//
	// (If the version is +incompatible, then the go.mod file must not exist:
	// +incompatible is not an ongoing opt-out from semantic import versioning.)
	incompatibleOk := map[string]bool{}
	canUseIncompatible := func(v string) bool {
		if r.codeDir != "" || r.pathMajor != "" {
			// A non-empty codeDir indicates a module within a subdirectory,
			// which necessarily has a go.mod file indicating the module boundary.