Language feature for new inline class mangling rules (since 1.4)

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

@@ -251,7 +251,8 @@ class GenerationState private constructor(
     val isInlineDisabled: Boolean = configuration.getBoolean(CommonConfigurationKeys.DISABLE_INLINE)
     val useTypeTableInSerializer: Boolean = configuration.getBoolean(JVMConfigurationKeys.USE_TYPE_TABLE)
     val unifiedNullChecks: Boolean = languageVersionSettings.apiVersion >= ApiVersion.KOTLIN_1_4
-    val functionsWithInlineClassReturnTypesMangled: Boolean = languageVersionSettings.apiVersion >= ApiVersion.KOTLIN_1_4
+    val functionsWithInlineClassReturnTypesMangled: Boolean =
+        languageVersionSettings.supportsFeature(LanguageFeature.MangleClassMembersReturningInlineClasses)
 
     val rootContext: CodegenContext<*> = RootContext(this)
 

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

@@ -619,6 +619,9 @@ class KotlinTypeMapper @JvmOverloads constructor(
         }
     }
 
+    private val shouldMangleByReturnType =
+        languageVersionSettings.supportsFeature(LanguageFeature.MangleClassMembersReturningInlineClasses)
+
     private fun mangleMemberNameIfRequired(
         name: String,
         descriptor: CallableMemberDescriptor,
@@ -657,7 +660,7 @@ class KotlinTypeMapper @JvmOverloads constructor(
         // so that we don't have to repeat the same logic in reflection
         // in case of properties without getter methods.
         if (kind !== OwnerKind.PROPERTY_REFERENCE_SIGNATURE || descriptor.isPropertyWithGetterSignaturePresent()) {
-            val suffix = getManglingSuffixBasedOnKotlinSignature(descriptor)
+            val suffix = getManglingSuffixBasedOnKotlinSignature(descriptor, shouldMangleByReturnType)
             if (suffix != null) {
                 newName += suffix
             } else if (kind === OwnerKind.ERASED_INLINE_CLASS) {
@@ -683,6 +686,7 @@ class KotlinTypeMapper @JvmOverloads constructor(
         } else newName
     }
 
+
     private fun CallableMemberDescriptor.isPropertyWithGetterSignaturePresent(): Boolean {
         val propertyDescriptor = when (this) {
             is PropertyDescriptor -> this

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

@@ -16,7 +16,10 @@ import org.jetbrains.kotlin.types.typeUtil.representativeUpperBound
 import java.security.MessageDigest
 import java.util.*
 
-fun getManglingSuffixBasedOnKotlinSignature(descriptor: CallableMemberDescriptor): String? {
+fun getManglingSuffixBasedOnKotlinSignature(
+    descriptor: CallableMemberDescriptor,
+    shouldMangleByReturnType: Boolean
+): String? {
     if (descriptor !is FunctionDescriptor) return null
     if (descriptor is ConstructorDescriptor) return null
     if (InlineClassDescriptorResolver.isSynthesizedBoxOrUnboxMethod(descriptor)) return null
@@ -30,9 +33,11 @@ fun getManglingSuffixBasedOnKotlinSignature(descriptor: CallableMemberDescriptor
     // If a class member function returns inline class value, mangle its name.
     // NB here function can be a suspend function JVM view with return type replaced with 'Any',
     // should unwrap it and take original return type instead.
-    val unwrappedDescriptor = descriptor.unwrapInitialDescriptorForSuspendFunction()
-    if (requiresFunctionNameManglingForReturnType(unwrappedDescriptor)) {
-        return "-" + md5base64(":" + getSignatureElementForMangling(unwrappedDescriptor.returnType!!))
+    if (shouldMangleByReturnType) {
+        val unwrappedDescriptor = descriptor.unwrapInitialDescriptorForSuspendFunction()
+        if (requiresFunctionNameManglingForReturnType(unwrappedDescriptor)) {
+            return "-" + md5base64(":" + getSignatureElementForMangling(unwrappedDescriptor.returnType!!))
+        }
     }
     return null
 }