// Copyright 2021 The Go Authors. All rights reserved.// Use of this source code is governed by a BSD-style// license that can be found in the LICENSE file.package typesimport ()// A goVersion is a Go language version string of the form "go1.%d"// where d is the minor version number. goVersion strings don't// contain release numbers ("go1.20.1" is not a valid goVersion).type goVersion string// asGoVersion returns v as a goVersion (e.g., "go1.20.1" becomes "go1.20").// If v is not a valid Go version, the result is the empty string.func asGoVersion( string) goVersion {returngoVersion(version.Lang())}// isValid reports whether v is a valid Go version.func ( goVersion) () bool {return != ""}// cmp returns -1, 0, or +1 depending on whether x < y, x == y, or x > y,// interpreted as Go versions.func ( goVersion) ( goVersion) int {returnversion.Compare(string(), string())}var (// Go versions that introduced language changes go1_9 = asGoVersion("go1.9") go1_13 = asGoVersion("go1.13") go1_14 = asGoVersion("go1.14") go1_17 = asGoVersion("go1.17") go1_18 = asGoVersion("go1.18") go1_20 = asGoVersion("go1.20") go1_21 = asGoVersion("go1.21") go1_22 = asGoVersion("go1.22")// current (deployed) Go version go_current = asGoVersion(fmt.Sprintf("go1.%d", goversion.Version)))// langCompat reports an error if the representation of a numeric// literal is not compatible with the current language version.func ( *Checker) ( *ast.BasicLit) { := .Valueiflen() <= 2 || .allowVersion(.pkg, , go1_13) {return }// len(s) > 2ifstrings.Contains(, "_") { .versionErrorf(, go1_13, "underscores in numeric literals")return }if [0] != '0' {return } := [1]if == 'b' || == 'B' { .versionErrorf(, go1_13, "binary literals")return }if == 'o' || == 'O' { .versionErrorf(, go1_13, "0o/0O-style octal literals")return }if .Kind != token.INT && ( == 'x' || == 'X') { .versionErrorf(, go1_13, "hexadecimal floating-point literals") }}// allowVersion reports whether the given package is allowed to use version v.func ( *Checker) ( *Package, positioner, goVersion) bool {// We assume that imported packages have all been checked, // so we only have to check for the local package.if != .pkg {returntrue }// If no explicit file version is specified, // fileVersion corresponds to the module version.vargoVersionif := .Pos(); .IsValid() {// We need version.Lang below because file versions // can be (unaltered) Config.GoVersion strings that // may contain dot-release information. = asGoVersion(.versions[.fileFor()]) }return !.isValid() || .cmp() >= 0}// verifyVersionf is like allowVersion but also accepts a format string and arguments// which are used to report a version error if allowVersion returns false. It uses the// current package.func ( *Checker) ( positioner, goVersion, string, ...interface{}) bool {if !.allowVersion(.pkg, , ) { .versionErrorf(, , , ...)returnfalse }returntrue}// TODO(gri) Consider a more direct (position-independent) mechanism// to identify which file we're in so that version checks// work correctly in the absence of correct position info.// fileFor returns the *ast.File which contains the position pos.// If there are no files, the result is nil.// The position must be valid.func ( *Checker) ( token.Pos) *ast.File {assert(.IsValid())// Eval and CheckExpr tests may not have any source files.iflen(.files) == 0 {returnnil }for , := range .files {if .FileStart <= && < .FileEnd {return } }panic(.sprintf("file not found for pos = %d (%s)", int(), .fset.Position()))}
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