Property accessors are now children of IrProperty.

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/IrSlots.kt

@@ -33,4 +33,6 @@ const val LOOP_CONDITION_SLOT = -2
 const val SETTER_ARGUMENT_INDEX = 0
 const val TRY_RESULT_SLOT = -1
 const val FINALLY_EXPRESSION_SLOT = -2
-const val NESTED_INITIALIZERS_SLOT = -1
+const val NESTED_INITIALIZERS_SLOT = -1
+const val PROPERTY_GETTER_SLOT = -1
+const val PROPERTY_SETTER_SLOT = -2

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrProperty.kt

@@ -28,8 +28,6 @@ interface IrProperty : IrDeclaration {
 
     override val declarationKind: IrDeclarationKind
         get() = IrDeclarationKind.PROPERTY
-
-    fun <D> acceptAccessors(visitor: IrElementVisitor<Unit, D>, data: D)
 }
 
 interface IrSimpleProperty : IrProperty {
@@ -49,21 +47,33 @@ abstract class IrPropertyBase(
 ) : IrDeclarationBase(startOffset, endOffset, origin), IrProperty {
     override var getter: IrPropertyGetter? = null
         set(newGetter) {
-            newGetter?.run { assert(property == null) { "$newGetter: should not have a property" } }
-            newGetter?.property = this
+            newGetter?.assertDetached()
+            field?.detach()
             field = newGetter
+            newGetter?.setTreeLocation(this, PROPERTY_GETTER_SLOT)
         }
 
     override var setter: IrPropertySetter? = null
         set(newSetter) {
-            newSetter?.run { assert(property == null) { "$newSetter: should not have a property" } }
-            newSetter?.property = this
+            newSetter?.assertDetached()
+            field?.detach()
             field = newSetter
+            newSetter?.setTreeLocation(this, PROPERTY_SETTER_SLOT)
         }
 
-    override fun <D> acceptAccessors(visitor: IrElementVisitor<Unit, D>, data: D) {
-        getter?.accept(visitor, data)
-        setter?.accept(visitor, data)
+    override fun getChild(slot: Int): IrElement? =
+            when (slot) {
+                PROPERTY_GETTER_SLOT -> getter
+                PROPERTY_SETTER_SLOT -> setter
+                else -> null
+            }
+
+    override fun replaceChild(slot: Int, newChild: IrElement) {
+        when (slot) {
+            PROPERTY_GETTER_SLOT -> getter = newChild.assertCast()
+            PROPERTY_SETTER_SLOT -> setter = newChild.assertCast()
+            else -> throwNoSuchSlot(slot)
+        }
     }
 }
 
@@ -85,13 +95,13 @@ class IrSimplePropertyImpl(
     override fun getChild(slot: Int): IrElement? =
             when (slot) {
                 INITIALIZER_SLOT -> valueInitializer
-                else -> null
+                else -> super.getChild(slot)
             }
 
     override fun replaceChild(slot: Int, newChild: IrElement) {
         when (slot) {
             INITIALIZER_SLOT -> valueInitializer = newChild.assertCast()
-            else -> throwNoSuchSlot(slot)
+            else -> super.replaceChild(slot, newChild)
         }
     }
 
@@ -100,6 +110,8 @@ class IrSimplePropertyImpl(
 
     override fun <D> acceptChildren(visitor: IrElementVisitor<Unit, D>, data: D) {
         valueInitializer?.accept(visitor, data)
+        getter?.accept(visitor, data)
+        setter?.accept(visitor, data)
     }
 }
 
@@ -121,13 +133,13 @@ class IrDelegatedPropertyImpl(
     override fun getChild(slot: Int): IrElement? =
             when (slot) {
                 INITIALIZER_SLOT -> delegateInitializer
-                else -> null
+                else -> super.getChild(slot)
             }
 
     override fun replaceChild(slot: Int, newChild: IrElement) {
         when (slot) {
             INITIALIZER_SLOT -> delegateInitializer = newChild.assertCast()
-            else -> throwNoSuchSlot(slot)
+            else -> super.replaceChild(slot, newChild)
         }
     }
 
@@ -136,5 +148,7 @@ class IrDelegatedPropertyImpl(
 
     override fun <D> acceptChildren(visitor: IrElementVisitor<Unit, D>, data: D) {
         delegateInitializer.accept(visitor, data)
+        getter?.accept(visitor, data)
+        setter?.accept(visitor, data)
     }
 }

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/declarations/IrPropertyAccessor.kt

@@ -24,7 +24,6 @@ import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 
 interface IrPropertyAccessor : IrFunction {
     override val descriptor: PropertyAccessorDescriptor
-    var property: IrProperty?
 }
 
 interface IrPropertyGetter : IrPropertyAccessor {
@@ -46,9 +45,7 @@ abstract class IrPropertyAccessorBase(
         endOffset: Int,
         origin: IrDeclarationOrigin,
         body: IrBody
-) : IrFunctionBase(startOffset, endOffset, origin, body), IrPropertyAccessor {
-    override var property: IrProperty? = null
-}
+) : IrFunctionBase(startOffset, endOffset, origin, body), IrPropertyAccessor
 
 class IrPropertyGetterImpl(
         startOffset: Int,

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/RenderIrElement.kt

@@ -43,13 +43,13 @@ class RenderIrElementVisitor : IrElementVisitor<String, Nothing?> {
             "FUN ${declaration.descriptor.render()}"
 
     override fun visitProperty(declaration: IrProperty, data: Nothing?): String =
-            "PROPERTY ${declaration.descriptor.render()} getter=${declaration.getter?.name()} setter=${declaration.setter?.name()}"
+            "PROPERTY ${declaration.descriptor.render()}"
 
     override fun visitPropertyGetter(declaration: IrPropertyGetter, data: Nothing?): String =
-            "PROPERTY_GETTER ${declaration.descriptor.render()} property=${declaration.property?.name()}"
+            "PROPERTY_GETTER ${declaration.descriptor.render()}"
 
     override fun visitPropertySetter(declaration: IrPropertySetter, data: Nothing?): String =
-            "PROPERTY_SETTER ${declaration.descriptor.render()} property=${declaration.property?.name()}"
+            "PROPERTY_SETTER ${declaration.descriptor.render()}"
 
     override fun visitClass(declaration: IrClass, data: Nothing?): String =
             "CLASS ${declaration.descriptor.kind} ${declaration.descriptor.name}"