<optional>: Extend compiler bug workaround to MSVC by StephanTLavavej · Pull Request #5407 · microsoft/STL (original) (raw)

#5369 revealed VSO-2444237 "[RWC][prod/fe][std:c++latest][Regression] LLVM failed with Assertion failed: ParseTree::Utility::SigStack::sigStack.size() == 1".

@xiangfan-ms tracked this down to the introduction of _Derived_from_optional and reduced it to a library-free repro. The compiler is having trouble with the lambda's templated function call operator.

To unblock our Real World Code test suite, we should extend the workaround we're currently using for EDG to also cover MSVC.