1

我发现 scala 编译器报告编译错误的方式不同取决于它是在编译时使用还是在运行时使用。

例如，对于一个简单的隐式未找到案例，在编译时报告是：

newSource1.scala:6: error: type mismatch;
  L|R
  f(new L)
    ^

在运行时，当评估相同的代码并直接捕获错误消息时：


  class TestCase(code: String, extra: String) {


  def toolbox(extra: String): ToolBox[universe.type] = {
    ToolBox(cm).mkToolBox(options = s"$opts $extra")
  }

    def compile(): Any = {
      import SpecHelpers._

      val tb = toolbox(extra)
      tb.eval(tb.parse(code))
    }

    def compileError(): String =
      Try(compile()) match {
        case Failure(ee) =>
          ee match {
            case te: ToolBoxError =>
              te.message.linesIterator.toList.drop(2).mkString("\n")
            case t =>
              throw t
          }
        case Success(_) =>
          sys.error("compiling succeeded")
      }
  }

行号和位置光标被省略：；

implicit error;
!I e: F[Arg]

有没有办法把缺失的部分补回来？

4

1 回答 1

4

您可以指定frontEnd（ToolBox默认frontEnd为mkSilentFrontEnd()）

val tb = cm.mkToolBox(
  frontEnd = new FrontEnd {
    override def display(info: Info): Unit = println(info)
  },
  options = "-Xlog-implicits -Vimplicits -Vimplicits-verbose-tree -d out" 
  // with `-d out` toolbox keeps `.class` files in directory `out` 
  // rather than in memory, so you can decompile `.class` files 
  // if you want to investigate auto-generated code
)

tb.compile(tb.parse(
  """implicit val i: Int = 1
    |implicitly[String]""".stripMargin))

//Info(source-<toolbox>,line-2,offset=34,implicit error;
//!I e: String,ERROR)
//Exception in thread "main" java.lang.ExceptionInInitializerError
//  at App.main(App.scala)
//Caused by: scala.tools.reflect.ToolBoxError: reflective compilation has failed:
//
//implicit error;
//!I e: String
//  at scala.tools.reflect.ToolBoxFactory$ToolBoxImpl$ToolBoxGlobal.throwIfErrors(ToolBoxFactory.scala:332)
//  at scala.tools.reflect.ToolBoxFactory$ToolBoxImpl$ToolBoxGlobal.wrapInPackageAndCompile(ToolBoxFactory.scala:214)
//  at scala.tools.reflect.ToolBoxFactory$ToolBoxImpl$ToolBoxGlobal.compile(ToolBoxFactory.scala:268)
//  at scala.tools.reflect.ToolBoxFactory$ToolBoxImpl.$anonfun$compile$13(ToolBoxFactory.scala:445)
//  at scala.tools.reflect.ToolBoxFactory$ToolBoxImpl$withCompilerApi$.apply(ToolBoxFactory.scala:371)
//  at scala.tools.reflect.ToolBoxFactory$ToolBoxImpl.compile(ToolBoxFactory.scala:438)
//  at App$.<clinit>(App.scala:20)
//  ... 1 more
于 2021-10-03T21:59:02.563 回答