From 3efa738bc0d4199a363f3b3f9096ee925d66205e Mon Sep 17 00:00:00 2001
From: Alexander Udalov <Alexander.Udalov@jetbrains.com>
Date: Mon, 8 Aug 2016 18:29:03 +0300
Subject: [PATCH] Fix NPE on .companionObjectInstance for built-in classes

 #KT-13370 Fixed
---
 .../box/reflection/classes/companionObject.kt | 19 +++++++++++++++++++
 .../box/reflection/classes/objectInstance.kt  |  2 ++
 .../kotlin/reflect/jvm/internal/KClassImpl.kt |  3 ++-
 3 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/compiler/testData/codegen/box/reflection/classes/companionObject.kt b/compiler/testData/codegen/box/reflection/classes/companionObject.kt
index af1a4d9444c..d0bc23f1750 100644
--- a/compiler/testData/codegen/box/reflection/classes/companionObject.kt
+++ b/compiler/testData/codegen/box/reflection/classes/companionObject.kt
@@ -25,5 +25,24 @@ fun box(): String {
 
     assertEquals(E.Companion, E::class.companionObjectInstance)
 
+    assertEquals(String, String::class.companionObjectInstance)
+    assertEquals(String, String.Companion::class.objectInstance)
+    assertEquals(Enum, Enum::class.companionObjectInstance)
+    assertEquals(Enum, Enum.Companion::class.objectInstance)
+    assertEquals(Double, Double::class.companionObjectInstance)
+    assertEquals(Double, Double.Companion::class.objectInstance)
+    assertEquals(Float, Float::class.companionObjectInstance)
+    assertEquals(Float, Float.Companion::class.objectInstance)
+    assertEquals(Int, Int::class.companionObjectInstance)
+    assertEquals(Int, Int.Companion::class.objectInstance)
+    assertEquals(Long, Long::class.companionObjectInstance)
+    assertEquals(Long, Long.Companion::class.objectInstance)
+    assertEquals(Short, Short::class.companionObjectInstance)
+    assertEquals(Short, Short.Companion::class.objectInstance)
+    assertEquals(Byte, Byte::class.companionObjectInstance)
+    assertEquals(Byte, Byte.Companion::class.objectInstance)
+    assertEquals(Char, Char::class.companionObjectInstance)
+    assertEquals(Char, Char.Companion::class.objectInstance)
+
     return "OK"
 }
diff --git a/compiler/testData/codegen/box/reflection/classes/objectInstance.kt b/compiler/testData/codegen/box/reflection/classes/objectInstance.kt
index 8189d66d9e0..ff9e264bef6 100644
--- a/compiler/testData/codegen/box/reflection/classes/objectInstance.kt
+++ b/compiler/testData/codegen/box/reflection/classes/objectInstance.kt
@@ -26,6 +26,8 @@ fun box(): String {
     assertEquals(3, B.Factory::class.objectInstance!!.foo())
 
     assertEquals(null, C::class.objectInstance)
+    assertEquals(null, String::class.objectInstance)
+    assertEquals(Unit, Unit::class.objectInstance)
 
     return "OK"
 }
diff --git a/core/reflection.jvm/src/kotlin/reflect/jvm/internal/KClassImpl.kt b/core/reflection.jvm/src/kotlin/reflect/jvm/internal/KClassImpl.kt
index b44d3d5b0b8..790cd71606c 100644
--- a/core/reflection.jvm/src/kotlin/reflect/jvm/internal/KClassImpl.kt
+++ b/core/reflection.jvm/src/kotlin/reflect/jvm/internal/KClassImpl.kt
@@ -16,6 +16,7 @@
 
 package kotlin.reflect.jvm.internal
 
+import org.jetbrains.kotlin.builtins.CompanionObjectMapping
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.descriptors.annotations.Annotated
 import org.jetbrains.kotlin.incremental.components.NoLookupLocation
@@ -127,7 +128,7 @@ internal class KClassImpl<T : Any>(override val jClass: Class<T>) :
         val descriptor = descriptor
         if (descriptor.kind != ClassKind.OBJECT) return@lazy null
 
-        val field = if (descriptor.isCompanionObject) {
+        val field = if (descriptor.isCompanionObject && !CompanionObjectMapping.hasMappingToObject(descriptor)) {
             jClass.enclosingClass.getDeclaredField(descriptor.name.asString())
         }
         else {