From a17730321646dc6fd24fb56973f518abef351ae9 Mon Sep 17 00:00:00 2001
From: Victor Turansky <victor.turansky@gmail.com>
Date: Tue, 14 Apr 2020 17:45:18 +0300
Subject: [PATCH] Strict contract for 'buildElement'

---
 kotlin-extensions/src/main/kotlin/kotlinext/js/Object.kt | 2 +-
 kotlin-react/src/main/kotlin/react/RBuilder.kt           | 6 ++++--
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/kotlin-extensions/src/main/kotlin/kotlinext/js/Object.kt b/kotlin-extensions/src/main/kotlin/kotlinext/js/Object.kt
index d8910b8b60503..cf31f80b68bd3 100644
--- a/kotlin-extensions/src/main/kotlin/kotlinext/js/Object.kt
+++ b/kotlin-extensions/src/main/kotlin/kotlinext/js/Object.kt
@@ -17,7 +17,7 @@ external interface JsObject {
     fun propertyIsEnumerable(v: String): Boolean
 }
 
-fun Any.asJsObject() = this as JsObject
+fun Any.asJsObject() = unsafeCast<JsObject>()
 
 external object Object {
     fun <P, T : P> getPrototypeOf(o: T): P?
diff --git a/kotlin-react/src/main/kotlin/react/RBuilder.kt b/kotlin-react/src/main/kotlin/react/RBuilder.kt
index 5f9ff8036f75e..7961ce70e34fc 100644
--- a/kotlin-react/src/main/kotlin/react/RBuilder.kt
+++ b/kotlin-react/src/main/kotlin/react/RBuilder.kt
@@ -85,8 +85,10 @@ fun buildElements(handler: RBuilder.() -> Unit): dynamic {
 
 open class RBuilderSingle : RBuilder()
 
-inline fun buildElement(handler: RBuilder.() -> Unit): ReactElement? =
-    RBuilder().apply(handler).childList.first() as ReactElement?
+inline fun buildElement(handler: RBuilder.() -> Unit): ReactElement =
+    RBuilder().apply(handler)
+        .childList.first()
+        .unsafeCast<ReactElement>()
 
 open class RElementBuilder<out P : RProps>(open val attrs: P) : RBuilder() {
     fun attrs(handler: P.() -> Unit) {