Use the work erased type directly in release builds

* So this behaviour aligns to the one used in continuable_base and promise_base.

include/continuable/continuable-types.hpp

@@ -89,19 +89,7 @@ using promise = promise_base<detail::erasure::callback<Args...>, //
 ///       callable object which is callable with a `void()` signature.
 ///
 /// \since 4.0.0
-class work : public fu2::unique_function<void()> {
+using work = detail::erasure::work;
-public:
-  work() = default;
-  ~work() = default;
-  work(work const&) = delete;
-  work(work&&) = default;
-  work& operator=(work const&) = delete;
-  work& operator=(work&&) = default;
-
-  using fu2::unique_function<void()>::unique_function;
-  using fu2::unique_function<void()>::operator=;
-  using fu2::unique_function<void()>::operator();
-};
 /// \}
 } // namespace cti
 

include/continuable/detail/other/erasure.hpp

@@ -177,6 +177,26 @@ public:
   }
 };
 #endif
+
+using work_erasure_t = fu2::unique_function<void()>;
+
+#ifdef CONTINUABLE_HAS_IMMEDIATE_TYPES
+using work = work_erasure_t;
+#else
+class work : public work_erasure_t {
+public:
+  work() = default;
+  ~work() = default;
+  work(work const&) = delete;
+  work(work&&) = default;
+  work& operator=(work const&) = delete;
+  work& operator=(work&&) = default;
+
+  using work_erasure_t::work_erasure_t;
+  using work_erasure_t::operator=;
+  using work_erasure_t::operator();
+};
+#endif // CONTINUABLE_HAS_IMMEDIATE_TYPES
 } // namespace erasure
 } // namespace detail
 } // namespace cti

test/unit-test/single/test-continuable-erasure.cpp

@@ -69,7 +69,7 @@ TEST(single_erasure_test, is_constructible_from_work) {
   });
 
   ASSERT_FALSE(flag);
-  mywork();
+  std::move(mywork)();
   ASSERT_TRUE(flag);
 }
 
@@ -84,6 +84,6 @@ TEST(single_erasure_test, is_assignable_from_work) {
   };
 
   ASSERT_FALSE(flag);
-  mywork();
+  std::move(mywork)();
   ASSERT_TRUE(flag);
 }