Details
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Type:
Bug
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Status: Resolved
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Priority:
Medium
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Resolution: Done
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Component/s: Compiler
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Labels:None
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Environment:
Apple Swift version 2.1.1 (swiftlang-700.1.101.15 clang-700.1.81)
Target: x86_64-apple-darwin15.2.0
Description
Define a protocol that contains a static function on it. Then write a protocol extension for said protocol that implements a function of the same name but without the static modifier.
When marking a class or struct as conforming to the protocol, the compiler will crash without letting the developer know the cause of the problem.
I ran into this issue by forgetting to add the modifier to the protocol extension. Moreover, the compiler wouldn't tell me that my conforming class wasn't implementing the specified method.
See the attached playground for an example.
If the function in the protocol extension has a different name, the compiler will catch it and let the developer know that the conforming class is missing said function.
Here is the stack trace that Xcode outputs:
0 swift 0x000000010e5c0fbb llvm::sys::PrintStackTrace(__sFILE*) + 43 1 swift 0x000000010e5c16fb SignalHandler(int) + 379 2 libsystem_platform.dylib 0x00007fff89510eaa _sigtramp + 26 3 libsystem_platform.dylib 0x00007fff535566a8 _sigtramp + 3389282328 4 swift 0x000000010c887707 swift::SILWitnessVisitor<(anonymous namespace)::SILGenConformance>::visitProtocolDecl(swift::ProtocolDecl*) + 999 5 swift 0x000000010c884ee5 swift::Lowering::SILGenModule::getWitnessTable(swift::ProtocolConformance*) + 277 6 swift 0x000000010c8d45b0 (anonymous namespace)::SILGenType::emitType() + 1264 7 swift 0x000000010c8d404e swift::Lowering::SILGenModule::visitNominalTypeDecl(swift::NominalTypeDecl*) + 30 8 swift 0x000000010c85cbdb swift::Lowering::SILGenModule::emitSourceFile(swift::SourceFile*, unsigned int) + 779 9 swift 0x000000010c85d790 swift::SILModule::constructSIL(swift::ModuleDecl*, swift::SILOptions&, swift::FileUnit*, llvm::Optional<unsigned int>, bool, bool) + 928 10 swift 0x000000010c85db3d swift::performSILGeneration(swift::FileUnit&, swift::SILOptions&, llvm::Optional<unsigned int>, bool) + 109 11 swift 0x000000010c6b1992 performCompile(swift::CompilerInstance&, swift::CompilerInvocation&, llvm::ArrayRef<char const*>, int&) + 11442 12 swift 0x000000010c6aead3 frontend_main(llvm::ArrayRef<char const*>, char const*, void*) + 2691 13 swift 0x000000010c6ab154 main + 2324 14 libdyld.dylib 0x00007fff8c4e65ad start + 1 15 libdyld.dylib 0x0000000000000049 start + 1941019293
Attachments
Activity
Should I close this ticket?
Nicolas Ameghino
added a comment - Should I close this ticket? I have had this same bug triggered by implementing a protocol with
class func x() -> Self
without protocol extensions.
Sophie Parker
added a comment - - edited I have had this same bug triggered by implementing a protocol with
class func x() -> Self
without protocol extensions. Sophie, were you using Xcode's Swift, or one of the snapshots from GitHub? If the former, I think we can call this fixed and close it.
Ah yes that was in Xcode Swift (2.1.1). I've been away so I was unable to download the snapshot and check it there, but given it's the same bug, I agree it should be closed.
Sophie Parker
added a comment - Ah yes that was in Xcode Swift (2.1.1). I've been away so I was unable to download the snapshot and check it there, but given it's the same bug, I agree it should be closed. Okay, I've marked it as "resolved". Nicolas, you can close it now, or when you get a chance to test that it's fixed (which could be an Xcode beta).
I'll close it down, test it in next Xcode beta and reopen if needs be, does that sound good?
Nicolas Ameghino
added a comment - I'll close it down, test it in next Xcode beta and reopen if needs be, does that sound good? Yep, that's fine. Thanks!
Current trunk handles this gracefully: