package build

import (
	"bytes"
	"errors"
	"fmt"
	"go/ast"
	"go/build/constraint"
	"go/doc"
	"go/token"
	"internal/buildcfg"
	"internal/godebug"
	"internal/goroot"
	"internal/goversion"
	"internal/platform"
	"io"
	"io/fs"
	"os"
	"os/exec"
	pathpkg "path"
	"path/filepath"
	"runtime"
	"slices"
	"strconv"
	"strings"
	"unicode"
	"unicode/utf8"
	_ "unsafe" // for linkname

func f[S ~[]E, E any](S) {}

func _() {
	f([]string{})
}
`
	// Per the go:build directive, the source must typecheck
	// even though the (module) Go version is set to go1.17.
	conf := Config{GoVersion: "go1.17"}
	mustTypecheck(src, &conf, nil)

	Unresolved         []*Ident        // unresolved identifiers in this file. Deprecated: see Object
	Comments           []*CommentGroup // list of all comments in the source file
	GoVersion          string          // minimum Go version required by //go:build or // +build directives
}

// Pos returns the position of the package declaration.
// (Use FileStart for the start of the entire file.)

        Dir        string        // directory holding local copy of files, if any
        GoMod      string        // path to go.mod file describing module, if any
        GoVersion  string        // go version used in module
        Retracted  []string      // retraction information, if any (with -retracted or -u)
        Deprecated string        // deprecation message, if any (with -u)

		goVers := gover.GoModLookup(gomod, "go")
		if gover.Compare(goVers, gover.Local()) > 0 {
			return &gover.TooNewError{What: r.ModulePath() + "@" + version, GoVersion: goVers}
		}
	} else if !errors.Is(err, fs.ErrNotExist) {
		return err
	}

	dl, err := r.code.ReadZip(ctx, rev, subdir, codehost.MaxZipFile)
	if err != nil {
		return err
	}

		If module-aware mode is disabled, GOMOD will be the empty string.
	GOTOOLDIR
		The directory where the go tools (compile, cover, doc, etc...) are installed.
	GOVERSION
		The version of the installed Go tree, as reported by runtime.Version.
	`,
}

var HelpFileType = &base.Command{
	UsageLine: "filetype",
	Short:     "file types",
	Long: `

	r.reportChanges(oldReqs, newReqs)

	if gowork := modload.FindGoWork(base.Cwd()); gowork != "" {
		wf, err := modload.ReadWorkFile(gowork)
		if err == nil && modload.UpdateWorkGoVersion(wf, modload.MainModules.GoVersion()) {
			modload.WriteWorkFile(gowork, wf)
		}
	}
}

// parseArgs parses command-line arguments and reports errors.
//
// The command-line arguments are of the form path@version or simply path, with

//	    Dir        string        // directory holding local copy of files, if any
//	    GoMod      string        // path to go.mod file describing module, if any
//	    GoVersion  string        // go version used in module
//	    Retracted  []string      // retraction information, if any (with -retracted or -u)
//	    Deprecated string        // deprecation message, if any (with -u)

		{"File", Type, 0},
		{"File.Comments", Field, 0},
		{"File.Decls", Field, 0},
		{"File.Doc", Field, 0},
		{"File.FileEnd", Field, 20},
		{"File.FileStart", Field, 20},
		{"File.GoVersion", Field, 21},
		{"File.Imports", Field, 0},
		{"File.Name", Field, 0},
		{"File.Package", Field, 0},
		{"File.Scope", Field, 0},
		{"File.Unresolved", Field, 0},
		{"FileExports", Func, 0},

// in the binary. setBuildInfo should only be called on a main package with no
// errors.
//
// This information can be retrieved using debug.ReadBuildInfo.
//
// Note that the GoVersion field is not set here to avoid encoding it twice.
// It is stored separately in the binary, mostly for historical reasons.
func (p *Package) setBuildInfo(ctx context.Context, autoVCS bool) {