+++
title = "Changelog"
weight = 80
+++

---
## v2.1 in progress [[project]](https://github.com/ned14/outcome/projects/1)

- `include/outcome/outcome.natvis` is now namespace permuted like the rest of
Outcome, so debugging Outcome based code in Visual Studio should look much
prettier than before.

- [#162](https://github.com/ned14/outcome/issues/162)
    - `.has_failure()` was returning false at times when it should have returned true.

- [#152](https://github.com/ned14/outcome/issues/152)
    - GCC 5 no longer can compile Outcome at all due to [https://stackoverflow.com/questions/45607450/gcc5-nested-variable-template-is-not-a-function-template](https://stackoverflow.com/questions/45607450/gcc5-nested-variable-template-is-not-a-function-template).
Added explicit version trap for GCC 5 to say it can not work. Note this is not a
breaking change, GCC 5 was never supported officially in any v2 Outcome.

- [#150](https://github.com/ned14/outcome/issues/150)
    - **BREAKING CHANGE** `result<T, E>`, `boost_result<T, E>` and `std_result<T, E>`
no longer implement hard UB on fetching a value from a valueless instance if `E` is
a UDT, they now fail to compile with a useful error message. If you wish hard UB,
use `unchecked<T, E>`, `boost_unchecked<T, E>` or `std_unchecked<T, E>` instead.

- [#140](https://github.com/ned14/outcome/issues/140)
    - Fixed a nasty corner case bug where value type's without a copy constructor
but with a move constructor would indicate via traits that copy construction
was available. Thanks to Microsoft's compiler team for reporting this issue.

- Added experimental `status_result` and `status_outcome` based on experimental
`status_code`.

- Boost edition is now 100% Boost, so defaults for `result` and `outcome` are
`boost::system::error_code::errc_t` and `boost::exception_ptr`. Moreover,
the test suite in the Boost edition now exclusively tests the Boost edition.
One can, of course, freely use the standalone edition with Boost, and the Boost
edition with `std` types.

- Renamed ADL discovered customisation point `throw_as_system_error_with_payload()`
to `outcome_throw_as_system_error_with_payload()`.

- [#135](https://github.com/ned14/outcome/issues/135)
    - Added much clearer compile failure when user tries `result<T, T>` or `outcome`
    where two or more types are identical. Thanks to Andrzej Krzemieński
    for suggesting a technique which combines SFINAE correctness with
    the remaining ability for `result<T, T>` etc to be a valid type, but
    not constructible.

- [#67](https://github.com/ned14/outcome/issues/67)
    - Fixed one of the oldest long open bugs in Outcome, that the noexcept
unit tests failed on OS X for an unknown reason.

- [#115](https://github.com/ned14/outcome/issues/115)
    - Outcome did not construct correctly from `failure_type`.

- Inexplicably outcome's error + exception constructor had been removed.
Nobody noticed during the Boost peer review, which is worrying seeing as that
constructor is needed for one of the main advertised features to Boost!

- [#107](https://github.com/ned14/outcome/issues/107) and [#116](https://github.com/ned14/outcome/issues/116)
    - `operator==` and `operator!=` now become disabled if the value, error and
    exception types do not implement the same operator.
    - Relatedly, both comparison operators simply didn't work right. Fixed.

- [#109](https://github.com/ned14/outcome/issues/109)
    - `swap()` now has correct `noexcept` calculation and now correctly orders
    the swaps to be whichever is the throwing swap first.

- Added reference dump of v2.1 ABI so we can check if ABI breakage detection
works in the next set of changes, plus Travis job to check ABI and API compatibility
per commit.

- [#124](https://github.com/ned14/outcome/issues/124)
    - `BOOST_OUTCOME_TRY` is now overloaded and selects `void` or `auto` edition
    according to input parameter count.

- [#120](https://github.com/ned14/outcome/issues/120)
    - Fix generation of double underscored temporary variables in
    `BOOST_OUTCOME_UNIQUE_NAME`, which is UB.

- [#110](https://github.com/ned14/outcome/issues/110)
    - Separated `result` from its hard coded dependency on the `<system_error>` header.
    - Renamed `result` and `outcome` to `basic_result` and `basic_outcome`.
    - Renamed `result.hpp` into `basic_result.hpp`.
    - Moved `<system_error>` and `<exception>` dependent code into new
    `std_result.hpp` and `std_outcome.hpp` header files.
    - Added `boost_result.hpp` and `boost_outcome.hpp` which use Boost.System
    and Boost.Exception (these are `result.hpp` and `outcome.hpp` in the Boost edition).

---
## v2.0 18th Jan 2018 [[release]](https://github.com/ned14/outcome/releases/tag/v2.0-boost-peer-review)

- Boost peer review edition. This is what was reviewed.
- Changelog from v1 can be found in the release notes for this release.
