Using custom swift-stdlib while running a swift package on mac OS

We have an executable that we're trying to test using a snapshot toolchain on mac OS. The exact command we're using looks as below -

/Library/Developer/Toolchains/swift-DEVELOPMENT-SNAPSHOT-2023-09-24-a.xctoolchain/usr/bin/swift run

We need to use the swift-stdlib from the snapshot toolchain, instead of the system swift-stdlib that comes with mac OS. But it looks like that is not happening and I know it because the snapshot toolchain's stdlib has certain fixes whose effects we're not seeing.

I saw a very similar forum post here where multiple solutions have been prescribed but none of them works for us.

  2. Pass -toolchain-stdlib-rpath to swiftc

Has anyone tackled and resolved this issue more recently?

We're not trying to test an executable. We're trying to run a Swift package using swift run.

It was clear in the title but I realized I put "executable" in the body.