Trying to coerce regular function to @convention(c) traps

let x : [@convention(c) () -> ()] = [ { print("Hello") }, { print("World") } ]
func callAll(_ xs: [() -> ()]) {
  for f in xs {
    f()
  }
}
callAll(x) 

Could not cast value of type '@convention(c) () -> ()' (0x7fff88b22ba8) to '() -> ()' (0x7fff88b22d70).
PLEASE submit a bug report to https://bugs.llvm.org/ and include the crash backtrace.


0  swift-frontend           0x00000001089cf245 llvm::sys::PrintStackTrace(llvm::raw_ostream&) + 37
1  swift-frontend           0x00000001089ce238 llvm::sys::RunSignalHandlers() + 248
2  swift-frontend           0x00000001089cf806 SignalHandler(int) + 262
3  libsystem_platform.dylib 0x00007fff2053ad7d _sigtramp + 29
4  libsystem_malloc.dylib   0x00007fff20336eb7 _malloc_zone_calloc + 59
5  libsystem_c.dylib        0x00007fff20449720 abort + 120
6  libswiftCore.dylib       0x00007fff2cbeea15 swift::fatalError(unsigned int, char const*, ...) + 149
7  libswiftCore.dylib       0x00007fff2cbe6e87 swift::swift_dynamicCastFailure(void const*, char const*, void const*, char const*, char const*) + 71
8  libswiftCore.dylib       0x00007fff2cbe6efa swift::swift_dynamicCastFailure(swift::TargetMetadata<swift::InProcess> const*, swift::TargetMetadata<swift::InProcess> const*, char const*) + 106
9  libswiftCore.dylib       0x00007fff2cbe8adc swift_dynamicCastImpl(swift::OpaqueValue*, swift::OpaqueValue*, swift::TargetMetadata<swift::InProcess> const*, swift::TargetMetadata<swift::InProcess> const*, swift::DynamicCastFlags) + 4220
10 libswiftCore.dylib       0x00007fff2c8db5f8 $ss15_arrayForceCastySayq_GSayxGr0_lF + 616
11 libswiftCore.dylib       0x000000010b703067 $ss15_arrayForceCastySayq_GSayxGr0_lF + 18446603344255548631
12 swift-frontend           0x0000000103dfc559 llvm::orc::runAsMain(int (*)(int, char**), llvm::ArrayRef<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > >, llvm::Optional<llvm::StringRef>) + 1305