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Merge pull request #9 from rollbear/master

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'optional<T&>::and_then(F&& f) &&' calls f with lvalue reference
This commit is contained in:
Simon Brand
2018-06-04 22:34:48 +01:00
committed by GitHub
parent f82f78b5b6 e8b28f2e34
commit d67e7c2eac
2 changed files with 17 additions and 12 deletions
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9
tests/extensions.cpp
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@@ -237,9 +237,14 @@ TEST_CASE("Monadic operations", "[monadic]") {
REQUIRE(!o18r);
const tl::optional<int> o19 = tl::nullopt;
auto o19r =
std::move(o19).and_then([](int i) { return tl::make_optional(42); });
auto o19r = std::move(o19).and_then([](int i) { return tl::make_optional(42); });
REQUIRE(!o19r);
int i = 3;
tl::optional<int&> o20{i};
std::move(o20).and_then([](int& r){return tl::optional<int&>{++r};});
REQUIRE(o20);
REQUIRE(i == 4);
}
SECTION("constexpr and_then") {

20
tl/optional.hpp
View File

@@ -1702,11 +1702,11 @@ public:
/// \group and_then
/// \synopsis template <class F>\nconstexpr auto and_then(F &&f) &&;
template <class F> TL_OPTIONAL_11_CONSTEXPR auto and_then(F &&f) && {
using result = detail::invoke_result_t<F, T &&>;
using result = detail::invoke_result_t<F, T &>;
static_assert(detail::is_optional<result>::value,
"F must return an optional");
return has_value() ? detail::invoke(std::forward<F>(f), std::move(**this))
return has_value() ? detail::invoke(std::forward<F>(f), **this)
: result(nullopt);
}
@@ -1725,11 +1725,11 @@ public:
/// \group and_then
/// \synopsis template <class F>\nconstexpr auto and_then(F &&f) const &&;
template <class F> constexpr auto and_then(F &&f) const && {
using result = detail::invoke_result_t<F, const T &&>;
using result = detail::invoke_result_t<F, const T &>;
static_assert(detail::is_optional<result>::value,
"F must return an optional");
return has_value() ? detail::invoke(std::forward<F>(f), std::move(**this))
return has_value() ? detail::invoke(std::forward<F>(f), **this)
: result(nullopt);
}
#endif
@@ -1757,12 +1757,12 @@ public:
/// \group and_then
/// \synopsis template <class F>\nconstexpr auto and_then(F &&f) &&;
template <class F>
TL_OPTIONAL_11_CONSTEXPR detail::invoke_result_t<F, T &&> and_then(F &&f) && {
using result = detail::invoke_result_t<F, T &&>;
TL_OPTIONAL_11_CONSTEXPR detail::invoke_result_t<F, T &> and_then(F &&f) && {
using result = detail::invoke_result_t<F, T &>;
static_assert(detail::is_optional<result>::value,
"F must return an optional");
return has_value() ? detail::invoke(std::forward<F>(f), std::move(**this))
return has_value() ? detail::invoke(std::forward<F>(f), **this)
: result(nullopt);
}
@@ -1782,12 +1782,12 @@ public:
/// \group and_then
/// \synopsis template <class F>\nconstexpr auto and_then(F &&f) const &&;
template <class F>
constexpr detail::invoke_result_t<F, const T &&> and_then(F &&f) const && {
using result = detail::invoke_result_t<F, const T &&>;
constexpr detail::invoke_result_t<F, const T &> and_then(F &&f) const && {
using result = detail::invoke_result_t<F, const T &>;
static_assert(detail::is_optional<result>::value,
"F must return an optional");
return has_value() ? detail::invoke(std::forward<F>(f), std::move(**this))
return has_value() ? detail::invoke(std::forward<F>(f), **this)
: result(nullopt);
}
#endif