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.
16 // A goVersion is a Go language version string of the form "go1.%d"
17 // where d is the minor version number. goVersion strings don't
18 // contain release numbers ("go1.20.1" is not a valid goVersion).
21 // asGoVersion returns v as a goVersion (e.g., "go1.20.1" becomes "go1.20").
22 // If v is not a valid Go version, the result is the empty string.
23 func asGoVersion(v string) goVersion {
24 return goVersion(version.Lang(v))
27 // isValid reports whether v is a valid Go version.
28 func (v goVersion) isValid() bool {
32 // cmp returns -1, 0, or +1 depending on whether x < y, x == y, or x > y,
33 // interpreted as Go versions.
34 func (x goVersion) cmp(y goVersion) int {
35 return version.Compare(string(x), string(y))
39 // Go versions that introduced language changes
40 go1_9 = asGoVersion("go1.9")
41 go1_13 = asGoVersion("go1.13")
42 go1_14 = asGoVersion("go1.14")
43 go1_17 = asGoVersion("go1.17")
44 go1_18 = asGoVersion("go1.18")
45 go1_20 = asGoVersion("go1.20")
46 go1_21 = asGoVersion("go1.21")
48 // current (deployed) Go version
49 go_current = asGoVersion(fmt.Sprintf("go1.%d", goversion.Version))
52 // langCompat reports an error if the representation of a numeric
53 // literal is not compatible with the current language version.
54 func (check *Checker) langCompat(lit *ast.BasicLit) {
56 if len(s) <= 2 || check.allowVersion(check.pkg, lit, go1_13) {
60 if strings.Contains(s, "_") {
61 check.versionErrorf(lit, go1_13, "underscores in numeric literals")
68 if radix == 'b' || radix == 'B' {
69 check.versionErrorf(lit, go1_13, "binary literals")
72 if radix == 'o' || radix == 'O' {
73 check.versionErrorf(lit, go1_13, "0o/0O-style octal literals")
76 if lit.Kind != token.INT && (radix == 'x' || radix == 'X') {
77 check.versionErrorf(lit, go1_13, "hexadecimal floating-point literals")
81 // allowVersion reports whether the given package is allowed to use version v.
82 func (check *Checker) allowVersion(pkg *Package, at positioner, v goVersion) bool {
83 // We assume that imported packages have all been checked,
84 // so we only have to check for the local package.
89 // If no explicit file version is specified,
90 // fileVersion corresponds to the module version.
91 var fileVersion goVersion
92 if pos := at.Pos(); pos.IsValid() {
93 // We need version.Lang below because file versions
94 // can be (unaltered) Config.GoVersion strings that
95 // may contain dot-release information.
96 fileVersion = asGoVersion(check.versions[check.fileFor(pos)])
98 return !fileVersion.isValid() || fileVersion.cmp(v) >= 0
101 // verifyVersionf is like allowVersion but also accepts a format string and arguments
102 // which are used to report a version error if allowVersion returns false. It uses the
104 func (check *Checker) verifyVersionf(at positioner, v goVersion, format string, args ...interface{}) bool {
105 if !check.allowVersion(check.pkg, at, v) {
106 check.versionErrorf(at, v, format, args...)
112 // TODO(gri) Consider a more direct (position-independent) mechanism
113 // to identify which file we're in so that version checks
114 // work correctly in the absence of correct position info.
116 // fileFor returns the *ast.File which contains the position pos.
117 // If there are no files, the result is nil.
118 // The position must be valid.
119 func (check *Checker) fileFor(pos token.Pos) *ast.File {
120 assert(pos.IsValid())
121 // Eval and CheckExpr tests may not have any source files.
122 if len(check.files) == 0 {
125 for _, file := range check.files {
126 if file.FileStart <= pos && pos < file.FileEnd {
130 panic(check.sprintf("file not found for pos = %d (%s)", int(pos), check.fset.Position(pos)))