We recently modified the installer for Nick Lockwood's SwiftFormat project to include the Swift runtime dlls, since the one installed on the machine might not be ABI-compatible. The installer will add its target folder to the system %Path%, which will then win when resolving swiftCore.dll and other Swift runtime dlls, breaking the toolchain programs like swift.exe.

Repro steps:

• Install a Swift toolchain different from SwiftFormat's (not 5.10.1)
• In a new command prompt, run swift.exe --version. It should work as expected.
• Install SwiftFormat from this release
• In a new command prompt, run swift.exe --version. It will now crash because it's picking up the Swift runtime binaries from the SwiftFormat installation.