Bug in IntelliJ IDEA Plugin

I have found a strange bug in IntelliJ IDEA Kotlin Plugin (1.2.20-release-IJ2017.3-1; JVM; Kotlin Stdlib version: 1.2.20). Here is a small example:

import org.jetbrains.spek.api.Spek
import org.jetbrains.spek.api.dsl.describe
import org.jetbrains.spek.api.dsl.on
import company.BugTest.bar
import company.BugTest.foo

object BugTest : Spek({
    describe("1") {
        on("1.1") {
            foo()
        }
        on("1.2") {
            bar()
        }
    }
}) {
    fun foo() {
        println("Ok")
    }

    private fun bar() {
        println("Almost ok")
    }
}

IDEA will mark this code as valid, but in fact it will fail to compile (i have tried with IDEA and Gradle) until the function “bar” is private.
I think, it is normal for language design, but IDEA plugin doesn’t handle it correctly.
And, here is a stacktrace:

org.jetbrains.kotlin.codegen.CompilationException: Back-end (JVM) Internal error: Do not know how to create accessor for descriptor org.jetbrains.kotlin.resolve.FunctionImportedFromObject@3b7b07d3
Cause: Do not know how to create accessor for descriptor org.jetbrains.kotlin.resolve.FunctionImportedFromObject@3b7b07d3
File being compiled and position: (15,13) in <dir>/BugTest.kt
The root cause was thrown at: syntheticAccessorUtil.kt:43
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.genQualified(ExpressionCodegen.java:328)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.genStatement(ExpressionCodegen.java:372)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.generateBlock(ExpressionCodegen.java:1193)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.generateBlock(ExpressionCodegen.java:1140)
	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.java:44)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.genQualified(ExpressionCodegen.java:307)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.genStatement(ExpressionCodegen.java:372)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.gen(ExpressionCodegen.java:338)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.returnExpression(ExpressionCodegen.java:1590)
	at org.jetbrains.kotlin.codegen.FunctionGenerationStrategy$FunctionDefault.doGenerateBody(FunctionGenerationStrategy.java:58)
	at org.jetbrains.kotlin.codegen.ClosureGenerationStrategy.doGenerateBody(ClosureGenerationStrategy.kt:31)
	at org.jetbrains.kotlin.codegen.FunctionGenerationStrategy$CodegenBased.generateBody(FunctionGenerationStrategy.java:78)
	at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethodBody(FunctionCodegen.java:568)
	at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethodBody(FunctionCodegen.java:331)
	at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethod(FunctionCodegen.java:297)
	at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethod(FunctionCodegen.java:176)
	at org.jetbrains.kotlin.codegen.ClosureCodegen.generateClosureBody(ClosureCodegen.java:189)
	at org.jetbrains.kotlin.codegen.ClosureCodegen.generateBody(ClosureCodegen.java:177)
	at org.jetbrains.kotlin.codegen.MemberCodegen.generate(MemberCodegen.java:142)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.genClosure(ExpressionCodegen.java:979)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.genClosure(ExpressionCodegen.java:953)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.visitLambdaExpression(ExpressionCodegen.java:944)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.visitLambdaExpression(ExpressionCodegen.java:120)
	at org.jetbrains.kotlin.psi.KtLambdaExpression.accept(KtLambdaExpression.java:37)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.genQualified(ExpressionCodegen.java:307)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.genQualified(ExpressionCodegen.java:289)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.gen(ExpressionCodegen.java:334)
	at org.jetbrains.kotlin.codegen.CallGenerator$DefaultCallGenerator.genValueAndPut(CallGenerator.kt:64)
	at org.jetbrains.kotlin.codegen.CallBasedArgumentGenerator.generateExpression(CallBasedArgumentGenerator.java:62)
	at org.jetbrains.kotlin.codegen.ArgumentGenerator.generate(ArgumentGenerator.kt:68)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.invokeMethodWithArguments(ExpressionCodegen.java:2297)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.invokeMethodWithArguments(ExpressionCodegen.java:2275)
	at org.jetbrains.kotlin.codegen.Callable$invokeMethodWithArguments$1.invoke(Callable.kt:44)
	at org.jetbrains.kotlin.codegen.Callable$invokeMethodWithArguments$1.invoke(Callable.kt:23)
	at org.jetbrains.kotlin.codegen.OperationStackValue.putSelector(StackValue.kt:75)
	at org.jetbrains.kotlin.codegen.StackValueWithLeaveTask.putSelector(StackValue.kt:67)
	at org.jetbrains.kotlin.codegen.StackValue.put(StackValue.java:105)
	at org.jetbrains.kotlin.codegen.StackValue.put(StackValue.java:98)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.putStackValue(ExpressionCodegen.java:354)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.gen(ExpressionCodegen.java:339)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.returnExpression(ExpressionCodegen.java:1590)
	at org.jetbrains.kotlin.codegen.FunctionGenerationStrategy$FunctionDefault.doGenerateBody(FunctionGenerationStrategy.java:58)
	at org.jetbrains.kotlin.codegen.ClosureGenerationStrategy.doGenerateBody(ClosureGenerationStrategy.kt:31)
	at org.jetbrains.kotlin.codegen.FunctionGenerationStrategy$CodegenBased.generateBody(FunctionGenerationStrategy.java:78)
	at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethodBody(FunctionCodegen.java:568)
	at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethodBody(FunctionCodegen.java:331)
	at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethod(FunctionCodegen.java:297)
	at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethod(FunctionCodegen.java:176)
	at org.jetbrains.kotlin.codegen.ClosureCodegen.generateClosureBody(ClosureCodegen.java:189)
	at org.jetbrains.kotlin.codegen.ClosureCodegen.generateBody(ClosureCodegen.java:177)
	at org.jetbrains.kotlin.codegen.MemberCodegen.generate(MemberCodegen.java:142)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.genClosure(ExpressionCodegen.java:979)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.genClosure(ExpressionCodegen.java:953)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.visitLambdaExpression(ExpressionCodegen.java:944)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.visitLambdaExpression(ExpressionCodegen.java:120)
	at org.jetbrains.kotlin.psi.KtLambdaExpression.accept(KtLambdaExpression.java:37)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.genQualified(ExpressionCodegen.java:307)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.genQualified(ExpressionCodegen.java:289)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.gen(ExpressionCodegen.java:334)
	at org.jetbrains.kotlin.codegen.CallGenerator$DefaultCallGenerator.genValueAndPut(CallGenerator.kt:64)
	at org.jetbrains.kotlin.codegen.CallBasedArgumentGenerator.generateExpression(CallBasedArgumentGenerator.java:62)
	at org.jetbrains.kotlin.codegen.ArgumentGenerator.generate(ArgumentGenerator.kt:68)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.invokeMethodWithArguments(ExpressionCodegen.java:2297)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.invokeMethodWithArguments(ExpressionCodegen.java:2275)
	at org.jetbrains.kotlin.codegen.Callable$invokeMethodWithArguments$1.invoke(Callable.kt:44)
	at org.jetbrains.kotlin.codegen.Callable$invokeMethodWithArguments$1.invoke(Callable.kt:23)
	at org.jetbrains.kotlin.codegen.OperationStackValue.putSelector(StackValue.kt:75)
	at org.jetbrains.kotlin.codegen.StackValueWithLeaveTask.putSelector(StackValue.kt:67)
	at org.jetbrains.kotlin.codegen.StackValue.put(StackValue.java:105)
	at org.jetbrains.kotlin.codegen.StackValue.put(StackValue.java:98)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.putStackValue(ExpressionCodegen.java:354)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.gen(ExpressionCodegen.java:339)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.returnExpression(ExpressionCodegen.java:1590)
	at org.jetbrains.kotlin.codegen.FunctionGenerationStrategy$FunctionDefault.doGenerateBody(FunctionGenerationStrategy.java:58)
	at org.jetbrains.kotlin.codegen.ClosureGenerationStrategy.doGenerateBody(ClosureGenerationStrategy.kt:31)
	at org.jetbrains.kotlin.codegen.FunctionGenerationStrategy$CodegenBased.generateBody(FunctionGenerationStrategy.java:78)
	at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethodBody(FunctionCodegen.java:568)
	at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethodBody(FunctionCodegen.java:331)
	at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethod(FunctionCodegen.java:297)
	at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethod(FunctionCodegen.java:176)
	at org.jetbrains.kotlin.codegen.ClosureCodegen.generateClosureBody(ClosureCodegen.java:189)
	at org.jetbrains.kotlin.codegen.ClosureCodegen.generateBody(ClosureCodegen.java:177)
	at org.jetbrains.kotlin.codegen.MemberCodegen.generate(MemberCodegen.java:142)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.genClosure(ExpressionCodegen.java:979)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.genClosure(ExpressionCodegen.java:953)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.visitLambdaExpression(ExpressionCodegen.java:944)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.visitLambdaExpression(ExpressionCodegen.java:120)
	at org.jetbrains.kotlin.psi.KtLambdaExpression.accept(KtLambdaExpression.java:37)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.genQualified(ExpressionCodegen.java:307)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.genQualified(ExpressionCodegen.java:289)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.gen(ExpressionCodegen.java:334)
	at org.jetbrains.kotlin.codegen.CallGenerator$DefaultCallGenerator.genValueAndPut(CallGenerator.kt:64)
	at org.jetbrains.kotlin.codegen.CallBasedArgumentGenerator.generateExpression(CallBasedArgumentGenerator.java:62)
	at org.jetbrains.kotlin.codegen.ArgumentGenerator.generate(ArgumentGenerator.kt:68)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.invokeMethodWithArguments(ExpressionCodegen.java:2297)
	at org.jetbrains.kotlin.codegen.ImplementationBodyCodegen.generateDelegationConstructorCall(ImplementationBodyCodegen.java:1481)
	at org.jetbrains.kotlin.codegen.ImplementationBodyCodegen.generateDelegatorToConstructorCall(ImplementationBodyCodegen.java:1445)
	at org.jetbrains.kotlin.codegen.ImplementationBodyCodegen.generatePrimaryConstructorImpl(ImplementationBodyCodegen.java:1040)
	at org.jetbrains.kotlin.codegen.ImplementationBodyCodegen.access$200(ImplementationBodyCodegen.java:93)
	at org.jetbrains.kotlin.codegen.ImplementationBodyCodegen$1.doGenerateBody(ImplementationBodyCodegen.java:991)
	at org.jetbrains.kotlin.codegen.FunctionGenerationStrategy$CodegenBased.generateBody(FunctionGenerationStrategy.java:78)
	at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethodBody(FunctionCodegen.java:568)
	at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethodBody(FunctionCodegen.java:331)
	at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethod(FunctionCodegen.java:297)
	at org.jetbrains.kotlin.codegen.ImplementationBodyCodegen.generatePrimaryConstructor(ImplementationBodyCodegen.java:987)
	at org.jetbrains.kotlin.codegen.ImplementationBodyCodegen.generateConstructors(ImplementationBodyCodegen.java:394)
	at org.jetbrains.kotlin.codegen.ClassBodyCodegen.generateBody(ClassBodyCodegen.java:92)
	at org.jetbrains.kotlin.codegen.MemberCodegen.generate(MemberCodegen.java:142)
	at org.jetbrains.kotlin.codegen.MemberCodegen.genClassOrObject(MemberCodegen.java:316)
	at org.jetbrains.kotlin.codegen.MemberCodegen.genClassOrObject(MemberCodegen.java:300)
	at org.jetbrains.kotlin.codegen.PackageCodegenImpl.generateClassOrObject(PackageCodegenImpl.java:157)
	at org.jetbrains.kotlin.codegen.PackageCodegenImpl.generateClassesAndObjectsInFile(PackageCodegenImpl.java:86)
	at org.jetbrains.kotlin.codegen.PackageCodegenImpl.generateFile(PackageCodegenImpl.java:119)
	at org.jetbrains.kotlin.codegen.PackageCodegenImpl.generate(PackageCodegenImpl.java:66)
	at org.jetbrains.kotlin.codegen.KotlinCodegenFacade.generatePackage(KotlinCodegenFacade.java:100)
	at org.jetbrains.kotlin.codegen.KotlinCodegenFacade.doGenerateFiles(KotlinCodegenFacade.java:78)
	at org.jetbrains.kotlin.codegen.KotlinCodegenFacade.compileCorrectFiles(KotlinCodegenFacade.java:45)
	at org.jetbrains.kotlin.cli.jvm.compiler.KotlinToJVMBytecodeCompiler.generate(KotlinToJVMBytecodeCompiler.kt:456)
	at org.jetbrains.kotlin.cli.jvm.compiler.KotlinToJVMBytecodeCompiler.compileModules(KotlinToJVMBytecodeCompiler.kt:152)
	at org.jetbrains.kotlin.cli.jvm.K2JVMCompiler.doExecute(K2JVMCompiler.kt:162)
	at org.jetbrains.kotlin.cli.jvm.K2JVMCompiler.doExecute(K2JVMCompiler.kt:63)
	at org.jetbrains.kotlin.cli.common.CLICompiler.execImpl(CLICompiler.java:109)
	at org.jetbrains.kotlin.cli.common.CLICompiler.execImpl(CLICompiler.java:53)
	at org.jetbrains.kotlin.cli.common.CLITool.exec(CLITool.kt:92)
	at org.jetbrains.kotlin.incremental.IncrementalJvmCompilerRunner.runCompiler(IncrementalJvmCompilerRunner.kt:451)
	at org.jetbrains.kotlin.incremental.IncrementalJvmCompilerRunner.runCompiler(IncrementalJvmCompilerRunner.kt:97)
	at org.jetbrains.kotlin.incremental.IncrementalCompilerRunner.compileIncrementally(IncrementalCompilerRunner.kt:218)
	at org.jetbrains.kotlin.incremental.IncrementalCompilerRunner.compile(IncrementalCompilerRunner.kt:89)
	at org.jetbrains.kotlin.daemon.CompileServiceImpl.execIncrementalCompiler(CompileServiceImpl.kt:518)
	at org.jetbrains.kotlin.daemon.CompileServiceImpl.access$execIncrementalCompiler(CompileServiceImpl.kt:97)
	at org.jetbrains.kotlin.daemon.CompileServiceImpl$compile$$inlined$ifAlive$lambda$2.invoke(CompileServiceImpl.kt:400)
	at org.jetbrains.kotlin.daemon.CompileServiceImpl$compile$$inlined$ifAlive$lambda$2.invoke(CompileServiceImpl.kt:97)
	at org.jetbrains.kotlin.daemon.CompileServiceImpl$doCompile$$inlined$ifAlive$lambda$2.invoke(CompileServiceImpl.kt:895)
	at org.jetbrains.kotlin.daemon.CompileServiceImpl$doCompile$$inlined$ifAlive$lambda$2.invoke(CompileServiceImpl.kt:97)
	at org.jetbrains.kotlin.daemon.common.DummyProfiler.withMeasure(PerfUtils.kt:137)
	at org.jetbrains.kotlin.daemon.CompileServiceImpl.checkedCompile(CompileServiceImpl.kt:925)
	at org.jetbrains.kotlin.daemon.CompileServiceImpl.doCompile(CompileServiceImpl.kt:894)
	at org.jetbrains.kotlin.daemon.CompileServiceImpl.compile(CompileServiceImpl.kt:399)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:357)
	at sun.rmi.transport.Transport$1.run(Transport.java:200)
	at sun.rmi.transport.Transport$1.run(Transport.java:197)
	at java.security.AccessController.doPrivileged(Native Method)
	at sun.rmi.transport.Transport.serviceCall(Transport.java:196)
	at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:568)
	at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:826)
	at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.lambda$run$0(TCPTransport.java:683)
	at java.security.AccessController.doPrivileged(Native Method)
	at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:682)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.UnsupportedOperationException: Do not know how to create accessor for descriptor org.jetbrains.kotlin.resolve.FunctionImportedFromObject@3b7b07d3
	at org.jetbrains.kotlin.codegen.SyntheticAccessorUtilKt.getAccessorNameSuffix(syntheticAccessorUtil.kt:43)
	at org.jetbrains.kotlin.codegen.context.CodegenContext.getAccessor(CodegenContext.java:475)
	at org.jetbrains.kotlin.codegen.context.CodegenContext.getAccessor(CodegenContext.java:438)
	at org.jetbrains.kotlin.codegen.context.CodegenContext.getAccessor(CodegenContext.java:409)
	at org.jetbrains.kotlin.codegen.context.CodegenContext.accessibleDescriptorIfNeeded(CodegenContext.java:656)
	at org.jetbrains.kotlin.codegen.context.CodegenContext.accessibleDescriptor(CodegenContext.java:579)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.accessibleFunctionDescriptor(ExpressionCodegen.java:2159)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.visitCallExpression(ExpressionCodegen.java:2077)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.visitCallExpression(ExpressionCodegen.java:120)
	at org.jetbrains.kotlin.psi.KtCallExpression.accept(KtCallExpression.java:35)
	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.visitReferenceExpression(KtVisitor.java:198)
	at org.jetbrains.kotlin.psi.KtVisitor.visitCallExpression(KtVisitor.java:278)
	at org.jetbrains.kotlin.psi.KtCallExpression.accept(KtCallExpression.java:35)
	at org.jetbrains.kotlin.codegen.ExpressionCodegen.genQualified(ExpressionCodegen.java:307)
	... 156 more

Maybe it is a known issue? Anyway, I hope it will help anyone (I spent more than hour to find the problem).