[PATCH] D107378: Make enum iteration with seq safe by default

[Aaron Ballman via Phabricator via llvm-commits]

aaron.ballman added inline comments.


================
Comment at: llvm/include/llvm/ADT/Sequence.h:105-106
+};
+constexpr force_iteration_on_noniterable_enum_t
+    force_iteration_on_noniterable_enum;
+
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kuhar wrote:
> aaron.ballman wrote:
> > I'm pretty sure this is an ODR violation without also declaring it as `inline` (this definition otherwise has internal linkage).
> What's the proper way to do it in the pre-C++17 world? I saw that both `llvm::None` and `std::piecewise_construct` do it the same way.
You need to use a function to wrap the variables, or you ignore the ODR issue and hope nothing explodes later. Good point on C++17 though, we don't currently support it. So I think this is "fine" for the moment and we can come back and fix it later once we bump to C++17.


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  https://reviews.llvm.org/D107378/new/

https://reviews.llvm.org/D107378