Merge pull request #1649 from jehelset/jeh/sequence-sender-dialects

Relax `__enable_sequence_sender` concept.

Author: ericniebler

include/exec/sequence_senders.hpp

@@ -134,7 +134,7 @@ namespace exec {
   template <class _Sender>
   concept __enable_sequence_sender = requires {
     typename _Sender::sender_concept;
-  } && stdexec::same_as<typename _Sender::sender_concept, sequence_sender_t>;
+  } && stdexec::derived_from<typename _Sender::sender_concept, sequence_sender_t>;
 
   template <class _Sender>
   inline constexpr bool enable_sequence_sender = __enable_sequence_sender<_Sender>;