[PATCH] D127187: [C++20] [Modules] Implement AllAdditionalTUReachable

Wed Jul 13 23:56:33 PDT 2022

iains added a comment.

Hi @ChuanqiXu, 
I have no comment on the technical content of the patch (it looks reasonable to me).

However, I wonder if we should be supplying this option at all because in:
https://eel.is/c++draft/module#reach-2
note2 says "[Note 2: It is advisable to avoid depending on the reachability of any additional translation units in programs intending to be portable. — end note]"

So by providing the option, we are effectively giving users an easy mechanism to make non-portable programs (and I'm fairly sure that would mean that they would not have the same characteristics between clang and GCC with this); 
So I'd like to know what (preferably real-world) code motivates the addition of this option.

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D127187/new/

https://reviews.llvm.org/D127187