FIR: Get rid of CompositeTransformResult

compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/Types.kt

@@ -60,7 +60,6 @@ val implicitStringTypeRefType = generatedType("types.impl", "FirImplicitStringTy
 val implicitUnitTypeRefType = generatedType("types.impl", "FirImplicitUnitTypeRef")
 val resolvePhaseType = type("fir.declarations", "FirResolvePhase")
 val stubReferenceType = generatedType("references.impl", "FirStubReference")
-val compositeTransformResultType = type("fir.visitors", "CompositeTransformResult")
 
 val abstractFirBasedSymbolType = type("fir.symbols", "AbstractFirBasedSymbol")
 val backingFieldSymbolType = type("fir.symbols.impl", "FirBackingFieldSymbol")

compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/printer/element.kt

@@ -133,9 +133,9 @@ fun SmartPrinter.printElement(element: Element) {
                 println("fun acceptChildren(visitor: FirVisitorVoid) = acceptChildren(visitor, null)")
                 println()
                 println("@Suppress(\"UNCHECKED_CAST\")")
-                println("fun <E : FirElement, D> transform(visitor: FirTransformer<D>, data: D): CompositeTransformResult<E> =")
+                println("fun <E : FirElement, D> transform(visitor: FirTransformer<D>, data: D): E =")
                 withIndent {
-                    println("accept(visitor, data) as CompositeTransformResult<E>")
+                    println("accept(visitor, data) as E")
                 }
                 println()
                 println("fun <D> transformChildren(transformer: FirTransformer<D>, data: D): FirElement")

compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/printer/transformer.kt

@@ -5,7 +5,6 @@
 
 package org.jetbrains.kotlin.fir.tree.generator.printer
 
-import org.jetbrains.kotlin.fir.tree.generator.compositeTransformResultType
 import org.jetbrains.kotlin.fir.tree.generator.context.AbstractFirTreeBuilder
 import org.jetbrains.kotlin.fir.tree.generator.model.Element
 import org.jetbrains.kotlin.util.SmartPrinter
@@ -22,14 +21,13 @@ fun printTransformer(elements: List<Element>, generationPath: File): GeneratedFi
         println("package $VISITOR_PACKAGE")
         println()
         elements.forEach { println("import ${it.fullQualifiedName}") }
-        println("import ${compositeTransformResultType.fullQualifiedName}")
         println()
         printGeneratedMessage()
 
-        println("abstract class FirTransformer<in D> : FirVisitor<CompositeTransformResult<FirElement>, D>() {")
+        println("abstract class FirTransformer<in D> : FirVisitor<FirElement, D>() {")
         println()
         withIndent {
-            println("abstract fun <E : FirElement> transformElement(element: E, data: D): CompositeTransformResult<E>")
+            println("abstract fun <E : FirElement> transformElement(element: E, data: D): E")
             println()
             for (element in elements) {
                 if (element == AbstractFirTreeBuilder.baseFirElement) continue
@@ -37,8 +35,8 @@ fun printTransformer(elements: List<Element>, generationPath: File): GeneratedFi
                 print("open fun ")
                 element.typeParameters.takeIf { it.isNotBlank() }?.let { print(it) }
                 println(
-                    "transform${element.name}($varName: ${element.typeWithArguments}, data: D): CompositeTransformResult<${element.transformerType
-                        .typeWithArguments}>${element.multipleUpperBoundsList()}{",
+                    "transform${element.name}($varName: ${element.typeWithArguments}, data: D): ${element.transformerType
+                        .typeWithArguments}${element.multipleUpperBoundsList()}{",
                 )
                 withIndent {
                     println("return transformElement($varName, data)")
@@ -53,8 +51,8 @@ fun printTransformer(elements: List<Element>, generationPath: File): GeneratedFi
                 element.typeParameters.takeIf { it.isNotBlank() }?.let { print(it) }
 
                 println(
-                    "visit${element.name}($varName: ${element.typeWithArguments}, data: D): CompositeTransformResult<${element.transformerType
-                        .typeWithArguments}>${element.multipleUpperBoundsList()}{",
+                    "visit${element.name}($varName: ${element.typeWithArguments}, data: D): ${element.transformerType
+                        .typeWithArguments}${element.multipleUpperBoundsList()}{",
                 )
                 withIndent {
                     println("return transform${element.name}($varName, data)")

compiler/fir/tree/tree-generator/src/org/jetbrains/kotlin/fir/tree/generator/printer/utils.kt

@@ -5,7 +5,6 @@
 
 package org.jetbrains.kotlin.fir.tree.generator.printer
 
-import org.jetbrains.kotlin.fir.tree.generator.compositeTransformResultType
 import org.jetbrains.kotlin.fir.tree.generator.context.AbstractFirTreeBuilder
 import org.jetbrains.kotlin.fir.tree.generator.firImplementationDetailType
 import org.jetbrains.kotlin.fir.tree.generator.model.*
@@ -52,10 +51,6 @@ fun Implementation.collectImports(base: List<String> = emptyList(), kind: Import
 fun Element.collectImports(): List<String> {
     val baseTypes = parents.mapTo(mutableListOf()) { it.fullQualifiedName }
     baseTypes += parentsArguments.values.flatMap { it.values }.mapNotNull { it.fullQualifiedName }
-    val isBaseFirElement = this == AbstractFirTreeBuilder.baseFirElement
-    if (isBaseFirElement) {
-        baseTypes += compositeTransformResultType.fullQualifiedName!!
-    }
     if (needPureAbstractElement) {
         baseTypes += pureAbstractElementType.fullQualifiedName!!
     }