On 1/21/20 6:21 AM, JunMa wrote:
Hi
When test gcc with cppcoro, I find case like:
int& awaitable::await_resume()
auto x1 = co_await awaitable;
decltype(auto) x2 = co_await awaitable;
Based on standard, typeof(x1) should be int, typeof(x2) is int&.
However, we get both x1 and x2 as int, this because we donot
consider indirect_ref which wrap await_resume call expression
(convert_from_reference), and it is invoked into type deduction
of auto and decltype(auto).
This patch wrap co_await expression with indirect_ref which should be
same with await_resume expression, and it sink await_resume expression
to real call_expr when replace co_await expression. it fix type deduction
of auto and decltype(auto) in coroutine.
Bootstrap and test on X86_64, is it OK?
+ /* Wrap co_await_expr. */
+ if (TREE_CODE (awrs_call) == INDIRECT_REF)
+ await_expr = build1_loc (loc, INDIRECT_REF, TREE_TYPE (awrs_call),
+ await_expr);
I think all you want here is:
await_expr = convert_from_reference (await_expr);
Regards
JunMa
gcc/cp
2020-01-21 Jun Ma <ju...@linux.alibaba.com>
* coroutines.cc (build_co_await): Wrap co_await with
indirect_ref when needed.
(co_await_expander): Sink to call_expr if await_resume
is wrapped by indirect_ref.
gcc/testsuite
2020-01-21 Jun Ma <ju...@linux.alibaba.com>
* g++.dg/coroutines/co-await-14-return-ref-to-auto.C: Add label.
--
Nathan Sidwell
