diff --git a/tdactor/td/actor/PromiseFuture.h b/tdactor/td/actor/PromiseFuture.h
index 23aff5f61..a4439f2d1 100644
--- a/tdactor/td/actor/PromiseFuture.h
+++ b/tdactor/td/actor/PromiseFuture.h
@@ -135,7 +135,7 @@ class LambdaPromise : public PromiseInterface<ValueT> {
       , on_fail_(use_ok_as_fail ? OnFail::Ok : OnFail::Fail)
       , has_lambda_(true) {
   }
-  template <class FromOkT>
+  template <class FromOkT, std::enable_if_t<!std::is_same<std::decay_t<FromOkT>, LambdaPromise>::value, int> = 0>
   LambdaPromise(FromOkT &&ok) : LambdaPromise(std::forward<FromOkT>(ok), Ignore(), true) {
   }
 
@@ -307,7 +307,7 @@ class Promise {
   }
   Promise(SafePromise<T> &&other);
   Promise &operator=(SafePromise<T> &&other);
-  template <class F>
+  template <class F, std::enable_if_t<!std::is_same<std::decay_t<F>, Promise>::value, int> = 0>
   Promise(F &&f) : promise_(promise_interface_ptr<T>(std::forward<F>(f))) {
   }
 
diff --git a/tdactor/td/actor/impl/Event.h b/tdactor/td/actor/impl/Event.h
index c61598c58..bd4c421fe 100644
--- a/tdactor/td/actor/impl/Event.h
+++ b/tdactor/td/actor/impl/Event.h
@@ -97,7 +97,7 @@ class LambdaEvent final : public CustomEvent {
     LOG(FATAL) << "Not supported";
     return nullptr;
   }
-  template <class FromLambdaT>
+  template <class FromLambdaT, std::enable_if_t<!std::is_same<std::decay_t<FromLambdaT>, LambdaEvent>::value, int> = 0>
   explicit LambdaEvent(FromLambdaT &&lambda) : f_(std::forward<FromLambdaT>(lambda)) {
   }
 
diff --git a/tdutils/td/utils/optional.h b/tdutils/td/utils/optional.h
index c54ea2b57..0004ec201 100644
--- a/tdutils/td/utils/optional.h
+++ b/tdutils/td/utils/optional.h
@@ -31,6 +31,9 @@ class optional {
   }
 
   optional &operator=(const optional &other) {
+    if (this == &other) {
+      return *this;
+    }
     if (other) {
       impl_ = Result<T>(other.value());
     } else {