Proposal Details

It would be great if *.go files can allow more fine-grained version constraints.
The go.mod file permits it - so it seems like an incongruency.

My project is dealing with compiled object files which have been compiled on a very specific go version/OS/arch. It is important to be able to differentiate between different versions of go with precision.

=== go.mod ===
module mymod
go 1.22.3

=== main1.go ===
//go:build go1.23.5 && !go1.23.6
package main
func main() {
	println("built using go1.23.5")
}

=== main2.go ===
//go:build go1.23.6 && !go1.24
package main
func main() {
	println("built using go1.23.6")
}

$ go1.23.5  run .
package mymod: build constraints exclude all Go files in /Users/x/Documents/test-go-build-constraints

$ go1.23.6  run .
package mymod: build constraints exclude all Go files in /Users/x/Documents/test-go-build-constraints