Implicit conversion from unique_function<R(Args...) const> to `uniq…

…ue_function<R(Args...)>`
Beyond-Engine · Oct 31, 2019 · b6f1b2a · b6f1b2a
1 parent 40e6be1
commit b6f1b2a
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Showing 3 changed files with 19 additions and 249 deletions.
diff --git a/include/unique_function.hpp b/include/unique_function.hpp
@@ -180,14 +180,20 @@ template <typename R, typename... Args> struct unique_function_base {
 template <typename R, typename... Args>
 class unique_function<R(Args...)>
     : public detail::unique_function_base<R, Args...> {
+  using base_type = detail::unique_function_base<R, Args...>;
+
 public:
   unique_function() = default;
 
   template <typename Func, class DFunc = std::decay_t<Func>,
             class = std::enable_if_t<!std::is_same_v<DFunc, unique_function> &&
                                      std::is_move_constructible_v<DFunc>>>
-  explicit unique_function(Func&& func)
-      : detail::unique_function_base<R, Args...>{std::forward<Func>(func)}
+  explicit unique_function(Func&& func) : base_type{std::forward<Func>(func)}
+  {
+  }
+
+  unique_function(unique_function<R(Args...) const>&& other)
+      : base_type{static_cast<base_type&&>(other)}
   {
   }
 

diff --git a/test/unique_function_test.cpp b/test/unique_function_test.cpp
@@ -240,6 +240,15 @@ TEST_CASE("const unique_function")
 {
   // beyond::unique_function<int() const> f2{[]() mutable { return 42; }};
 
-  beyond::unique_function<int() const> f{[]() { return 42; }};
-  REQUIRE(f() == 42);
+  SECTION("A unique_function to const function")
+  {
+    beyond::unique_function<int() const> f{[]() { return 42; }};
+    REQUIRE(f() == 42);
+
+    SECTION("const specialization can implicit convert to none-const version")
+    {
+      beyond::unique_function<int()> f2 = std::move(f);
+      REQUIRE(f2() == 42);
+    }
+  }
 }
diff --git a/test/unique_function_test.cpp.autosave b/test/unique_function_test.cpp.autosave