[Type checker] Warn about overrides of NSObject.hashValue. #18407
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NSObject.hashValue is provided to satisfy the hashValue constraint of the Hashable protocol. However, it is not the correct customization point for interoperating with Objective-C, because Objective-C code will call through the -hash method. Warn about overrides of NSObject.hashValue; users should override NSObject.hash instead. Fixes rdar://problem/42780635.
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@swift-ci please smoke test |
jrose-apple
reviewed
Jul 31, 2018
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| public static func == (lhs: NSObject, rhs: NSObject) -> Bool { | ||
| return lhs.isEqual(rhs) | ||
| } |
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These should live in ObjectiveC.swift, not Foundation.swift.
| if (auto classDecl = | ||
| baseVar->getDeclContext()->getAsClassOrClassExtensionContext()) { | ||
| if (classDecl->getBaseName().userFacingName() == "NSObject" && | ||
| baseVar->getBaseName().userFacingName() == "hashValue") { |
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Nitpick: classDecl->getName().is("NSObject") && baseVar->getName() == ctx.Id_hashValue.
lorentey
reviewed
Jul 31, 2018
| if (auto baseVar = dyn_cast<VarDecl>(base)) { | ||
| if (auto classDecl = | ||
| baseVar->getDeclContext()->getAsClassOrClassExtensionContext()) { | ||
| if (classDecl->getBaseName().userFacingName() == "NSObject" && |
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This will also trigger on custom classes that happen to be named NSObject, right? Would it be possible to make this a more specific match?
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Sure, I can check for the ObjectiveC module.
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... or Foundation, I guess, for corelibs Foundation.
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Oof, that's fun. Good catch.
This was referenced Jan 24, 2019
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NSObject.hashValue is provided to satisfy the hashValue constraint of
the Hashable protocol. However, it is not the correct customization
point for interoperating with Objective-C, because Objective-C code
will call through the -hash method. Warn about overrides of
NSObject.hashValue; users should override NSObject.hash instead.
Fixes rdar://problem/42780635.