z.go
                quux/              (go code in package main)
                    y.go


The code in z.go is imported as "foo/internal/baz", but that
import statement can only appear in source files in the subtree
rooted at foo. The source files foo/f.go, foo/bar/x.go, and
foo/quux/y.go can all import "foo/internal/baz", but the source file
crash/bang/b.go cannot.

	// from updating go.mod and go.sum or reporting errors when updates are
	// needed. A package should set this if it would cause go.mod to be written
	// multiple times (for example, 'go get' calls LoadPackages multiple times) or
	// if it needs some other operation to be successful before go.mod and go.sum
	// can be written (for example, 'go mod download' must download modules before

// Copyright 2023 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.

//go:generate go run mktests.go

// Copyright 2023 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.

//go:generate go run mktests.go

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package modcmd

import (
	"context"
	"encoding/json"
	"errors"
	"os"
	"runtime"
	"sync"

	"cmd/go/internal/base"
	"cmd/go/internal/cfg"
	"cmd/go/internal/gover"
	"cmd/go/internal/modfetch"
	"cmd/go/internal/modfetch/codehost"
	"cmd/go/internal/modload"

// IsLang reports whether v denotes the overall Go language version
// and not a specific release. Starting with the Go 1.21 release, "1.x" denotes
// the overall language version; the first release is "1.x.0".
// The distinction is important because the relative ordering is
//
//	1.21 < 1.21rc1 < 1.21.0
//
// meaning that Go 1.21rc1 and Go 1.21.0 will both handle go.mod files that
// say "go 1.21", but Go 1.21rc1 will not handle files that say "go 1.21.0".

// created by cgo -cdefs and then converted to Go
// cgo -cdefs defs_netbsd.go defs_netbsd_arm.go

package runtime

const (
	_EINTR  = 0x4
	_EFAULT = 0xe
	_EAGAIN = 0x23

	_O_WRONLY   = 0x1
	_O_NONBLOCK = 0x4
	_O_CREAT    = 0x200
	_O_TRUNC    = 0x400
	_O_CLOEXEC  = 0x400000

	_PROT_NONE  = 0x0
	_PROT_READ  = 0x1
	_PROT_WRITE = 0x2
	_PROT_EXEC  = 0x4

	_MAP_ANON    = 0x1000
	_MAP_PRIVATE = 0x2

	run("go tool compile -p=main -importcfg", tmp("importcfg"), " -pack -o", tmp("linkmain.a"), "helloworld.go")
	run("go tool link -importcfg", tmp("importcfg"), "-o", tmp("linkmain.exe"), tmp("linkmain.o"))
	run("go tool link -importcfg", tmp("importcfg"), "-o", tmp("linkmain.exe"), tmp("linkmain.a"))

	// linkmain.go is not
	run("go tool compile -importcfg", tmp("importcfg"), "-p=notmain -o", tmp("linkmain1.o"), "linkmain.go")

// Copyright 2023 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 version provides operations on [Go versions]
// in [Go toolchain name syntax]: strings like
// "go1.20", "go1.21.0", "go1.22rc2", and "go1.23.4-bigcorp".
//
// [Go versions]: https://go.dev/doc/toolchain#version
// [Go toolchain name syntax]: https://go.dev/doc/toolchain#name

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

//go:build go1.16
// +build go1.16

// Package buildtag defines an Analyzer that checks build tags.
package buildtag

import (
	"go/ast"
	"go/build/constraint"
	"go/parser"
	"go/token"
	"strings"
	"unicode"

	"golang.org/x/tools/go/analysis"