[libcxx] Remove use of default function template parameters in type traits. Fixes DR20484
Summary: This patch moves the SFINAE for __is_destructor_welformed out of the function template parameters. type_traits must compile in c++03 mode since it is included in c++03 headers.
3c2eac6...
by
Marshall Clow <email address hidden>
In response to bug #20362, change the order of operations in vector move assignment so that if the allocator move assignment throws, we aren't left with two objects pointing at the same memory. This is not a complete fix; I am unconvinced that a complete fix is possible. With this change in place, we will leak the old contents of the vector. LWG issue #2106, when adopted, will make this problem illegal. Thanks to Thomas Koeppe for the report and analysis.
[libcxx] Add <experimental/utility> header for LFTS.
Summary:
This patch adds the `<experimental/utility>` header as specified in the latest draft of the library fundamentals TS.
`<experimental/utility>` only contains `class erased_type`.
This patch also updates the documentation to list the `erased_type` class as "initial implementation complete".
Test Plan:
Three test cases where added:
1. Test that `_LIBCPP_VERSION` is defined.
2. Test that `<utility>` has been included.
3. Test that `erased_type` is in the correct namespace and is constexpr default constructible.
