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package dotty.tools.dotc
package transform
import core._
import Names._
import dotty.tools.dotc.ast.tpd
import dotty.tools.dotc.core.Phases.NeedsCompanions
import dotty.tools.dotc.transform.TreeTransforms._
import ast.Trees._
import Flags._
import Types._
import Constants.Constant
import Contexts.Context
import Symbols._
import SymDenotations._
import Decorators._
import dotty.tools.dotc.core.Annotations.ConcreteAnnotation
import dotty.tools.dotc.core.Denotations.SingleDenotation
import scala.collection.mutable
import DenotTransformers._
import typer.Checking
import Names.Name
import NameOps._
import StdNames._
/** The first tree transform
* - ensures there are companion objects for all classes except module classes
* - eliminates some kinds of trees: Imports, NamedArgs
* - stubs out native methods
*/
class FirstTransform extends MiniPhaseTransform with IdentityDenotTransformer with AnnotationTransformer { thisTransformer =>
import ast.tpd._
override def phaseName = "firstTransform"
private var addCompanionPhases: List[NeedsCompanions] = _
def needsCompanion(cls: ClassSymbol)(implicit ctx: Context) =
addCompanionPhases.exists(_.isCompanionNeeded(cls))
override def prepareForUnit(tree: tpd.Tree)(implicit ctx: Context): TreeTransform = {
addCompanionPhases = ctx.phasePlan.flatMap(_ collect { case p: NeedsCompanions => p })
this
}
def transformInfo(tp: Type, sym: Symbol)(implicit ctx: Context): Type = tp
override def checkPostCondition(tree: Tree)(implicit ctx: Context): Unit = tree match {
case Select(qual, _) if tree.symbol.exists =>
assert(qual.tpe derivesFrom tree.symbol.owner, i"non member selection of ${tree.symbol.showLocated} from ${qual.tpe}")
case _: TypeTree =>
case _: Import | _: NamedArg | _: TypTree =>
assert(false, i"illegal tree: $tree")
case _ =>
}
/** 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, forClass: Symbol): Thicket = {
val modul = ctx.newCompleteModuleSymbol(ctx.owner, name, Synthetic, Synthetic,
defn.ObjectType :: Nil, Scopes.newScope)
val mc = modul.moduleClass
if (ctx.owner.isClass) modul.enteredAfter(thisTransformer)
ctx.synthesizeCompanionMethod(nme.COMPANION_CLASS_METHOD, forClass, mc).enteredAfter(thisTransformer)
ctx.synthesizeCompanionMethod(nme.COMPANION_MODULE_METHOD, mc, forClass).enteredAfter(thisTransformer)
ModuleDef(modul, Nil)
}
def addMissingCompanions(stats: List[Tree]): List[Tree] = stats map {
case stat: TypeDef if (singleClassDefs contains stat.name) && needsCompanion(stat.symbol.asClass) =>
val objName = stat.name.toTermName
val nameClash = stats.exists {
case other: MemberDef =>
other.name == objName && other.symbol.info.isParameterless
case _ =>
false
}
val uniqueName = if (nameClash) objName.avoidClashName else objName
Thicket(stat :: newCompanion(uniqueName, stat.symbol).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_errorR).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 => transform(tree.arg)
case tree => tree
}
// invariants: all modules have companion objects
// all types are TypeTrees
// all this types are explicit
}
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