[IR generator] Use ImplementationKind instead of Element.Kind

This is a step towards commonizing the code generator between
FIR and IR: KT-61970

compiler/ir/ir.tree/tree-generator/src/org/jetbrains/kotlin/ir/generator/model/Model.kt

@@ -6,7 +6,7 @@
 package org.jetbrains.kotlin.ir.generator.model
 
 import com.squareup.kotlinpoet.CodeBlock
-import org.jetbrains.kotlin.generators.tree.TypeKind
+import org.jetbrains.kotlin.generators.tree.ImplementationKind
 import org.jetbrains.kotlin.ir.generator.config.ElementConfig
 import org.jetbrains.kotlin.ir.generator.config.FieldConfig
 import org.jetbrains.kotlin.ir.generator.util.*
@@ -25,7 +25,7 @@ class Element(
     var visitorParent: ElementRef? = null
     var transformerReturnType: Element? = null
     val targetKind = config.typeKind
-    var kind: Kind? = null
+    var kind: ImplementationKind? = null
     val typeName
         get() = elementName2typeName(name)
     val allParents: List<ClassOrElementRef>
@@ -51,15 +51,6 @@ class Element(
 
     override fun toString() = name
 
-    enum class Kind(val typeKind: TypeKind) {
-        FinalClass(TypeKind.Class),
-        OpenClass(TypeKind.Class),
-        AbstractClass(TypeKind.Class),
-        SealedClass(TypeKind.Class),
-        Interface(TypeKind.Interface),
-        SealedInterface(TypeKind.Interface),
-    }
-
     companion object {
         fun elementName2typeName(name: String) = "Ir" + name.replaceFirstChar(Char::uppercaseChar)
     }

compiler/ir/ir.tree/tree-generator/src/org/jetbrains/kotlin/ir/generator/model/configureInterfacesAndAbstractClasses.kt

@@ -5,6 +5,7 @@
 
 package org.jetbrains.kotlin.ir.generator.model
 
+import org.jetbrains.kotlin.generators.tree.ImplementationKind
 import org.jetbrains.kotlin.generators.tree.TypeKind
 import org.jetbrains.kotlin.generators.util.Node
 import org.jetbrains.kotlin.generators.util.solveGraphForClassVsInterface
@@ -39,9 +40,9 @@ private fun updateKinds(nodes: List<NodeImpl>, solution: List<Boolean>) {
         val element = nodes[index].element
         if (isClass) {
             check(element.targetKind != TypeKind.Interface) { element }
-            element.kind = Element.Kind.AbstractClass
+            element.kind = ImplementationKind.AbstractClass
         } else {
-            element.kind = Element.Kind.Interface
+            element.kind = ImplementationKind.Interface
         }
     }
 }

compiler/ir/ir.tree/tree-generator/src/org/jetbrains/kotlin/ir/generator/print/Elements.kt

@@ -6,6 +6,7 @@
 package org.jetbrains.kotlin.ir.generator.print
 
 import com.squareup.kotlinpoet.*
+import org.jetbrains.kotlin.generators.tree.ImplementationKind
 import org.jetbrains.kotlin.generators.tree.TypeKind
 import org.jetbrains.kotlin.ir.generator.BASE_PACKAGE
 import org.jetbrains.kotlin.ir.generator.elementTransformerType
@@ -28,11 +29,11 @@ fun printElements(generationPath: File, model: Model) = sequence {
         }.apply {
             addModifiers(
                 when (element.kind) {
-                    Element.Kind.SealedClass -> listOf(KModifier.SEALED)
+                    ImplementationKind.SealedClass -> listOf(KModifier.SEALED)
-                    Element.Kind.SealedInterface -> listOf(KModifier.SEALED)
+                    ImplementationKind.SealedInterface -> listOf(KModifier.SEALED)
-                    Element.Kind.AbstractClass -> listOf(KModifier.ABSTRACT)
+                    ImplementationKind.AbstractClass -> listOf(KModifier.ABSTRACT)
-                    Element.Kind.FinalClass -> listOf(KModifier.FINAL)
+                    ImplementationKind.FinalClass -> listOf(KModifier.FINAL)
-                    Element.Kind.OpenClass -> listOf(KModifier.OPEN)
+                    ImplementationKind.OpenClass -> listOf(KModifier.OPEN)
                     else -> emptyList()
                 }
             )