From dbbc4ec2813b3414fd9998d363aad0ec8219d28e Mon Sep 17 00:00:00 2001
From: Mikhail Glukhikh <mikhail.glukhikh@jetbrains.com>
Date: Tue, 19 Jul 2016 16:40:43 +0300
Subject: [PATCH] Array<Subtype> can be now cast to Array<Supertype(?)> without
 CAST_NEVER_SUCCEEDS #KT-6391 Fixed (cherry picked from commit 2629d55)

---
 .../src/org/jetbrains/kotlin/types/CastDiagnosticsUtil.kt | 8 ++++++--
 .../diagnostics/tests/cast/AsWithOtherParameter.kt        | 7 +++++++
 .../diagnostics/tests/cast/AsWithOtherParameter.txt       | 1 +
 3 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/compiler/frontend/src/org/jetbrains/kotlin/types/CastDiagnosticsUtil.kt b/compiler/frontend/src/org/jetbrains/kotlin/types/CastDiagnosticsUtil.kt
index ba09dd4bcec..db816bff4f1 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/types/CastDiagnosticsUtil.kt
+++ b/compiler/frontend/src/org/jetbrains/kotlin/types/CastDiagnosticsUtil.kt
@@ -25,6 +25,7 @@ import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.types.checker.KotlinTypeChecker
 import org.jetbrains.kotlin.types.checker.TypeCheckingProcedure
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
+import org.jetbrains.kotlin.types.typeUtil.isPrimitiveNumberType
 
 object CastDiagnosticsUtil {
 
@@ -46,8 +47,11 @@ object CastDiagnosticsUtil {
             if (KotlinBuiltIns.isArray(lhsType)) {
                 val lhsArgument = lhsType.arguments.firstOrNull()
                 val rhsArgument = rhsType.arguments.firstOrNull()
-                if (lhsArgument != null && rhsArgument != null && lhsArgument.type.constructor == rhsArgument.type.constructor) {
-                    return true
+                if (lhsArgument != null && rhsArgument != null) {
+                    if (lhsArgument.type.constructor == rhsArgument.type.constructor) return true
+                    if (KotlinTypeChecker.DEFAULT.isSubtypeOf(TypeUtils.makeNotNullable(lhsArgument.type), rhsArgument.type)) {
+                        return true
+                    }
                 }
             }
         }
diff --git a/compiler/testData/diagnostics/tests/cast/AsWithOtherParameter.kt b/compiler/testData/diagnostics/tests/cast/AsWithOtherParameter.kt
index 97e355b37e8..a3665133963 100644
--- a/compiler/testData/diagnostics/tests/cast/AsWithOtherParameter.kt
+++ b/compiler/testData/diagnostics/tests/cast/AsWithOtherParameter.kt
@@ -23,5 +23,12 @@ fun checkArrays2(): Array<Wrapper<String>> {
     return <!UNCHECKED_CAST!>someArray as Array<Wrapper<String>><!>
 }
 
+fun checkArrays3() {
+    val someArray = arrayOfNulls<String>(1)
+    <!UNCHECKED_CAST!>someArray as Array<Any><!>
+    val intArray = arrayOfNulls<Int>(1)
+    <!UNCHECKED_CAST!>intArray as Array<Any><!>
+}
+
 fun println(s: String) = s
 
diff --git a/compiler/testData/diagnostics/tests/cast/AsWithOtherParameter.txt b/compiler/testData/diagnostics/tests/cast/AsWithOtherParameter.txt
index e27b19b636e..67aaffa013a 100644
--- a/compiler/testData/diagnostics/tests/cast/AsWithOtherParameter.txt
+++ b/compiler/testData/diagnostics/tests/cast/AsWithOtherParameter.txt
@@ -2,6 +2,7 @@ package
 
 public fun checkArrays(): kotlin.Array<kotlin.Any>
 public fun checkArrays2(): kotlin.Array<Wrapper<kotlin.String>>
+public fun checkArrays3(): kotlin.Unit
 public fun println(/*0*/ s: kotlin.String): kotlin.String
 public fun </*0*/ T> test(/*0*/ clazz: Class<T>): kotlin.Unit
 public fun use(): kotlin.Unit