Hello, It seems the guix's go package is broken when the go tool is used for incremental builds. Any attempt to use 'install' or 'build -i' results in an attempt to write to the store. A one-liner: guix environment --ad-hoc go -- bash -c 'export t=$(mktemp -d); cd $t && export GOPATH=$(pwd) GOBIN=$(pwd)/bin && go install cmd/go; cd && rm -rf $t' Another command reports that (seemingly) the entire stdlib is marked as stale: guix environment --ad-hoc go -- bash -c 'export t=$(mktemp -d); cd $t && export GOPATH=$(pwd) GOBIN=$(pwd)/bin && go list -f '\''{{join .Deps "\n"}}'\'' cmd/go | xargs -n1 go list -f '\''{{if .Stale}}{{.ImportPath}}: {{.StaleReason}}{{end}}'\''; cd && rm -rf $t' The function for determining staleness is here (after the giant comment explaining the reasoning): https://golang.org/src/cmd/go/pkg.go#L1111 I don't see anything wrong with the package definition, but could be missing something. My only hunch at this point is that something might be modifying src/runtime/internal/sys/zversion.go, as that entire file is included in the build ID computation. Thanks,