Refactor fictitious function class kinds, reuse in J<->K map

core/descriptor.loader.java/src/org/jetbrains/kotlin/platform/JavaToKotlinClassMap.java

@@ -21,6 +21,7 @@ import org.jetbrains.annotations.Nullable;
 import org.jetbrains.kotlin.builtins.CompanionObjectMapping;
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns;
 import org.jetbrains.kotlin.builtins.PrimitiveType;
+import org.jetbrains.kotlin.builtins.functions.FunctionClassDescriptor;
 import org.jetbrains.kotlin.descriptors.ClassDescriptor;
 import org.jetbrains.kotlin.name.ClassId;
 import org.jetbrains.kotlin.name.FqName;
@@ -77,11 +78,8 @@ public class JavaToKotlinClassMap implements PlatformToKotlinClassMap {
         for (int i = 0; i < 23; i++) {
             add(ClassId.topLevel(new FqName("kotlin.jvm.functions.Function" + i)), builtIns.getFunction(i));
 
-            for (String kFun : Arrays.asList(
-                    "kotlin.reflect.KFunction",
-                    "kotlin.reflect.KMemberFunction",
-                    "kotlin.reflect.KExtensionFunction"
-            )) {
+            for (FunctionClassDescriptor.Kind kind : FunctionClassDescriptor.Kinds.KFunctions) {
+                String kFun = kind.getPackageFqName() + "." + kind.getClassNamePrefix();
                 addKotlinToJava(new FqNameUnsafe(kFun + i), ClassId.topLevel(new FqName(kFun)));
             }
         }

core/descriptors/src/org/jetbrains/kotlin/builtins/KotlinBuiltIns.java

@@ -21,7 +21,6 @@ import kotlin.jvm.functions.Function1;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.jetbrains.kotlin.builtins.functions.BuiltInFictitiousFunctionClassFactory;
-import org.jetbrains.kotlin.builtins.functions.FunctionClassDescriptor;
 import org.jetbrains.kotlin.descriptors.*;
 import org.jetbrains.kotlin.descriptors.annotations.AnnotationDescriptor;
 import org.jetbrains.kotlin.descriptors.annotations.AnnotationDescriptorImpl;
@@ -771,10 +770,8 @@ public class KotlinBuiltIns {
 
         if (!BUILT_INS_PACKAGE_NAME.equals(first(segments))) return false;
 
-        return BuiltInFictitiousFunctionClassFactory.parseClassName(
-                last(segments).asString(),
-                FunctionClassDescriptor.Kinds.Functions
-        ) != null;
+        String shortName = last(segments).asString();
+        return BuiltInFictitiousFunctionClassFactory.parseClassName(shortName, BUILT_INS_PACKAGE_FQ_NAME) != null;
     }
 
     @Nullable

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

@@ -16,13 +16,11 @@
 
 package org.jetbrains.kotlin.builtins.functions
 
-import org.jetbrains.kotlin.builtins.KOTLIN_REFLECT_FQ_NAME
-import org.jetbrains.kotlin.builtins.KotlinBuiltIns.BUILT_INS_PACKAGE_FQ_NAME
 import org.jetbrains.kotlin.builtins.functions.FunctionClassDescriptor.Kind
-import org.jetbrains.kotlin.builtins.functions.FunctionClassDescriptor.Kinds
 import org.jetbrains.kotlin.descriptors.ClassDescriptor
 import org.jetbrains.kotlin.descriptors.ModuleDescriptor
 import org.jetbrains.kotlin.name.ClassId
+import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.serialization.deserialization.ClassDescriptorFactory
 import org.jetbrains.kotlin.storage.StorageManager
 import kotlin.platform.platformStatic
@@ -38,8 +36,8 @@ public class BuiltInFictitiousFunctionClassFactory(
     private data class KindWithArity(val kind: Kind, val arity: Int)
 
     companion object {
-        platformStatic public fun parseClassName(className: String, allowedKinds: Set<Kind>): KindWithArity? {
-            for (kind in allowedKinds) {
+        platformStatic public fun parseClassName(className: String, packageFqName: FqName): KindWithArity? {
+            for (kind in FunctionClassDescriptor.Kinds.byPackage(packageFqName)) {
                 val prefix = kind.classNamePrefix
                 if (!className.startsWith(prefix)) continue
 
@@ -72,14 +70,7 @@ public class BuiltInFictitiousFunctionClassFactory(
         if ("Function" !in className) return null // An optimization
 
         val packageFqName = classId.getPackageFqName()
-
-        val allowedKinds = when (packageFqName) {
-            BUILT_INS_PACKAGE_FQ_NAME -> Kinds.Functions
-            KOTLIN_REFLECT_FQ_NAME -> Kinds.KFunctions
-            else -> return null
-        }
-
-        val kindWithArity = parseClassName(className, allowedKinds) ?: return null
+        val kindWithArity = parseClassName(className, packageFqName) ?: return null
         val (kind, arity) = kindWithArity // KT-5100
 
         val containingPackageFragment = module.getPackage(packageFqName)!!.getFragments().single()

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

@@ -16,6 +16,7 @@
 
 package org.jetbrains.kotlin.builtins.functions
 
+import org.jetbrains.kotlin.builtins.KOTLIN_REFLECT_FQ_NAME
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns.BUILT_INS_PACKAGE_FQ_NAME
 import org.jetbrains.kotlin.builtins.functions.FunctionClassDescriptor.Kind
@@ -24,6 +25,7 @@ import org.jetbrains.kotlin.descriptors.annotations.Annotations
 import org.jetbrains.kotlin.descriptors.annotations.AnnotationsImpl
 import org.jetbrains.kotlin.descriptors.impl.AbstractClassDescriptor
 import org.jetbrains.kotlin.descriptors.impl.TypeParameterDescriptorImpl
+import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.resolve.scopes.StaticScopeForKotlinClass
 import org.jetbrains.kotlin.storage.StorageManager
@@ -50,11 +52,11 @@ public class FunctionClassDescriptor(
         val arity: Int
 ) : AbstractClassDescriptor(storageManager, functionKind.numberedClassName(arity)) {
 
-    public enum class Kind(val classNamePrefix: String) {
-        Function("Function"),
-        KFunction("KFunction"),
-        KMemberFunction("KMemberFunction"),
-        KExtensionFunction("KExtensionFunction");
+    public enum class Kind(val packageFqName: FqName, val classNamePrefix: String) {
+        Function(BUILT_INS_PACKAGE_FQ_NAME, "Function"),
+        KFunction(KOTLIN_REFLECT_FQ_NAME, "KFunction"),
+        KMemberFunction(KOTLIN_REFLECT_FQ_NAME, "KMemberFunction"),
+        KExtensionFunction(KOTLIN_REFLECT_FQ_NAME, "KExtensionFunction");
         // TODO: KMemberExtensionFunction
 
         fun numberedClassName(arity: Int) = Name.identifier("$classNamePrefix$arity")
@@ -64,7 +66,13 @@ public class FunctionClassDescriptor(
 
     public object Kinds {
         val Functions = EnumSet.of(Kind.Function)
-        val KFunctions = EnumSet.of(Kind.KFunction, Kind.KMemberFunction, Kind.KExtensionFunction)
+        val KFunctions = EnumSet.complementOf(Functions)
+
+        fun byPackage(fqName: FqName) = when (fqName) {
+            BUILT_INS_PACKAGE_FQ_NAME -> Functions
+            KOTLIN_REFLECT_FQ_NAME -> KFunctions
+            else -> error(fqName)
+        }
     }
 
     private val staticScope = StaticScopeForKotlinClass(this)