org.scalameta.internal.FreeLocalFinder.scala Maven / Gradle / Ivy

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Bag of private and public helpers used in scala.meta's APIs and implementations

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package org.scalameta
package internal

import scala.reflect.macros.blackbox.Context

trait FreeLocalFinder {
  val c: Context

  import c.internal._
  import c.internal.decorators._
  import c.universe._

  def freeLocals(tree: Tree): Map[String, Tree] = {
    object freeLocalFinder extends Traverser {
      private val localRefs = scala.collection.mutable.ListBuffer[Tree]()
      private val localSyms = scala.collection.mutable.Set[Symbol]()
      def registerLocalSym(sym: Symbol): Unit = if (sym != null && sym != NoSymbol) localSyms += sym
      def processLocalDef(tree: Tree): Unit = if (tree.symbol != null && tree.symbol != NoSymbol) {
        val sym = tree.symbol
        registerLocalSym(sym)
        registerLocalSym(sym.deSkolemize)
        registerLocalSym(sym.companion)
        sym match {
          case sym: ClassSymbol => registerLocalSym(sym.module)
          case sym: ModuleSymbol => registerLocalSym(sym.moduleClass)
          case _ => ;
        }
      }
      override def traverse(tree: Tree): Unit = {
        val sym = tree.symbol
        tree match {
          case tree: Ident
              if !sym.owner.isClass && tree.name != termNames.WILDCARD && !sym.isMethod =>
            localRefs += tree
          case tree: This if !sym.isPackageClass => localRefs += tree
          case _: DefTree | Function(_, _) | Template(_, _, _) =>
            processLocalDef(tree); super.traverse(tree)
          case _ => super.traverse(tree)
        }
      }
      def freeLocals = localRefs.filter(ref => !localSyms.contains(ref.symbol))
    }
    freeLocalFinder.traverse(tree)
    freeLocalFinder.freeLocals.map(tree => tree.symbol.name.toString -> tree.duplicate).toMap
  }
}