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.
4 5 package types
6 7 import (
8 "fmt"
9 "go/version"
10 "internal/goversion"
11 )
12 13 // A goVersion is a Go language version string of the form "go1.%d"
14 // where d is the minor version number. goVersion strings don't
15 // contain release numbers ("go1.20.1" is not a valid goVersion).
16 type goVersion string
17 18 // asGoVersion returns v as a goVersion (e.g., "go1.20.1" becomes "go1.20").
19 // If v is not a valid Go version, the result is the empty string.
20 func asGoVersion(v string) goVersion {
21 return goVersion(version.Lang(v))
22 }
23 24 // isValid reports whether v is a valid Go version.
25 func (v goVersion) isValid() bool {
26 return v != ""
27 }
28 29 // cmp returns -1, 0, or +1 depending on whether x < y, x == y, or x > y,
30 // interpreted as Go versions.
31 func (x goVersion) cmp(y goVersion) int {
32 return version.Compare(string(x), string(y))
33 }
34 35 var (
36 // Go versions that introduced language changes
37 go1_9 = asGoVersion("go1.9")
38 go1_13 = asGoVersion("go1.13")
39 go1_14 = asGoVersion("go1.14")
40 go1_17 = asGoVersion("go1.17")
41 go1_18 = asGoVersion("go1.18")
42 go1_20 = asGoVersion("go1.20")
43 go1_21 = asGoVersion("go1.21")
44 go1_22 = asGoVersion("go1.22")
45 go1_23 = asGoVersion("go1.23")
46 47 // current (deployed) Go version
48 go_current = asGoVersion(fmt.Sprintf("go1.%d", goversion.Version))
49 )
50 51 // allowVersion reports whether the current effective Go version
52 // (which may vary from one file to another) is allowed to use the
53 // feature version (want).
54 func (check *Checker) allowVersion(want goVersion) bool {
55 return !check.version.isValid() || check.version.cmp(want) >= 0
56 }
57 58 // verifyVersionf is like allowVersion but also accepts a format string and arguments
59 // which are used to report a version error if allowVersion returns false.
60 func (check *Checker) verifyVersionf(at positioner, v goVersion, format string, args ...interface{}) bool {
61 if !check.allowVersion(v) {
62 check.versionErrorf(at, v, format, args...)
63 return false
64 }
65 return true
66 }
67