Problem with running Swift REPL on Windows command prompt - swift

Question

I'm following the swift getting started documentation and I've installed Swift along with its dependencies in Visual studio:
I added Python (v3.9) to the path (although the guide does use 3.7, I'm not sure whether it would make a difference):
path %ProgramFiles(x86)%\Microsoft Visual Studio\Shared\Python39_64;%PATH%
I also entered this line which supposedly adds a few extra parameters which must be passed to the REPL (not entirely sure what exactly it does):
set SWIFTFLAGS=-sdk %SDKROOT% -I %SDKROOT%/usr/lib/swift -L %SDKROOT%/usr/lib/swift/windows
swift repl -target x86_64-unknown-windows-msvc %SWIFTFLAGS%
This starts the REPL and I'm presented with the following:
Welcome to compnerd.org Swift version 5.6.2 (swift-5.6.2-RELEASE).
Type :help for assistance.
1>
I try to enter 1 + 2 as a test to make sure everything is working properly but I am met with an error instead:
Assertion failed: false && "called into swift language runtime stub", file D:\a\1\s\llvm-project\lldb\source\Plugins\LanguageRuntime\Swift\SwiftLanguageRuntime.cpp, line 369
PLEASE submit a bug report to https://bugs.llvm.org/ and include the crash backtrace.
#0 0x00007ff739ced645 (C:\Library\Developer\Toolchains\unknown-Asserts-development.xctoolchain\usr\bin\lldb.exe+0x1d645)
#1 0x00007ffc6eeb1881 (C:\WINDOWS\System32\ucrtbase.dll+0x71881)
#2 0x00007ffc6eeb2851 (C:\WINDOWS\System32\ucrtbase.dll+0x72851)
#3 0x00007ffc6eeb426e (C:\WINDOWS\System32\ucrtbase.dll+0x7426e)
#4 0x00007ffc6eeb4165 (C:\WINDOWS\System32\ucrtbase.dll+0x74165)
#5 0x00007ffc6eeb44f1 (C:\WINDOWS\System32\ucrtbase.dll+0x744f1)
#6 0x00007ffbf02aa1d5 PyInit__lldb (C:\Library\Developer\Toolchains\unknown-Asserts-development.xctoolchain\usr\bin\liblldb.dll+0x83a1d5)
#7 0x00007ffbf525f724 PyInit__lldb (C:\Library\Developer\Toolchains\unknown-Asserts-development.xctoolchain\usr\bin\liblldb.dll+0x57ef724)
#8 0x00007ffbf5265031 PyInit__lldb (C:\Library\Developer\Toolchains\unknown-Asserts-development.xctoolchain\usr\bin\liblldb.dll+0x57f5031)
#9 0x00007ffbf52628a2 PyInit__lldb (C:\Library\Developer\Toolchains\unknown-Asserts-development.xctoolchain\usr\bin\liblldb.dll+0x57f28a2)
#10 0x00007ffbf525cbcb PyInit__lldb (C:\Library\Developer\Toolchains\unknown-Asserts-development.xctoolchain\usr\bin\liblldb.dll+0x57ecbcb)
#11 0x00007ffbeffd7d2b PyInit__lldb (C:\Library\Developer\Toolchains\unknown-Asserts-development.xctoolchain\usr\bin\liblldb.dll+0x567d2b)
#12 0x00007ffbeffe6c52 PyInit__lldb (C:\Library\Developer\Toolchains\unknown-Asserts-development.xctoolchain\usr\bin\liblldb.dll+0x576c52)
#13 0x00007ffbeffb4806 PyInit__lldb (C:\Library\Developer\Toolchains\unknown-Asserts-development.xctoolchain\usr\bin\liblldb.dll+0x544806)
#14 0x00007ffbeff6265a PyInit__lldb (C:\Library\Developer\Toolchains\unknown-Asserts-development.xctoolchain\usr\bin\liblldb.dll+0x4f265a)
#15 0x00007ffbeff6106e PyInit__lldb (C:\Library\Developer\Toolchains\unknown-Asserts-development.xctoolchain\usr\bin\liblldb.dll+0x4f106e)
#16 0x00007ffc6ee61bb2 (C:\WINDOWS\System32\ucrtbase.dll+0x21bb2)
#17 0x00007ffc70947034 (C:\WINDOWS\System32\KERNEL32.DLL+0x17034)
#18 0x00007ffc713a2651 (C:\WINDOWS\SYSTEM32\ntdll.dll+0x52651)
I've tried uninstalling and reinstalling components and playing with the parameters, but to no avail.
Any help would be greatly appreciated.

Answer 1

This is not a true solution, but a workaround that is working on my Windows PC. Assuming Swift is installed on its default location, you need to
set SDKROOT environment variable to C:\Library\Developer\Platforms\Windows.platform\Developer\SDKs\Windows.sdk
(just once in your Windows system environment variables)
instead of running swift repl, you run
lldb "--repl=-sdk %SDKROOT% -target x86_64-unknown-windows-msvc"
(you can make this as a swiftrepl.cmd file and put it into a folder on your path)
as first command you enter
:expr (void*)LoadLibraryA("C:/Program Files/swift/runtime-development/usr/bin/swiftCore.dll")
I know it is ugly, but it works.
lldb "--repl=-sdk %SDKROOT% -target x86_64-unknown-windows-msvc"
Welcome to compnerd.org Swift version 5.7 (swift-5.7-RELEASE).
Type :help for assistance.
1> :expr (void*)LoadLibraryA("C:/Program Files/swift/runtime-development/usr/bin/swiftCore.dll")
(void *) $0 = 0x00007ffa2a090000
1> 1+2
$R0: Int = 3
2> let str="test"
str: String = "test"