if m.Version == "" && MainModules.Contains(m.Path) {
		return module.Version{Path: m.Path, Version: "none"}, nil
	}

	list, _, err := versions(ctx, m.Path, CheckAllowed)
	if err != nil {
		if errors.Is(err, os.ErrNotExist) {
			return module.Version{Path: m.Path, Version: "none"}, nil
		}
		return module.Version{}, err
	}

					// The module graph is incomplete, so we don't know what version we're
					// actually upgrading from.
					// mgErr is already set, so just skip this module.
					continue
				}
			}

			allowed := CheckAllowed
			if IsRevisionQuery(path, vers) || mode&ListRetracted != 0 {
				// Allow excluded and retracted versions if the user asked for a
				// specific revision or used 'go list -retracted'.
				allowed = nil
			}