Restore FunctionClassKind for compatibility with Android IDEA plugin

core/descriptors/src/org/jetbrains/kotlin/builtins/functions/FunctionClassDescriptor.kt

@@ -18,6 +18,8 @@ import org.jetbrains.kotlin.resolve.scopes.MemberScope
 import org.jetbrains.kotlin.storage.StorageManager
 import org.jetbrains.kotlin.types.*
 import org.jetbrains.kotlin.types.checker.KotlinTypeRefiner
+import org.jetbrains.kotlin.utils.IDEAPlatforms
+import org.jetbrains.kotlin.utils.IDEAPluginsCompatibilityAPI
 import org.jetbrains.kotlin.utils.addToStdlib.shouldNotBeCalled
 
 /**
@@ -137,4 +139,7 @@ class FunctionClassDescriptor(
         private val functionClassId = ClassId(BUILT_INS_PACKAGE_FQ_NAME, Name.identifier("Function"))
         private val kFunctionClassId = ClassId(KOTLIN_REFLECT_FQ_NAME, Name.identifier("KFunction"))
     }
+
+    @IDEAPluginsCompatibilityAPI(IDEAPlatforms._223, message = "Please migrate to the functionTypeKind", plugins = "android")
+    val functionKind: FunctionClassKind = FunctionClassKind.getFunctionClassKind(functionTypeKind)
 }

core/descriptors/src/org/jetbrains/kotlin/builtins/functions/FunctionClassKind.kt

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * 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.builtins.functions
+
+import org.jetbrains.kotlin.utils.IDEAPlatforms
+import org.jetbrains.kotlin.utils.IDEAPluginsCompatibilityAPI
+
+@IDEAPluginsCompatibilityAPI(IDEAPlatforms._223, message = "Please migrate to the FunctionTypeKind", plugins = "android")
+enum class FunctionClassKind {
+    Function,
+    SuspendFunction,
+    KFunction,
+    KSuspendFunction,
+    UNKNOWN;
+
+    companion object {
+        fun getFunctionClassKind(functionTypeKind: FunctionTypeKind): FunctionClassKind = when (functionTypeKind) {
+            FunctionTypeKind.Function -> Function
+            FunctionTypeKind.SuspendFunction -> SuspendFunction
+            FunctionTypeKind.KFunction -> KFunction
+            FunctionTypeKind.KSuspendFunction -> KSuspendFunction
+            else -> UNKNOWN
+        }
+    }
+}