Clang format

.clang-format

@@ -0,0 +1 @@
+BasedOnStyle: LLVM

optional.hpp

@@ -7,39 +7,52 @@
 // public domain worldwide. This software is distributed without any warranty.
 //
 // You should have received a copy of the CC0 Public Domain Dedication
-// along with this software. If not, see <http://creativecommons.org/publicdomain/zero/1.0/>.
+// along with this software. If not, see
+// <http://creativecommons.org/publicdomain/zero/1.0/>.
 ///
 
+#include <exception>
+#include <functional>
+#include <new>
 #include <type_traits>
 #include <utility>
-#include <exception>
-#include <new>
-#include <functional>
 
 namespace tl {
 namespace detail {
 template <class T> using remove_cv_t = typename std::remove_cv<T>::type;
 template <class T> using remove_const_t = typename std::remove_const<T>::type;
-        template <class T> using remove_volatile_t = typename std::remove_volatile<T>::type;
+template <class T>
+using remove_volatile_t = typename std::remove_volatile<T>::type;
 template <class T> using add_cv_t = typename std::add_cv<T>::type;
 template <class T> using add_const_t = typename std::add_const<T>::type;
 template <class T> using add_volatile_t = typename std::add_volatile<T>::type;
-        template <class T> using remove_reference_t = typename std::remove_reference<T>::type;
+template <class T>
-        template <class T> using add_lvalue_reference_t = typename std::add_lvalue_reference<T>::type;
+using remove_reference_t = typename std::remove_reference<T>::type;
-        template <class T> using add_rvalue_reference_t = typename std::add_rvalue_reference<T>::type;
+template <class T>
-        template <class T> using remove_pointer_t = typename std::remove_pointer<T>::type;
+using add_lvalue_reference_t = typename std::add_lvalue_reference<T>::type;
+template <class T>
+using add_rvalue_reference_t = typename std::add_rvalue_reference<T>::type;
+template <class T>
+using remove_pointer_t = typename std::remove_pointer<T>::type;
 template <class T> using add_pointer_t = typename std::add_pointer<T>::type;
 template <class T> using make_signed_t = typename std::make_signed<T>::type;
 template <class T> using make_unsigned_t = typename std::make_unsigned<T>::type;
 template <class T> using remove_extent_t = typename std::remove_extent<T>::type;
-        template <class T> using remove_all_extents_t = typename std::remove_all_extents<T>::type;
+template <class T>
-        template <std::size_t N, std::size_t A=N> using aligned_storage_t = typename std::aligned_storage<N,A>::type;
+using remove_all_extents_t = typename std::remove_all_extents<T>::type;
-        template <std::size_t N, class... Ts> using aligned_union_t = typename std::aligned_union<N,Ts...>::type;
+template <std::size_t N, std::size_t A = N>
+using aligned_storage_t = typename std::aligned_storage<N, A>::type;
+template <std::size_t N, class... Ts>
+using aligned_union_t = typename std::aligned_union<N, Ts...>::type;
 template <class T> using decay_t = typename std::decay<T>::type;
-        template <bool E, class T=void> using enable_if_t = typename std::enable_if<E,T>::type;
+template <bool E, class T = void>
-        template <bool B, class T, class F> using conditional_t = typename std::conditional<B,T,F>::type;
+using enable_if_t = typename std::enable_if<E, T>::type;
-        template <class... Ts> using common_type_t = typename std::common_type<Ts...>::type;
+template <bool B, class T, class F>
-        template <class T> using underlying_type_t = typename std::underlying_type<T>::type;
+using conditional_t = typename std::conditional<B, T, F>::type;
+template <class... Ts>
+using common_type_t = typename std::common_type<Ts...>::type;
+template <class T>
+using underlying_type_t = typename std::underlying_type<T>::type;
 template <class T> using result_of_t = typename std::result_of<T>::type;
 
 template <class...> struct conjunction : std::true_type {};
@@ -58,16 +71,14 @@ namespace tl {
 static constexpr in_place_t in_place{};
 
 // [optional.optional], class template optional
-    template <class T>
+template <class T> class optional;
-    class optional;
 
 namespace detail {
 template <class T, class U>
-        using enable_forward_value = detail::enable_if_t<
+using enable_forward_value =
-            std::is_constructible<T, U&&>::value &&
+    detail::enable_if_t<std::is_constructible<T, U &&>::value &&
                         !std::is_same<detail::decay_t<U>, in_place_t>::value &&
-            !std::is_same<optional<T>, detail::decay_t<U>>::value
+                        !std::is_same<optional<T>, detail::decay_t<U>>::value>;
-            >;
 
 template <class T, class U, class Other>
 using enable_from_other = detail::enable_if_t<
@@ -79,16 +90,14 @@ namespace tl {
     !std::is_convertible<optional<U> &, T>::value &&
     !std::is_convertible<optional<U> &&, T>::value &&
     !std::is_convertible<const optional<U> &, T>::value &&
-            !std::is_convertible<const optional<U>&&, T>::value
+    !std::is_convertible<const optional<U> &&, T>::value>;
-            >;
 
 template <class T, class U>
 using enable_assign_forward = detail::enable_if_t<
     !std::is_same<optional<T>, detail::decay_t<U>>::value &&
-            !detail::conjunction<std::is_scalar<T>, std::is_same<T, detail::decay_t<U>>>::value &&
+    !detail::conjunction<std::is_scalar<T>,
-            std::is_constructible<T, U>::value &&
+                         std::is_same<T, detail::decay_t<U>>>::value &&
-            std::is_assignable<T&, U>::value
+    std::is_constructible<T, U>::value && std::is_assignable<T &, U>::value>;
-            >;
 
 template <class T, class U, class Other>
 using enable_assign_from_other = detail::enable_if_t<
@@ -105,66 +114,73 @@ namespace tl {
     !std::is_assignable<T &, optional<U> &>::value &&
     !std::is_assignable<T &, optional<U> &&>::value &&
     !std::is_assignable<T &, const optional<U> &>::value &&
-            !std::is_assignable<T&, const optional<U>&&>::value
+    !std::is_assignable<T &, const optional<U> &&>::value>;
-            >;
-
 
 // https://stackoverflow.com/questions/26744589/what-is-a-proper-way-to-implement-is-swappable-to-test-for-the-swappable-concept
 namespace swap_adl_tests {
-            // if swap ADL finds this then it would call std::swap otherwise (same signature)
+// if swap ADL finds this then it would call std::swap otherwise (same
+// signature)
 struct tag {};
 
 template <class T> tag swap(T &, T &);
 template <class T, std::size_t N> tag swap(T (&a)[N], T (&b)[N]);
 
-            // helper functions to test if an unqualified swap is possible, and if it becomes std::swap
+// helper functions to test if an unqualified swap is possible, and if it
+// becomes std::swap
 template <class, class> std::false_type can_swap(...) noexcept(false);
-            template<class T, class U, class = decltype(swap(std::declval<T&>(), std::declval<U&>()))>
+template <class T, class U,
-            std::true_type can_swap(int) noexcept(
+          class = decltype(swap(std::declval<T &>(), std::declval<U &>()))>
-                noexcept(swap(std::declval<T&>(), std::declval<U&>()))
+std::true_type can_swap(int) noexcept(noexcept(swap(std::declval<T &>(),
-                );
+                                                    std::declval<U &>())));
 
 template <class, class> std::false_type uses_std(...);
 template <class T, class U>
-            std::is_same<decltype(swap(std::declval<T&>(), std::declval<U&>())), tag> uses_std(int);
+std::is_same<decltype(swap(std::declval<T &>(), std::declval<U &>())), tag>
+uses_std(int);
 
 template <class T>
-            struct is_std_swap_noexcept : std::integral_constant<bool,
+struct is_std_swap_noexcept
+    : std::integral_constant<bool,
                              std::is_nothrow_move_constructible<T>::value &&
-                                                                 std::is_nothrow_move_assignable<T>::value
+                                 std::is_nothrow_move_assignable<T>::value> {};
-                                                                 > { };
 
 template <class T, std::size_t N>
 struct is_std_swap_noexcept<T[N]> : is_std_swap_noexcept<T> {};
 
 template <class T, class U>
-            struct is_adl_swap_noexcept : std::integral_constant<bool, noexcept(can_swap<T, U>(0))> { };
+struct is_adl_swap_noexcept
+    : std::integral_constant<bool, noexcept(can_swap<T, U>(0))> {};
 }
 
 template <class T, class U = T>
-        struct is_swappable : std::integral_constant<bool,
+struct is_swappable
+    : std::integral_constant<
+          bool,
           decltype(detail::swap_adl_tests::can_swap<T, U>(0))::value &&
               (!decltype(detail::swap_adl_tests::uses_std<T, U>(0))::value ||
-                                                      (std::is_move_assignable<T>::value && std::is_move_constructible<T>::value))
+               (std::is_move_assignable<T>::value &&
-                                                     > {};
+                std::is_move_constructible<T>::value))> {};
 
 template <class T, std::size_t N>
-        struct is_swappable<T[N], T[N]> : std::integral_constant<bool,
+struct is_swappable<T[N], T[N]>
+    : std::integral_constant<
+          bool,
           decltype(detail::swap_adl_tests::can_swap<T[N], T[N]>(0))::value &&
-                                                                 (!decltype(detail::swap_adl_tests::uses_std<T[N], T[N]>(0))::value ||
+              (!decltype(
-                                                                  is_swappable<T, T>::value)
+                   detail::swap_adl_tests::uses_std<T[N], T[N]>(0))::value ||
-                                                                 > {};
+               is_swappable<T, T>::value)> {};
 
 template <class T, class U = T>
-        struct is_nothrow_swappable : std::integral_constant<bool,
+struct is_nothrow_swappable
-                                                             is_swappable<T, U>::value && (
+    : std::integral_constant<
-                                                                 (decltype(detail::swap_adl_tests::uses_std<T, U>(0))::value &&
+          bool,
-                                                                  detail::swap_adl_tests::is_std_swap_noexcept<T>::value)
+          is_swappable<T, U>::value &&
-                                                                 ||
+              ((decltype(detail::swap_adl_tests::uses_std<T, U>(0))::value
+                    &&detail::swap_adl_tests::is_std_swap_noexcept<T>::value) ||
                (!decltype(detail::swap_adl_tests::uses_std<T, U>(0))::value &&
-                                                                  detail::swap_adl_tests::is_adl_swap_noexcept<T, U>::value)
+                    detail::swap_adl_tests::is_adl_swap_noexcept<T,
-                                                                 )
+                                                                 U>::value))> {
-                                                             > {};
+};
 }
 
 // [optional.nullopt], no-value state indicator
@@ -172,124 +188,156 @@ namespace tl {
   struct do_not_use {};
   constexpr explicit nullopt_t(do_not_use, do_not_use) noexcept {}
 };
-    static constexpr nullopt_t nullopt{nullopt_t::do_not_use{}, nullopt_t::do_not_use{}};
+static constexpr nullopt_t nullopt{nullopt_t::do_not_use{},
+                                   nullopt_t::do_not_use{}};
 
 // [optional.bad.access], class bad_optional_access
 class bad_optional_access : public std::exception {
 public:
   bad_optional_access() = default;
-        const char* what() const noexcept {
+  const char *what() const noexcept { return "Optional has no value"; }
-            return "Optional has no value";
-        }
 };
 
 // [optional.relops], relational operators
 template <class T, class U>
-    inline constexpr bool operator==(const optional<T>& lhs, const optional<U>& rhs) {
+inline constexpr bool operator==(const optional<T> &lhs,
-        return lhs.has_value() == rhs.has_value() && (!lhs.has_value() || *lhs == *rhs);
+                                 const optional<U> &rhs) {
+  return lhs.has_value() == rhs.has_value() &&
+         (!lhs.has_value() || *lhs == *rhs);
 }
 template <class T, class U>
-    inline constexpr bool operator!=(const optional<T>& lhs, const optional<U>& rhs) {
+inline constexpr bool operator!=(const optional<T> &lhs,
-        return lhs.has_value() != rhs.has_value() || (lhs.has_value() && *lhs != *rhs);
+                                 const optional<U> &rhs) {
+  return lhs.has_value() != rhs.has_value() ||
+         (lhs.has_value() && *lhs != *rhs);
 }
 template <class T, class U>
-    inline constexpr bool operator<(const optional<T>& lhs, const optional<U>& rhs) {
+inline constexpr bool operator<(const optional<T> &lhs,
+                                const optional<U> &rhs) {
   return rhs.has_value() && (!lhs.has_value() || *lhs < *rhs);
 }
 template <class T, class U>
-    inline constexpr bool operator>(const optional<T>& lhs, const optional<U>& rhs) {
+inline constexpr bool operator>(const optional<T> &lhs,
+                                const optional<U> &rhs) {
   return lhs.has_value() && (!rhs.has_value() || *lhs > *rhs);
 }
 template <class T, class U>
-    inline constexpr bool operator<=(const optional<T>& lhs, const optional<U>& rhs) {
+inline constexpr bool operator<=(const optional<T> &lhs,
+                                 const optional<U> &rhs) {
   return !lhs.has_value() || (rhs.has_value() && *lhs <= *rhs);
 }
 template <class T, class U>
-    inline constexpr bool operator>=(const optional<T>& lhs, const optional<U>& rhs) {
+inline constexpr bool operator>=(const optional<T> &lhs,
+                                 const optional<U> &rhs) {
   return !rhs.has_value() || (lhs.has_value() && *lhs >= *rhs);
 }
 
 // [optional.nullops], comparison with nullopt
-    template <class T> inline constexpr bool operator==(const optional<T>& lhs, nullopt_t) noexcept {
+template <class T>
+inline constexpr bool operator==(const optional<T> &lhs, nullopt_t) noexcept {
   return !lhs.has_value();
 }
-    template <class T> inline constexpr bool operator==(nullopt_t, const optional<T>& rhs) noexcept {
+template <class T>
+inline constexpr bool operator==(nullopt_t, const optional<T> &rhs) noexcept {
   return !rhs.has_value();
 }
-    template <class T> inline constexpr bool operator!=(const optional<T>& lhs, nullopt_t) noexcept {
+template <class T>
+inline constexpr bool operator!=(const optional<T> &lhs, nullopt_t) noexcept {
   return lhs.has_value();
 }
-    template <class T> inline constexpr bool operator!=(nullopt_t, const optional<T>& rhs) noexcept {
+template <class T>
+inline constexpr bool operator!=(nullopt_t, const optional<T> &rhs) noexcept {
   return rhs.has_value();
 }
-    template <class T> inline constexpr bool operator<(const optional<T>&, nullopt_t) noexcept {
+template <class T>
+inline constexpr bool operator<(const optional<T> &, nullopt_t) noexcept {
   return false;
 }
-    template <class T> inline constexpr bool operator<(nullopt_t, const optional<T>& rhs) noexcept {
+template <class T>
+inline constexpr bool operator<(nullopt_t, const optional<T> &rhs) noexcept {
   return rhs.has_value();
 }
-    template <class T> inline constexpr bool operator<=(const optional<T>& lhs, nullopt_t) noexcept {
+template <class T>
+inline constexpr bool operator<=(const optional<T> &lhs, nullopt_t) noexcept {
   return !lhs.has_value();
 }
-    template <class T> inline constexpr bool operator<=(nullopt_t, const optional<T>&) noexcept {
+template <class T>
+inline constexpr bool operator<=(nullopt_t, const optional<T> &) noexcept {
   return true;
 }
-    template <class T> inline constexpr bool operator>(const optional<T>& lhs, nullopt_t) noexcept {
+template <class T>
+inline constexpr bool operator>(const optional<T> &lhs, nullopt_t) noexcept {
   return lhs.has_value();
 }
-    template <class T> inline constexpr bool operator>(nullopt_t, const optional<T>&) noexcept {
+template <class T>
+inline constexpr bool operator>(nullopt_t, const optional<T> &) noexcept {
   return false;
 }
-    template <class T> inline constexpr bool operator>=(const optional<T>&, nullopt_t) noexcept {
+template <class T>
+inline constexpr bool operator>=(const optional<T> &, nullopt_t) noexcept {
   return true;
 }
-    template <class T> inline constexpr bool operator>=(nullopt_t, const optional<T>& rhs) noexcept {
+template <class T>
+inline constexpr bool operator>=(nullopt_t, const optional<T> &rhs) noexcept {
   return !rhs.has_value();
 }
 
 // [optional.comp_with_t], comparison with T
-    template <class T, class U> inline constexpr bool operator==(const optional<T>& lhs, const U& rhs) {
+template <class T, class U>
+inline constexpr bool operator==(const optional<T> &lhs, const U &rhs) {
   return lhs.has_value() ? *lhs == rhs : false;
 }
-    template <class T, class U> inline constexpr bool operator==(const U& lhs, const optional<T>& rhs) {
+template <class T, class U>
+inline constexpr bool operator==(const U &lhs, const optional<T> &rhs) {
   return rhs.has_value() ? lhs == *rhs : false;
 }
-    template <class T, class U> inline constexpr bool operator!=(const optional<T>& lhs, const U& rhs) {
+template <class T, class U>
+inline constexpr bool operator!=(const optional<T> &lhs, const U &rhs) {
   return lhs.has_value() ? *lhs != lhs : true;
 }
-    template <class T, class U> inline constexpr bool operator!=(const U& lhs, const optional<T>& rhs) {
+template <class T, class U>
+inline constexpr bool operator!=(const U &lhs, const optional<T> &rhs) {
   return rhs.has_value() ? lhs != *rhs : true;
 }
-    template <class T, class U> inline constexpr bool operator<(const optional<T>& lhs, const U& rhs) {
+template <class T, class U>
+inline constexpr bool operator<(const optional<T> &lhs, const U &rhs) {
   return lhs.has_value() ? *lhs < lhs : true;
 }
-    template <class T, class U> inline constexpr bool operator<(const U& lhs, const optional<T>& rhs) {
+template <class T, class U>
+inline constexpr bool operator<(const U &lhs, const optional<T> &rhs) {
   return rhs.has_value() ? lhs < *rhs : false;
 }
-    template <class T, class U> inline constexpr bool operator<=(const optional<T>& lhs, const U& rhs) {
+template <class T, class U>
+inline constexpr bool operator<=(const optional<T> &lhs, const U &rhs) {
   return lhs.has_value() ? *lhs <= lhs : true;
 }
-    template <class T, class U> inline constexpr bool operator<=(const U& lhs, const optional<T>& rhs) {
+template <class T, class U>
+inline constexpr bool operator<=(const U &lhs, const optional<T> &rhs) {
   return rhs.has_value() ? lhs <= *rhs : false;
 }
-    template <class T, class U> inline constexpr bool operator>(const optional<T>& lhs, const U& rhs) {
+template <class T, class U>
+inline constexpr bool operator>(const optional<T> &lhs, const U &rhs) {
   return lhs.has_value() ? *lhs > lhs : false;
 }
-    template <class T, class U> inline constexpr bool operator>(const U& lhs, const optional<T>& rhs) {
+template <class T, class U>
+inline constexpr bool operator>(const U &lhs, const optional<T> &rhs) {
   return rhs.has_value() ? lhs > *rhs : true;
 }
-    template <class T, class U> inline constexpr bool operator>=(const optional<T>& lhs, const U& rhs) {
+template <class T, class U>
+inline constexpr bool operator>=(const optional<T> &lhs, const U &rhs) {
   return lhs.has_value() ? *lhs >= lhs : false;
 }
-    template <class T, class U> inline constexpr bool operator>=(const U& lhs, const optional<T>& rhs) {
+template <class T, class U>
+inline constexpr bool operator>=(const U &lhs, const optional<T> &rhs) {
   return rhs.has_value() ? lhs >= *rhs : true;
 }
 
-
 // [optional.specalg], specialized algorithms
-    template <class T, detail::enable_if_t<std::is_move_constructible<T>::value>* = nullptr,
+template <class T,
+          detail::enable_if_t<std::is_move_constructible<T>::value> * = nullptr,
           detail::enable_if_t<detail::is_swappable<T>::value> * = nullptr>
-    void swap(optional<T>& lhs, optional<T>& rhs) noexcept(noexcept(lhs.swap(rhs))) {
+void swap(optional<T> &lhs,
+          optional<T> &rhs) noexcept(noexcept(lhs.swap(rhs))) {
   return lhs.swap(rhs);
 }
 
@@ -302,7 +350,8 @@ namespace tl {
   return optional<T>(in_place, std::forward<Args>(args)...);
 }
 template <class T, class U, class... Args>
-    inline constexpr optional<T> make_optional(std::initializer_list<U> il, Args&&... args) {
+inline constexpr optional<T> make_optional(std::initializer_list<U> il,
+                                           Args &&... args) {
   return optional<T>(in_place, il, std::forward<Args>(args)...);
 }
 }
@@ -310,8 +359,7 @@ namespace tl {
 // [optional.hash], hash support
 namespace std {
 // TODO SFINAE
-    template <class T>
+template <class T> struct hash<tl::optional<T>> {
-    struct hash<tl::optional<T>> {
   ::std::size_t operator()(const tl::optional<T> &o) const {
     if (!o.has_value())
       return 0;
@@ -325,8 +373,7 @@ namespace tl {
 namespace detail {
 template <class T, bool = ::std::is_trivially_destructible<T>::value>
 struct optional_storage_base {
-            constexpr optional_storage_base() noexcept
+  constexpr optional_storage_base() noexcept : m_dummy(), m_has_value(false) {}
-                : m_dummy(), m_has_value(false) {}
 
   template <class... U>
   constexpr optional_storage_base(in_place_t, U &&... u) noexcept
@@ -348,11 +395,8 @@ namespace tl {
   bool m_has_value;
 };
 
-        template <class T>
+template <class T> struct optional_storage_base<T, true> {
-        struct optional_storage_base<T, true> {
+  constexpr optional_storage_base() noexcept : m_dummy(), m_has_value(false) {}
-            constexpr optional_storage_base() noexcept
-                : m_dummy(), m_has_value(false) {}
-
 
   template <class... U>
   constexpr optional_storage_base(in_place_t, U &&... u) noexcept
@@ -370,9 +414,9 @@ namespace tl {
 };
 }
 
-    template <class T>
+template <class T> class optional : private detail::optional_storage_base<T> {
-    class optional : private detail::optional_storage_base<T> {
   using base = detail::optional_storage_base<T>;
+
 public:
   using value_type = T;
 
@@ -387,33 +431,42 @@ namespace tl {
   }
 
   // TODO conditionally disable
-        constexpr optional(optional&& rhs) noexcept(std::is_nothrow_move_constructible<T>::value) {
+  constexpr optional(optional &&rhs) noexcept(
+      std::is_nothrow_move_constructible<T>::value) {
     if (rhs.has_value()) {
       this->m_has_value = true;
       new (std::addressof(this->m_value)) T(std::move(*rhs));
     }
   }
   template <class... Args>
-        constexpr explicit optional(detail::enable_if_t<std::is_constructible<T, Args...>::value, in_place_t>,
+  constexpr explicit optional(
+      detail::enable_if_t<std::is_constructible<T, Args...>::value, in_place_t>,
       Args &&... args)
       : base(in_place, std::forward<Args>(args)...) {}
   template <class U, class... Args>
   constexpr explicit optional(
-            detail::enable_if_t<std::is_constructible<T, std::initializer_list<U>&, Args&&...>::value, in_place_t>,
+      detail::enable_if_t<std::is_constructible<T, std::initializer_list<U> &,
+                                                Args &&...>::value,
+                          in_place_t>,
       std::initializer_list<U> il, Args &&... args) {
     this->m_has_value = true;
     new (std::addressof(this->m_value)) T(il, std::forward<Args>(args)...);
   }
 
-        template <class U = T, detail::enable_if_t<std::is_convertible<U&&, T>::value>* = nullptr,
+  template <
+      class U = T,
+      detail::enable_if_t<std::is_convertible<U &&, T>::value> * = nullptr,
       detail::enable_forward_value<T, U> * = nullptr>
   constexpr optional(U &&u) : base(in_place, std::forward<U>(u)) {}
 
-        template <class U = T, detail::enable_if_t<!std::is_convertible<U&&, T>::value>* = nullptr,
+  template <
+      class U = T,
+      detail::enable_if_t<!std::is_convertible<U &&, T>::value> * = nullptr,
       detail::enable_forward_value<T, U> * = nullptr>
   constexpr explicit optional(U &&u) : base(in_place, std::forward<U>(u)) {}
 
-        template <class U, detail::enable_from_other<T,U,const U&>* = nullptr,
+  template <
+      class U, detail::enable_from_other<T, U, const U &> * = nullptr,
       detail::enable_if_t<std::is_convertible<const U &, T>::value> * = nullptr>
   optional(const optional<U> &rhs) {
     this->m_has_value = true;
@@ -421,21 +474,23 @@ namespace tl {
   }
 
   template <class U, detail::enable_from_other<T, U, const U &> * = nullptr,
-                  detail::enable_if_t<!std::is_convertible<const U&, T>::value>* = nullptr>
+            detail::enable_if_t<!std::is_convertible<const U &, T>::value> * =
+                nullptr>
   optional(const optional<U> &rhs) {
     this->m_has_value = true;
     new (std::addressof(this->m_value)) T(*rhs);
   }
 
-        template <class U, detail::enable_from_other<T,U,U&&>* = nullptr,
+  template <
+      class U, detail::enable_from_other<T, U, U &&> * = nullptr,
       detail::enable_if_t<std::is_convertible<U &&, T>::value> * = nullptr>
   optional(optional<U> &&rhs) {
     this->m_has_value = true;
     new (std::addressof(this->m_value)) T(std::move(*rhs));
   }
 
-
+  template <
-        template <class U, detail::enable_from_other<T,U,U&&>* = nullptr,
+      class U, detail::enable_from_other<T, U, U &&> * = nullptr,
       detail::enable_if_t<!std::is_convertible<U &&, T>::value> * = nullptr>
   explicit optional(optional<U> &&rhs) {
     this->m_has_value = true;
@@ -458,8 +513,7 @@ namespace tl {
     if (has_value()) {
       if (rhs.has_value()) {
         this->m_value = rhs.m_value;
-                }
+      } else {
-                else {
         this->m_value.~T();
         this->m_has_value = false;
       }
@@ -472,13 +526,13 @@ namespace tl {
   }
 
   // TODO conditionally delete, check exception guarantee
-        optional& operator=(optional&& rhs)
+  optional &operator=(optional &&rhs) noexcept(
-            noexcept(std::is_nothrow_move_assignable<T>::value && std::is_nothrow_move_constructible<T>::value) {
+      std::is_nothrow_move_assignable<T>::value
+          &&std::is_nothrow_move_constructible<T>::value) {
     if (has_value()) {
       if (rhs.has_value()) {
         this->m_value = std::move(rhs.m_value);
-                }
+      } else {
-                else {
         this->m_value.~T();
         this->m_has_value = false;
       }
@@ -491,26 +545,24 @@ namespace tl {
   }
 
   // TODO conditionally delete, check exception guarantee
-        template <class U = T,
+  template <class U = T, detail::enable_assign_forward<T, U> * = nullptr>
-                  detail::enable_assign_forward<T,U>* = nullptr>
   optional &operator=(U &&u) {
     if (has_value()) {
       this->m_value = std::forward<U>(u);
-            }
+    } else {
-            else {
       new (std::addressof(this->m_value)) T(std::forward<U>(u));
       this->m_has_value = true;
     }
   }
 
   // TODO check exception guarantee
-        template <class U, detail::enable_assign_from_other<T,U,const U&>* = nullptr>
+  template <class U,
+            detail::enable_assign_from_other<T, U, const U &> * = nullptr>
   optional &operator=(const optional<U> &rhs) {
     if (has_value()) {
       if (rhs.has_value()) {
         this->m_value = rhs.m_value;
-                }
+      } else {
-                else {
         this->m_value.~T();
         this->m_has_value = false;
       }
@@ -528,8 +580,7 @@ namespace tl {
     if (has_value()) {
       if (rhs.has_value()) {
         this->m_value = std::move(rhs.m_value);
-                }
+      } else {
-                else {
         this->m_value.~T();
         this->m_has_value = false;
       }
@@ -550,27 +601,27 @@ namespace tl {
   }
 
   template <class U, class... Args>
-        detail::enable_if_t<std::is_constructible<T, std::initializer_list<U>&, Args&&...>::value, T&>
+  detail::enable_if_t<
+      std::is_constructible<T, std::initializer_list<U> &, Args &&...>::value,
+      T &>
   emplace(std::initializer_list<U> il, Args &&... args) {
     *this = nullopt;
     new (std::addressof(this->m_value)) T(il, std::forward<Args>(args)...);
   }
 
   // [optional.swap], swap
-        void swap(optional& rhs)
+  void
-            noexcept(std::is_nothrow_move_constructible<T>::value && detail::is_nothrow_swappable<T>::value)
+  swap(optional &rhs) noexcept(std::is_nothrow_move_constructible<T>::value
-        {
+                                   &&detail::is_nothrow_swappable<T>::value) {
     if (has_value()) {
       if (rhs.has_value()) {
         using std::swap;
         swap(**this, *rhs);
-                }
+      } else {
-                else {
         new (&rhs.m_value) T(std::move(this->m_value));
         this->m_value.T::~T();
       }
-            }
+    } else if (rhs.has_value()) {
-            else if (rhs.has_value()) {
       new (std::addressof(this->m_value)) T(std::move(rhs.m_value));
       rhs.m_value.T::~T();
     }
@@ -580,50 +631,44 @@ namespace tl {
   constexpr const T *operator->() const {
     return std::addressof(this->m_value);
   }
-        constexpr T* operator->() {
+  constexpr T *operator->() { return std::addressof(this->m_value); }
-            return std::addressof(this->m_value);
+  constexpr const T &operator*() const & { return this->m_value; }
-        }
+  constexpr T &operator*() & { return this->m_value; }
-        constexpr const T& operator*() const& {
+  constexpr T &&operator*() && { return std::move(this->m_value); }
-            return this->m_value;
+  constexpr const T &&operator*() const && { return std::move(this->m_value); }
-        }
-        constexpr T& operator*() & {
-            return this->m_value;
-        }
-        constexpr T&& operator*() && {
-            return std::move(this->m_value);
-        }
-        constexpr const T&& operator*() const&& {
-            return std::move(this->m_value);
-        }
   constexpr explicit operator bool() const noexcept {
     return this->m_has_value;
   }
-        constexpr bool has_value() const noexcept {
+  constexpr bool has_value() const noexcept { return this->m_has_value; }
-            return this->m_has_value;
-        }
   constexpr const T &value() const & {
-            if (has_value()) return this->m_value;
+    if (has_value())
+      return this->m_value;
     throw bad_optional_access();
   }
   constexpr T &value() & {
-            if (has_value()) return this->m_value;
+    if (has_value())
+      return this->m_value;
     throw bad_optional_access();
   }
   constexpr T &&value() && {
-            if (has_value()) return std::move(this->m_value);
+    if (has_value())
+      return std::move(this->m_value);
     throw bad_optional_access();
   }
   constexpr const T &&value() const && {
-            if (has_value()) return std::move(this->m_value);
+    if (has_value())
+      return std::move(this->m_value);
     throw bad_optional_access();
   }
   template <class U> constexpr T value_or(U &&u) const & {
-            static_assert(std::is_copy_constructible<T>::value && std::is_convertible<U&&, T>::value,
+    static_assert(std::is_copy_constructible<T>::value &&
+                      std::is_convertible<U &&, T>::value,
                   "T must be copy constructible and convertible from U");
     return has_value() ? **this : static_cast<T>(std::forward<U>(u));
   }
   template <class U> constexpr T value_or(U &&u) && {
-            static_assert(std::is_move_constructible<T>::value && std::is_convertible<U&&, T>::value,
+    static_assert(std::is_move_constructible<T>::value &&
+                      std::is_convertible<U &&, T>::value,
                   "T must be move constructible and convertible from U");
     return has_value() ? **this : static_cast<T>(std::forward<U>(u));
   }