From f747fb2afaa12168b7760f001a69b8a401cd62ca Mon Sep 17 00:00:00 2001
From: Vladimir Pinchuk <vladimir.pinchuk01@gmail.com>
Date: Thu, 10 Oct 2024 13:08:20 +0300
Subject: [PATCH] etl/delegate: fix accident creation of a delegate to an
 rvalue delegate when copying/assigning from delegate with mismatching
 signature

---
 include/etl/private/delegate_cpp11.h | 29 ++++++++++++++++++----------
 1 file changed, 19 insertions(+), 10 deletions(-)

diff --git a/include/etl/private/delegate_cpp11.h b/include/etl/private/delegate_cpp11.h
index 8f438602c..7e79c977b 100644
--- a/include/etl/private/delegate_cpp11.h
+++ b/include/etl/private/delegate_cpp11.h
@@ -83,16 +83,25 @@ namespace etl
     }
   };
 
+  //*****************************************************************
+  /// The tag to identify an etl::delegate.
+  ///\ingroup delegate
+  //*****************************************************************
+  struct delegate_tag
+  {
+  };
+
   //*************************************************************************
   /// Declaration.
   //*************************************************************************
-  template <typename T> class delegate;
+  template <typename T>
+  class delegate;
 
   //*************************************************************************
   /// Specialisation.
   //*************************************************************************
   template <typename TReturn, typename... TParams>
-  class delegate<TReturn(TParams...)> final
+  class delegate<TReturn(TParams...)> final : public delegate_tag
   {
   public:
 
@@ -111,7 +120,7 @@ namespace etl
     //*************************************************************************
     // Construct from lambda or functor.
     //*************************************************************************
-    template <typename TLambda, typename = etl::enable_if_t<etl::is_class<TLambda>::value && !etl::is_same<etl::delegate<TReturn(TParams...)>, TLambda>::value, void>>
+    template <typename TLambda, typename = etl::enable_if_t<etl::is_class<TLambda>::value && !etl::is_base_of<delegate_tag, TLambda>::value, void>>
     ETL_CONSTEXPR14 delegate(TLambda& instance)
     {
       assign((void*)(&instance), lambda_stub<TLambda>);
@@ -120,7 +129,7 @@ namespace etl
     //*************************************************************************
     // Construct from const lambda or functor.
     //*************************************************************************
-    template <typename TLambda, typename = etl::enable_if_t<etl::is_class<TLambda>::value && !etl::is_same<etl::delegate<TReturn(TParams...)>, TLambda>::value, void>>
+    template <typename TLambda, typename = etl::enable_if_t<etl::is_class<TLambda>::value && !etl::is_base_of<delegate_tag, TLambda>::value, void>>
     ETL_CONSTEXPR14 delegate(const TLambda& instance)
     {
       assign((void*)(&instance), const_lambda_stub<TLambda>);
@@ -139,7 +148,7 @@ namespace etl
     //*************************************************************************
     /// Create from Lambda or Functor.
     //*************************************************************************
-    template <typename TLambda, typename = etl::enable_if_t<etl::is_class<TLambda>::value && !etl::is_same<etl::delegate<TReturn(TParams...)>, TLambda>::value, void>>
+    template <typename TLambda, typename = etl::enable_if_t<etl::is_class<TLambda>::value && !etl::is_base_of<delegate_tag, TLambda>::value, void>>
     ETL_NODISCARD
     static ETL_CONSTEXPR14 delegate create(TLambda& instance)
     {
@@ -149,7 +158,7 @@ namespace etl
     //*************************************************************************
     /// Create from const Lambda or Functor.
     //*************************************************************************
-    template <typename TLambda, typename = etl::enable_if_t<etl::is_class<TLambda>::value && !etl::is_same<etl::delegate<TReturn(TParams...)>, TLambda>::value, void>>
+    template <typename TLambda, typename = etl::enable_if_t<etl::is_class<TLambda>::value && !etl::is_base_of<delegate_tag, TLambda>::value, void>>
     ETL_NODISCARD
       static ETL_CONSTEXPR14 delegate create(const TLambda& instance)
     {
@@ -257,7 +266,7 @@ namespace etl
     //*************************************************************************
     /// Set from Lambda or Functor.
     //*************************************************************************
-    template <typename TLambda, typename = etl::enable_if_t<etl::is_class<TLambda>::value && !etl::is_same<etl::delegate<TReturn(TParams...)>, TLambda>::value, void>>
+    template <typename TLambda, typename = etl::enable_if_t<etl::is_class<TLambda>::value && !etl::is_base_of<delegate_tag, TLambda>::value, void>>
     ETL_CONSTEXPR14 void set(TLambda& instance)
     {
       assign((void*)(&instance), lambda_stub<TLambda>);
@@ -266,7 +275,7 @@ namespace etl
     //*************************************************************************
     /// Set from const Lambda or Functor.
     //*************************************************************************
-    template <typename TLambda, typename = etl::enable_if_t<etl::is_class<TLambda>::value && !etl::is_same<etl::delegate<TReturn(TParams...)>, TLambda>::value, void>>
+    template <typename TLambda, typename = etl::enable_if_t<etl::is_class<TLambda>::value && !etl::is_base_of<delegate_tag, TLambda>::value, void>>
     ETL_CONSTEXPR14 void set(const TLambda& instance)
     {
       assign((void*)(&instance), const_lambda_stub<TLambda>);
@@ -427,7 +436,7 @@ namespace etl
     //*************************************************************************
     /// Create from Lambda or Functor.
     //*************************************************************************
-    template <typename TLambda, typename = etl::enable_if_t<etl::is_class<TLambda>::value && !etl::is_same<etl::delegate<TReturn(TParams...)>, TLambda>::value, void>>
+    template <typename TLambda, typename = etl::enable_if_t<etl::is_class<TLambda>::value && !etl::is_base_of<delegate_tag, TLambda>::value, void>>
     ETL_CONSTEXPR14 delegate& operator =(TLambda& instance)
     {
       assign((void*)(&instance), lambda_stub<TLambda>);
@@ -437,7 +446,7 @@ namespace etl
     //*************************************************************************
     /// Create from const Lambda or Functor.
     //*************************************************************************
-    template <typename TLambda, typename = etl::enable_if_t<etl::is_class<TLambda>::value && !etl::is_same<etl::delegate<TReturn(TParams...)>, TLambda>::value, void>>
+    template <typename TLambda, typename = etl::enable_if_t<etl::is_class<TLambda>::value && !etl::is_base_of<delegate_tag, TLambda>::value, void>>
     ETL_CONSTEXPR14 delegate& operator =(const TLambda& instance)
     {
       assign((void*)(&instance), const_lambda_stub<TLambda>);