[cxx-interop] Prevent crash when importing a std::optional of nonescapable #83973
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susmonteiro
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| auto *vd = cast<VarDecl>(member); | ||
| if (!isNonEscapable) { | ||
| if (const auto *fd = dyn_cast<clang::FieldDecl>(nd)) |
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Non-escapable is viral to the parents, so we should expect the parent record to be non-escapable when an indirect field is non-escapable. Would doing the same thing for both direct and indirect fields run into problems?
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That's a good point, thanks. We can do the same thing for indirect fields by assuming that an anonymous union/struct can never be escapable, and thus we can compare the escapability of these indirect fields directly with the outer record (i.e. skipping the comparison with the anonymous record)
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| } | ||
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| // CHECK: error: a function with a ~Escapable result needs a parameter to depend on | ||
| // CHECK-NO-LIFETIMES: test.swift:11:32: error: a function cannot return a ~Escapable result |
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You can make these line numbers resilient to this type of cascading change using:
// CHECK-NO-LIFETIMES: test.swift:[[@LINE+1]]:32: error: a function cannot return a ~Escapable result
By default this would be broken by split-files if you use FileCheck %s, since the line numbers change. This can be resolved by either using Filecheck %t/test.swift, or calling split-files --leading-lines which pads each file to preserve line numbers.
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Oh interesting, thanks!
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When we tried to create a
std::optionalof a nonescapable type in Swift, the compiler would run into an assertion failure. This is becausestd::optionalhas an anonymous union where one of its members would be of this nonescapable type.Turns out that we were not handling anonymous unions with nonescapable members correctly. Fields of anonymous unions are injected to the parent as
IndirectFieldDecl, so we need to handle these indirect fields the same way we handle "normal" fields.rdar://156704699