Scalafix:解析对象应用方法

Question

我有一个定义了apply方法的对象，然后使用它

object Ob {
  def apply(i: Int) = ()
  def apply(s: String) = ()
}

object Use {
  def someMethod(i: Int) = ()

  Ob(1)
  someMethod(1)
}

当使用scalafix/scalameta时，我找不到一种方法来获得实际apply方法的句柄(在我的例子中，我试图检查参数名称和类型是否符合scalafix规则)

当我匹配并打印解析的SymbolInformation时，我得到了对该对象的引用。所以这就是

import scalafix.v1._
import scala.meta._

class NamedLiteralArguments extends SemanticRule("NamedLiteralArguments") {
  val minParam = 2

  override def fix(implicit doc: SemanticDocument): Patch = {
    doc.tree
      .collect {
        case Term.Apply(fun, args) =>
          println(fun.symbol.info)

          Patch.empty
      }
  }

打印

Some(test/Ob. => final object Ob extends AnyRef { +2 decls })
Some(test/Use.someMethod(). => method someMethod(i: Int): Unit)

但是我想让它解析确切的apply方法。

(Scalafix版本0.9.20)

Answer 1

在build.sbt中打开"-P:semanticdb:synthetics:on"

scalacOptions ++= List(
  "-Yrangepos",
  "-P:semanticdb:synthetics:on",
)

然后

import scalafix.v1._
import scala.meta._

class MyRule extends SemanticRule("MyRule") {
  override def fix(implicit doc: SemanticDocument): Patch = {
    doc.tree
      .collect {
        case t: Term =>
          println(s"t=$t=${t.structure}, t.symbol.info=${t.symbol.info}, t.synthetics=${t.synthetics.map(_.symbol.map(_.info))}")

          Patch.empty
      }.asPatch
  }
}

打印

t=Ob=Term.Name("Ob"), t.symbol.info=Some(_empty_/Ob. => final object Ob extends AnyRef { +2 decls }), t.synthetics=List()
t=apply=Term.Name("apply"), t.symbol.info=Some(_empty_/Ob.apply(). => method apply(i: Int): Unit), t.synthetics=List()
t=i=Term.Name("i"), t.symbol.info=Some(_empty_/Ob.apply().(i) => param i: Int), t.synthetics=List()
t=()=Lit.Unit, t.symbol.info=None, t.synthetics=List()
t=apply=Term.Name("apply"), t.symbol.info=Some(_empty_/Ob.apply(+1). => method apply(s: String): Unit), t.synthetics=List()
t=s=Term.Name("s"), t.symbol.info=Some(_empty_/Ob.apply(+1).(s) => param s: String), t.synthetics=List()
t=()=Lit.Unit, t.symbol.info=None, t.synthetics=List()
t=Use=Term.Name("Use"), t.symbol.info=Some(_empty_/Use. => final object Use extends AnyRef { +1 decls }), t.synthetics=List()
t=someMethod=Term.Name("someMethod"), t.symbol.info=Some(_empty_/Use.someMethod(). => method someMethod(i: Int): Unit), t.synthetics=List()
t=i=Term.Name("i"), t.symbol.info=Some(_empty_/Use.someMethod().(i) => param i: Int), t.synthetics=List()
t=()=Lit.Unit, t.symbol.info=None, t.synthetics=List()
t=Ob(1)=Term.Apply(Term.Name("Ob"), List(Lit.Int(1))), t.symbol.info=Some(_empty_/Ob. => final object Ob extends AnyRef { +2 decls }), t.synthetics=List()
t=Ob=Term.Name("Ob"), t.symbol.info=Some(_empty_/Ob. => final object Ob extends AnyRef { +2 decls }), t.synthetics=List(Some(Some(_empty_/Ob.apply(). => method apply(i: Int): Unit)))
t=1=Lit.Int(1), t.symbol.info=None, t.synthetics=List()
t=someMethod(1)=Term.Apply(Term.Name("someMethod"), List(Lit.Int(1))), t.symbol.info=Some(_empty_/Use.someMethod(). => method someMethod(i: Int): Unit), t.synthetics=List()
t=someMethod=Term.Name("someMethod"), t.symbol.info=Some(_empty_/Use.someMethod(). => method someMethod(i: Int): Unit), t.synthetics=List()
t=1=Lit.Int(1), t.symbol.info=None, t.synthetics=List()

请注意这一行

t=Ob=Term.Name("Ob"), ..., t.synthetics=List(Some(Some(_empty_/Ob.apply(). => method apply(i: Int): Unit)))

请参见：

https://scalameta.org/docs/semanticdb/specification.html#synthetic

https://scalameta.org/docs/semanticdb/specification.html#synthetic-1

https://scalacenter.github.io/scalafix/docs/developers/semantic-tree.html#look-up-inferred-type-parameter

所以

class MyRule extends SemanticRule("MyRule") {
  override def fix(implicit doc: SemanticDocument): Patch = {
    doc.tree
      .collect {
        case Term.Apply(fun, args) =>
          println(fun.symbol.info + ", " + fun.synthetics.map(_.symbol.map(_.info)))
          Patch.empty
      }.asPatch
  }
}

将打印

Some(_empty_/Ob. => final object Ob extends AnyRef { +2 decls }), List(Some(Some(_empty_/Ob.apply(). => method apply(i: Int): Unit)))
Some(_empty_/Use.someMethod(). => method someMethod(i: Int): Unit), List()