# Exception during code generation (inlining suspend functions)

**URL:** <https://discuss.kotlinlang.org/t/exception-during-code-generation-inlining-suspend-functions/9500>\
**Category:** Support\
**Created:** [September 19, 2018, 8:17pm UTC](https://discuss.kotlinlang.org/t/exception-during-code-generation-inlining-suspend-functions/9500 "2018-09-19T20:17:55Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![togrias](https://avatars.discourse-cdn.com/v4/letter/t/45deac/32.png) [@togrias](https://discuss.kotlinlang.org/u/togrias)\
**Post date:** [September 19, 2018, 8:17pm UTC](https://discuss.kotlinlang.org/t/exception-during-code-generation-inlining-suspend-functions/9500/1 "2018-09-19T20:17:55Z")

</div>

The combination of the following code causes a compiler exception:

```
inline fun <T,R> AsyncConnection<T>.mapEdges(crossinline transform: suspend (T) -> R): AsyncConnection<R> {

return object: AsyncConnection<R> {
	override suspend fun loadEdges(): List<Edge<R>> {
		return this@mapEdges.loadEdges().mapSuspend { DefaultEdge(transform(it.node), it.cursor) }
	}
	override suspend fun loadPageInfo(): PageInfo = this@mapEdges.loadPageInfo()
}

```

}

```
inline fun <T,R> AsyncConnection<T>.mapEdges(crossinline transform: suspend (T) -> R): AsyncConnection<R> {

return object: AsyncConnection<R> {
	override suspend fun loadEdges(): List<Edge<R>> {
		return this@mapEdges.loadEdges().mapSuspend { DefaultEdge(transform(it.node), it.cursor) }
	}
	override suspend fun loadPageInfo(): PageInfo = this@mapEdges.loadPageInfo()
}

```

}

> Error:Kotlin: [Internal Error] java.lang.IllegalStateException: Backend Internal error: Exception during code generation  
> Cause: Back-end (JVM) Internal error: Couldn’t inline method call ‘mapSuspend’ into  
> public open suspend fun loadEdges(continuation:

---

<div class="post-metadata">

**Author:** ![Alexey.Belkov](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.kotlinlang.org/alexey.belkov/32/5215_2.png) [@Alexey.Belkov](https://discuss.kotlinlang.org/u/Alexey.Belkov)\
**Post date:** [September 20, 2018, 10:52am UTC](https://discuss.kotlinlang.org/t/exception-during-code-generation-inlining-suspend-functions/9500/2 "2018-09-20T10:52:56Z")

</div>

Thanks for the report. Please share your `build.gradle` file with all dependencies, so we can reproduce this problem with your sample code. You can do it by submitting an issue here: [http://kotl.in/issue](http://kotl.in/issue).