fixes #15076 (#15329)

tests/arc/tasyncleak2.nim

@@ -0,0 +1,88 @@
+discard """
+  output: "success"
+  cmd: "nim c --gc:orc $file"
+"""
+
+# issue #15076
+import deques, strutils, asyncdispatch
+
+proc doNothing(): Future[void] =
+  #[
+  var
+    :env
+    :env_1
+  try:
+    `=destroy`(:env)
+    internalNew(:env)
+    `=sink`(:env.retFuture1, newFuture("doNothing"))
+
+    `=destroy_1`(:env_1)
+    internalNew(:env_1)
+    `=`(:env_1.:up, :env)
+    `=sink_1`(:env.nameIterVar2, (doNothingIter, :env_1))
+
+    (doNothingNimAsyncContinue, :env)()
+    return `=_1`(result, :env.retFuture1)
+  finally:
+    `=destroy`(:env)
+  ]#
+
+  var retFuture = newFuture[void]("doNothing")
+  iterator doNothingIter(): FutureBase {.closure.} =
+    # inspected ARC code: looks correct!
+    block:
+      var qqq = initDeque[string]()
+      for i in 0 .. 1000:
+        qqq.addLast($i)
+    complete(retFuture) # env.up.retFuture1
+
+  var nameIterVar = doNothingIter  # iter_Env -> retFuture ->
+
+  proc doNothingNimAsyncContinue() {.closure.} =
+    # inspected ARC code: looks correct
+    if not nameIterVar.finished:
+      var next_gensym0 = nameIterVar()
+      while (not next_gensym0.isNil) and next_gensym0.finished:
+        next_gensym0 = nameIterVar()
+        if nameIterVar.finished:
+          break
+      if next_gensym0 != nil:
+        {.gcsafe.}:
+          next_gensym0.addCallback cast[proc () {.closure, gcsafe.}](doNothingNimAsyncContinue)
+
+  doNothingNimAsyncContinue()
+  return retFuture
+
+proc main(): Future[void] =
+  template await[T](f_gensym12: Future[T]): auto {.used.} =
+    var internalTmpFuture_gensym12: FutureBase = f_gensym12
+    yield internalTmpFuture_gensym12
+    (cast[type(f_gensym12)](internalTmpFuture_gensym12)).read()
+
+  var retFuture = newFuture[void]("main")
+  iterator mainIter(): FutureBase {.closure.} =
+    block:
+      for x in 0 .. 1000:
+        await doNothing()
+    complete(retFuture)
+
+  var nameIterVar_gensym11 = mainIter
+  proc mainNimAsyncContinue() {.closure.} =
+    if not nameIterVar_gensym11.finished:
+      var next_gensym11 = unown nameIterVar_gensym11()
+      while (not next_gensym11.isNil) and next_gensym11.finished:
+        next_gensym11 = unown nameIterVar_gensym11()
+        if nameIterVar_gensym11.finished:
+          break
+      if next_gensym11 != nil:
+        {.gcsafe.}:
+          next_gensym11.addCallback cast[proc () {.closure, gcsafe.}](mainNimAsyncContinue)
+
+  mainNimAsyncContinue()
+  return retFuture
+
+for i in 0..9:
+  waitFor main()
+  GC_fullCollect()
+  assert getOccupiedMem() < 1024
+echo "success"