[CJS BE] don't crash when intersection types passed for a reified parameter

#KT-37163 Fixed

libraries/stdlib/js/src/kotlin/reflect/KClassImpl.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2018 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * 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.
  */
 
@@ -62,5 +62,16 @@ internal object NothingKClassImpl : KClassImpl<Nothing>(js("Object")) {
 
     override fun equals(other: Any?): Boolean = other === this
 
+    override fun hashCode(): Int = 0
+}
+
+internal class ErrorKClass : KClass<Nothing> {
+    override val simpleName: String? get() = error("Unknown simpleName for ErrorKClass")
+    override val qualifiedName: String? get() = error("Unknown qualifiedName for ErrorKClass")
+
+    override fun isInstance(value: Any?): Boolean = error("Can's check isInstance on ErrorKClass")
+
+    override fun equals(other: Any?): Boolean = other === this
+
     override fun hashCode(): Int = 0
 }

libraries/stdlib/js/src/kotlin/reflect/reflection.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2018 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * 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.
  */
 
@@ -9,7 +9,20 @@ import kotlin.reflect.*
 import kotlin.reflect.js.internal.*
 
 @JsName("getKClass")
-internal fun <T : Any> getKClass(jClass: JsClass<T>): KClass<T> = getOrCreateKClass(jClass)
+internal fun <T : Any> getKClass(jClass: Any /* JsClass<T> | Array<JsClass<T>> */): KClass<T> {
+    return if (js("Array").isArray(jClass)) {
+        getKClassM(jClass.unsafeCast<Array<JsClass<T>>>())
+    } else {
+        getKClass1(jClass.unsafeCast<JsClass<T>>())
+    }
+}
+
+@JsName("getKClassM")
+internal fun <T : Any> getKClassM(jClasses: Array<JsClass<T>>): KClass<T> = when (jClasses.size) {
+    1 -> getKClass1(jClasses[0])
+    0 -> NothingKClassImpl.unsafeCast<KClass<T>>()
+    else -> ErrorKClass().unsafeCast<KClass<T>>()
+}
 
 @JsName("getKClassFromExpression")
 internal fun <T : Any> getKClassFromExpression(e: T): KClass<T> =
@@ -37,7 +50,7 @@ internal fun <T : Any> getKClassFromExpression(e: T): KClass<T> =
                         constructor === js("Error") -> PrimitiveClasses.throwableClass
                         else -> {
                             val jsClass: JsClass<T> = constructor
-                            getOrCreateKClass(jsClass)
+                            getKClass1(jsClass)
                         }
                     }
                 }
@@ -45,7 +58,8 @@ internal fun <T : Any> getKClassFromExpression(e: T): KClass<T> =
         }
     }.unsafeCast<KClass<T>>()
 
-private fun <T : Any> getOrCreateKClass(jClass: JsClass<T>): KClass<T> {
+@JsName("getKClass1")
+internal fun <T : Any> getKClass1(jClass: JsClass<T>): KClass<T> {
     if (jClass === js("String")) return PrimitiveClasses.stringClass.unsafeCast<KClass<T>>()
 
     val metadata = jClass.asDynamic().`$metadata$`