1 // Copyright 2021 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
14 // A version represents a released Go version.
19 func (v version) String() string {
20 return fmt.Sprintf("go%d.%d", v.major, v.minor)
23 func (v version) equal(u version) bool {
24 return v.major == u.major && v.minor == u.minor
27 func (v version) before(u version) bool {
28 return v.major < u.major || v.major == u.major && v.minor < u.minor
31 func (v version) after(u version) bool {
32 return v.major > u.major || v.major == u.major && v.minor > u.minor
35 // Go versions that introduced language changes.
37 go0_0 = version{0, 0} // no version specified
39 go1_13 = version{1, 13}
40 go1_14 = version{1, 14}
41 go1_17 = version{1, 17}
42 go1_18 = version{1, 18}
43 go1_20 = version{1, 20}
44 go1_21 = version{1, 21}
47 // parseGoVersion parses a Go version string (such as "go1.12")
48 // and returns the version, or an error. If s is the empty
49 // string, the version is 0.0.
50 func parseGoVersion(s string) (v version, err error) {
51 bad := func() (version, error) {
52 return version{}, fmt.Errorf("invalid Go version syntax %q", s)
57 if !strings.HasPrefix(s, "go") {
62 for ; i < len(s) && '0' <= s[i] && s[i] <= '9'; i++ {
63 if i >= 10 || i == 0 && s[i] == '0' {
66 v.major = 10*v.major + int(s[i]) - '0'
68 if i > 0 && i == len(s) {
71 if i == 0 || s[i] != '.' {
76 // We really should not accept "go1.0",
77 // but we didn't reject it from the start
78 // and there are now programs that use it.
83 for ; i < len(s) && '0' <= s[i] && s[i] <= '9'; i++ {
84 if i >= 10 || i == 0 && s[i] == '0' {
87 v.minor = 10*v.minor + int(s[i]) - '0'
89 // Accept any suffix after the minor number.
90 // We are only looking for the language version (major.minor)
91 // but want to accept any valid Go version, like go1.21.0
96 // langCompat reports an error if the representation of a numeric
97 // literal is not compatible with the current language version.
98 func (check *Checker) langCompat(lit *ast.BasicLit) {
100 if len(s) <= 2 || check.allowVersion(check.pkg, lit, go1_13) {
104 if strings.Contains(s, "_") {
105 check.versionErrorf(lit, go1_13, "underscores in numeric literals")
112 if radix == 'b' || radix == 'B' {
113 check.versionErrorf(lit, go1_13, "binary literals")
116 if radix == 'o' || radix == 'O' {
117 check.versionErrorf(lit, go1_13, "0o/0O-style octal literals")
120 if lit.Kind != token.INT && (radix == 'x' || radix == 'X') {
121 check.versionErrorf(lit, go1_13, "hexadecimal floating-point literals")
125 // allowVersion reports whether the given package
126 // is allowed to use version major.minor.
127 func (check *Checker) allowVersion(pkg *Package, at positioner, v version) bool {
128 // We assume that imported packages have all been checked,
129 // so we only have to check for the local package.
130 if pkg != check.pkg {
134 // If the source file declares its Go version and at references a valid
135 // position, use that to decide.
136 if pos := at.Pos(); pos.IsValid() && check.posVers != nil {
137 fileStart := check.fset.File(pos).Pos(0)
138 if src, ok := check.posVers[fileStart]; ok && src.major >= 1 {
139 return !src.before(v)
143 // Otherwise fall back to the version in the checker.
144 return check.version.equal(go0_0) || !check.version.before(v)
147 // verifyVersionf is like allowVersion but also accepts a format string and arguments
148 // which are used to report a version error if allowVersion returns false. It uses the
150 func (check *Checker) verifyVersionf(at positioner, v version, format string, args ...interface{}) bool {
151 if !check.allowVersion(check.pkg, at, v) {
152 check.versionErrorf(at, v, format, args...)