假设我有以下java类：
package com.test;
public class Outer {
public static class Inner { public static final String VAL = "Inner"; }
}
正如您所期望的那样，我可以从 scala 代码中引用VAL常量，但是当我尝试使用 scala 工具箱编译器编译引用该字段的代码时，它会失败。（堆栈跟踪遵循下面的示例）。
这段代码说明了我的意思：
import scala.reflect.runtime.universe
import scala.tools.reflect.ToolBox
object Issue extends App {
val mirror = universe.runtimeMirror(getClass.getClassLoader)
val toolbox = ToolBox(mirror).mkToolBox()
println (com.test.Outer.Inner.VAL) // prints 'Inner'
val tree = toolbox.parse("com.test.Outer.Inner.VAL")
val compiled = toolbox.compile(tree)() // fails to compile
}
这是我得到的异常跟踪：
Exception in thread "main" scala.tools.reflect.ToolBoxError: reflective compilation has failed:
value Inner is not a member of object com.test.Outer
at scala.tools.reflect.ToolBoxFactory$ToolBoxImpl$ToolBoxGlobal.throwIfErrors(ToolBoxFactory.scala:319)
at scala.tools.reflect.ToolBoxFactory$ToolBoxImpl$ToolBoxGlobal.compile(ToolBoxFactory.scala:252)
at scala.tools.reflect.ToolBoxFactory$ToolBoxImpl.compile(ToolBoxFactory.scala:416)
at Issue$delayedInit$body.apply(Issue.scala:8)
at scala.Function0$class.apply$mcV$sp(Function0.scala:40)
at scala.runtime.AbstractFunction0.apply$mcV$sp(AbstractFunction0.scala:12)
at scala.App$$anonfun$main$1.apply(App.scala:71)
at scala.App$$anonfun$main$1.apply(App.scala:71)
at scala.collection.immutable.List.foreach(List.scala:318)
at scala.collection.generic.TraversableForwarder$class.foreach(TraversableForwarder.scala:32)
at scala.App$class.main(App.scala:71)
at Issue$.main(Issue.scala:3)
at Issue.main(Issue.scala)
有没有人遇到过这个？有什么我可以改变的（即编译器选项）来使它工作吗？
谢谢。
编辑
这是我用“-verbose -Yissue-debug”编译时得到的：
[reflect-compiler] made Scala package scala
[reflect-compiler] unpickling Scala package package and package scala, owner = package scala
[reflect-compiler] made Scala package java
[reflect-compiler] made Scala package lang
[reflect-compiler] made Scala package runtime
[reflect-compiler] made Scala package annotation
[reflect-compiler] unpickling Scala package package and package runtime, owner = package runtime
[reflect-compiler] made Scala package collection
[reflect-compiler] unpickling Scala package package and package collection, owner = package collection
[reflect-compiler] translating reflection info for Java class java.lang.Object
[reflect-compiler] unpickling Scala class Unit and object Unit, owner = package scala
[reflect-compiler] translating reflection info for Java class java.lang.Throwable
[reflect-compiler] unpickling Scala class Long and object Long, owner = package scala
[reflect-compiler] translating reflection info for Java class java.lang.InterruptedException
[reflect-compiler] unpickling Scala class Int and object Int, owner = package scala
[reflect-compiler] unpickling Scala class Boolean and object Boolean, owner = package scala
[reflect-compiler] translating reflection info for Java class java.lang.String
[reflect-compiler] translating reflection info for Java class java.lang.CloneNotSupportedException
[reflect-compiler] made Scala package io
[reflect-compiler] translating reflection info for Java interface java.io.Serializable
[reflect-compiler] translating reflection info for Java interface java.lang.CharSequence
[reflect-compiler] unpickling Scala class Char and object Char, owner = package scala
[reflect-compiler] translating reflection info for Java class java.io.ObjectStreamField
[reflect-compiler] made Scala package util
[reflect-compiler] unpickling Scala class Float and object Float, owner = package scala
[reflect-compiler] unpickling Scala class Double and object Double, owner = package scala
[reflect-compiler] unpickling Scala class Byte and object Byte, owner = package scala
[reflect-compiler] translating reflection info for Java class java.lang.StringBuffer
[reflect-compiler] translating reflection info for Java class java.util.Locale
[reflect-compiler] translating reflection info for Java class java.io.UnsupportedEncodingException
[reflect-compiler] made Scala package nio
[reflect-compiler] made Scala package charset
[reflect-compiler] translating reflection info for Java class java.nio.charset.Charset
[reflect-compiler] translating reflection info for Java class java.lang.StringBuilder
[reflect-compiler] translating reflection info for Java interface java.lang.Comparable
[reflect-compiler] made Scala package beans
parsing com.test.Outer.Inner.VAL
importing com.test.Outer.Inner.VAL
compiling com.test.Outer.Inner.VAL
[reflect-compiler] unpickling Scala class Predef and object Predef, owner = package scala
[reflect-compiler] unpickling Scala class ClassfileAnnotation and object ClassfileAnnotation, owner = package annotation
[reflect-compiler] unpickling Scala class Annotation and object Annotation, owner = package annotation
[reflect-compiler] unpickling Scala class StaticAnnotation and object StaticAnnotation, owner = package annotation
[reflect-compiler] made Scala package reflect
[reflect-compiler] unpickling Scala package package and package reflect, owner = package reflect
[reflect-compiler] made Scala package api
[reflect-compiler] unpickling Scala package package and package api, owner = package api
[reflect-compiler] unpickling Scala class Universe and object Universe, owner = package api
[reflect-compiler] unpickling Scala class Symbols and object Symbols, owner = package api
[reflect-compiler] unpickling Scala class Types and object Types, owner = package api
[reflect-compiler] unpickling Scala class FlagSets and object FlagSets, owner = package api
[reflect-compiler] unpickling Scala class Scopes and object Scopes, owner = package api
[reflect-compiler] unpickling Scala class Names and object Names, owner = package api
[reflect-compiler] unpickling Scala class Trees and object Trees, owner = package api
[reflect-compiler] unpickling Scala class Constants and object Constants, owner = package api
[reflect-compiler] unpickling Scala class Annotations and object Annotations, owner = package api
[reflect-compiler] unpickling Scala class Positions and object Positions, owner = package api
[reflect-compiler] unpickling Scala class Exprs and object Exprs, owner = package api
[reflect-compiler] unpickling Scala class TypeTags and object TypeTags, owner = package api
[reflect-compiler] unpickling Scala class TagInterop and object TagInterop, owner = package api
[reflect-compiler] unpickling Scala class StandardDefinitions and object StandardDefinitions, owner = package api
[reflect-compiler] unpickling Scala class StandardNames and object StandardNames, owner = package api
[reflect-compiler] unpickling Scala class BuildUtils and object BuildUtils, owner = package api
[reflect-compiler] unpickling Scala class Mirrors and object Mirrors, owner = package api
[reflect-compiler] unpickling Scala class Printers and object Printers, owner = package api
[reflect-compiler] unpickling Scala class Importers and object Importers, owner = package api
[reflect-compiler] made Scala package runtime
[reflect-compiler] unpickling Scala package package and package runtime, owner = package runtime
[reflect-compiler] unpickling Scala class StringContext and object StringContext, owner = package scala
[reflect-compiler] unpickling Scala class Product and object Product, owner = package scala
[reflect-compiler] unpickling Scala class Equals and object Equals, owner = package scala
[reflect-compiler] unpickling Scala class Serializable and object Serializable, owner = package scala
[reflect-compiler] made Scala package immutable
[reflect-compiler] unpickling Scala package package and package immutable, owner = package immutable
[reflect-compiler] unpickling Scala class Array and object Array, owner = package scala
[reflect-compiler] translating reflection info for Java interface java.lang.Cloneable
[reflect-compiler] unpickling Scala class AnyVal and object AnyVal, owner = package scala
[reflect-compiler] unpickling Scala class NotNull and object NotNull, owner = package scala
[reflect-compiler] unpickling Scala class LowPriorityImplicits and object LowPriorityImplicits, owner = package scala
[reflect-compiler] made Scala package com
[reflect-compiler] unpickling Scala class Dynamic and object Dynamic, owner = package scala
[reflect-compiler] made Scala package test
[reflect-compiler] translating reflection info for Java class com.test.Outer
[reflect-compiler] *** missing: Inner/true/object Outer/false/class scala.reflect.runtime.SynchronizedOps$$anon$1
java.lang.Exception
at scala.tools.nsc.typechecker.Contexts$Context.issue(Contexts.scala:399)
at scala.tools.nsc.typechecker.ContextErrors$ErrorUtils$.issueTypeError(ContextErrors.scala:84)
at scala.tools.nsc.typechecker.ContextErrors$ErrorUtils$.issueNormalTypeError(ContextErrors.scala:69)
at scala.tools.nsc.typechecker.ContextErrors$TyperContextErrors$TyperErrorGen$.NotAMemberError(ContextErrors.scala:331)
at scala.tools.nsc.typechecker.Typers$Typer.handleMissing$1(Typers.scala:4846)
at scala.tools.nsc.typechecker.Typers$Typer.scala$tools$nsc$typechecker$Typers$Typer$$typedSelect$1(Typers.scala:4851)
at scala.tools.nsc.typechecker.Typers$Typer.typedSelectOrSuperCall$1(Typers.scala:4938)
at scala.tools.nsc.typechecker.Typers$Typer.typed1(Typers.scala:5551)
at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:5630)
at scala.tools.nsc.typechecker.Typers$Typer.typedQualifier(Typers.scala:5710)
at scala.tools.nsc.typechecker.Typers$Typer.typedQualifier(Typers.scala:5716)
at scala.tools.nsc.typechecker.Typers$Typer.typedSelectOrSuperCall$1(Typers.scala:4918)
at scala.tools.nsc.typechecker.Typers$Typer.typed1(Typers.scala:5551)
at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:5630)
at scala.tools.nsc.typechecker.Typers$Typer.transformedOrTyped(Typers.scala:5825)
at scala.tools.nsc.typechecker.Typers$Typer.typedDefDef(Typers.scala:2250)
at scala.tools.nsc.typechecker.Typers$Typer.typed1(Typers.scala:5557)
at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:5630)
at scala.tools.nsc.typechecker.Typers$Typer.scala$tools$nsc$typechecker$Typers$Typer$$typedStat$1(Typers.scala:2921)
at scala.tools.nsc.typechecker.Typers$Typer$$anonfun$62.apply(Typers.scala:3025)
at scala.tools.nsc.typechecker.Typers$Typer$$anonfun$62.apply(Typers.scala:3025)
at scala.collection.immutable.List.loop$1(List.scala:170)
at scala.collection.immutable.List.mapConserve(List.scala:186)
at scala.tools.nsc.typechecker.Typers$Typer.typedStats(Typers.scala:3025)
at scala.tools.nsc.typechecker.Typers$Typer.typedTemplate(Typers.scala:1914)
at scala.tools.nsc.typechecker.Typers$Typer.typedModuleDef(Typers.scala:1794)
at scala.tools.nsc.typechecker.Typers$Typer.typed1(Typers.scala:5572)
at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:5630)
at scala.tools.nsc.typechecker.Typers$Typer.scala$tools$nsc$typechecker$Typers$Typer$$typedStat$1(Typers.scala:2921)
at scala.tools.nsc.typechecker.Typers$Typer$$anonfun$62.apply(Typers.scala:3025)
at scala.tools.nsc.typechecker.Typers$Typer$$anonfun$62.apply(Typers.scala:3025)
at scala.collection.immutable.List.loop$1(List.scala:170)
at scala.collection.immutable.List.mapConserve(List.scala:186)
at scala.tools.nsc.typechecker.Typers$Typer.typedStats(Typers.scala:3025)
at scala.tools.nsc.typechecker.Typers$Typer.typedPackageDef$1(Typers.scala:5288)
at scala.tools.nsc.typechecker.Typers$Typer.typed1(Typers.scala:5575)
at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:5630)
at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:5687)
at scala.tools.nsc.typechecker.Analyzer$typerFactory$$anon$3.apply(Analyzer.scala:99)
at scala.tools.nsc.Global$GlobalPhase.applyPhase(Global.scala:463)
at scala.tools.nsc.typechecker.Analyzer$typerFactory$$anon$3$$anonfun$run$1.apply(Analyzer.scala:91)
at scala.tools.nsc.typechecker.Analyzer$typerFactory$$anon$3$$anonfun$run$1.apply(Analyzer.scala:91)
at scala.collection.Iterator$class.foreach(Iterator.scala:727)
at scala.collection.AbstractIterator.foreach(Iterator.scala:1157)
at scala.tools.nsc.typechecker.Analyzer$typerFactory$$anon$3.run(Analyzer.scala:91)
at scala.tools.nsc.Global$Run.compileUnitsInternal(Global.scala:1582)
at scala.tools.nsc.Global$Run.compileUnits(Global.scala:1556)
at scala.tools.reflect.ToolBoxFactory$ToolBoxImpl$ToolBoxGlobal.compile(ToolBoxFactory.scala:251)
at scala.tools.reflect.ToolBoxFactory$ToolBoxImpl.compile(ToolBoxFactory.scala:416)
at Issue$delayedInit$body.apply(Issue.scala:8)
at scala.Function0$class.apply$mcV$sp(Function0.scala:40)
at scala.runtime.AbstractFunction0.apply$mcV$sp(AbstractFunction0.scala:12)
at scala.App$$anonfun$main$1.apply(App.scala:71)
at scala.App$$anonfun$main$1.apply(App.scala:71)
at scala.collection.immutable.List.foreach(List.scala:318)
at scala.collection.generic.TraversableForwarder$class.foreach(TraversableForwarder.scala:32)
at scala.App$class.main(App.scala:71)
at Issue$.main(Issue.scala:3)
at Issue.main(Issue.scala)
Exception in thread "main" scala.tools.reflect.ToolBoxError: reflective compilation has failed:
[namer in 31ms]
[packageobjects in 0ms]
value Inner is not a member of object com.test.Outer
[typer in 211ms]
[total in 247ms]
[reset] recursing in package <root>
at scala.tools.reflect.ToolBoxFactory$ToolBoxImpl$ToolBoxGlobal.throwIfErrors(ToolBoxFactory.scala:319)
at scala.tools.reflect.ToolBoxFactory$ToolBoxImpl$ToolBoxGlobal.compile(ToolBoxFactory.scala:252)
at scala.tools.reflect.ToolBoxFactory$ToolBoxImpl.compile(ToolBoxFactory.scala:416)
at Issue$delayedInit$body.apply(Issue.scala:8)
at scala.Function0$class.apply$mcV$sp(Function0.scala:40)
at scala.runtime.AbstractFunction0.apply$mcV$sp(AbstractFunction0.scala:12)
at scala.App$$anonfun$main$1.apply(App.scala:71)
at scala.App$$anonfun$main$1.apply(App.scala:71)
at scala.collection.immutable.List.foreach(List.scala:318)
at scala.collection.generic.TraversableForwarder$class.foreach(TraversableForwarder.scala:32)
at scala.App$class.main(App.scala:71)
at Issue$.main(Issue.scala:3)
at Issue.main(Issue.scala)
编辑 2
我认为这是反射 API 中的一个错误，但我不确定。我已经调试了打字阶段并提出了以下建议：
在com.test.Outer分配了适当的符号后，我们进入了 的打字阶段com.test.Outer.Inner。
它在那里查找Inner使用的符号scala.reflect.internal.Scopes.Scope#lookupEntry(Name)。
检查所查看的范围表明它确实包含 a ScopeEntryfor a ClassSymbolofInner但范围符号名称和方法name参数之间的相等性测试是使用完成的Object#equals（即equals没有被覆盖），并且两个名称实例不相同。
关于符号名称和传递的名称参数的最后一点是我看到它们具有相同的index字段。我不确定这意味着什么，但我的印象是这意味着它们在名称表中引用相同的名称，所以它们是相等的（？）（虽然两者之间有一个区别，一个是TermName和符号的名称是一个TypeName)。
无论如何，我可能会打开一个错误 Scala 的错误跟踪器，只是想在这里总结一下。