Fix "Return type must be specified in explicit API mode"

Author: ALikhachev

kotlinx-coroutines-core/common/src/internal/DispatchedTask.kt

@@ -23,7 +23,7 @@ internal const val MODE_ATOMIC = 0
  * **DO NOT CHANGE THE CONSTANT VALUE**. It is being into the user code from [suspendCancellableCoroutine].
  */
 @PublishedApi
-internal const val MODE_CANCELLABLE = 1
+internal const val MODE_CANCELLABLE: Int = 1
 
 /**
  * Cancellable dispatch mode for [suspendCancellableCoroutineReusable].

kotlinx-coroutines-core/common/src/selects/SelectUnbiased.kt

@@ -36,7 +36,7 @@ internal class UnbiasedSelectBuilderImpl<in R>(uCont: Continuation<R>) :
     val clauses = arrayListOf<() -> Unit>()
 
     @PublishedApi
-    internal fun handleBuilderException(e: Throwable) = instance.handleBuilderException(e)
+    internal fun handleBuilderException(e: Throwable): Unit = instance.handleBuilderException(e)
 
     @PublishedApi
     internal fun initSelectResult(): Any? {

kotlinx-coroutines-core/jvm/src/internal/LockFreeLinkedList.kt

@@ -11,13 +11,13 @@ import kotlinx.coroutines.*
 private typealias Node = LockFreeLinkedListNode
 
 @PublishedApi
-internal const val UNDECIDED = 0
+internal const val UNDECIDED: Int = 0
 
 @PublishedApi
-internal const val SUCCESS = 1
+internal const val SUCCESS: Int = 1
 
 @PublishedApi
-internal const val FAILURE = 2
+internal const val FAILURE: Int = 2
 
 @PublishedApi
 internal val CONDITION_FALSE: Any = Symbol("CONDITION_FALSE")