🍒[cxx-interop] Avoid circular reference errors when importing C++ structs #69365
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When importing a C++ struct, if its owning module requires cplusplus, Swift tried to auto-conform it to certain protocols from the Cxx module. This triggers name lookup in the clang struct, specifically for `__beginUnsafe()` and `__endUnsafe()` methods, which imports all of the base structs including their methods. This moves the import of base structs out of the name lookup request, preventing cycles. rdar://116426238 (cherry picked from commit 4632d89)
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@swift-ci please test |
DougGregor
approved these changes
Oct 26, 2023
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Explanation:
When importing a C++ struct, if its owning module
requires cplusplus, Swift tried to auto-conform it to certain protocols from the Cxx module. This triggers name lookup in the clang struct, specifically for__beginUnsafe()and__endUnsafe()methods, which imports all of the base structs including their methods.This moves the import of base structs out of the name lookup request, preventing cycles.
Scope: All of the code changes are on a C++ interop only code path.
Risk: Low, only takes effect when C++ interop is enabled.
Testing: Covered by LIT tests.
Original PR: #69327
rdar://116426238
(cherry picked from commit 4632d89)