Generate synthetic box method for each erased inline class

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

@@ -27,6 +27,13 @@ class TypeMappingMode private constructor(
         @JvmField
         val GENERIC_ARGUMENT = TypeMappingMode()
 
+        /**
+         * see KotlinTypeMapper.forceBoxedReturnType()
+         * This configuration should be called only for method return type
+         */
+        @JvmField
+        val RETURN_TYPE_BOXED = TypeMappingMode(needInlineClassWrapping = true)
+
         /**
          * kotlin.Int is mapped to I
          */