[cxx-interop] Do not import typedef members of clang::RecordDecls #85072
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In C++, it is legal to have a typedef to an invalid type (e.g., a templated type that cannot be instantiated). We should not import these eagerly in Swift, because doing so causes spurious type errors that would not otherwise appear in C++---this is validated by the test that is added in this patch, which runs clang. Instead, we can rely on these types being lazily imported on-demand, i.e., only when the type is referenced directly in Swift or indirectly by an imported decl that is used in Swift. rdar://145238539
j-hui
requested review from
Xazax-hun,
beccadax,
egorzhdan,
fahadnayyar,
hnrklssn,
ian-twilightcoder,
susmonteiro and
zoecarver
as code owners
|
@swift-ci please test |
hnrklssn
reviewed
Oct 22, 2025
| // CHECK-NEXT: typealias UsingBool = Bool | ||
| // CHECK-NEXT: } | ||
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| //--- Inputs/CxxErrHeader.h |
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@swift-ci please test macOS |
Xazax-hun
approved these changes
Oct 23, 2025
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In C++, it is legal to have a typedef to an invalid type (e.g., a templated type that cannot be instantiated). We should not import these eagerly in Swift, because doing so causes spurious type errors that would not otherwise appear in C++---this is validated by the test that is added in this patch, which runs clang.
Instead, we can rely on these types being lazily imported on-demand, i.e., only when the type is referenced directly in Swift or indirectly by an imported decl that is used in Swift.
rdar://145238539