diff --git a/source/concurrency/asyncscope.d b/source/concurrency/asyncscope.d
index 98d1cb0..8c311fa 100644
--- a/source/concurrency/asyncscope.d
+++ b/source/concurrency/asyncscope.d
@@ -14,6 +14,12 @@ auto asyncScope() @safe {
   return as;
 }
 
+auto asyncScope(shared StopSource source) @safe {
+  // ensure NRVO
+  auto as = shared AsyncScope(source);
+  return as;
+}
+
 struct AsyncScope {
 private:
   import concurrency.bitfield : SharedBitField;
@@ -23,6 +29,7 @@ private:
   shared Promise!void completion;
   shared StopSource stopSource;
   Throwable throwable;
+  shared StopCallback cb;
 
   void forward() @trusted nothrow shared {
     import core.atomic : atomicLoad;
@@ -61,13 +68,18 @@ public:
       cleanup.syncWait();
   }
 
-  this(shared StopSource stopSource) @safe shared {
+  this(shared StopSource stopSource) @trusted shared {
     completion = new shared Promise!void;
     this.stopSource = stopSource;
+    cb = cast(shared)this.stopSource.onStop(() @safe shared nothrow => cast(void)this.stop());
   }
 
   auto cleanup() @safe shared {
     stop();
+    return onComplete();
+  }
+
+  auto onComplete() @safe shared {
     return completion.sender();
   }
 
@@ -76,6 +88,7 @@ public:
   }
 
   bool stop() nothrow @trusted shared {
+    cb.dispose();
     import core.atomic : MemoryOrder;
     if ((flag.load!(MemoryOrder.acq) & Flag.stopped) > 0)
       return false;
diff --git a/source/concurrency/stoptoken.d b/source/concurrency/stoptoken.d
index 9c2602a..9b3978d 100644
--- a/source/concurrency/stoptoken.d
+++ b/source/concurrency/stoptoken.d
@@ -4,7 +4,7 @@ module concurrency.stoptoken;
 // it is licensed under the Creative Commons Attribution 4.0 Internation License http://creativecommons.org/licenses/by/4.0
 
 class StopSource {
-  private stop_state state;
+  private shared stop_state state;
   bool stop() nothrow @safe {
     return state.request_stop();
   }
@@ -51,28 +51,23 @@ struct NeverStopToken {
   enum isStopPossible = false;
 }
 
-StopCallback onStop(StopSource stopSource, void delegate() nothrow @safe shared callback) nothrow @safe {
-  auto cb = new StopCallback(callback);
-  if (stopSource.state.try_add_callback(cb, true))
-    cb.source = stopSource;
-  return cb;
-}
-
-StopCallback onStop(StopSource stopSource, void function() nothrow @safe callback) nothrow @trusted {
-  import std.functional : toDelegate;
-  return stopSource.onStop(cast(void delegate() nothrow @safe shared)callback.toDelegate);
-}
-
-StopCallback onStop(StopToken)(StopToken stopToken, void delegate() nothrow @safe shared callback) nothrow @safe {
-  if (stopToken.isStopPossible) {
-    return stopToken.source.onStop(callback);
+StopCallback onStop(Source)(Source stopSource, void delegate() nothrow @safe shared callback) nothrow @trusted {
+  static if (is(shared Source == shared StopSource)) {
+    auto cb = new StopCallback(callback);
+    if (stopSource.state.try_add_callback(cb, true))
+      cb.source = cast(shared)stopSource;
+    return cb;
+  } else {
+    if (stopSource.isStopPossible) {
+      return stopSource.source.onStop(callback);
+    }
+    return new StopCallback(callback);
   }
-  return new StopCallback(callback);
 }
 
-StopCallback onStop(StopToken)(StopToken stopToken, void function() nothrow @safe callback) nothrow @trusted {
+StopCallback onStop(Source)(Source stopSource, void function() nothrow @safe callback) nothrow @trusted {
   import std.functional : toDelegate;
-  return stopToken.onStop(cast(void delegate() nothrow @safe shared)callback.toDelegate);
+  return stopSource.onStop(cast(void delegate() nothrow @safe shared)callback.toDelegate);
 }
 
 class StopCallback {
@@ -105,16 +100,20 @@ private:
   }
 
   void delegate() nothrow shared @safe callback;
-  StopSource source;
+  shared StopSource source;
 
-  StopCallback next_ = null;
-  StopCallback* prev_ = null;
-  bool* isRemoved_ = null;
+  shared StopCallback next_ = null;
+  shared StopCallback* prev_ = null;
+  shared bool* isRemoved_ = null;
   shared bool callbackFinishedExecuting = false;
 
   void execute() nothrow @safe {
     callback();
   }
+
+  void execute() nothrow @safe shared {
+    callback();
+  }
 }
 
 deprecated("Use regular StopToken") alias StopTokenObject = StopToken;
@@ -155,31 +154,31 @@ private struct stop_state {
     }
 
 public:
-  void add_token_reference() nothrow @safe @nogc {
+  void add_token_reference() nothrow @safe @nogc shared {
     // TODO: want to use atomicFetchAdd but (proper) support is only recent
     // state_.atomicFetchAdd!(MemoryOrder.raw)(token_ref_increment);
     state_.atomicOp!"+="(token_ref_increment);
   }
 
-  void remove_token_reference() nothrow @safe @nogc {
+  void remove_token_reference() nothrow @safe @nogc shared {
     // TODO: want to use atomicFetchSub but (proper) support is only recent
     // state_.atomicFetchSub!(MemoryOrder.acq_rel)(token_ref_increment);
     state_.atomicOp!"-="(token_ref_increment);
   }
 
-  void add_source_reference() nothrow @safe @nogc {
+  void add_source_reference() nothrow @safe @nogc shared {
     // TODO: want to use atomicFetchAdd but (proper) support is only recent
     // state_.atomicFetchAdd!(MemoryOrder.raw)(source_ref_increment);
     state_.atomicOp!"+="(source_ref_increment);
   }
 
-  void remove_source_reference() nothrow @safe @nogc {
+  void remove_source_reference() nothrow @safe @nogc shared {
     // TODO: want to use atomicFetchSub but (proper) support is only recent
     // state_.atomicFetchSub!(MemoryOrder.acq_rel)(source_ref_increment);
     state_.atomicOp!"-="(source_ref_increment);
   }
 
-  bool request_stop() nothrow @safe {
+  bool request_stop() nothrow @safe shared {
 
     if (!try_lock_and_signal_until_signalled()) {
       // Stop has already been requested.
@@ -188,7 +187,7 @@ public:
 
     // Set the 'stop_requested' signal and acquired the lock.
 
-    signallingThread_ = Thread.getThis();
+    signallingThread_ = getThis();
 
     while (head_ !is null) {
       // Dequeue the head of the queue
@@ -212,7 +211,7 @@ public:
       // If the destructor runs on some other thread then the other
       // thread will block waiting for this thread to signal that the
       // callback has finished executing.
-      bool isRemoved = false;
+      shared bool isRemoved = false;
       (() @trusted => cb.isRemoved_ = &isRemoved)(); // the pointer to the stack here is removed 3 lines down.
 
       cb.execute();
@@ -238,15 +237,15 @@ public:
     return true;
   }
 
-  bool is_stop_requested() nothrow @safe @nogc {
+  bool is_stop_requested() nothrow @safe @nogc shared {
     return is_stop_requested(state_.atomicLoad!(MemoryOrder.acq));
   }
 
-  bool is_stop_requestable() nothrow @safe @nogc {
+  bool is_stop_requestable() nothrow @safe @nogc shared {
     return is_stop_requestable(state_.atomicLoad!(MemoryOrder.acq));
   }
 
-  bool try_add_callback(StopCallback cb, bool incrementRefCountIfSuccessful) nothrow @safe {
+  bool try_add_callback(StopCallback cb, bool incrementRefCountIfSuccessful) nothrow @safe shared {
     ulong oldState;
     do {
       goto load_state;
@@ -272,7 +271,7 @@ public:
       cb.next_.prev_ = &cb.next_;
     }
     () @trusted { cb.prev_ = &head_; } ();
-    head_ = cb;
+    () @trusted { head_ = cast(shared)cb; } ();
 
     if (incrementRefCountIfSuccessful) {
       unlock_and_increment_token_ref_count();
@@ -285,7 +284,7 @@ public:
     return true;
   }
 
-  void remove_callback(StopCallback cb) nothrow @safe @nogc {
+  void remove_callback(StopCallback cb) nothrow @safe @nogc shared {
     lock();
 
     if (cb.prev_ !is null) {
@@ -306,7 +305,7 @@ public:
     // Callback has either already executed or is executing
     // concurrently on another thread.
 
-    if (signallingThread_ is Thread.getThis()) {
+    if (signallingThread_ is getThis()) {
       // Callback executed on this thread or is still currently executing
       // and is deregistering itself from within the callback.
       if (cb.isRemoved_ !is null) {
@@ -342,7 +341,11 @@ private:
     return is_stop_requested(state) || (state >= source_ref_increment);
   }
 
-  bool try_lock_and_signal_until_signalled() nothrow @safe @nogc {
+  shared(Thread) getThis() @trusted @nogc nothrow shared {
+    return cast(shared)Thread.getThis();
+  }
+
+  bool try_lock_and_signal_until_signalled() nothrow @safe @nogc shared {
     ulong oldState;
     do {
       oldState = state_.atomicLoad!(MemoryOrder.acq);
@@ -360,7 +363,7 @@ private:
     return true;
   }
 
-  void lock() nothrow @safe @nogc {
+  void lock() nothrow @safe @nogc shared {
     ulong oldState;
     do {
       oldState = state_.atomicLoad!(MemoryOrder.raw);
@@ -373,19 +376,19 @@ private:
         oldState | locked_flag));
   }
 
-  void unlock() nothrow @safe @nogc {
+  void unlock() nothrow @safe @nogc shared {
     // TODO: want to use atomicFetchSub but (proper) support is only recent
     // state_.atomicFetchSub!(MemoryOrder.rel)(locked_flag);
     state_.atomicOp!"-="(locked_flag);
   }
 
-  void unlock_and_increment_token_ref_count() nothrow @safe @nogc {
+  void unlock_and_increment_token_ref_count() nothrow @safe @nogc shared {
     // TODO: want to use atomicFetchSub but (proper) support is only recent
     // state_.atomicFetchSub!(MemoryOrder.rel)(locked_flag - token_ref_increment);
     state_.atomicOp!"-="(locked_flag - token_ref_increment);
   }
 
-  void unlock_and_decrement_token_ref_count() nothrow @safe @nogc {
+  void unlock_and_decrement_token_ref_count() nothrow @safe @nogc shared {
     // TODO: want to use atomicFetchSub but (proper) support is only recent
     // state_.atomicFetchSub!(MemoryOrder.acq_rel)(locked_flag + token_ref_increment);
     state_.atomicOp!"-="(locked_flag + token_ref_increment);
diff --git a/tests/ut/concurrency/asyncscope.d b/tests/ut/concurrency/asyncscope.d
index 6218585..5202264 100644
--- a/tests/ut/concurrency/asyncscope.d
+++ b/tests/ut/concurrency/asyncscope.d
@@ -182,3 +182,30 @@ auto waitingTask() {
   s.spawn(VoidSender().withScheduler(localThreadScheduler));
   s.cleanup.syncWait.assumeOk;
 }
+
+@("onComplete.inline")
+@safe unittest {
+  auto s = asyncScope();
+
+  s.stop();
+  s.onComplete().syncWait.assumeOk;
+}
+
+@("onComplete.wait")
+@safe unittest {
+  import concurrency.thread : ThreadSender;
+  import concurrency.stoptoken : StopSource;
+  import concurrency.operations : then;
+
+  auto source = new shared StopSource();
+  auto s = asyncScope(source);
+
+  s.spawn(ThreadSender().then(() shared @trusted {
+        import core.thread : Thread;
+        import core.time : msecs;
+        Thread.sleep(10.msecs);
+        source.stop();
+      }));
+
+  s.onComplete().syncWait.assumeOk;
+}