[cxx-interop] Re-enable warnings for unannotated C++ APIs returning SWIFT_SHARED_REFERENCE types under an experimental feature flag #82488
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…S_(UN)RETAINED warning (swiftlang#81411)" This reverts commit 49aea31.
… per source location
fahadnayyar
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test/Interop/Cxx/foreign-reference/Inputs/cxx-functions-and-methods-returning-frt.h
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Jul 10, 2025
False positives on large codebases still needs to be addressed: rdar://150800115
The warnings are off by default in this patch. WDYM by inverting the flag? |
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My bad! I misunderstood something. |
Xazax-hun
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…{diagID, SourceLocation}
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…WIFT_SHARED_REFERENCE types under an experimental feature flag (swiftlang#82488) This patch re-enables diagnostics for unannotated C++ functions or methods returning `SWIFT_SHARED_REFERENCE` types. These warnings now fire only **once per source location**, even in the presence of multiple template instantiations. This avoids diagnostic duplication that was a key source of noise in the compilation of larger codebases. These warnings were previously disabled starting in **Swift 6.2** via [PR-swiftlang#81411](swiftlang#81411) due to concerns around false positives and excessive duplication in projects adopting C++ interop. This patch addresses the duplication issue by adding source-location-based caching, which ensures that a warning is emitted only once per source location, even across template instantiations with different types. However, the false positive issue remains to be investigated and will be addressed in a follow-up patch. Until that happens, the warnings are gated behind a new experimental feature flag: `WarnUnannotatedReturnOfCxxFrt`. This feature will be enabled by default only after thorough qualification and testing on large C++ codebases. rdar://154261051
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This patch re-enables diagnostics for unannotated C++ functions or methods returning
SWIFT_SHARED_REFERENCEtypes. These warnings now fire only once per source location, even in the presence of multiple template instantiations. This avoids diagnostic duplication that was a key source of noise in the compilation of larger codebases.These warnings were previously disabled starting in Swift 6.2 via PR-#81411 due to concerns around false positives and excessive duplication in projects adopting C++ interop. This patch addresses the duplication issue by adding source-location-based caching, which ensures that a warning is emitted only once per source location, even across template instantiations with different types.
However, the false positive issue remains to be investigated and will be addressed in a follow-up patch. Until that happens, the warnings are gated behind a new experimental feature flag:
WarnUnannotatedReturnOfCxxFrt. This feature will be enabled by default only after thorough qualification and testing on large C++ codebases.rdar://154261051