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"
15 // A goVersion is a Go language version string of the form "go1.%d"
16 // where d is the minor version number. goVersion strings don't
17 // contain release numbers ("go1.20.1" is not a valid goVersion).
20 // asGoVersion returns v as a goVersion (e.g., "go1.20.1" becomes "go1.20").
21 // If v is not a valid Go version, the result is the empty string.
22 func asGoVersion(v string) goVersion {
23 return goVersion(version.Lang(v))
26 // isValid reports whether v is a valid Go version.
27 func (v goVersion) isValid() bool {
31 // cmp returns -1, 0, or +1 depending on whether x < y, x == y, or x > y,
32 // interpreted as Go versions.
33 func (x goVersion) cmp(y goVersion) int {
34 return version.Compare(string(x), string(y))
38 // Go versions that introduced language changes
39 go1_9 = asGoVersion("go1.9")
40 go1_13 = asGoVersion("go1.13")
41 go1_14 = asGoVersion("go1.14")
42 go1_17 = asGoVersion("go1.17")
43 go1_18 = asGoVersion("go1.18")
44 go1_20 = asGoVersion("go1.20")
45 go1_21 = asGoVersion("go1.21")
47 // current (deployed) Go version
48 go_current = asGoVersion(fmt.Sprintf("go1.%d", goversion.Version))
51 // langCompat reports an error if the representation of a numeric
52 // literal is not compatible with the current language version.
53 func (check *Checker) langCompat(lit *syntax.BasicLit) {
55 if len(s) <= 2 || check.allowVersion(check.pkg, lit, go1_13) {
59 if strings.Contains(s, "_") {
60 check.versionErrorf(lit, go1_13, "underscores in numeric literals")
67 if radix == 'b' || radix == 'B' {
68 check.versionErrorf(lit, go1_13, "binary literals")
71 if radix == 'o' || radix == 'O' {
72 check.versionErrorf(lit, go1_13, "0o/0O-style octal literals")
75 if lit.Kind != syntax.IntLit && (radix == 'x' || radix == 'X') {
76 check.versionErrorf(lit, go1_13, "hexadecimal floating-point literals")
80 // allowVersion reports whether the given package is allowed to use version v.
81 func (check *Checker) allowVersion(pkg *Package, at poser, v goVersion) bool {
82 // We assume that imported packages have all been checked,
83 // so we only have to check for the local package.
88 // If no explicit file version is specified,
89 // fileVersion corresponds to the module version.
90 var fileVersion goVersion
91 if pos := at.Pos(); pos.IsKnown() {
92 // We need version.Lang below because file versions
93 // can be (unaltered) Config.GoVersion strings that
94 // may contain dot-release information.
95 fileVersion = asGoVersion(check.versions[base(pos)])
97 return !fileVersion.isValid() || fileVersion.cmp(v) >= 0
100 // verifyVersionf is like allowVersion but also accepts a format string and arguments
101 // which are used to report a version error if allowVersion returns false. It uses the
103 func (check *Checker) verifyVersionf(at poser, v goVersion, format string, args ...interface{}) bool {
104 if !check.allowVersion(check.pkg, at, v) {
105 check.versionErrorf(at, v, format, args...)
111 // base finds the underlying PosBase of the source file containing pos,
112 // skipping over intermediate PosBase layers created by //line directives.
113 // The positions must be known.
114 func base(pos syntax.Pos) *syntax.PosBase {
115 assert(pos.IsKnown())
119 if bb == nil || bb == b {