{
/* Build a compound expression that sets the
initial-await-resume-called variable true and then calls the
- initial suspend expression await resume. */
+ initial suspend expression await resume.
+ In the case that the user decides to make the initial await
+ await_resume() return a value, we need to discard it and, it is
+ a reference type, look past the indirection. */
+ if (INDIRECT_REF_P (initial_await))
+ initial_await = TREE_OPERAND (initial_await, 0);
tree vec = TREE_OPERAND (initial_await, 3);
tree aw_r = TREE_VEC_ELT (vec, 2);
+ aw_r = convert_to_void (aw_r, ICV_STATEMENT, tf_warning_or_error);
tree update = build2 (MODIFY_EXPR, boolean_type_node, i_a_r_c,
boolean_true_node);
aw_r = cp_build_compound_expr (update, aw_r, tf_warning_or_error);
--- /dev/null
+#ifdef __clang__
+#include <experimental/coroutine>
+namespace std {
+ using namespace std::experimental;
+}
+#else
+#include <coroutine>
+#endif
+#include <optional>
+
+struct future
+{
+ using value_type = int;
+ struct promise_type;
+ using handle_type = std::coroutine_handle<promise_type>;
+
+ handle_type _coroutine;
+
+ future(handle_type h) : _coroutine{h} {}
+
+ ~future() noexcept{
+ if (_coroutine) {
+ _coroutine.destroy();
+ }
+ }
+
+ value_type get() {
+ auto ptr = _coroutine.promise()._value;
+ return *ptr;
+ }
+
+ struct promise_type {
+ std::optional<value_type> _value = std::nullopt;
+
+ future get_return_object() {
+ return future{handle_type::from_promise(*this)};
+ }
+ void return_value(value_type val) {
+ _value = static_cast<value_type &&>(val);
+ }
+ auto initial_suspend() noexcept {
+ class awaiter {
+ std::optional<value_type> & value;
+ public:
+ explicit awaiter(std::optional<value_type> & val) noexcept : value{val} {}
+ bool await_ready() noexcept { return value.has_value(); }
+ void await_suspend(handle_type) noexcept { }
+ value_type & await_resume() noexcept { return *value; }
+ };
+
+ return awaiter{_value};
+ }
+ std::suspend_always final_suspend() noexcept {
+ return {};
+ }
+ //void return_void() {}
+ void unhandled_exception() {}
+ };
+};
+
+future create_future()
+{ co_return 2021; }
+
+int main()
+{ auto f = create_future(); }