)

type stdFilter int8

const (
	omitStd = stdFilter(iota)
	includeStd
)

// matchPackages is like m.MatchPackages, but uses a local variable (rather than
// a global) for tags, can include or exclude packages in the standard library,
// and is restricted to the given list of modules.
func matchPackages(ctx context.Context, m *search.Match, tags map[string]bool, filter stdFilter, modules []module.Version) {

//
// If any errors may have caused the set of packages to be incomplete,
// MatchPackages appends those errors to m.Errs.
func (m *Match) MatchPackages() {
	m.Pkgs = []string{}
	if m.IsLocal() {
		m.AddError(fmt.Errorf("internal error: MatchPackages: %s is not a valid package pattern", m.pattern))
		return
	}

	if m.IsLiteral() {
		m.Pkgs = []string{m.pattern}
		return
	}

	CGO, internal/syscall/unix < net/internal/cgotest;


`

// listStdPkgs returns the same list of packages as "go list std".
func listStdPkgs(goroot string) ([]string, error) {
	// Based on cmd/go's matchPackages function.
	var pkgs []string

	src := filepath.Join(goroot, "src") + string(filepath.Separator)
	walkFn := func(path string, d fs.DirEntry, err error) error {
		if err != nil || !d.IsDir() || path == src {

					}
					matchPackages(ctx, m, opts.Tags, omitStd, matchModules)
				} else {
					// Starting with the packages in the main module,
					// enumerate the full list of "all".
					m.Pkgs = ld.computePatternAll()
				}

			case m.Pattern() == "std" || m.Pattern() == "cmd":
				if m.Pkgs == nil {
					m.MatchPackages() // Locate the packages within GOROOT/src.
				}

			return nil, nil, &WildcardInFirstElementError{Pattern: pattern, Query: query}
		}
		match = func(mod module.Version, roots []string, isLocal bool) *search.Match {
			m := search.NewMatch(pattern)
			matchPackages(ctx, m, imports.AnyTags(), omitStd, []module.Version{mod})
			return m
		}
	} else {
		match = func(mod module.Version, roots []string, isLocal bool) *search.Match {
			m := search.NewMatch(pattern)

package load

import (
	"path/filepath"
	"strings"

	"cmd/go/internal/search"
	"cmd/internal/pkgpattern"
)

// MatchPackage(pattern, cwd)(p) reports whether package p matches pattern in the working directory cwd.
func MatchPackage(pattern, cwd string) func(*Package) bool {
	switch {
	case search.IsRelativePath(pattern):
		// Split pattern into leading pattern-free directory path

		}
		if v[0] == '\'' || v[0] == '"' {
			return fmt.Errorf("parameter may not start with quote character %c", v[0])
		}
		pattern := strings.TrimSpace(v[:i])
		match = MatchPackage(pattern, cwd)
		v = v[i+1:]
	}
	flags, err := quoted.Split(v)
	if err != nil {
		return err
	}
	if flags == nil {
		flags = []string{}
	}
	f.values = append(f.values, ppfValue{match, flags})

	var writeCoverMetaAct *work.Action

	if cfg.BuildCoverPkg != nil {
		match := make([]func(*load.Package) bool, len(cfg.BuildCoverPkg))
		for i := range cfg.BuildCoverPkg {
			match[i] = load.MatchPackage(cfg.BuildCoverPkg[i], base.Cwd())
		}

		// Select for coverage all dependencies matching the -coverpkg
		// patterns.
		plist := load.TestPackageList(ctx, pkgOpts, pkgs)

		// the specific packages selected by the user-specified pattern(s).
		match = make([]func(*Package) bool, len(cfg.BuildCoverPkg))
		for i := range cfg.BuildCoverPkg {
			match[i] = MatchPackage(cfg.BuildCoverPkg[i], base.Cwd())
		}
	} else {
		// Without -coverpkg, instrument only packages in the main module
		// (if any), as well as packages/files specifically named on the
		// command line.