if gover.IsToolchain(m.Path) {
		return "", ErrToolchain
	}
	dir, err := cacheDir(ctx, m.Path)
	if err != nil {
		return "", err
	}
	if !gover.ModIsValid(m.Path, m.Version) {
		return "", fmt.Errorf("non-semver module version %q", m.Version)
	}
	if module.CanonicalVersion(m.Version) != m.Version {
		return "", fmt.Errorf("non-canonical module version %q", m.Version)
	}

	case strings.HasPrefix(query, "<"):
		v := query[len("<"):]
		if !gover.ModIsValid(path, v) {
			return badVersion(v)
		}
		qm.filter = func(mv string) bool { return gover.ModCompare(qm.path, mv, v) < 0 }
		if !matchesMajor(v) {
			qm.preferIncompatible = true
		}

	case strings.HasPrefix(query, ">="):
		v := query[len(">="):]
		if !gover.ModIsValid(path, v) {
			return badVersion(v)
		}

		} else {
			data, err = lockedfile.Read(gomodActual)
		}
		if err != nil {
			return "", nil, module.VersionError(m, fmt.Errorf("reading %s: %v", base.ShortPath(name), err))
		}
	} else {
		if !gover.ModIsValid(m.Path, m.Version) {
			// Disallow the broader queries supported by fetch.Lookup.
			base.Fatalf("go: internal error: %s@%s: unexpected invalid semantic version", m.Path, m.Version)
		}
		name = "go.mod"