Hi All,

RocksDB failed to build on MSVC under /std:c++latest mode due to "error C2668: 'folly::bit_cast': ambiguous call to overloaded function" on https://github.com/facebook/rocksdb/blob/master/third-party/folly/folly/synchronization/DistributedMutex-inl.h#L1377, we changed the "bit_cast" to "folly::bit_cast" as workaround. This is a third-party library, not sure if it needs to be modified by you, so reported to you first.

repro steps:

1. open VS2019 x64 tool command
2. git clone https://github.com/facebook/rocksdb.git rocksdb
3. mkdir rocksdb\build_amd64 && cd rocksdb\build_amd64
4. set CL=/std:c++latest
5. cmake -G "Visual Studio 16 2019" -A x64 -DCMAKE_SYSTEM_VERSION=10.0.18362.0 .
6. msbuild /m /p:Platform=x64 /p:Configuration=Release rocksdb.sln /t:Rebuild /p:BuildInParallel=true

errors:
DistributedMutex.cpp
F:\gitP\facebook\rocksdb\third-party\folly\folly\synchronization\DistributedMutex-inl.h(1377,1): error C2668: 'folly::bit_cast': ambiguous call to overloaded function
F:\gitP\facebook\rocksdb\third-party\folly\folly\lang\Bits.h(30,4): note: could be 'To folly::bit_cast<uintptr_t,folly::detail::distributed_mutex::Waiter,0>(const From &) noexcept'
with
[
To=uintptr_t,
Atomic=std::atomic,
From=folly::detail::distributed_mutex::Waiterstd::atomic *
]
C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\VC\Tools\MSVC\14.26.28801\include\bit(33,26): note: or '_To std::bit_cast<uintptr_t,Waiter,0>(const _From &) noexcept' [found using argument-dependent lookup]
with
[
_To=uintptr_t,
Waiter=folly::detail::distributed_mutex::Waiterstd::atomic,
_From=folly::detail::distributed_mutex::Waiterstd::atomic *
]