From 3d745a4b0c99b90edffa3fdcddf40783c7776c6b Mon Sep 17 00:00:00 2001
From: Eugene Kabanov <eugene.kabanov@status.im>
Date: Mon, 6 Apr 2020 15:49:09 +0300
Subject: [PATCH] Fix Nim's issue #13889
 https://github.com/nim-lang/Nim/issues/13889. (#90)

---
 chronos/asyncmacro2.nim |  4 +---
 tests/testbugs.nim      | 20 ++++++++++++++++++++
 2 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/chronos/asyncmacro2.nim b/chronos/asyncmacro2.nim
index 2978ba5..eb7822a 100644
--- a/chronos/asyncmacro2.nim
+++ b/chronos/asyncmacro2.nim
@@ -47,9 +47,7 @@ template createCb(retFutureSym, iteratorNameSym,
             raise newException(AssertionError, msg % strName)
         else:
           {.gcsafe.}:
-            {.push hint[ConvFromXtoItselfNotNeeded]: off.}
-            next.callback = identName
-            {.pop.}
+            next.addCallback(identName)
     except CancelledError:
       retFutureSym.cancel()
     except CatchableError as exc:
diff --git a/tests/testbugs.nim b/tests/testbugs.nim
index 5f6b9e1..f1be45f 100644
--- a/tests/testbugs.nim
+++ b/tests/testbugs.nim
@@ -56,6 +56,23 @@ suite "Asynchronous issues test suite":
       discard await withTimeout(sleepAsync(4.milliseconds), 4.milliseconds)
     result = true
 
+  proc testMultipleAwait(): Future[bool] {.async.} =
+    var promise = newFuture[void]()
+    var checkstr = ""
+
+    proc believers(name: string) {.async.} =
+      await promise
+      checkstr = checkstr & name
+
+    asyncCheck believers("Foo")
+    asyncCheck believers("Bar")
+    asyncCheck believers("Baz")
+
+    await sleepAsync(100.milliseconds)
+    promise.complete()
+    await sleepAsync(100.milliseconds)
+    result = (checkstr == "FooBarBaz")
+
   test "Issue #6":
     check waitFor(issue6()) == true
 
@@ -64,3 +81,6 @@ suite "Asynchronous issues test suite":
 
   test "Callback-race double completion [withTimeout()] test":
     check waitFor(testWithTimeout()) == true
+
+  test "Multiple await on single future test [Nim's issue #13889]":
+    check waitFor(testMultipleAwait()) == true