scala 开发人员如何处理带有 shapeless 的 scala 代码中不正确的 IDE(Idea) 错误 [英] How do scala developers cope with incorrect IDE(Idea) errors in scala code with shapeless

问题描述

这是一个带有具体示例的一般问题.

人们如何进入 scala 并将其用于大型项目，以解决工具/IDE 的不可靠性问题?您是否只接受整个源代码中的红色标记?

我遇到了另一个 Scala 代码库，其中工作代码被idea 标记为红色无法解析符号代表.

我开始了一个游乐场项目来探索代码库中的一个库 - shapeless(据我所知，它是 Scala 社区中备受推崇的库).

我从官方无形指南的第一页写了非常基本的代码.

包示例进口无形._对象你好扩展应用{val genericEmployee = Generic[Employee].to(Employee("Dave", isOld = true))val genericIceCream = Generic[IceCream].to(IceCream("yellow", isInCone = false))def genericCsv (gen: String :: Boolean :: HNil) :List[String] = List(gen(0), gen(1).toString())println(genericCsv(genericIceCream).toString())}案例类员工(名称:字符串，isOld:布尔值)case class IceCream (name: String, isInCone: Boolean)

gen(0) 和 gen(1) 被标记为 在 hlist.At[String :: Boolean :: HNil 处没有找到参数的隐式，Nat#N]

代码有效.

我还记得由 Akka HTTP 引起的错误但不是真正的错误.

解决方案

IntelliJ 支持依赖于 shapeless 等宏的库似乎存在根本性的困难

<块引用>

如何处理错误的错误?

所以，事实是你必须记住，有时没有勺子错误.为了帮助我们修复突出显示的故障，您可以将其报告给YouTrack 照常或在错误的高亮处按 Alt+Enter:

This is a general question with a specific example.

How do people getting into scala and using it for big projects handle unreliability of tools/IDE? Do you just accept red markings all over your source code?

I encounter yet another scala codebase where working code is flagged red by idea Cannot resolve symbol Repr.

I start a playground project to explore one of libraries in the codebase - shapeless (as I understand it a highly regarded library in scala community).

I write extremely basic code from the first page of official shapeless guide.

package example
import shapeless._

object Hello extends App {
  val genericEmployee = Generic[Employee].to(Employee("Dave", isOld = true))
  val genericIceCream = Generic[IceCream].to(IceCream("yellow", isInCone = false))

  def genericCsv (gen: String :: Boolean :: HNil) :List[String] = List(gen(0), gen(1).toString())

  println(genericCsv(genericIceCream).toString())
}

case class Employee (name: String, isOld: Boolean)

case class IceCream (name: String, isInCone: Boolean)

gen(0) and gen(1) are flagged with No implicits found for parameter at hlist.At[String :: Boolean :: HNil, Nat#N]

The code works.

I also remember errors-but-not-real-errors being caused by Akka HTTP.

解决方案

There seems to be a fundamental difficulty in IntelliJ supporting libraries relying on macros such as shapeless

@niktrop

Shapeless is heavily using macros. We have no way to support them generically.

@joroKr21

there is a fundamental barrier for whitebox macros. You have to run a complete typecheck and expand them just to see what type they return and this is not feasible to do on every keystroke. Blackbox macros on the other hand shouldn't pose such problems.

@olafurpg

scala-compiler and intellij-scala are different typecheckers, scala-reflect macros are currently implemented against scala-compiler APIs which makes them difficult to support in alternative scala compilers.

---

You could try reporting highlighting errors as a bug at

https://youtrack.jetbrains.com/issues/SCL

Here is an example you could use as a template

https://youtrack.jetbrains.com/issue/SCL-16091

Select the affected subsystem as Error Highlighting

This feature is called Type-aware highlighting and can be disabled by clicking on the little T icon in bottom right corner

How to deal with false errors?

So, the truth is you have to remember that sometimes there’s no spoon error. To help us to fix a highlighting glitch you may report it to YouTrack as usual or by pressing Alt+Enter on wrong highlight:

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