Basic inline class mapping to the underlying representation

core/descriptors.jvm/src/org/jetbrains/kotlin/load/kotlin/TypeMappingMode.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2016 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.load.kotlin
@@ -21,6 +10,7 @@ import org.jetbrains.kotlin.types.Variance
 
 class TypeMappingMode private constructor(
         val needPrimitiveBoxing: Boolean = true,
+        val needInlineClassWrapping: Boolean = false,
         val isForAnnotationParameter: Boolean = false,
         // Here DeclarationSiteWildcards means wildcard generated because of declaration-site variance
         val skipDeclarationSiteWildcards: Boolean = false,
@@ -43,6 +33,18 @@ class TypeMappingMode private constructor(
         @JvmField
         val DEFAULT = TypeMappingMode(genericArgumentMode = GENERIC_ARGUMENT, needPrimitiveBoxing = false)
 
+        /**
+         * kotlin.Int is mapped to I
+         * inline class Foo(val x: Int) is mapped to LFoo;
+         * but in signature fun bar(f: Foo), Foo is mapped to I
+         */
+        @JvmField
+        val CLASS_DECLARATION = TypeMappingMode(
+            genericArgumentMode = GENERIC_ARGUMENT,
+            needPrimitiveBoxing = false,
+            needInlineClassWrapping = true
+        )
+
         /**
          * kotlin.Int is mapped to Ljava/lang/Integer;
          * No projections allowed in immediate arguments

core/descriptors.jvm/src/org/jetbrains/kotlin/load/kotlin/typeSignatureMapping.kt

@@ -19,6 +19,7 @@ import org.jetbrains.kotlin.resolve.DescriptorUtils
 import org.jetbrains.kotlin.resolve.descriptorUtil.fqNameUnsafe
 import org.jetbrains.kotlin.resolve.jvm.JvmClassName
 import org.jetbrains.kotlin.resolve.jvm.JvmPrimitiveType
+import org.jetbrains.kotlin.resolve.underlyingRepresentation
 import org.jetbrains.kotlin.types.*
 import org.jetbrains.kotlin.types.typeUtil.replaceArgumentsWithStarProjections
 import org.jetbrains.kotlin.utils.DO_NOTHING_3
@@ -128,6 +129,13 @@ fun <T : Any> mapType(
         }
 
         descriptor is ClassDescriptor -> {
+            if (descriptor.isInline && !mode.needInlineClassWrapping) {
+                val underlyingType = descriptor.underlyingRepresentation()?.type
+                if (underlyingType != null) {
+                    return mapType(underlyingType, factory, mode, typeMappingConfiguration, descriptorTypeWriter, writeGenericType)
+                }
+            }
+
             val jvmType =
                 if (mode.isForAnnotationParameter && KotlinBuiltIns.isKClass(descriptor)) {
                     factory.javaLangClassType

core/descriptors/src/org/jetbrains/kotlin/resolve/inlineClassesUtils.kt

@@ -0,0 +1,14 @@
+/*
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.resolve
+
+import org.jetbrains.kotlin.descriptors.ClassDescriptor
+import org.jetbrains.kotlin.descriptors.ValueParameterDescriptor
+
+fun ClassDescriptor.underlyingRepresentation(): ValueParameterDescriptor? {
+    if (!isInline) return null
+    return unsubstitutedPrimaryConstructor?.valueParameters?.singleOrNull()
+}