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package dotty.tools.dotc
package transform
import core._
import Names._
import Types._
import TreeTransforms.{TransformerInfo, MiniPhaseTransform, TreeTransformer}
import ast.Trees.flatten
import Flags._
import Contexts.Context
import Symbols._
import Denotations._, SymDenotations._
import Decorators.StringInterpolators
import scala.collection.mutable
import DenotTransformers._
import Names.Name
import NameOps._
import TypeUtils._
/** A transformer that removes repeated parameters (T*) from all types, replacing
* them with Seq types.
*/
class ElimRepeated extends MiniPhaseTransform with InfoTransformer { thisTransformer =>
import ast.tpd._
override def name = "elimRepeated"
def transformInfo(tp: Type, sym: Symbol)(implicit ctx: Context): Type =
elimRepeated(tp)
private def elimRepeated(tp: Type)(implicit ctx: Context): Type = tp.stripTypeVar match {
case tp @ MethodType(paramNames, paramTypes) =>
val resultType1 = elimRepeated(tp.resultType)
val paramTypes1 =
if (paramTypes.nonEmpty && paramTypes.last.isRepeatedParam)
paramTypes.init :+ paramTypes.last.underlyingIfRepeated(tp.isJava)
else paramTypes
tp.derivedMethodType(paramNames, paramTypes1, resultType1)
case tp: PolyType =>
tp.derivedPolyType(tp.paramNames, tp.paramBounds, elimRepeated(tp.resultType))
case tp =>
tp
}
def transformTypeOfTree(tree: Tree)(implicit ctx: Context): Tree =
tree.withType(elimRepeated(tree.tpe))
override def transformIdent(tree: Ident)(implicit ctx: Context, info: TransformerInfo): Tree =
transformTypeOfTree(tree)
override def transformSelect(tree: Select)(implicit ctx: Context, info: TransformerInfo): Tree =
transformTypeOfTree(tree)
override def transformApply(tree: Apply)(implicit ctx: Context, info: TransformerInfo): Tree =
transformTypeOfTree(tree)
override def transformTypeApply(tree: TypeApply)(implicit ctx: Context, info: TransformerInfo): Tree =
transformTypeOfTree(tree)
/** If method overrides a Java varargs method, add a varargs bridge.
*/
override def transformDefDef(tree: DefDef)(implicit ctx: Context, info: TransformerInfo): Tree = {
assert(ctx.phase == thisTransformer)
def overridesJava = tree.symbol.allOverriddenSymbols.exists(_ is JavaDefined)
if (tree.symbol.info.isVarArgsMethod && overridesJava)
addVarArgsBridge(tree)(ctx.withPhase(thisTransformer.next))
else
tree
}
/** Add a Java varargs bridge
* @param ddef the original method definition which is assumed to override
* a Java varargs method JM up to this phase.
* @return a thicket consisting of `ddef` and a varargs bridge method
* which overrides the Java varargs method JM from this phase on
* and forwards to `ddef`.
*/
private def addVarArgsBridge(ddef: DefDef)(implicit ctx: Context): Tree = {
val original = ddef.symbol.asTerm
val bridge = original.copy(
flags = ddef.symbol.flags &~ Private | Artifact,
info = toJavaVarArgs(ddef.symbol.info)).enteredAfter(thisTransformer).asTerm
val bridgeDef = polyDefDef(bridge, trefs => vrefss => {
val (vrefs :+ varArgRef) :: vrefss1 = vrefss
val elemtp = varArgRef.tpe.widen.argTypes.head
ref(original.termRef)
.appliedToTypes(trefs)
.appliedToArgs(vrefs :+ TreeGen.wrapArray(varArgRef, elemtp))
.appliedToArgss(vrefss1)
})
Thicket(ddef, bridgeDef)
}
/** Convert type from Scala to Java varargs method */
private def toJavaVarArgs(tp: Type)(implicit ctx: Context): Type = tp match {
case tp: PolyType =>
tp.derivedPolyType(tp.paramNames, tp.paramBounds, toJavaVarArgs(tp.resultType))
case tp: MethodType =>
val inits :+ last = tp.paramTypes
val last1 = last.underlyingIfRepeated(isJava = true)
tp.derivedMethodType(tp.paramNames, inits :+ last1, tp.resultType)
}
}
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