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package dotty.tools.dotc
package transform
import core._
import Names._
import TreeTransforms.{TransformerInfo, MiniPhaseTransform, TreeTransformer}
import ast.Trees._
import Flags._
import Types._
import Constants.Constant
import Contexts.Context
import Symbols._
import scala.collection.mutable
import DenotTransformers._
import typer.Checking
import Names.Name
import NameOps._
/** The first tree transform
* - ensures there are companion objects for all classes except module classes
* - eliminates some kinds of trees: Imports, NamedArgs, all TypTrees other than TypeTree
* - checks the bounds of AppliedTypeTrees
* - stubs out native methods
*/
class FirstTransform extends MiniPhaseTransform with IdentityDenotTransformer { thisTransformer =>
import ast.tpd._
override def phaseName = "companions"
/** Reorder statements so that module classes always come after their companion classes, add missing companion classes */
private def reorderAndComplete(stats: List[Tree])(implicit ctx: Context): List[Tree] = {
val moduleClassDefs, singleClassDefs = mutable.Map[Name, Tree]()
def reorder(stats: List[Tree]): List[Tree] = stats match {
case (stat: TypeDef) :: stats1 if stat.symbol.isClass =>
if (stat.symbol is Flags.Module) {
moduleClassDefs += (stat.name -> stat)
singleClassDefs -= stat.name.stripModuleClassSuffix
val stats1r = reorder(stats1)
if (moduleClassDefs contains stat.name) stat :: stats1r else stats1r
} else {
def stats1r = reorder(stats1)
val normalized = moduleClassDefs remove stat.name.moduleClassName match {
case Some(mcdef) =>
mcdef :: stats1r
case None =>
singleClassDefs += (stat.name -> stat)
stats1r
}
stat :: normalized
}
case stat :: stats1 => stat :: reorder(stats1)
case Nil => Nil
}
def newCompanion(name: TermName): Thicket = {
val modul = ctx.newCompleteModuleSymbol(ctx.owner, name, Synthetic, Synthetic,
defn.ObjectClass.typeRef :: Nil, Scopes.newScope)
if (ctx.owner.isClass) modul.enteredAfter(thisTransformer)
ModuleDef(modul, Nil)
}
def addMissingCompanions(stats: List[Tree]): List[Tree] = stats map {
case stat: TypeDef if singleClassDefs contains stat.name =>
Thicket(stat :: newCompanion(stat.name.toTermName).trees)
case stat => stat
}
addMissingCompanions(reorder(stats))
}
override def transformDefDef(ddef: DefDef)(implicit ctx: Context, info: TransformerInfo) =
if (ddef.symbol.hasAnnotation(defn.NativeAnnot)) {
ddef.symbol.resetFlag(Deferred)
DefDef(ddef.symbol.asTerm,
_ => ref(defn.Sys_error).withPos(ddef.pos)
.appliedTo(Literal(Constant("native method stub"))))
} else ddef
override def transformStats(trees: List[Tree])(implicit ctx: Context, info: TransformerInfo): List[Tree] =
ast.Trees.flatten(reorderAndComplete(trees)(ctx.withPhase(thisTransformer.next)))
override def transformOther(tree: Tree)(implicit ctx: Context, info: TransformerInfo) = tree match {
case tree: Import => EmptyTree
case tree: NamedArg => tree.arg
case AppliedTypeTree(tycon, args) =>
val tparams = tycon.tpe.typeSymbol.typeParams
Checking.checkBounds(
args, tparams.map(_.info.bounds), (tp, argTypes) => tp.substDealias(tparams, argTypes))
TypeTree(tree.tpe).withPos(tree.pos)
case tree =>
if (tree.isType) TypeTree(tree.tpe, tree).withPos(tree.pos)
else tree
}
}
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