diff --git a/compiler/backend/src/org/jetbrains/kotlin/codegen/optimization/boxing/BoxedBasicValue.kt b/compiler/backend/src/org/jetbrains/kotlin/codegen/optimization/boxing/BoxedBasicValue.kt
index 3224938157a..2a6f2f30af7 100644
--- a/compiler/backend/src/org/jetbrains/kotlin/codegen/optimization/boxing/BoxedBasicValue.kt
+++ b/compiler/backend/src/org/jetbrains/kotlin/codegen/optimization/boxing/BoxedBasicValue.kt
@@ -56,7 +56,7 @@ class TaintedBoxedValue(private val boxedBasicValue: CleanBoxedValue) : BoxedBas
 
 
 class BoxedValueDescriptor(
-    private val boxedType: Type,
+    boxedType: Type,
     val boxingInsn: AbstractInsnNode,
     val progressionIterator: ProgressionIteratorBasicValue?,
     val generationState: GenerationState
diff --git a/compiler/backend/src/org/jetbrains/kotlin/codegen/optimization/boxing/RedundantBoxingMethodTransformer.kt b/compiler/backend/src/org/jetbrains/kotlin/codegen/optimization/boxing/RedundantBoxingMethodTransformer.kt
index 46646e36112..5844d1f8e0c 100644
--- a/compiler/backend/src/org/jetbrains/kotlin/codegen/optimization/boxing/RedundantBoxingMethodTransformer.kt
+++ b/compiler/backend/src/org/jetbrains/kotlin/codegen/optimization/boxing/RedundantBoxingMethodTransformer.kt
@@ -38,6 +38,10 @@ import java.util.*
 class RedundantBoxingMethodTransformer(private val generationState: GenerationState) : MethodTransformer() {
 
     override fun transform(internalClassName: String, node: MethodNode) {
+        val insns = node.instructions.toArray()
+        if (insns.none { it.isBoxing(generationState) || it.isMethodInsnWith(Opcodes.INVOKEINTERFACE) { name == "next" } })
+            return
+
         val interpreter = RedundantBoxingInterpreter(node.instructions, generationState)
         val frames = analyze(internalClassName, node, interpreter)