Support KClass.isInstance/cast/safeCast in stdlib-only reflection implementation

#KT-14720 Fixed

core/descriptors.runtime/src/org/jetbrains/kotlin/descriptors/runtime/structure/reflectClassUtil.kt

@@ -40,18 +40,6 @@ val Class<*>.primitiveByWrapper: Class<*>?
 val Class<*>.wrapperByPrimitive: Class<*>?
     get() = PRIMITIVE_TO_WRAPPER[this]
 
-private val FUNCTION_CLASSES =
-    listOf(
-        Function0::class.java, Function1::class.java, Function2::class.java, Function3::class.java, Function4::class.java,
-        Function5::class.java, Function6::class.java, Function7::class.java, Function8::class.java, Function9::class.java,
-        Function10::class.java, Function11::class.java, Function12::class.java, Function13::class.java, Function14::class.java,
-        Function15::class.java, Function16::class.java, Function17::class.java, Function18::class.java, Function19::class.java,
-        Function20::class.java, Function21::class.java, Function22::class.java
-    ).mapIndexed { i, clazz -> clazz to i }.toMap()
-
-val Class<*>.functionClassArity: Int?
-    get() = FUNCTION_CLASSES[this]
-
 /**
  * NOTE: does not perform a Java -> Kotlin mapping. If this is not expected, consider using KClassImpl#classId instead
  */

core/reflection.jvm/src/kotlin/reflect/full/KClasses.kt

@@ -24,11 +24,8 @@ import org.jetbrains.kotlin.types.TypeSubstitutor
 import org.jetbrains.kotlin.types.Variance
 import org.jetbrains.kotlin.utils.DFS
 import kotlin.reflect.*
-import kotlin.reflect.jvm.internal.KCallableImpl
-import kotlin.reflect.jvm.internal.KClassImpl
-import kotlin.reflect.jvm.internal.KFunctionImpl
-import kotlin.reflect.jvm.internal.KTypeImpl
-import kotlin.reflect.jvm.internal.KotlinReflectionInternalError
+import kotlin.reflect.jvm.internal.*
+import kotlin.reflect.safeCast as commonSafeCast
 
 /**
  * Returns the primary constructor of this class, or `null` if this class has no primary constructor.
@@ -253,6 +250,7 @@ fun KClass<*>.isSuperclassOf(derived: KClass<*>): Boolean =
  */
 @SinceKotlin("1.1")
 fun <T : Any> KClass<T>.cast(value: Any?): T {
+    // Note: can't use kotlin.reflect.cast because it throws ClassCastException.
     if (!isInstance(value)) throw TypeCastException("Value cannot be cast to $qualifiedName")
     return value as T
 }
@@ -265,9 +263,9 @@ fun <T : Any> KClass<T>.cast(value: Any?): T {
  * @see [KClass.cast]
  */
 @SinceKotlin("1.1")
-fun <T : Any> KClass<T>.safeCast(value: Any?): T? {
-    return if (isInstance(value)) value as T else null
-}
+fun <T : Any> KClass<T>.safeCast(value: Any?): T? =
+    @UseExperimental(ExperimentalStdlibApi::class)
+    commonSafeCast(value)
 
 
 /**

core/reflection.jvm/src/kotlin/reflect/jvm/internal/KClassImpl.kt

@@ -20,8 +20,6 @@ import org.jetbrains.kotlin.builtins.CompanionObjectMapping
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.descriptors.runtime.components.ReflectKotlinClass
-import org.jetbrains.kotlin.descriptors.runtime.structure.functionClassArity
-import org.jetbrains.kotlin.descriptors.runtime.structure.wrapperByPrimitive
 import org.jetbrains.kotlin.incremental.components.NoLookupLocation
 import org.jetbrains.kotlin.load.java.JvmAbi
 import org.jetbrains.kotlin.load.kotlin.header.KotlinClassHeader
@@ -36,7 +34,6 @@ import org.jetbrains.kotlin.serialization.deserialization.MemberDeserializer
 import org.jetbrains.kotlin.serialization.deserialization.descriptors.DeserializedClassDescriptor
 import org.jetbrains.kotlin.utils.compact
 import kotlin.jvm.internal.ClassReference
-import kotlin.jvm.internal.TypeIntrinsics
 import kotlin.reflect.*
 import kotlin.reflect.jvm.internal.KDeclarationContainerImpl.MemberBelonginess.DECLARED
 import kotlin.reflect.jvm.internal.KDeclarationContainerImpl.MemberBelonginess.INHERITED
@@ -218,13 +215,7 @@ internal class KClassImpl<T : Any>(override val jClass: Class<T>) : KDeclaration
 
     override val objectInstance: T? get() = data().objectInstance
 
-    override fun isInstance(value: Any?): Boolean {
-        // TODO: use Kotlin semantics for mutable/read-only collections once KT-11754 is supported (see TypeIntrinsics)
-        jClass.functionClassArity?.let { arity ->
-            return TypeIntrinsics.isFunctionOfArity(value, arity)
-        }
-        return (jClass.wrapperByPrimitive ?: jClass).isInstance(value)
-    }
+    override fun isInstance(value: Any?): Boolean = ClassReference.isInstance(value, jClass)
 
     override val typeParameters: List<KTypeParameter> get() = data().typeParameters