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.
8 "cmd/compile/internal/syntax"
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 var errVersionSyntax = errors.New("invalid Go version syntax")
49 // parseGoVersion parses a Go version string (such as "go1.12")
50 // and returns the version, or an error. If s is the empty
51 // string, the version is 0.0.
52 func parseGoVersion(s string) (v version, err error) {
56 if !strings.HasPrefix(s, "go") {
57 return version{}, errVersionSyntax
61 for ; i < len(s) && '0' <= s[i] && s[i] <= '9'; i++ {
62 if i >= 10 || i == 0 && s[i] == '0' {
63 return version{}, errVersionSyntax
65 v.major = 10*v.major + int(s[i]) - '0'
67 if i > 0 && i == len(s) {
70 if i == 0 || s[i] != '.' {
71 return version{}, errVersionSyntax
75 // We really should not accept "go1.0",
76 // but we didn't reject it from the start
77 // and there are now programs that use it.
82 for ; i < len(s) && '0' <= s[i] && s[i] <= '9'; i++ {
83 if i >= 10 || i == 0 && s[i] == '0' {
84 return version{}, errVersionSyntax
86 v.minor = 10*v.minor + int(s[i]) - '0'
88 if i > 0 && i == len(s) {
91 return version{}, errVersionSyntax
94 // langCompat reports an error if the representation of a numeric
95 // literal is not compatible with the current language version.
96 func (check *Checker) langCompat(lit *syntax.BasicLit) {
98 if len(s) <= 2 || check.allowVersion(check.pkg, lit, go1_13) {
102 if strings.Contains(s, "_") {
103 check.versionErrorf(lit, go1_13, "underscores in numeric literals")
110 if radix == 'b' || radix == 'B' {
111 check.versionErrorf(lit, go1_13, "binary literals")
114 if radix == 'o' || radix == 'O' {
115 check.versionErrorf(lit, go1_13, "0o/0O-style octal literals")
118 if lit.Kind != syntax.IntLit && (radix == 'x' || radix == 'X') {
119 check.versionErrorf(lit, go1_13, "hexadecimal floating-point literals")
123 // allowVersion reports whether the given package
124 // is allowed to use version major.minor.
125 func (check *Checker) allowVersion(pkg *Package, at poser, v version) bool {
126 // We assume that imported packages have all been checked,
127 // so we only have to check for the local package.
128 if pkg != check.pkg {
132 // If the source file declares its Go version, use that to decide.
133 if check.posVers != nil {
134 if src, ok := check.posVers[base(at.Pos())]; ok && src.major >= 1 {
135 return !src.before(v)
139 // Otherwise fall back to the version in the checker.
140 return check.version.equal(go0_0) || !check.version.before(v)
143 // allowVersionf is like allowVersion but also accepts a format string and arguments
144 // which are used to report a version error if allowVersion returns false.
145 func (check *Checker) allowVersionf(pkg *Package, at poser, v version, format string, args ...interface{}) bool {
146 if !check.allowVersion(pkg, at, v) {
147 check.versionErrorf(at, v, format, args...)
153 // base finds the underlying PosBase of the source file containing pos,
154 // skipping over intermediate PosBase layers created by //line directives.
155 func base(pos syntax.Pos) *syntax.PosBase {
159 if bb == nil || bb == b {