[SR-10128] Compiler crashes when generic type constraint is the associated type of another protocol which the class also conforms to which and has a default implementation #52530
Comments
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I cannot reproduce this on 5.1, so I assume it's fixed. |
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I'm seeing this with a near-master with asserts: @rjmccall, does this look familiar? |
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I tried this. |
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The crash has moved higher up the stack to SIL. This is definitely a bug in the GSB 0. Program arguments: ./bin/swift -frontend -emit-ir -sdk /Applications/Xcode-beta.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.15.sdk -
1. Swift version 5.1.1-dev (Swift 4043d43d43)
2. While generating SIL witness table protocol conformance to 'ProtoB' (at <stdin>:3:1) for type 'Foo<T>' (declared at [<stdin>:14:1 - line:14:32] RangeText="class Foo<T: ProtoA>: ProtoB { ")
3. While generating protocol witness thunk SIL function "@$s4main3FooCyqd__GAA6ProtoBA2aEP5stuffSivgTW".
for getter for stuff (at <stdin>:9:9)
0 swift 0x00000001059c5c28 llvm::sys::PrintStackTrace(llvm::raw_ostream&) + 40
1 swift 0x00000001059c4b68 llvm::sys::RunSignalHandlers() + 248
2 swift 0x00000001059c6247 SignalHandler(int) + 295
3 libsystem_platform.dylib 0x00007fff67f6ab1d _sigtramp + 29
4 libdyld.dylib 0x00007fff67d5a065 dyldGlobalLockRelease() + 0
5 libsystem_c.dylib 0x00007fff67e40a1c abort + 120
6 libsystem_c.dylib 0x00007fff67e3fcd6 err + 0
7 swift 0x0000000105ad6893 swift::Lowering::SILGenModule::useConformance(swift::ProtocolConformanceRef) (.cold.1) + 35
8 swift 0x0000000101daba57 swift::Lowering::SILGenModule::useConformance(swift::ProtocolConformanceRef) + 535
9 swift 0x0000000101dab8ec swift::Lowering::SILGenModule::useConformance(swift::ProtocolConformanceRef) + 172
10 swift 0x0000000101dac044 swift::SILInstructionVisitor<LazyConformanceEmitter, void>::visit(swift::SILInstruction*) + 1060
11 swift 0x0000000101dabbf8 swift::Lowering::SILGenModule::emitLazyConformancesForFunction(swift::SILFunction*) + 136
12 swift 0x0000000101dfaa8f swift::Lowering::SILGenModule::emitProtocolWitness(swift::ProtocolConformanceRef, swift::SILLinkage, swift::IsSerialized_t, swift::SILDeclRef, swift::SILDeclRef, swift::Lowering::IsFreeFunctionWitness_t, swift::Witness) + 2111
13 swift 0x0000000101dfc87b (anonymous namespace)::SILGenWitnessTable<(anonymous namespace)::SILGenConformance>::addMethodImplementation(swift::SILDeclRef, swift::SILDeclRef, swift::Witness) + 283
14 swift 0x0000000101dfc72a (anonymous namespace)::SILGenWitnessTable<(anonymous namespace)::SILGenConformance>::addMethod(swift::SILDeclRef) + 362
15 swift 0x0000000101dfc5a8 void llvm::function_ref<void (swift::AccessorDecl*)>::callback_fn<swift::SILWitnessVisitor<(anonymous namespace)::SILGenConformance>::visitAbstractStorageDecl(swift::AbstractStorageDecl*)::'lambda'(swift::AccessorDecl*)>(long, swift::AccessorDecl*) + 72
16 swift 0x00000001027f8876 swift::AbstractStorageDecl::visitExpectedOpaqueAccessors(llvm::function_ref<void (swift::AccessorKind)>) const + 166
17 swift 0x00000001027f87bc swift::AbstractStorageDecl::visitOpaqueAccessors(llvm::function_ref<void (swift::AccessorDecl*)>) const + 44
18 swift 0x0000000101dfc33a swift::SILWitnessVisitor<(anonymous namespace)::SILGenConformance>::visitProtocolDecl(swift::ProtocolDecl*) + 1530
19 swift 0x0000000101dfa0e4 swift::Lowering::SILGenModule::getWitnessTable(swift::NormalProtocolConformance*) + 356
20 swift 0x0000000101dfbb85 (anonymous namespace)::SILGenType::emitType() + 1317
21 swift 0x0000000101dfb659 swift::Lowering::SILGenModule::visitNominalTypeDecl(swift::NominalTypeDecl*) + 25
22 swift 0x0000000101d26e13 swift::Lowering::SILGenModule::emitSourceFile(swift::SourceFile*) + 915
23 swift 0x0000000101d27d52 swift::SILModule::constructSIL(swift::ModuleDecl*, swift::Lowering::TypeConverter&, swift::SILOptions&, swift::FileUnit*) + 322
24 swift 0x0000000101d28131 swift::performSILGeneration(swift::ModuleDecl*, swift::Lowering::TypeConverter&, swift::SILOptions&) + 17
25 swift 0x0000000101a2ae3d performCompile(swift::CompilerInstance&, swift::CompilerInvocation&, llvm::ArrayRef<char const*>, int&, swift::FrontendObserver*, swift::UnifiedStatsReporter*) + 8205
26 swift 0x0000000101a27ec8 swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) + 3080
27 swift 0x00000001019cd0be main + 734
28 libdyld.dylib 0x00007fff67d692e5 start + 1
29 libdyld.dylib 0x0000000000000006 start + 2552851746 |
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Pulling this back since it hasn't been resolved. |
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Comment by Frank Langel (JIRA) @glbrntt Hi George, could you advise on the best way of fixing this issue.
Any advise to get this fix quickly would be much appreciated Kind regards Frank |
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fll (JIRA User) I only reported the bug so can't help you there I'm afraid! |
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Comment by Frank Langel (JIRA) Hi George, thank you for the response. Who would be a good contact/person to talk to drive this forward? Thanks a lot Frank |
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fll (JIRA User) We're aware of this as a structural problem with the GSB. It has the propensity to drop certain kinds of requirements if they are not referenced in a certain structural way. In fact, a much smaller reproducer is protocol Requirement {}
extension C : P {}
class C<T> where T : Requirement {}
protocol P {
associatedtype T : Requirement
func f()
}
extension P {
func f() {}
}This is going to sound very strange, but the workaround is to force a data dependency on the requirement that isn't otherwise referenced by the protocol. In my example above, that means the function "f" needs to use "T" in some way. protocol Requirement {}
extension C : P {}
class C<T> where T : Requirement {}
protocol P {
associatedtype T : Requirement
func f(_ : T)
}
extension P {
func f(_ : T) {}
}We are in the process of re-evaluating the algorithms underpinning the GSB and hope we can arrive at a resolution to this issue that will leave us with not just a more correct facility, but a faster one too! |
AnthonyLatsis
added
the
crash
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Environment
Xcode 10.2 beta 4
Additional Detail from JIRA
md5: f46d160b1e3f4181dc3a360dd5fd62d6
duplicates:
is duplicated by:
relates to:
Issue Description:
The compiler crashes with the following code:
Stacktrace:
The text was updated successfully, but these errors were encountered: