IR: refuse to copy classes in InitializersLowering

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/lower/InitializersLowering.kt

@@ -15,12 +15,12 @@ import org.jetbrains.kotlin.ir.expressions.impl.IrGetValueImpl
 import org.jetbrains.kotlin.ir.expressions.impl.IrSetFieldImpl
 import org.jetbrains.kotlin.ir.util.constructedClass
 import org.jetbrains.kotlin.ir.util.deepCopyWithSymbols
+import org.jetbrains.kotlin.ir.util.render
 import org.jetbrains.kotlin.ir.visitors.*
 
 object SYNTHESIZED_INIT_BLOCK : IrStatementOriginImpl("SYNTHESIZED_INIT_BLOCK")
 
-open class InitializersLowering(context: CommonBackendContext) : InitializersLoweringBase(context), BodyLoweringPass {
-
+class InitializersLowering(context: CommonBackendContext) : InitializersLoweringBase(context), BodyLoweringPass {
     override fun lower(irFile: IrFile) {
         runOnFilePostfix(irFile, true)
     }
@@ -29,31 +29,22 @@ open class InitializersLowering(context: CommonBackendContext) : InitializersLow
         if (container !is IrConstructor) return
 
         val irClass = container.constructedClass
-
         val instanceInitializerStatements = extractInitializers(irClass) {
             (it is IrField && !it.isStatic) || (it is IrAnonymousInitializer && !it.isStatic)
         }
+        val block = IrBlockImpl(irClass.startOffset, irClass.endOffset, context.irBuiltIns.unitType, null, instanceInitializerStatements)
+        // Check that the initializers contain no local classes. Deep-copying them is a disaster for code size, and liable to break randomly.
+        block.accept(object : IrElementVisitorVoid {
+            override fun visitElement(element: IrElement) =
+                element.acceptChildren(this, null)
+
+            override fun visitClass(declaration: IrClass) =
+                throw AssertionError("class in initializer should have been moved out by LocalClassPopupLowering: ${declaration.render()}")
+        }, null)
 
         container.body?.transformChildrenVoid(object : IrElementTransformerVoid() {
-            override fun visitInstanceInitializerCall(expression: IrInstanceInitializerCall): IrExpression {
-                return IrBlockImpl(irClass.startOffset, irClass.endOffset, context.irBuiltIns.unitType, null, instanceInitializerStatements)
-                    .deepCopyWithSymbols(container).also {
-                        // Handle declarations, copied from initializers
-                        // Otherwise local classes inside them won't get processed.
-                        // Yes, there are such cases - see testData/codegen/box/properties/complexPropertyInitializer.kt
-                        it.acceptVoid(object : IrElementVisitorVoid {
-                            override fun visitElement(element: IrElement) {
-                                element.acceptChildrenVoid(this)
-                            }
-
-                            override fun visitConstructor(declaration: IrConstructor) {
-                                super.visitConstructor(declaration)
-
-                                declaration.body?.let { lower(it, declaration) }
-                            }
-                        })
-                    }
-            }
+            override fun visitInstanceInitializerCall(expression: IrInstanceInitializerCall): IrExpression =
+                block.deepCopyWithSymbols(container)
         })
     }
 }
@@ -61,7 +52,7 @@ open class InitializersLowering(context: CommonBackendContext) : InitializersLow
 abstract class InitializersLoweringBase(open val context: CommonBackendContext) {
     protected fun extractInitializers(irClass: IrClass, filter: (IrDeclaration) -> Boolean) =
         // TODO What about fields that were added by lowerings? e.g. captured outer class or locals?
-        ArrayList(irClass.declarations).mapNotNull { if (it is IrProperty) it.backingField else it }.filter(filter).mapNotNull {
+        irClass.declarations.mapNotNull { if (it is IrProperty) it.backingField else it }.filter(filter).mapNotNull {
             when (it) {
                 is IrField -> handleField(irClass, it)
                 is IrAnonymousInitializer -> handleAnonymousInitializer(it)

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/JsLoweringPhases.kt

@@ -504,7 +504,9 @@ private val initializersLoweringPhase = makeBodyLoweringPhase(
     ::InitializersLowering,
     name = "InitializersLowering",
     description = "Merge init block and field initializers into [primary] constructor",
-    prerequisite = setOf(enumClassConstructorLoweringPhase, primaryConstructorLoweringPhase, annotationConstructorLowering)
+    prerequisite = setOf(
+        enumClassConstructorLoweringPhase, primaryConstructorLoweringPhase, annotationConstructorLowering, localClassExtractionPhase
+    )
 )
 
 private val initializersCleanupLoweringPhase = makeDeclarationTransformerPhase(

compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/WasmLoweringPhases.kt

@@ -228,7 +228,7 @@ private val initializersLoweringPhase = makeWasmModulePhase(
     ::InitializersLowering,
     name = "InitializersLowering",
     description = "Merge init block and field initializers into [primary] constructor",
-    prerequisite = setOf(primaryConstructorLoweringPhase)
+    prerequisite = setOf(primaryConstructorLoweringPhase, localClassExtractionPhase)
 )
 
 private val initializersCleanupLoweringPhase = makeWasmModulePhase(