Kapt: Enums inside enum values should be forbidden (KT-22582)

plugins/kapt3/kapt3-compiler/src/org/jetbrains/kotlin/kapt3/stubs/ClassFileToSourceStubConverter.kt

@@ -22,6 +22,7 @@ import com.sun.tools.javac.parser.Tokens
 import com.sun.tools.javac.tree.JCTree
 import com.sun.tools.javac.tree.JCTree.*
 import com.sun.tools.javac.tree.TreeMaker
+import com.sun.tools.javac.tree.TreeScanner
 import kotlinx.kapt.KaptIgnored
 import org.jetbrains.kotlin.codegen.state.GenerationState
 import org.jetbrains.kotlin.descriptors.*
@@ -182,9 +183,42 @@ class ClassFileToSourceStubConverter(
             _bindings[clazz.name] = this
         }
 
+        postProcess(topLevel)
+
         return KaptStub(topLevel, lineMappings.serialize())
     }
 
+    private fun postProcess(topLevel: JCCompilationUnit) {
+        topLevel.accept(object : TreeScanner() {
+            override fun visitClassDef(clazz: JCClassDecl) {
+                // Delete enums inside enum values
+                if (clazz.isEnum()) {
+                    for (child in clazz.defs) {
+                        if (child is JCVariableDecl) {
+                            deleteAllEnumsInside(child)
+                        }
+                    }
+                }
+
+                super.visitClassDef(clazz)
+            }
+
+            private fun JCClassDecl.isEnum() = mods.flags and Opcodes.ACC_ENUM.toLong() != 0L
+
+            private fun deleteAllEnumsInside(def: JCTree) {
+                def.accept(object : TreeScanner() {
+                    override fun visitClassDef(clazz: JCClassDecl) {
+                        clazz.defs = mapJList(clazz.defs) { child ->
+                            if (child is JCClassDecl && child.isEnum()) null else child
+                        }
+
+                        super.visitClassDef(clazz)
+                    }
+                })
+            }
+        })
+    }
+
     private fun convertImports(file: KtFile, classDeclaration: JCClassDecl): JavacList<JCTree> {
         val imports = mutableListOf<JCTree.JCImport>()
         val importedShortNames = mutableSetOf<String>()

plugins/kapt3/kapt3-compiler/testData/converter/enums.kt

@@ -10,4 +10,14 @@ enum class Enum2(@Anno1("first") val col: String, @Anno1("second") val col2: Int
 
     private fun privateEnumFun() {}
     public fun publicEnumFun() {}
+}
+
+enum class Nested1 {
+    WHITE {
+        enum class Nested2 {
+            BLACK {
+                enum class Nested3 { RED }
+            }
+        }
+    };
 }

plugins/kapt3/kapt3-compiler/testData/converter/enums.txt

@@ -60,3 +60,16 @@ public enum Enum2 {
     int col2) {
     }
 }
+
+////////////////////
+
+
+import java.lang.System;
+
+@kotlin.Metadata()
+public enum Nested1 {
+    /*public static final*/ WHITE /* = new Nested1() */;
+
+    Nested1() {
+    }
+}