Multiple minor fixes.

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

@@ -16,6 +16,7 @@
 
 package org.jetbrains.kotlin.ir
 
+import org.jetbrains.kotlin.ir.util.render
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 
 interface IrElement {
@@ -73,7 +74,7 @@ fun IrElement.assertDetached() {
 }
 
 fun IrElement.throwNoSuchSlot(slot: Int): Nothing =
-        throw AssertionError("$this: no such slot $slot")
+        throw AssertionError("${this.render()}: no such slot $slot")
 
 inline fun <reified T : IrElement> IrElement.assertCast(): T =
         if (this is T) this else throw AssertionError("Expected ${T::class.simpleName}: $this")

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/descriptors/IrSyntheticPropertyAccessorDescriptor.kt

@@ -27,7 +27,8 @@ import org.jetbrains.kotlin.descriptors.impl.PropertySetterDescriptorImpl
 
 interface IrSyntheticPropertyAccessorDescriptor : PropertyAccessorDescriptor {
     enum class Kind {
-        STATIC_PROPERTY
+        STATIC_PROPERTY,
+        MEMBER_PROPERTY
     }
 
     val kind: Kind

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/expressions/IrPropertyAccessorCall.kt

@@ -18,9 +18,7 @@ package org.jetbrains.kotlin.ir.expressions
 
 import org.jetbrains.kotlin.descriptors.CallableDescriptor
 import org.jetbrains.kotlin.descriptors.ClassDescriptor
-import org.jetbrains.kotlin.ir.SETTER_ARGUMENT_INDEX
-import org.jetbrains.kotlin.ir.assertDetached
-import org.jetbrains.kotlin.ir.detach
+import org.jetbrains.kotlin.ir.*
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 
 abstract class IrPropertyAccessorCallBase(
@@ -106,4 +104,17 @@ class IrSetterCallImpl(
         argumentImpl?.detach()
         argumentImpl = null
     }
+
+    override fun getChild(slot: Int): IrElement? =
+            when (slot) {
+                SETTER_ARGUMENT_INDEX -> argumentImpl
+                else -> super.getChild(slot)
+            }
+
+    override fun replaceChild(slot: Int, newChild: IrElement) {
+        when (slot) {
+            SETTER_ARGUMENT_INDEX -> putArgument(slot, newChild.assertCast())
+            else -> super.replaceChild(slot, newChild)
+        }
+    }
 }