Remove Fix-it suggestion for unsafeBitcast #40523
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| @@ -818,15 +818,6 @@ static void diagSyntacticUseRestrictions(const Expr *E, const DeclContext *DC, | |||
| return; | |||
| } | |||
| } | |||
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| // Unchecked casting to a subclass is better done by unsafeDowncast. | |||
| if (fromTy->isBindableToSuperclassOf(toTy)) { | |||
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I read the description and the opting for removing the diagnostic all together, but I still wonder if it would be better to still emit this diagnostic when we and only when we know that we have both (from and to) concrete types. In that case we can know is x is T statically and safely emit the diagnostic and fix-it.
That is normally how those runtime diagnostics warnings are emitted, only when compiler can know that information at compile time, so in the example, generic parameters there is no way to know that at compile time.
To me it makes sense to just extend the check and still emit diagnostic when it can know for sure, but is just a personal opinion, since was stated in the ticket that removing diagnostic was also fine.
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+1 to leaving it in place, but restricting it to when we have sufficient information.
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Thank you @LucianoPAlmeida and @compnerd for the suggestions, It makes sense to do that. I will try to find way to apply it for concrete types atleast.
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It sounds like what we want here is to check that both sides are ClassDecl and that "from" class declaration is a subclass of "to" declaration via ClassDecl::sSuperclassOf(ClassDecl *)
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Guys pardon me for posting this here but would be really helpful if someone could help me resolve this issue - https://forums.swift.org/t/swift-ios-build-error-due-to-sdk-versions/54373 , Thanks |
Remove Fix-it suggestion for unsafeBitcast to change it into unsafeDowncast. The compiler suggest this but on applying the fix it fails at debugPrecondition(x is T). The options were either to remove fix it entirely or apply only when we know x is T for sure. Tried to find if x is T but not able to get this data at this step of the pipeline (the dynamic type casting/ mimicking is operator using swiftDynamicCast seems to happen during runtime). Hence opted for entirely removing the fix it
Resolves SR-14943.