SumFoldMap.scala

package fix

import scalafix.Patch
import scalafix.v1.SyntacticDocument
import scalafix.v1.SyntacticRule
import scala.meta.Position
import scala.meta.Term
import scalafix.lint.Diagnostic
import scalafix.lint.LintSeverity

class SumFoldMap extends SyntacticRule("SumFoldMap") {
  override def fix(implicit doc: SyntacticDocument): Patch = {
    doc.tree.collect {
      case t @ Term.Select(
            Term.Apply(
              Term.Select(
                _,
                Term.Name("map")
              ),
              func :: Nil // TODO 色々なパターン正確に検知するのが面倒なので雑
            ),
            Term.Name("sum")
          ) =>
        Patch.lint(SumFoldMapWran(t.pos))
    }.asPatch
  }
}

case class SumFoldMapWran(override val position: Position) extends Diagnostic {
  override def message: String = "gakuzzzzさんに見つかる前に、mapしてsumはfoldMapに書き換えましょう"

  override def severity = LintSeverity.Warning
}