一般情况下,我们会倾向于打开各种warning,以便规范我们的代码.不过,scala有时候有些warning也是蛮扯的.比如这么一段

$ scala -Xlint:missing-interpolator
Welcome to Scala version 2.11.7 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_05).
Type in expressions to have them evaluated.
Type :help for more information.

scala> val key="value"; println("$key")
<console>:12: warning: possible missing interpolator: detected interpolated identifier `$key`
        println("$key")
                ^
$key
key: String = value

因为key是变量,它提示我们检测到了interpolated identifier,也就是那个"$". 因为有代码是这样写的:

scala> val key="value"; println(s"$key")
value
key: String = value

编译器提示我们可能我们是想写成如上那样. 若我们的确希望这么写,那按照提示修改即可.但是有时候我们想要显示的就是"$key",那应该怎么办呢?

个人的话,会这样写:

scala> val key="value"; println(s"$$key")
$key
key: String = value

scala有人开了个类似的issue,不过没人回答.不知道是否会有别人有更好的solution,可以点击这个地址围观.


上面这个在 IntelliJ IDEA 下会被坑,后来我老老实实在 scalacOptions 里面加上一个开关关掉了这个(当然也会关掉一些关于这个的有用的提示...)

object CompileSettings extends AutoPlugin {
  override def trigger = allRequirements

  override def projectSettings = Seq(
    scalacOptions ++= Seq(
      "-optimise",
      "-deprecation", // Emit warning and location for usages of deprecated APIs.
      "-feature", // Emit warning and location for usages of features that should be imported explicitly.
      "-unchecked", // Enable additional warnings where generated code depends on assumptions.
      "-Xfatal-warnings", // Fail the compilation if there are any warnings.
      "-Xlint", // Enable recommended additional warnings.
      "-Ywarn-adapted-args", // Warn if an argument list is modified to match the receiver.
      "-Ywarn-dead-code", // Warn when dead code is identified.
      "-Ywarn-inaccessible", // Warn about inaccessible types in method signatures.
      "-Ywarn-nullary-override", // Warn when non-nullary overrides nullary, e.g. def foo() over def foo.
      "-Ywarn-numeric-widen", // Warn when numerics are widened.
      "-Yinline-warnings", //
      "-language:postfixOps", // See the Scala docs for value scala.language.postfixOps for a discussion
      "-Xlint:-warn-missing-interpolator" // ignore error(warning): possible missing interpolator: detected interpolated identifier
    //,"-target:jvm-1.8" // force use jvm 1.8
    ),
    //javacOptions in compile ++= Seq("-target", "1.8", "-source", "1.8"), // force use jvm 1.8
    compileOrder in Compile := CompileOrder.Mixed,
    compileOrder in Test := CompileOrder.Mixed,
    testOptions in Test += Tests.Argument(TestFrameworks.Specs2, "junitxml", "console"),
    scalacOptions in Test ~= { (options: Seq[String]) =>
      options filterNot (_ == "-Ywarn-dead-code") // Allow dead code in tests (to support using mockito).
    },
    parallelExecution in Test := false,
    unmanagedBase := baseDirectory.value / "project/lib")

}

补充: 前面 "-Xlint:-warn-missing-interpolator" 这个好像版本相关?

来自的你,很高兴你能看到这儿。若本文对你有所用处,或者内容有什么不足之处,敬请毫不犹豫给个回复。谢谢!