我有以下代码(使用 RxKotlin 0.40.1 ):
class Result<T, E>(val data: T? = null, val error: E? = null)
fun <T, E> wrapResult(errorInfoFactory: (Throwable) -> E): (Observable<T>) -> Observable<Result<T, E>> = { it.map { Result<T, E>(it) }.onErrorReturn { Result<T, E>(error = errorInfoFactory(it)) } }
仅供参考,需要轻松转换 Observable
,这可能会将错误抛给 Observable
,它始终返回 Result
对象,因此 onError
永远不会被触发 .
我想像这样使用它:
fun dangerousOperation() = 0
fun getErrorMessage(t: Throwable) = "error occurred"
fun test() {
val resultObservable = Observable.fromCallable(::dangerousOperation).compose(wrapResult(::getErrorMessage))
}
Android Studio 1.5.1 与 Kotlin plugin 1.0.0-release-IJ141-56 并未突出显示此代码中的任何错误 . 但是当我尝试构建它时,我得到错误:
//错误:(24,9)org.jetbrains.kotlin.codegen.CompilationException:后端(JVM)内部错误:遇到错误类型:org.jetbrains.kotlin.types.ErrorUtils$UninferredParameterTypeConstructor@68754e6(ErrorTypeImpl) . //原因:遇到错误类型:org.jetbrains.kotlin.types.ErrorUtils$UninferredParameterTypeConstructor@68754e6(ErrorTypeImpl) . //正在编译的文件和位置:(24,9)在/home/d/work/workspace/Hitch-hiking-Stats/app/src/main/java/ru/netimen/hitch_hikingstats/MemoryRepo.kt // PsiElement: val resultObservable = Observable.just(dangerousOperation()) . compose(wrapResult(:: getErrorMessage))//引发根本原因:JetTypeMapper.java:435 // at org.jetbrains.kotlin.codegen.ExpressionCodegen.genQualified( ExpressionCodegen.java:299)// at org.jetbrains.kotlin.codegen.ExpressionCodegen.genStatement(ExpressionCodegen.java:339)// at org.jetbrains.kotlin.codegen.ExpressionCodegen.generateBlock(ExpressionCodegen.java:1532)// at org.jetbrains.kotlin.codegen.ExpressionCodegen.generateBlock(ExpressionCodegen.java:1485)// at org.jetbrains.kotlin.codegen.CodegenStatementVisitor.visitBlockExpression(CodegenStatementVisitor.java:56)// at org.jetbrains.kotlin.codegen .CodegenStatementVisitor.visitBlockExpression(CodegenStatementVisitor.java:22)// at org.jetbrains.kotlin.psi.KtBlockExpression.accept(KtBlockExpression.ja va:44)// at org.jetbrains.kotlin.codegen.ExpressionCodegen.genQualified(ExpressionCodegen.java:280)// at org.jetbrains.kotlin.codegen.ExpressionCodegen.genStatement(ExpressionCodegen.java:339)// at org .jetbrains.kotlin.codegen.ExpressionCodegen.gen(ExpressionCodegen.java:309)// at org.jetbrains.kotlin.codegen.ExpressionCodegen.returnExpression(ExpressionCodegen.java:1873)// at org.jetbrains.kotlin.codegen.FunctionGenerationStrategy $ FunctionDefault.doGenerateBody(FunctionGenerationStrategy.java:50)// at org.jetbrains.kotlin.codegen.FunctionGenerationStrategy $ CodegenBased.generateBody(FunctionGenerationStrategy.java:72)// at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethodBody(FunctionCodegen) .java:364)// at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethod(FunctionCodegen.java:203)// at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethod(FunctionCodegen.java:138)
但是当我将 test
函数更改为
fun test() {
val resultObservable = Observable.fromCallable(::dangerousOperation).compose(wrapResult<Int, String>(::getErrorMessage))
}
一切都编好了 . 但是,如果IDE没有突出显示任何错误,当我没有明确指定 wrapResult
的泛型参数时,为什么会出现该异常?
1 回答
这是编译器错误:https://youtrack.jetbrains.com/issue/KT-11144 . 出现此错误的主要原因是:函数
wrapResult
仅在自己的返回类型中使用泛型参数T
.