diff --git a/chronos/internal/asyncfutures.nim b/chronos/internal/asyncfutures.nim
index 1a2be7577..d08425202 100644
--- a/chronos/internal/asyncfutures.nim
+++ b/chronos/internal/asyncfutures.nim
@@ -786,7 +786,7 @@ template orImpl*[T, Y](fut1: Future[T], fut2: Future[Y]): untyped =
   fut2.addCallback(cb)
 
   retFuture.cancelCallback = cancellation
-  return retFuture
+  retFuture
 
 proc `or`*[T, Y](fut1: Future[T], fut2: Future[Y]): Future[void] =
   ## Returns a future which will complete once either ``fut1`` or ``fut2``
@@ -801,7 +801,7 @@ proc `or`*[T, Y](fut1: Future[T], fut2: Future[Y]): Future[void] =
   ## completed, the result future will also be completed.
   ##
   ## If cancelled, ``fut1`` and ``fut2`` futures WILL NOT BE cancelled.
-  var retFuture = newFuture[void]("chronos.or")
+  var retFuture = newFuture[void]("chronos.or()")
   orImpl(fut1, fut2)
 
 
@@ -1410,6 +1410,8 @@ proc withTimeout*[T](fut: Future[T], timeout: Duration): Future[bool] {.
   var
     retFuture = newFuture[bool]("chronos.withTimeout",
                                 {FutureFlag.OwnCancelSchedule})
+      # We set `OwnCancelSchedule` flag, because we going to cancel `retFuture`
+      # manually at proper time.
     moment: Moment
     timer: TimerCallback
     timeouted = false
@@ -1536,6 +1538,8 @@ proc wait*[T](fut: Future[T], timeout = InfiniteDuration): Future[T] =
   ## should return, because it can't be cancelled too.
   var
     retFuture = newFuture[T]("chronos.wait()", {FutureFlag.OwnCancelSchedule})
+      # We set `OwnCancelSchedule` flag, because we going to cancel `retFuture`
+      # manually at proper time.
 
   waitImpl(fut, retFuture, timeout)
 
@@ -1665,10 +1669,9 @@ proc `or`*[T, Y, E1, E2](
     fut1: InternalRaisesFuture[T, E1],
     fut2: InternalRaisesFuture[Y, E2]): auto =
   type
-    InternalRaisesFutureRaises = union(E1, E2)
+    InternalRaisesFutureRaises = union(E1, E2).union((CancelledError,))
 
-  let
-    retFuture = newFuture[void]("chronos.wait()", {FutureFlag.OwnCancelSchedule})
+  let retFuture = newFuture[void]("chronos.or()", {})
   orImpl(fut1, fut2)
 
 proc wait*(fut: InternalRaisesFuture, timeout = InfiniteDuration): auto =
@@ -1678,6 +1681,8 @@ proc wait*(fut: InternalRaisesFuture, timeout = InfiniteDuration): auto =
     InternalRaisesFutureRaises = E.prepend(CancelledError, AsyncTimeoutError)
 
   let
-    retFuture = newFuture[T]("chronos.wait()", {FutureFlag.OwnCancelSchedule})
+    retFuture = newFuture[T]("chronos.wait()", {OwnCancelSchedule})
+      # We set `OwnCancelSchedule` flag, because we going to cancel `retFuture`
+      # manually at proper time.
 
   waitImpl(fut, retFuture, timeout)
diff --git a/chronos/internal/raisesfutures.nim b/chronos/internal/raisesfutures.nim
index 5b91f4152..ed85c036e 100644
--- a/chronos/internal/raisesfutures.nim
+++ b/chronos/internal/raisesfutures.nim
@@ -142,7 +142,7 @@ macro union*(tup0: typedesc, tup1: typedesc): typedesc =
     if not found:
       result.add err
 
-  for err2 in getType(getTypeInst(tup1)[1])[1..^1]:
+  for err2 in tup1.members():
     result.add err2
   if result.len == 0:
     result = makeNoRaises()
diff --git a/tests/testbugs.nim b/tests/testbugs.nim
index fc4af3a45..3f2f4e420 100644
--- a/tests/testbugs.nim
+++ b/tests/testbugs.nim
@@ -135,6 +135,16 @@ suite "Asynchronous issues test suite":
     await server.closeWait()
     return true
 
+  proc testOrDeadlock(): Future[bool] {.async.} =
+    proc f(): Future[void] {.async.} =
+      await sleepAsync(2.seconds) or sleepAsync(1.seconds)
+    let fx = f()
+    try:
+      await fx.cancelAndWait().wait(2.seconds)
+    except AsyncTimeoutError:
+      return false
+    true
+
   test "Issue #6":
     check waitFor(issue6()) == true
 
@@ -152,3 +162,6 @@ suite "Asynchronous issues test suite":
 
   test "IndexError crash test":
     check waitFor(testIndexError()) == true
+
+  test "`or` deadlock [#516] test":
+    check waitFor(testOrDeadlock()) == true
diff --git a/tests/testfut.nim b/tests/testfut.nim
index fc2401d04..aee3b1537 100644
--- a/tests/testfut.nim
+++ b/tests/testfut.nim
@@ -1594,6 +1594,19 @@ suite "Future[T] behavior test suite":
     discard someFut.tryCancel()
     await someFut
 
+  asyncTest "wait() should allow cancellation test (depends on race())":
+    proc testFoo(): Future[bool] {.async.} =
+      let
+        resFut = sleepAsync(2.seconds).wait(3.seconds)
+        timeFut = sleepAsync(1.seconds)
+        cancelFut = cancelAndWait(resFut)
+      discard await race(cancelFut, timeFut)
+      if cancelFut.finished():
+        return (resFut.cancelled() and cancelFut.completed())
+      false
+
+    check (await testFoo()) == true
+
   asyncTest "withTimeout() cancellation undefined behavior test #1":
     proc testInnerFoo(fooFut: Future[void]): Future[TestFooConnection] {.
          async.} =
@@ -1654,6 +1667,19 @@ suite "Future[T] behavior test suite":
     discard someFut.tryCancel()
     await someFut
 
+  asyncTest "withTimeout() should allow cancellation test (depends on race())":
+    proc testFoo(): Future[bool] {.async.} =
+      let
+        resFut = sleepAsync(2.seconds).withTimeout(3.seconds)
+        timeFut = sleepAsync(1.seconds)
+        cancelFut = cancelAndWait(resFut)
+      discard await race(cancelFut, timeFut)
+      if cancelFut.finished():
+        return (resFut.cancelled() and cancelFut.completed())
+      false
+
+    check (await testFoo()) == true
+
   asyncTest "Cancellation behavior test":
     proc testInnerFoo(fooFut: Future[void]) {.async.} =
       await fooFut
diff --git a/tests/testmacro.nim b/tests/testmacro.nim
index 9b19c6891..d646303a3 100644
--- a/tests/testmacro.nim
+++ b/tests/testmacro.nim
@@ -491,7 +491,7 @@ suite "Exceptions tracking":
     proc testit2 {.async: (raises: [IOError]).} =
       raise (ref IOError)()
 
-    proc test {.async: (raises: [ValueError, IOError]).} =
+    proc test {.async: (raises: [CancelledError, ValueError, IOError]).} =
       await testit() or testit2()
 
     proc noraises() {.raises: [].} =