pkg go/build, type MultiplePackageError struct, Files []string
pkg go/build, type MultiplePackageError struct, Packages []string

# CL 135110044 go/token: implement PositionFor accessors, Robert Griesemer <******@****.***>
pkg go/token, method (*File) PositionFor(Pos, bool) Position
pkg go/token, method (*FileSet) PositionFor(Pos, bool) Position

func parsePackage(writer io.Writer, pkg *build.Package, userPath string) *Package {
	// include tells parser.ParseDir which files to include.
	// That means the file must be in the build package's GoFiles or CgoFiles
	// list only (no tag-ignored files, tests, swig or other non-Go files).
	include := func(info fs.FileInfo) bool {
		for _, name := range pkg.GoFiles {
			if name == info.Name() {
				return true
			}

	}

	// run the test for all order permutations of the incoming files
	for _, perm := range [][len(sources)]int{
		{0, 1, 2},
		{0, 2, 1},
		{1, 0, 2},
		{1, 2, 0},
		{2, 0, 1},
		{2, 1, 0},
	} {
		// create file order permutation
		files := make([]*ast.File, len(sources))
		for i := range perm {
			files[i] = orig[perm[i]]
		}

		// type-check package with given file order permutation

	CFiles            []string // .c source files
	CXXFiles          []string // .cc, .cpp and .cxx source files
	MFiles            []string // .m (Objective-C) source files
	HFiles            []string // .h, .hh, .hpp and .hxx source files
	FFiles            []string // .f, .F, .for and .f90 Fortran source files
	SFiles            []string // .s source files

				outputfiles = outputfiles[1:]
				numInputs := len(flag.Args())
				numOutputs := len(outputfiles)
				if numOutputs != numInputs {
					return fmt.Errorf("number of output files (%d) not equal to number of input files (%d)", numOutputs, numInputs)
				}
				if err := readPackageConfig(*pkgcfg); err != nil {
					return err
				}
				return nil
			} else {
				if *outfilelist != "" {

		{"(*File).Size", Method, 0},
		{"(*FileSet).AddFile", Method, 0},
		{"(*FileSet).Base", Method, 0},
		{"(*FileSet).File", Method, 0},
		{"(*FileSet).Iterate", Method, 0},
		{"(*FileSet).Position", Method, 0},
		{"(*FileSet).PositionFor", Method, 4},
		{"(*FileSet).Read", Method, 0},
		{"(*FileSet).RemoveFile", Method, 20},
		{"(*FileSet).Write", Method, 0},
		{"(*Position).IsValid", Method, 0},

	// order of the files, only on the presentation order to
	// the type-checker.
	for _, test := range []struct {
		files []*ast.File
		want  string
	}{
		{[]*ast.File{fileA, fileB}, "[a = 1 b = 2]"},
		{[]*ast.File{fileB, fileA}, "[b = 2 a = 1]"},
	} {
		var info Info
		if _, err := new(Config).Check("main", fset, test.files, &info); err != nil {
			t.Fatal(err)
		}

func scannerMode(mode uint) uint {
	var m uint = scanner.InsertSemis
	if mode&ParseComments != 0 {
		m |= scanner.ScanComments
	}
	return m
}

func (p *parser) init(fset *token.FileSet, filename string, src []byte, mode uint) {
	p.file = fset.AddFile(filename, fset.Base(), len(src))
	p.scanner.Init(p.file, src, p, scannerMode(mode))

	p.mode = mode

    assertEquals("gz", Files.getFileExtension("blah.tar.gz"));
    assertEquals("", Files.getFileExtension("/"));
    assertEquals("", Files.getFileExtension("."));
    assertEquals("", Files.getFileExtension(".."));
    assertEquals("", Files.getFileExtension("..."));
    assertEquals("", Files.getFileExtension("blah"));
    assertEquals("", Files.getFileExtension("blah."));
    assertEquals("", Files.getFileExtension(".blah."));

    assertEquals("gz", Files.getFileExtension("blah.tar.gz"));
    assertEquals("", Files.getFileExtension("/"));
    assertEquals("", Files.getFileExtension("."));
    assertEquals("", Files.getFileExtension(".."));
    assertEquals("", Files.getFileExtension("..."));
    assertEquals("", Files.getFileExtension("blah"));
    assertEquals("", Files.getFileExtension("blah."));
    assertEquals("", Files.getFileExtension(".blah."));