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A comment on LLVM 13.0. Parent comment

Re:LLVM 13.0 by pjmlp on Tuesday October 05, 2021 @04:36PM (#28765281)
From the point of view from C++20 support it definitely looks like that from the outside.

Which you pretty much confirmed by giving examples completely unrelated to ISO.

How is that migration to C++20 modules support going?

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Re:LLVM 13.0 by dxf on Tuesday October 05, 2021 @05:45PM (#28766046)
If you are asking, "Is Google helping with any C++20 support upstream?" the answer is Yes.

E.g. for standard concepts in libc++:

std::derived_from (D74292) std::convertible_to (D77961) Arithmetic concepts (D88131) std::move_constructible (D96230) std::copy_constructible (D96232) std::invocable (D96235) std::regular_invocable (D96235) etc.

Google is _big_ and C++ is used for many projects that build with disparate toolchains (even if they are all based on Clang/LLVM); each project can have different needs to adopt parts of C++20 sooner than the others, and different costs for doing so. Moving from Clang modules to C++ standard modules is an effort that, for some of our projects, lives at the nexus of "Are Standard Modules sufficiently done upstream to be able to replace our use of Clang modules?" and "What is the cost of doing that?" and "What is the benefit of making that switch?" For other projects, adopting standard modules is a more straightforward calculus.

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Re:LLVM 13.0 by pjmlp on Wednesday October 06, 2021 @01:58AM (#28769691)
Fair enough, thanks for the clarification.
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