[NI] Add test for obsolete issue

#KT-30858 Obsolete

compiler/testData/codegen/box/coroutines/kt30858.kt

@@ -0,0 +1,36 @@
+// !LANGUAGE: +NewInference
+// IGNORE_BACKEND: JVM_IR, NATIVE
+// WITH_RUNTIME
+// WITH_COROUTINES
+
+class MyReceiveChannel<out E>
+interface MyProducerScope<in E>
+interface MyCoroutineScope
+
+suspend inline fun <E> MyReceiveChannel<E>.myConsumeEach(action: (E) -> Unit) {}
+
+suspend fun myDelay(timeMillis: Long) {}
+
+fun myLaunch(
+    block: suspend MyCoroutineScope.() -> Unit
+) {}
+
+@UseExperimental(kotlin.experimental.ExperimentalTypeInference::class)
+public fun <E> myProduce(@BuilderInference block: suspend MyProducerScope<E>.() -> Unit) {}
+
+fun <T> MyReceiveChannel<T>.debounce(period: Long) {
+    myProduce {
+        myConsumeEach {
+            myLaunch {
+                myDelay(period)
+            }
+        }
+    }
+}
+
+fun box(): String {
+    val m = MyReceiveChannel<String>()
+    m.debounce(42)
+
+    return "OK"
+}