Due to an oversight, when users use an unexported declaration from
implicit global module, the diagnostic will show "please #include"
instead of "please import". This patch corrects the behavior.
Also previously, when users use an unexported declarations from module
partitions, the diagnostic message will always show the partition name
no matter if that partition name is visible to the users. Now the users
may only see the partition name if the users are in the same module with
the partition unit.
Close https://github.com/llvm/llvm-project/issues/71347
Previously I misread the concept of module purview. I thought if a
declaration attached to a unnamed module, it can't be part of the module
purview. But after the issue report, I recognized that module purview is
more of a concept about locations instead of semantics.
Concretely, the things in the language linkage after module declarations
can be exported.
This patch refactors `Module::isModulePurview()` and introduces some
possible code cleanups.
Close https://github.com/llvm/llvm-project/issues/60405
See the discussion in the above link for the background.
What the patch does:
- Rename `Module::ModuleKind::GlobalModuleFragment` to
`Module::ModuleKind::ExplicitGlobalModuleFragment`.
- Add another module kind `ImplicitGlobalModuleFragment` to
`ModuleKind`.
- Create an implicit global module fragment for the language linkage
declarations inside a module purview.
- If the language linkage lives inside the scope of an export decl,
the created modules is marked as exported to outer modules.
- In fact, Sema will only create at most 2 implicit global module
fragments to avoid creating a lot of unnecessary modules in the edging
case.
Reviewed By: iains
Differential Revision: https://reviews.llvm.org/D144367
