): Tree => Unit =
-		{
-			val v: Transformer = new Transformer {
-				override def transform(tree: Tree): Tree = { f(tree); super.transform(tree) }
-			}
-			(tree: Tree) => v.transform(tree)
-		}
 
 		/* Local definitions in the macro.  This is used to ensure
 		* references are to M instances defined outside of the macro call.*/
@@ -137,13 +123,13 @@ object Instance
 
 		// a function that checks the provided tree for illegal references to M instances defined in the
 		//  expression passed to the macro and for illegal dereferencing of M instances.
-		val checkQual = visitor {
+		val checkQual: Tree => Unit = {
 			case s @ ApplyTree(fun, qual :: Nil) => if(isWrapper(fun)) c.error(s.pos, DynamicDependencyError)
 			case id @ Ident(name) if illegalReference(id.symbol) => c.error(id.pos, DynamicReferenceError)
 			case _ => ()
 		}
 		// adds the symbols for all non-Ident subtrees to `defs`.
-		val defSearch = visitor {
+		val defSearch: Tree => Unit = {
 			case _: Ident => ()
 			case tree => if(tree.symbol ne null) defs += tree.symbol; 
 		}
@@ -160,7 +146,7 @@ object Instance
 		// no inputs, so construct M[T] via Instance.pure or pure+flatten
 		def pure(body: Tree): Tree =
 		{
-			val typeApplied = TypeApply(Select(instance, PureName), typeTree(treeType) :: Nil)
+			val typeApplied = TypeApply(Select(instance, PureName), TypeTree(treeType) :: Nil)
 			val p = ApplyTree(typeApplied, Function(Nil, body) :: Nil)
 			if(t.isLeft) p else flatten(p)
 		}
@@ -168,7 +154,7 @@ object Instance
 		// the returned Tree will have type M[T]
 		def flatten(m: Tree): Tree =
 		{
-			val typedFlatten = TypeApply(Select(instance, FlattenName), typeTree(tt.tpe) :: Nil)
+			val typedFlatten = TypeApply(Select(instance, FlattenName), TypeTree(tt.tpe) :: Nil)
 			ApplyTree(typedFlatten, m :: Nil)
 		}
 
@@ -177,7 +163,7 @@ object Instance
 		{
 			val variable = input.local
 			val param = ValDef(parameterModifiers, variable.name, variable.tpt, EmptyTree)
-			val typeApplied = TypeApply(Select(instance, MapName), variable.tpt :: typeTree(treeType) :: Nil)
+			val typeApplied = TypeApply(Select(instance, MapName), variable.tpt :: TypeTree(treeType) :: Nil)
 			val mapped = ApplyTree(typeApplied, input.expr :: Function(param :: Nil, body) :: Nil)
 			if(t.isLeft) mapped else flatten(mapped)
 		}
@@ -189,8 +175,8 @@ object Instance
 			val param = freshMethodParameter( appliedType(result.representationC, util.idTC :: Nil) )
 			val bindings = result.extract(param)
 			val f = Function(param :: Nil, Block(bindings, body))
-			val ttt = typeTree(treeType)
-			val typedApp = TypeApply(Select(instance, ApplyName), typeTree(result.representationC) :: ttt :: Nil)
+			val ttt = TypeTree(treeType)
+			val typedApp = TypeApply(Select(instance, ApplyName), TypeTree(result.representationC) :: ttt :: Nil)
 			val app = ApplyTree(ApplyTree(typedApp, result.input :: f :: Nil), result.alistInstance :: Nil)
 			if(t.isLeft) app else flatten(app)
 		}
@@ -202,7 +188,7 @@ object Instance
 		//  the bound value of the input
 		def addType(tpe: Type, qual: Tree): Tree =
 		{
-			checkQual(qual)
+			qual.foreach(checkQual)
 			val vd = util.freshValDef(tpe, qual.symbol)
 			inputs ::= new Input(tpe, qual, vd)
 			Ident(vd.name)
@@ -223,7 +209,7 @@ object Instance
 		}
 
 		// collects all definitions in the tree.  used for finding illegal references
-		defSearch(tree)
+		tree.foreach(defSearch)
 
 		// applies the transformation
 		//   resetting attributes: a) must be local b) must be done

util/appmacro/KListBuilder.scala

@@ -24,7 +24,7 @@ object KListBuilder extends TupleBuilder
 		val kconsTC: Type = kconsTpe.typeConstructor
 
 		/** This is the L in the type function [L[x]] ...  */
-		val tcVariable: Symbol = newTCVariable(NoSymbol)
+		val tcVariable: TypeSymbol = newTCVariable(NoSymbol)
 
 		/** Instantiates KCons[h, t <: KList[L], L], where L is the type constructor variable */
 		def kconsType(h: Type, t: Type): Type =
@@ -52,7 +52,7 @@ object KListBuilder extends TupleBuilder
 		val representationC = PolyType(tcVariable :: Nil, klistType)
 		val resultType = appliedType(representationC, idTC :: Nil)
 		val input = klist
-		val alistInstance = TypeApply(Select(Ident(alist), "klist"), typeTree(representationC) :: Nil)
+		val alistInstance = TypeApply(Select(Ident(alist), "klist"), TypeTree(representationC) :: Nil)
 		def extract(param: ValDef) = bindKList(param, Nil, inputs.map(_.local))
 	}
 }

util/appmacro/TupleNBuilder.scala

@@ -35,7 +35,7 @@ object TupleNBuilder extends TupleBuilder
 		val input: Tree = mkTuple(inputs.map(_.expr))
 		val alistInstance: Tree = {
 			val select = Select(Ident(alist), TupleMethodName + inputs.size.toString)
-			TypeApply(select, inputs.map(in => typeTree(in.tpe)))
+			TypeApply(select, inputs.map(in => TypeTree(in.tpe)))
 		}
 		def extract(param: ValDef): List[ValDef] = bindTuple(param, Nil, inputs.map(_.local), 1)