PFR does not work with non-copyable aggregates on MSVC 17.10

[Kaiyakha]

I was surprised to find out PFR fails to compile the following non-copyable aggregate Entity with MSVC 17.10:

struct Field final {
  Field() = default;
  Field(const Field&) = delete;
};

struct Entity final {
  Field x;
};

Entity e;

boost::pfr::get<0>(e);

The output says the tuple index is out of bounds. I also tried pfr::for_each_field which resulted in that scary If there is no other failed static asserts then something went wrong. My colleagues use Clang and they say the code above works just fine. The latest GCC also didn't show any issues.

[apolukhin]

I'm afraid this is a MSVC issue. Looks like guaranteed copy elision is not supported by the compiler.

Anyway, I have no access to that compiler. If there's a known workaround, I'd appreciate a PR.

[denzor200]

Have you tried -DBOOST_PFR_HAS_GUARANTEED_COPY_ELISION=0 ?