import Foundation

public enum Result<T, Error: Swift.Error> {
    case success(T)
    case failure(Error)

    /// Returns the value from `Success` Results or `throw`s the error.
    public func dematerialize() throws -> T {
        switch self {
        case let .success(value):
            return value
        case let .failure(error):
            throw error
        }
    }
}

$ swift build
Compile Swift Module 'Result' (1 sources)
/Result/Result/Result.swift:13:10: error: unable to find implicit conversion function 'Swift._stdlib_getErrorEmbeddedNSError'
                        throw error
                              ^
SIL verification failed: Basic blocks cannot be empty: !BB.empty()
In function:
sil_scope 1 { loc "/Result/Result/Result.swift":8:14 parent @_TFO6Result6Result13dematerializefzT_x : $@convention(method) <τ_0_0, τ_0_1 where τ_0_1 : Error> (@in_guaranteed Result<τ_0_0, τ_0_1>) -> (@out τ_0_0, @error Error) }
sil_scope 2 { loc "/Result/Result/Result.swift":15:2 parent 1 }
sil_scope 3 { loc "/Result/Result/Result.swift":14:3 parent 2 }
sil_scope 4 { loc "/Result/Result/Result.swift":14:3 parent 3 }
sil_scope 5 { loc "/Result/Result/Result.swift":11:11 parent 4 }
sil_scope 6 { loc "/Result/Result/Result.swift":14:3 parent 3 }
sil_scope 7 { loc "/Result/Result/Result.swift":13:10 parent 6 }

// Result.dematerialize() throws -> A
sil @_TFO6Result6Result13dematerializefzT_x : $@convention(method) <T, Error where Error : Error> (@in_guaranteed Result<T, Error>) -> (@out T, @error Error) {
// %0                                             // user: %9
// %1                                             // users: %4, %2
bb0(%0 : $*T, %1 : $*Result<T, Error>):
  debug_value_addr %1 : $*Result<T, Error>, let, name "self", argno 1, loc "/Result/Result/Result.swift":8:14, scope 1 // id: %2
  %3 = alloc_stack $Result<T, Error>, loc "/Result/Result/Result.swift":9:10, scope 2 // users: %20, %14, %11, %6, %5, %4
  copy_addr %1 to [initialization] %3 : $*Result<T, Error>, loc "/Result/Result/Result.swift":9:10, scope 2 // id: %4
  switch_enum_addr %3 : $*Result<T, Error>, case #Result.success!enumelt.1: bb1, case #Result.failure!enumelt.1: bb2, loc "/Result/Result/Result.swift":10:12, scope 3 // id: %5

bb1:                                              // Preds: bb0
  %6 = unchecked_take_enum_data_addr %3 : $*Result<T, Error>, #Result.success!enumelt.1, loc "/Result/Result/Result.swift":10:12, scope 3 // user: %8
  %7 = alloc_stack $T, let, name "value", loc "/Result/Result/Result.swift":10:21, scope 4 // users: %10, %9, %8
  copy_addr [take] %6 to [initialization] %7 : $*T, loc "/Result/Result/Result.swift":10:21, scope 4 // id: %8
  copy_addr [take] %7 to [initialization] %0 : $*T, loc "/Result/Result/Result.swift":11:11, scope 5 // id: %9
  dealloc_stack %7 : $*T, loc "/Result/Result/Result.swift":15:2, scope 5 // id: %10
  dealloc_stack %3 : $*Result<T, Error>, loc "/Result/Result/Result.swift":15:2, scope 5 // id: %11
  %12 = tuple (), loc "/Result/Result/Result.swift":15:2, scope 2 // user: %13
  return %12 : $(), loc "/Result/Result/Result.swift":11:4, scope 2 // id: %13

bb2:                                              // Preds: bb0
  %14 = unchecked_take_enum_data_addr %3 : $*Result<T, Error>, #Result.failure!enumelt.1, loc "/Result/Result/Result.swift":12:12, scope 3 // user: %16
  %15 = alloc_stack $Error, let, name "error", loc "/Result/Result/Result.swift":12:21, scope 6 // users: %19, %18, %16
  copy_addr [take] %14 to [initialization] %15 : $*Error, loc "/Result/Result/Result.swift":12:21, scope 6 // id: %16
  %17 = builtin "willThrow"(undef : $Error) : $(), loc "/Result/Result/Result.swift":13:4, scope 7
  destroy_addr %15 : $*Error, loc "/Result/Result/Result.swift":15:2, scope 7 // id: %18
  dealloc_stack %15 : $*Error, loc "/Result/Result/Result.swift":15:2, scope 7 // id: %19
  dealloc_stack %3 : $*Result<T, Error>, loc "/Result/Result/Result.swift":15:2, scope 7 // id: %20
  throw undef : $Error, loc "/Result/Result/Result.swift":13:4, scope 2 // id: %21

bb3:

bb4:

bb5:
}

0  swift           0x0000000003349ae8 llvm::sys::PrintStackTrace(llvm::raw_ostream&) + 40
1  swift           0x00000000033482e6 llvm::sys::RunSignalHandlers() + 54
2  swift           0x000000000334a616
3  libpthread.so.0 0x00007fc1fc2a8d10
4  libc.so.6       0x00007fc1fabf01c7 gsignal + 55
5  libc.so.6       0x00007fc1fabf1e2a abort + 362
6  swift           0x0000000000d03e06
7  swift           0x0000000000d014e8
8  swift           0x0000000000cff708 swift::SILFunction::verify(bool) const + 40
9  swift           0x0000000000938ce8
10 swift           0x00000000009427bd
11 swift           0x0000000000938a71
12 swift           0x00000000009de91c
13 swift           0x00000000009de42d
14 swift           0x000000000093f37b
15 swift           0x0000000000940082 swift::SILModule::constructSIL(swift::ModuleDecl*, swift::SILOptions&, swift::FileUnit*, llvm::Optional<unsigned int>, bool, bool) + 482
16 swift           0x0000000000940616 swift::performSILGeneration(swift::FileUnit&, swift::SILOptions&, llvm::Optional<unsigned int>, bool) + 118
17 swift           0x00000000007e0d8d
18 swift           0x00000000007dcc51 swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) + 2833
19 swift           0x00000000007a738b main + 2715
20 libc.so.6       0x00007fc1fabdbac0 __libc_start_main + 240
21 swift           0x00000000007a4e99 _start + 41
Stack dump:
0.  Program arguments: /swift-development/build/buildbot_linux/none-swift_package_sandbox_linux-x86_64/usr/bin/swift -frontend -c -primary-file /Result/Result/Result.swift -target x86_64-unknown-linux-gnu -disable-objc-interop -I /Result/.build/debug -enable-testing -g -module-cache-path /Result/.build/debug/ModuleCache -D SWIFT_PACKAGE -emit-module-doc-path /Result/.build/debug/Result.build/Result~partial.swiftdoc -Onone -parse-as-library -module-name Result -emit-module-path /Result/.build/debug/Result.build/Result~partial.swiftmodule -emit-dependencies-path /Result/.build/debug/Result.build/Result.d -emit-reference-dependencies-path /Result/.build/debug/Result.build/Result.swiftdeps -num-threads 8 -o /Result/.build/debug/Result.build/Result.swift.o 
1.  While emitting SIL for 'dematerialize' at /Result/Result/Result.swift:8:9
<unknown>:0: error: unable to execute command: Aborted
<unknown>:0: error: compile command failed due to signal (use -v to see invocation)
<unknown>:0: error: build had 1 command failures
swift-build: error: exit(1): /swift-development/build/buildbot_linux/none-swift_package_sandbox_linux-x86_64/usr/bin/swift-build-tool -f /Result/.build/debug.yaml