When running swift build on Windows I get the following error: compiled module was created by a newer version of the compiler
I can use the Swift REPL, the swift package init command works, swift--version works as well.
I can compile Swift code via CMake and the SwiftSupport module.
I have installed the current dev trunk of swift (5.6 as the time of writing).
The error also occurs when creating a new Package with swift package init and then running swift build
I have tried the current release branch as well, which gave me the same error.
Did you upgrade from a previous installation? If so, did you uninstall the previous version first? It seems like it may be picking up something unintentionally. Perhaps you can spot something by running swift build -v.