[SR-14223] [AutoDiff] Crash when differentiating apply with opened existential argument

[dan-zheng]

Previous ID	SR-14223
Radar	None
Original Reporter	@dan-zheng
Type	Bug

Additional Detail from JIRA

Votes	0
Component/s	Compiler
Labels	Bug, AutoDiff
Assignee	None
Priority	Medium

md5: 923c0c746d9ba320bd8cbd46e5b6a6c2

Issue Description:

public protocol TensorView {
 associatedtype Element
}
public protocol DifferentiableTensorView: TensorView & Differentiable where Self == TangentVector {}

public protocol PlatformAPI {
 func abs<T>(_ x: T) -> T where T: DifferentiableTensorView, T.Element: Numeric
}
public class CpuService: PlatformAPI {
 public func abs<T>(_ x: T) -> T where T: DifferentiableTensorView, T.Element: Numeric \{ x }
}

public final class Platform {
 public static var service: PlatformAPI = CpuService()
}

@differentiable( where T: DifferentiableTensorView)
public func abs<T: DifferentiableTensorView>(_ x: T) -> T where T.Element: Numeric {
 Platform.service.abs(x)
}

swift: /home/danielzheng/swift-master/swift/lib/AST/ASTContext.cpp:3307: swift::SILFunctionType::SILFunctionType(swift::GenericSignature, swift::SILFunctionType::ExtInfo, swift::SILCoroutineKind, swift::ParameterConvention, ArrayRef<swift::SILParameterInfo>, ArrayRef<swift::SIL
YieldInfo>, ArrayRef<swift::SILResultInfo>, Optional<swift::SILResultInfo>, swift::SubstitutionMap, swift::SubstitutionMap, const swift::ASTContext &, swift::RecursiveTypeProperties, swift::ProtocolConformanceRef): Assertion `!WitnessMethodConformance.isInvalid() && "witness_method SIL function without a conformance"' failed.
Stack dump:
0.      Program arguments: /home/danielzheng/swift-master/build/Ninja-ReleaseAssert/swift-linux-x86_64/bin/swift -frontend -c -primary-file swift/test/AutoDiff/compiler_crashers/tf1181-apply-opened-opened-existential-argument.swift -target x86_64-unknown-linux-gnu -disable-objc-interop -color-diagnostics -module-name main -o /tmp/tf1181-apply-opened-opened-existential-argument-3a917d.o 
1.      Swift version 5.3-dev (LLVM f66b332548, Swift dee6c0b09f)
2.      While evaluating request ExecuteSILPipelineRequest(Run pipelines { Guaranteed Passes } on SIL for main.main)
3.      While running pass #&#8203;105 SILModuleTransform "Differentiation".
4.      While processing // differentiability witness for abs<A>(_:)
sil_differentiability_witness [serialized] [parameters 0] [results 0] <T where T : DifferentiableTensorView, T.Element : Numeric> @$s4main3absyxxAA24DifferentiableTensorViewRzSj7ElementAA0dE0PRpzlF : $@convention(thin) <T where T : DifferentiableTensorView, T.Element : Numeric> (@in_guaranteed T) -> @out T {
}
 on SIL function "@$s4main3absyxxAA24DifferentiableTensorViewRzSj7ElementAA0dE0PRpzlF".
 for 'abs(_:)' (at swift/test/AutoDiff/compiler_crashers/tf1181-apply-opened-opened-existential-argument.swift:27:8)
 #&#8203;0 0x00000000051bd514 PrintStackTraceSignalHandler(void*) (/home/danielzheng/swift-master/build/Ninja-ReleaseAssert/swift-linux-x86_64/bin/swift+0x51bd514)
 #&#8203;1 0x00000000051bb10e llvm::sys::RunSignalHandlers() (/home/danielzheng/swift-master/build/Ninja-ReleaseAssert/swift-linux-x86_64/bin/swift+0x51bb10e)
 #&#8203;2 0x00000000051bd7ec SignalHandler(int) (/home/danielzheng/swift-master/build/Ninja-ReleaseAssert/swift-linux-x86_64/bin/swift+0x51bd7ec)
 #&#8203;3 0x00007f160b5e2890 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x12890)
 #&#8203;4 0x00007f1609e84e97 raise (/lib/x86_64-linux-gnu/libc.so.6+0x3ee97)
 #&#8203;5 0x00007f1609e86801 abort (/lib/x86_64-linux-gnu/libc.so.6+0x40801)
 #&#8203;6 0x00007f1609e7639a (/lib/x86_64-linux-gnu/libc.so.6+0x3039a)
 #&#8203;7 0x00007f1609e76412 (/lib/x86_64-linux-gnu/libc.so.6+0x30412)
 #&#8203;8 0x00000000017998be swift::SILFunctionType::SILFunctionType(swift::GenericSignature, swift::SILFunctionType::ExtInfo, swift::SILCoroutineKind, swift::ParameterConvention, llvm::ArrayRef<swift::SILParameterInfo>, llvm::ArrayRef<swift::SILYieldInfo>, llvm::ArrayRef<swift::SILResultInfo>, llvm::Optional<swift::SILResultInfo>, swift::SubstitutionMap, swift::SubstitutionMap, swift::ASTContext const&, swift::RecursiveTypeProperties, swift::ProtocolConformanceRef) (/home/danielzheng/swift-master/build/Ninja-ReleaseAssert/swift-linux-x86_64/bin/swift+0x17998be)
 #&#8203;9 0x000000000179a806 swift::SILFunctionType::get(swift::GenericSignature, swift::SILFunctionType::ExtInfo, swift::SILCoroutineKind, swift::ParameterConvention, llvm::ArrayRef<swift::SILParameterInfo>, llvm::ArrayRef<swift::SILYieldInfo>, llvm::ArrayRef<swift::SILResultInfo>, llvm::Optional<swift::SILResultInfo>, swift::SubstitutionMap, swift::SubstitutionMap, swift::ASTContext const&, swift::ProtocolConformanceRef) (/home/danielzheng/swift-master/build/Ninja-ReleaseAssert/swift-linux-x86_64/bin/swift+0x179a806)
#&#8203;10 0x00000000010bf7e8 (anonymous namespace)::SILTypeSubstituter::substSILFunctionType(swift::CanTypeWrapper<swift::SILFunctionType>, bool) (/home/danielzheng/swift-master/build/Ninja-ReleaseAssert/swift-linux-x86_64/bin/swift+0x10bf7e8)
#&#8203;11 0x00000000010be86c swift::SILType::subst(swift::Lowering::TypeConverter&, llvm::function_ref<swift::Type (swift::SubstitutableType*)>, llvm::function_ref<swift::ProtocolConformanceRef (swift::CanType, swift::Type, swift::ProtocolDecl*)>, swift::CanGenericSignature, bool) const (/home/danielzheng/swift-master/build/Ninja-ReleaseAssert/swift-linux-x86_64/bin/swift+0x10be86c)
#&#8203;12 0x00000000010ae3fe swift::GenericEnvironment::mapTypeIntoContext(swift::SILModule&, swift::SILType) const (/home/danielzheng/swift-master/build/Ninja-ReleaseAssert/swift-linux-x86_64/bin/swift+0x10ae3fe)
#&#8203;13 0x0000000000f1a1e1 swift::autodiff::LinearMapInfo::addLinearMapToStruct(swift::autodiff::ADContext&, swift::ApplyInst*) (/home/danielzheng/swift-master/build/Ninja-ReleaseAssert/swift-linux-x86_64/bin/swift+0xf1a1e1)
#&#8203;14 0x0000000000f17925 swift::autodiff::LinearMapInfo::generateDifferentiationDataStructures(swift::autodiff::ADContext&, swift::SILFunction*) (/home/danielzheng/swift-master/build/Ninja-ReleaseAssert/swift-linux-x86_64/bin/swift+0xf17925)
#&#8203;15 0x0000000000f2615f swift::autodiff::VJPEmitter::VJPEmitter(swift::autodiff::ADContext&, swift::SILFunction*, swift::SILDifferentiabilityWitness*, swift::SILFunction*, swift::autodiff::DifferentiationInvoker) (/home/danielzheng/swift-master/build/Ninja-ReleaseAssert/swift-linux-x86_64/bin/swift+0xf2615f)
#&#8203;16 0x0000000000e7efff (anonymous namespace)::DifferentiationTransformer::canonicalizeDifferentiabilityWitness(swift::SILFunction*, swift::SILDifferentiabilityWitness*, swift::autodiff::DifferentiationInvoker, swift::IsSerialized_t) (/home/danielzheng/swift-master/build/Ninja-ReleaseAssert/swift-linux-x86_64/bin/swift+0xe7efff)
...