[meta] Add in-house impl of hb_is_convertible()
diff --git a/src/hb-meta.hh b/src/hb-meta.hh
index 4ec3702..0ea5774 100644
--- a/src/hb-meta.hh
+++ b/src/hb-meta.hh
@@ -132,31 +132,7 @@
/* TODO Add feature-parity to std::decay. */
template <typename T> using hb_decay = hb_remove_const<hb_remove_reference<T>>;
-template <typename From, typename To>
-struct hb_is_convertible
-{
- private:
- static constexpr bool from_void = hb_is_same (void, hb_decay<From>);
- static constexpr bool to_void = hb_is_same (void, hb_decay<To> );
- static constexpr bool either_void = from_void || to_void;
- static constexpr bool both_void = from_void && to_void;
-
- static hb_true_type impl2 (typename std::conditional<to_void, int, To>::type);
-
- template <typename T>
- static auto impl (hb_priority<1>) -> decltype (impl2 (hb_declval (T)));
- template <typename T>
- static hb_false_type impl (hb_priority<0>);
- public:
- static constexpr bool value = both_void ||
- (!either_void &&
- decltype (impl<typename std::conditional<from_void, int, From>::type> (hb_prioritize))::value);
-};
-#define hb_is_convertible(From,To) hb_is_convertible<From, To>::value
-
-template <typename Base, typename Derived>
-using hb_is_base_of = hb_is_convertible<hb_decay<Derived> *, hb_decay<Base> *>;
-#define hb_is_base_of(Base,Derived) hb_is_base_of<Base, Derived>::value
+#define hb_is_convertible(From,To) std::is_convertible<From, To>::value
template <typename From, typename To>
using hb_is_cr_convertible = hb_bool_constant<
diff --git a/src/test-meta.cc b/src/test-meta.cc
index 0fb2385..ae9b56b 100644
--- a/src/test-meta.cc
+++ b/src/test-meta.cc
@@ -81,20 +81,6 @@
static_assert (hb_is_convertible (int *, void *), "");
static_assert (!hb_is_convertible (void *, int *), "");
- static_assert (hb_is_base_of (void, void), "");
- static_assert (hb_is_base_of (void, int), "");
- static_assert (!hb_is_base_of (int, void), "");
-
- static_assert (hb_is_base_of (int, int), "");
- static_assert (hb_is_base_of (const int, int), "");
- static_assert (hb_is_base_of (int, const int), "");
-
- static_assert (hb_is_base_of (X, X), "");
- static_assert (hb_is_base_of (X, Y), "");
- static_assert (hb_is_base_of (const X, Y), "");
- static_assert (hb_is_base_of (X, const Y), "");
- static_assert (!hb_is_base_of (Y, X), "");
-
/* TODO Add more meaningful tests. */
return 0;