在 kotlin 中使用 'let' 时，我的变量名和 'it' 有什么区别？
What is the difference between my variable name and 'it' when using 'let' in kotlin?
在下面的代码片段中，两个Codeblocks有什么区别？
如果我检查 println(name==it)，那 returns 是真的，那么他们一定引用了同一个对象，对吧？
然而，当 name 变量有一个值时，一切正常，但是一旦我将它设置为 null，Codeblock 1 就可以工作（意思是，let 块根本不会被执行），但 Codeblock 2 会抛出错误。当 name 为空时，为什么 kotlin 不只是 skip/ignore 代码块 2？
fun main() {
var name:String? = "Cedric"
//name = null
//Codeblock 1
name?.let{
println("The length of name is ${name.length}")
}
//Codeblock 1
name?.let{
println("The length of name is ${it.length}")
}
}
非常感谢，如有任何帮助，我们将不胜感激。
代码块 2 实际上给出了 compile-time 错误，而代码块 1 则没有。我认为这只是一个奇怪的 linting 错误，因为这两种情况应该被同等对待。
据我了解，您发现了编译器中的错误。我在 Android studio 和 IntelliJ 中有两种不同的行为。
如果编译时，编译后的代码被优化，反编译时看起来像这样：
public final void main() {
Object name = "Cedric";
name = (String)null;
}
万一它没有编译我得到一个错误：
org.jetbrains.kotlin.codegen.CompilationException: Back-end (JVM) Internal error: Failed to generate expression: KtNameReferenceExpression
File being compiled: (12,45) in D:/Projekti/kotlin playground/src/Main.kt
The root cause java.lang.AssertionError was thrown at: org.jetbrains.kotlin.codegen.ExpressionCodegen.visitSimpleNameExpression(ExpressionCodegen.java:1797)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.genQualified(ExpressionCodegen.java:326)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.genQualified(ExpressionCodegen.java:286)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.visitDotQualifiedExpression(ExpressionCodegen.java:3258)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.visitDotQualifiedExpression(ExpressionCodegen.java:112)
at org.jetbrains.kotlin.psi.KtDotQualifiedExpression.accept(KtDotQualifiedExpression.kt:32)
at org.jetbrains.kotlin.codegen.CodegenStatementVisitor.visitKtElement(CodegenStatementVisitor.java:31)
at org.jetbrains.kotlin.codegen.CodegenStatementVisitor.visitKtElement(CodegenStatementVisitor.java:22)
at org.jetbrains.kotlin.psi.KtVisitor.visitExpression(KtVisitor.java:182)
at org.jetbrains.kotlin.psi.KtVisitor.visitQualifiedExpression(KtVisitor.java:286)
at org.jetbrains.kotlin.psi.KtVisitor.visitDotQualifiedExpression(KtVisitor.java:302)
at org.jetbrains.kotlin.psi.KtDotQualifiedExpression.accept(KtDotQualifiedExpression.kt:32)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.genQualified(ExpressionCodegen.java:304)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.genStatement(ExpressionCodegen.java:409)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.gen(ExpressionCodegen.java:366)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.invokeAppend(ExpressionCodegen.java:4108)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.invokeAppendForEntries(ExpressionCodegen.java:874)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.lambda$visitStringTemplateExpression(ExpressionCodegen.java:864)
at org.jetbrains.kotlin.codegen.OperationStackValue.putSelector(StackValue.kt:79)
at org.jetbrains.kotlin.codegen.StackValue.put(StackValue.java:122)
at org.jetbrains.kotlin.codegen.StackValue.put(StackValue.java:115)
at org.jetbrains.kotlin.codegen.CallGenerator$DefaultCallGenerator.genValueAndPut(CallGenerator.kt:71)
at org.jetbrains.kotlin.codegen.CallBasedArgumentGenerator.generateExpression(CallBasedArgumentGenerator.kt:42)
at org.jetbrains.kotlin.codegen.ArgumentGenerator.generate(ArgumentGenerator.kt:68)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.invokeMethodWithArguments(ExpressionCodegen.java:2534)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.invokeMethodWithArguments(ExpressionCodegen.java:2506)
at org.jetbrains.kotlin.codegen.Callable$invokeMethodWithArguments.invoke(Callable.kt:41)
at org.jetbrains.kotlin.codegen.Callable$invokeMethodWithArguments.invoke(Callable.kt:13)
at org.jetbrains.kotlin.codegen.OperationStackValue.putSelector(StackValue.kt:79)
at org.jetbrains.kotlin.codegen.StackValueWithLeaveTask.putSelector(StackValue.kt:67)
at org.jetbrains.kotlin.codegen.StackValue.put(StackValue.java:122)
at org.jetbrains.kotlin.codegen.StackValue.put(StackValue.java:115)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.putStackValue(ExpressionCodegen.java:386)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.gen(ExpressionCodegen.java:367)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.returnExpression(ExpressionCodegen.java:1731)
at org.jetbrains.kotlin.codegen.FunctionGenerationStrategy$FunctionDefault.doGenerateBody(FunctionGenerationStrategy.java:64)
at org.jetbrains.kotlin.codegen.ClosureGenerationStrategy.doGenerateBody(ClosureGenerationStrategy.kt:35)
at org.jetbrains.kotlin.codegen.FunctionGenerationStrategy$CodegenBased.generateBody(FunctionGenerationStrategy.java:84)
at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethodBody(FunctionCodegen.java:654)
at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethodBody(FunctionCodegen.java:479)
at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethod(FunctionCodegen.java:261)
at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethod(FunctionCodegen.java:177)
at org.jetbrains.kotlin.codegen.ClosureCodegen.generateClosureBody(ClosureCodegen.java:181)
at org.jetbrains.kotlin.codegen.ClosureCodegen.generateBody(ClosureCodegen.java:169)
at org.jetbrains.kotlin.codegen.MemberCodegen.generate(MemberCodegen.java:129)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.genClosure(ExpressionCodegen.java:1038)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.genClosure(ExpressionCodegen.java:1008)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.visitLambdaExpression(ExpressionCodegen.java:999)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.visitLambdaExpression(ExpressionCodegen.java:112)
at org.jetbrains.kotlin.psi.KtLambdaExpression.accept(KtLambdaExpression.java:40)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.genQualified(ExpressionCodegen.java:304)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.genQualified(ExpressionCodegen.java:286)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.gen(ExpressionCodegen.java:358)
at org.jetbrains.kotlin.codegen.CallGenerator$DefaultCallGenerator.genValueAndPut(CallGenerator.kt:70)
at org.jetbrains.kotlin.codegen.CallBasedArgumentGenerator.generateExpression(CallBasedArgumentGenerator.kt:42)
at org.jetbrains.kotlin.codegen.ArgumentGenerator.generate(ArgumentGenerator.kt:68)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.invokeMethodWithArguments(ExpressionCodegen.java:2534)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.invokeMethodWithArguments(ExpressionCodegen.java:2506)
at org.jetbrains.kotlin.codegen.Callable$invokeMethodWithArguments.invoke(Callable.kt:41)
at org.jetbrains.kotlin.codegen.Callable$invokeMethodWithArguments.invoke(Callable.kt:13)
at org.jetbrains.kotlin.codegen.OperationStackValue.putSelector(StackValue.kt:79)
at org.jetbrains.kotlin.codegen.CoercionValue.putSelector(StackValue.kt:31)
at org.jetbrains.kotlin.codegen.StackValue.put(StackValue.java:122)
at org.jetbrains.kotlin.codegen.StackValue.put(StackValue.java:115)
at org.jetbrains.kotlin.codegen.StackValue$StackValueWithSimpleReceiver.putReceiver(StackValue.java:2089)
at org.jetbrains.kotlin.codegen.StackValueWithLeaveTask.putReceiver(StackValue.kt:63)
at org.jetbrains.kotlin.codegen.StackValue.put(StackValue.java:120)
at org.jetbrains.kotlin.codegen.StackValue.put(StackValue.java:115)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.putStackValue(ExpressionCodegen.java:386)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.gen(ExpressionCodegen.java:367)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.returnExpression(ExpressionCodegen.java:1731)
at org.jetbrains.kotlin.codegen.FunctionGenerationStrategy$FunctionDefault.doGenerateBody(FunctionGenerationStrategy.java:64)
at org.jetbrains.kotlin.codegen.FunctionGenerationStrategy$CodegenBased.generateBody(FunctionGenerationStrategy.java:84)
at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethodBody(FunctionCodegen.java:654)
at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethodBody(FunctionCodegen.java:479)
at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethod(FunctionCodegen.java:261)
at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethod(FunctionCodegen.java:177)
at org.jetbrains.kotlin.codegen.FunctionCodegen.gen(FunctionCodegen.java:148)
at org.jetbrains.kotlin.codegen.MemberCodegen.genSimpleMember(MemberCodegen.java:197)
at org.jetbrains.kotlin.codegen.PackagePartCodegen.generateBody(PackagePartCodegen.java:95)
at org.jetbrains.kotlin.codegen.MemberCodegen.generate(MemberCodegen.java:129)
at org.jetbrains.kotlin.codegen.PackageCodegenImpl.generateFile(PackageCodegenImpl.java:145)
at org.jetbrains.kotlin.codegen.PackageCodegenImpl.generate(PackageCodegenImpl.java:70)
at org.jetbrains.kotlin.codegen.DefaultCodegenFactory.generatePackage(CodegenFactory.kt:88)
at org.jetbrains.kotlin.codegen.DefaultCodegenFactory.generateModule(CodegenFactory.kt:67)
at org.jetbrains.kotlin.codegen.KotlinCodegenFacade.compileCorrectFiles(KotlinCodegenFacade.java:35)
at org.jetbrains.kotlin.idea.internal.KotlinBytecodeToolWindow$Companion.compileSingleFile(KotlinBytecodeToolWindow.kt:335)
at org.jetbrains.kotlin.idea.internal.KotlinBytecodeToolWindow$Companion.getBytecodeForFile(KotlinBytecodeToolWindow.kt:248)
at org.jetbrains.kotlin.idea.internal.KotlinBytecodeToolWindow$UpdateBytecodeToolWindowTask.processRequest(KotlinBytecodeToolWindow.kt:127)
at org.jetbrains.kotlin.idea.internal.KotlinBytecodeToolWindow$UpdateBytecodeToolWindowTask.processRequest(KotlinBytecodeToolWindow.kt:74)
at org.jetbrains.kotlin.idea.util.LongRunningReadTask.run(LongRunningReadTask.java:115)
at com.intellij.openapi.application.impl.ApplicationImpl.runReadAction(ApplicationImpl.java:869)
at org.jetbrains.kotlin.idea.util.LongRunningReadTask.lambda$runWithWriteActionPriority[=11=](LongRunningReadTask.java:235)
at com.intellij.openapi.progress.impl.CoreProgressManager.lambda$runProcess(CoreProgressManager.java:166)
at com.intellij.openapi.progress.impl.CoreProgressManager.registerIndicatorAndRun(CoreProgressManager.java:627)
at com.intellij.openapi.progress.impl.CoreProgressManager.executeProcessUnderProgress(CoreProgressManager.java:572)
at com.intellij.openapi.progress.impl.ProgressManagerImpl.executeProcessUnderProgress(ProgressManagerImpl.java:61)
at com.intellij.openapi.progress.impl.CoreProgressManager.runProcess(CoreProgressManager.java:153)
at org.jetbrains.kotlin.idea.util.LongRunningReadTask.runWithWriteActionPriority(LongRunningReadTask.java:235)
at org.jetbrains.kotlin.idea.util.LongRunningReadTask.run(LongRunningReadTask.java:110)
at com.intellij.util.RunnableCallable.call(RunnableCallable.java:20)
at com.intellij.util.RunnableCallable.call(RunnableCallable.java:11)
at com.intellij.openapi.application.impl.ApplicationImpl.call(ApplicationImpl.java:255)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: java.lang.AssertionError: Couldn't find descriptor for 'length'
at org.jetbrains.kotlin.codegen.ExpressionCodegen.visitSimpleNameExpression(ExpressionCodegen.java:1797)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.visitSimpleNameExpression(ExpressionCodegen.java:112)
at org.jetbrains.kotlin.psi.KtNameReferenceExpression.accept(KtNameReferenceExpression.kt:59)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.genQualified(ExpressionCodegen.java:304)
... 105 more
编译器似乎没有遵循代码优化。因此，即使它应该或不应该编译，也有两种不同的行为，这意味着其中一种是不正确的。
在下面的代码片段中，两个Codeblocks有什么区别？
如果我检查 println(name==it)，那 returns 是真的，那么他们一定引用了同一个对象，对吧？
然而，当 name 变量有一个值时，一切正常，但是一旦我将它设置为 null，Codeblock 1 就可以工作（意思是，let 块根本不会被执行），但 Codeblock 2 会抛出错误。当 name 为空时，为什么 kotlin 不只是 skip/ignore 代码块 2？
fun main() {
var name:String? = "Cedric"
//name = null
//Codeblock 1
name?.let{
println("The length of name is ${name.length}")
}
//Codeblock 1
name?.let{
println("The length of name is ${it.length}")
}
}
非常感谢，如有任何帮助，我们将不胜感激。
代码块 2 实际上给出了 compile-time 错误，而代码块 1 则没有。我认为这只是一个奇怪的 linting 错误，因为这两种情况应该被同等对待。
据我了解，您发现了编译器中的错误。我在 Android studio 和 IntelliJ 中有两种不同的行为。 如果编译时，编译后的代码被优化，反编译时看起来像这样：
public final void main() {
Object name = "Cedric";
name = (String)null;
}
万一它没有编译我得到一个错误：
org.jetbrains.kotlin.codegen.CompilationException: Back-end (JVM) Internal error: Failed to generate expression: KtNameReferenceExpression
File being compiled: (12,45) in D:/Projekti/kotlin playground/src/Main.kt
The root cause java.lang.AssertionError was thrown at: org.jetbrains.kotlin.codegen.ExpressionCodegen.visitSimpleNameExpression(ExpressionCodegen.java:1797)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.genQualified(ExpressionCodegen.java:326)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.genQualified(ExpressionCodegen.java:286)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.visitDotQualifiedExpression(ExpressionCodegen.java:3258)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.visitDotQualifiedExpression(ExpressionCodegen.java:112)
at org.jetbrains.kotlin.psi.KtDotQualifiedExpression.accept(KtDotQualifiedExpression.kt:32)
at org.jetbrains.kotlin.codegen.CodegenStatementVisitor.visitKtElement(CodegenStatementVisitor.java:31)
at org.jetbrains.kotlin.codegen.CodegenStatementVisitor.visitKtElement(CodegenStatementVisitor.java:22)
at org.jetbrains.kotlin.psi.KtVisitor.visitExpression(KtVisitor.java:182)
at org.jetbrains.kotlin.psi.KtVisitor.visitQualifiedExpression(KtVisitor.java:286)
at org.jetbrains.kotlin.psi.KtVisitor.visitDotQualifiedExpression(KtVisitor.java:302)
at org.jetbrains.kotlin.psi.KtDotQualifiedExpression.accept(KtDotQualifiedExpression.kt:32)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.genQualified(ExpressionCodegen.java:304)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.genStatement(ExpressionCodegen.java:409)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.gen(ExpressionCodegen.java:366)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.invokeAppend(ExpressionCodegen.java:4108)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.invokeAppendForEntries(ExpressionCodegen.java:874)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.lambda$visitStringTemplateExpression(ExpressionCodegen.java:864)
at org.jetbrains.kotlin.codegen.OperationStackValue.putSelector(StackValue.kt:79)
at org.jetbrains.kotlin.codegen.StackValue.put(StackValue.java:122)
at org.jetbrains.kotlin.codegen.StackValue.put(StackValue.java:115)
at org.jetbrains.kotlin.codegen.CallGenerator$DefaultCallGenerator.genValueAndPut(CallGenerator.kt:71)
at org.jetbrains.kotlin.codegen.CallBasedArgumentGenerator.generateExpression(CallBasedArgumentGenerator.kt:42)
at org.jetbrains.kotlin.codegen.ArgumentGenerator.generate(ArgumentGenerator.kt:68)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.invokeMethodWithArguments(ExpressionCodegen.java:2534)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.invokeMethodWithArguments(ExpressionCodegen.java:2506)
at org.jetbrains.kotlin.codegen.Callable$invokeMethodWithArguments.invoke(Callable.kt:41)
at org.jetbrains.kotlin.codegen.Callable$invokeMethodWithArguments.invoke(Callable.kt:13)
at org.jetbrains.kotlin.codegen.OperationStackValue.putSelector(StackValue.kt:79)
at org.jetbrains.kotlin.codegen.StackValueWithLeaveTask.putSelector(StackValue.kt:67)
at org.jetbrains.kotlin.codegen.StackValue.put(StackValue.java:122)
at org.jetbrains.kotlin.codegen.StackValue.put(StackValue.java:115)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.putStackValue(ExpressionCodegen.java:386)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.gen(ExpressionCodegen.java:367)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.returnExpression(ExpressionCodegen.java:1731)
at org.jetbrains.kotlin.codegen.FunctionGenerationStrategy$FunctionDefault.doGenerateBody(FunctionGenerationStrategy.java:64)
at org.jetbrains.kotlin.codegen.ClosureGenerationStrategy.doGenerateBody(ClosureGenerationStrategy.kt:35)
at org.jetbrains.kotlin.codegen.FunctionGenerationStrategy$CodegenBased.generateBody(FunctionGenerationStrategy.java:84)
at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethodBody(FunctionCodegen.java:654)
at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethodBody(FunctionCodegen.java:479)
at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethod(FunctionCodegen.java:261)
at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethod(FunctionCodegen.java:177)
at org.jetbrains.kotlin.codegen.ClosureCodegen.generateClosureBody(ClosureCodegen.java:181)
at org.jetbrains.kotlin.codegen.ClosureCodegen.generateBody(ClosureCodegen.java:169)
at org.jetbrains.kotlin.codegen.MemberCodegen.generate(MemberCodegen.java:129)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.genClosure(ExpressionCodegen.java:1038)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.genClosure(ExpressionCodegen.java:1008)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.visitLambdaExpression(ExpressionCodegen.java:999)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.visitLambdaExpression(ExpressionCodegen.java:112)
at org.jetbrains.kotlin.psi.KtLambdaExpression.accept(KtLambdaExpression.java:40)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.genQualified(ExpressionCodegen.java:304)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.genQualified(ExpressionCodegen.java:286)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.gen(ExpressionCodegen.java:358)
at org.jetbrains.kotlin.codegen.CallGenerator$DefaultCallGenerator.genValueAndPut(CallGenerator.kt:70)
at org.jetbrains.kotlin.codegen.CallBasedArgumentGenerator.generateExpression(CallBasedArgumentGenerator.kt:42)
at org.jetbrains.kotlin.codegen.ArgumentGenerator.generate(ArgumentGenerator.kt:68)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.invokeMethodWithArguments(ExpressionCodegen.java:2534)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.invokeMethodWithArguments(ExpressionCodegen.java:2506)
at org.jetbrains.kotlin.codegen.Callable$invokeMethodWithArguments.invoke(Callable.kt:41)
at org.jetbrains.kotlin.codegen.Callable$invokeMethodWithArguments.invoke(Callable.kt:13)
at org.jetbrains.kotlin.codegen.OperationStackValue.putSelector(StackValue.kt:79)
at org.jetbrains.kotlin.codegen.CoercionValue.putSelector(StackValue.kt:31)
at org.jetbrains.kotlin.codegen.StackValue.put(StackValue.java:122)
at org.jetbrains.kotlin.codegen.StackValue.put(StackValue.java:115)
at org.jetbrains.kotlin.codegen.StackValue$StackValueWithSimpleReceiver.putReceiver(StackValue.java:2089)
at org.jetbrains.kotlin.codegen.StackValueWithLeaveTask.putReceiver(StackValue.kt:63)
at org.jetbrains.kotlin.codegen.StackValue.put(StackValue.java:120)
at org.jetbrains.kotlin.codegen.StackValue.put(StackValue.java:115)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.putStackValue(ExpressionCodegen.java:386)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.gen(ExpressionCodegen.java:367)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.returnExpression(ExpressionCodegen.java:1731)
at org.jetbrains.kotlin.codegen.FunctionGenerationStrategy$FunctionDefault.doGenerateBody(FunctionGenerationStrategy.java:64)
at org.jetbrains.kotlin.codegen.FunctionGenerationStrategy$CodegenBased.generateBody(FunctionGenerationStrategy.java:84)
at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethodBody(FunctionCodegen.java:654)
at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethodBody(FunctionCodegen.java:479)
at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethod(FunctionCodegen.java:261)
at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethod(FunctionCodegen.java:177)
at org.jetbrains.kotlin.codegen.FunctionCodegen.gen(FunctionCodegen.java:148)
at org.jetbrains.kotlin.codegen.MemberCodegen.genSimpleMember(MemberCodegen.java:197)
at org.jetbrains.kotlin.codegen.PackagePartCodegen.generateBody(PackagePartCodegen.java:95)
at org.jetbrains.kotlin.codegen.MemberCodegen.generate(MemberCodegen.java:129)
at org.jetbrains.kotlin.codegen.PackageCodegenImpl.generateFile(PackageCodegenImpl.java:145)
at org.jetbrains.kotlin.codegen.PackageCodegenImpl.generate(PackageCodegenImpl.java:70)
at org.jetbrains.kotlin.codegen.DefaultCodegenFactory.generatePackage(CodegenFactory.kt:88)
at org.jetbrains.kotlin.codegen.DefaultCodegenFactory.generateModule(CodegenFactory.kt:67)
at org.jetbrains.kotlin.codegen.KotlinCodegenFacade.compileCorrectFiles(KotlinCodegenFacade.java:35)
at org.jetbrains.kotlin.idea.internal.KotlinBytecodeToolWindow$Companion.compileSingleFile(KotlinBytecodeToolWindow.kt:335)
at org.jetbrains.kotlin.idea.internal.KotlinBytecodeToolWindow$Companion.getBytecodeForFile(KotlinBytecodeToolWindow.kt:248)
at org.jetbrains.kotlin.idea.internal.KotlinBytecodeToolWindow$UpdateBytecodeToolWindowTask.processRequest(KotlinBytecodeToolWindow.kt:127)
at org.jetbrains.kotlin.idea.internal.KotlinBytecodeToolWindow$UpdateBytecodeToolWindowTask.processRequest(KotlinBytecodeToolWindow.kt:74)
at org.jetbrains.kotlin.idea.util.LongRunningReadTask.run(LongRunningReadTask.java:115)
at com.intellij.openapi.application.impl.ApplicationImpl.runReadAction(ApplicationImpl.java:869)
at org.jetbrains.kotlin.idea.util.LongRunningReadTask.lambda$runWithWriteActionPriority[=11=](LongRunningReadTask.java:235)
at com.intellij.openapi.progress.impl.CoreProgressManager.lambda$runProcess(CoreProgressManager.java:166)
at com.intellij.openapi.progress.impl.CoreProgressManager.registerIndicatorAndRun(CoreProgressManager.java:627)
at com.intellij.openapi.progress.impl.CoreProgressManager.executeProcessUnderProgress(CoreProgressManager.java:572)
at com.intellij.openapi.progress.impl.ProgressManagerImpl.executeProcessUnderProgress(ProgressManagerImpl.java:61)
at com.intellij.openapi.progress.impl.CoreProgressManager.runProcess(CoreProgressManager.java:153)
at org.jetbrains.kotlin.idea.util.LongRunningReadTask.runWithWriteActionPriority(LongRunningReadTask.java:235)
at org.jetbrains.kotlin.idea.util.LongRunningReadTask.run(LongRunningReadTask.java:110)
at com.intellij.util.RunnableCallable.call(RunnableCallable.java:20)
at com.intellij.util.RunnableCallable.call(RunnableCallable.java:11)
at com.intellij.openapi.application.impl.ApplicationImpl.call(ApplicationImpl.java:255)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: java.lang.AssertionError: Couldn't find descriptor for 'length'
at org.jetbrains.kotlin.codegen.ExpressionCodegen.visitSimpleNameExpression(ExpressionCodegen.java:1797)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.visitSimpleNameExpression(ExpressionCodegen.java:112)
at org.jetbrains.kotlin.psi.KtNameReferenceExpression.accept(KtNameReferenceExpression.kt:59)
at org.jetbrains.kotlin.codegen.ExpressionCodegen.genQualified(ExpressionCodegen.java:304)
... 105 more
编译器似乎没有遵循代码优化。因此，即使它应该或不应该编译，也有两种不同的行为，这意味着其中一种是不正确的。