org.jetbrains.kotlin.backend.common.lower.LocalClassPopupLowering.kt Maven / Gradle / Ivy

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package org.jetbrains.kotlin.backend.common.lower

import org.jetbrains.kotlin.backend.common.BackendContext
import org.jetbrains.kotlin.backend.common.FileLoweringPass
import org.jetbrains.kotlin.backend.common.IrElementTransformerVoidWithContext
import org.jetbrains.kotlin.backend.common.ir.addChild
import org.jetbrains.kotlin.ir.IrStatement
import org.jetbrains.kotlin.ir.declarations.IrClass
import org.jetbrains.kotlin.ir.declarations.IrDeclarationContainer
import org.jetbrains.kotlin.ir.declarations.IrFile
import org.jetbrains.kotlin.ir.expressions.impl.IrCompositeImpl

//This lower takes part of old LocalDeclarationLowering job to pop up local classes from functions
class LocalClassPopupLowering(val context: BackendContext) : FileLoweringPass {

    override fun lower(irFile: IrFile) {
        val extractedLocalClasses = arrayListOf>()

        irFile.transform(object : IrElementTransformerVoidWithContext() {

            override fun visitClassNew(declaration: IrClass): IrStatement {
                val newDeclaration = super.visitClassNew(declaration)
                if (newDeclaration !is IrClass || !newDeclaration.isLocalNotInner()) {
                    return newDeclaration
                }

                val newContainer = allScopes.asReversed().drop(1/*skip self*/).firstOrNull {
                    //find first class local or not;
                    // to reproduce original LocalDeclarationLowering behaviour add: '&& !it.irElement.isLocal' condition
                    it.irElement is IrClass
                }?.irElement as? IrClass ?: currentFile
                extractedLocalClasses.add(newDeclaration to newContainer)
                return IrCompositeImpl(declaration.startOffset, declaration.endOffset, context.irBuiltIns.unitType)
            }
        }, null)

        for ((local, newContainer) in extractedLocalClasses) {
            newContainer.addChild(local)
        }
    }
}