is<T>() - add specialisation for recursive_wrapper<T> + update test…

…s (ref #102)
mapbox · May 11, 2016 · c6ae1ea · c6ae1ea
1 parent 04dc3a4
commit c6ae1ea
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Showing 2 changed files with 17 additions and 2 deletions.
diff --git a/include/mapbox/variant.hpp b/include/mapbox/variant.hpp
@@ -653,13 +653,20 @@ class variant
         return *this;
     }
 
-    template <typename T>
+    template <typename T, typename std::enable_if<
+                          (detail::direct_type<T, Types...>::index != detail::invalid_value)>::type* = nullptr>
     VARIANT_INLINE bool is() const
     {
-        static_assert(detail::has_type<T, Types...>::value, "invalid type in T in `is<T>()` for this variant");
         return type_index == detail::direct_type<T, Types...>::index;
     }
 
+    template <typename T,typename std::enable_if<
+                         (detail::direct_type<recursive_wrapper<T>, Types...>::index != detail::invalid_value)>::type* = nullptr>
+    VARIANT_INLINE bool is() const
+    {
+        return type_index == detail::direct_type<recursive_wrapper<T>, Types...>::index;
+    }
+
     VARIANT_INLINE bool valid() const
     {
         return type_index != detail::invalid_value;

diff --git a/test/t/variant.cpp b/test/t/variant.cpp
@@ -568,3 +568,11 @@ TEST_CASE("storing reference wrappers to consts works")
     },
                       mapbox::util::bad_variant_access&);
 }
+
+TEST_CASE("recursive wrapper")
+{
+    using variant_type = mapbox::util::variant<mapbox::util::recursive_wrapper<int>>;
+    variant_type v(1);
+    REQUIRE(v.is<int>());
+    REQUIRE(v.get<int>() == 1);
+}