Don't mangle synthesized 'box' function for inline classes

compiler/backend/src/org/jetbrains/kotlin/codegen/state/inlineClassManglingUtils.kt

@@ -8,6 +8,7 @@ package org.jetbrains.kotlin.codegen.state
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.load.kotlin.getRepresentativeUpperBound
 import org.jetbrains.kotlin.resolve.DescriptorUtils.SUCCESS_OR_FAILURE_FQ_NAME
+import org.jetbrains.kotlin.resolve.InlineClassDescriptorResolver.BOX_METHOD_NAME
 import org.jetbrains.kotlin.resolve.descriptorUtil.fqNameSafe
 import org.jetbrains.kotlin.resolve.descriptorUtil.fqNameUnsafe
 import org.jetbrains.kotlin.resolve.isInlineClassType
@@ -17,6 +18,7 @@ import java.security.MessageDigest
 fun getInlineClassValueParametersManglingSuffix(descriptor: CallableMemberDescriptor): String? {
     if (descriptor !is FunctionDescriptor) return null
     if (descriptor is ConstructorDescriptor) return null
+    if (descriptor.isSynthesizedBoxMethod()) return null
 
     val actualValueParameterTypes = listOfNotNull(descriptor.extensionReceiverParameter?.type) + descriptor.valueParameters.map { it.type }
 
@@ -39,6 +41,11 @@ private fun KotlinType.isTypeParameterWithUpperBoundThatRequiresMangling(): Bool
     return getRepresentativeUpperBound(descriptor).requiresFunctionNameMangling()
 }
 
+private fun FunctionDescriptor.isSynthesizedBoxMethod() =
+    kind == CallableMemberDescriptor.Kind.SYNTHESIZED &&
+            containingDeclaration.let { it is ClassDescriptor && it.isInline } &&
+            name == BOX_METHOD_NAME
+
 private fun collectSignatureForMangling(types: List<KotlinType>) =
     types.joinToString { getSignatureElementForMangling(it) }
 

compiler/testData/codegen/bytecodeText/inlineClasses/synthesizedBoxMethodIsNotMangled.kt

@@ -0,0 +1,11 @@
+// !LANGUAGE: +InlineClasses
+
+inline class Z1(val x: Int)
+inline class Z2(val x: Z1)
+
+fun test(zs: MutableList<Z2>, z: Z2) {
+    zs.add(z)
+}
+
+// 1 public final static box\(I\)LZ2;
+// 1 INVOKESTATIC Z2\$Erased.box \(I\)LZ2;

compiler/tests/org/jetbrains/kotlin/codegen/BytecodeTextTestGenerated.java

@@ -2133,6 +2133,11 @@ public class BytecodeTextTestGenerated extends AbstractBytecodeTextTest {
             runTest("compiler/testData/codegen/bytecodeText/inlineClasses/skipCallToUnderlyingValueOfInlineClass.kt");
         }
 
+        @TestMetadata("synthesizedBoxMethodIsNotMangled.kt")
+        public void testSynthesizedBoxMethodIsNotMangled() throws Exception {
+            runTest("compiler/testData/codegen/bytecodeText/inlineClasses/synthesizedBoxMethodIsNotMangled.kt");
+        }
+
         @TestMetadata("uIntArrayIteratorWithoutBoxing.kt")
         public void testUIntArrayIteratorWithoutBoxing() throws Exception {
             runTest("compiler/testData/codegen/bytecodeText/inlineClasses/uIntArrayIteratorWithoutBoxing.kt");