go/scanner: remove (exported) InsertSemis mode

This is a relic from the times when we switched
to automatic semicolon insertion. It's still use-
ful to have a non-exported switch for testing.

R=golang-dev, r, rsc
CC=golang-dev
https://golang.org/cl/5528077

src/cmd/godoc/format.go

@@ -231,7 +231,7 @@ func commentSelection(src []byte) Selection {
 	var s scanner.Scanner
 	fset := token.NewFileSet()
 	file := fset.AddFile("", fset.Base(), len(src))
-	s.Init(file, src, nil, scanner.ScanComments+scanner.InsertSemis)
+	s.Init(file, src, nil, scanner.ScanComments)
 	return func() (seg []int) {
 		for {
 			pos, tok, lit := s.Scan()

src/pkg/exp/types/check_test.go

@@ -111,7 +111,7 @@ func expectedErrors(t *testing.T, testname string, files map[string]*ast.File) m
 		// set otherwise the position information returned here will
 		// not match the position information collected by the parser
 		s.Init(getFile(filename), src, nil, scanner.ScanComments)
-		var prev token.Pos // position of last non-comment token
+		var prev token.Pos // position of last non-comment, non-semicolon token
 
 	scanFile:
 		for {
@@ -124,6 +124,12 @@ func expectedErrors(t *testing.T, testname string, files map[string]*ast.File) m
 				if len(s) == 2 {
 					errors[prev] = string(s[1])
 				}
+			case token.SEMICOLON:
+				// ignore automatically inserted semicolon
+				if lit == "\n" {
+					break
+				}
+				fallthrough
 			default:
 				prev = pos
 			}

src/pkg/go/parser/parser.go

@@ -67,7 +67,7 @@ type parser struct {
 
 // scannerMode returns the scanner mode bits given the parser's mode bits.
 func scannerMode(mode uint) uint {
-	var m uint = scanner.InsertSemis
+	var m uint
 	if mode&ParseComments != 0 {
 		m |= scanner.ScanComments
 	}

src/pkg/go/scanner/scanner.go

@@ -90,8 +90,8 @@ func (S *Scanner) next() {
 // They control scanner behavior.
 //
 const (
-	ScanComments = 1 << iota // return comments as COMMENT tokens
-	InsertSemis              // automatically insert semicolons
+	ScanComments    = 1 << iota // return comments as COMMENT tokens
+	dontInsertSemis             // do not automatically insert semicolons - for testing only
 )
 
 // Init prepares the scanner S to tokenize the text src by setting the
@@ -104,7 +104,7 @@ const (
 // Calls to Scan will use the error handler err if they encounter a
 // syntax error and err is not nil. Also, for each error encountered,
 // the Scanner field ErrorCount is incremented by one. The mode parameter
-// determines how comments and semicolons are handled.
+// determines how comments are handled.
 //
 // Note that Init may call err if there is an error in the first character
 // of the file.
@@ -673,7 +673,7 @@ scanAgain:
 		}
 	}
 
-	if S.mode&InsertSemis != 0 {
+	if S.mode&dontInsertSemis == 0 {
 		S.insertSemi = insertSemi
 	}
 

src/pkg/go/scanner/scanner_test.go

@@ -223,7 +223,7 @@ func TestScan(t *testing.T) {
 
 	// verify scan
 	var s Scanner
-	s.Init(fset.AddFile("", fset.Base(), len(src)), []byte(src), &testErrorHandler{t}, ScanComments)
+	s.Init(fset.AddFile("", fset.Base(), len(src)), []byte(src), &testErrorHandler{t}, ScanComments|dontInsertSemis)
 	index := 0
 	epos := token.Position{"", 0, 1, 1} // expected position
 	for {
@@ -430,14 +430,14 @@ var lines = []string{
 
 func TestSemis(t *testing.T) {
 	for _, line := range lines {
-		checkSemi(t, line, InsertSemis)
-		checkSemi(t, line, InsertSemis|ScanComments)
+		checkSemi(t, line, 0)
+		checkSemi(t, line, ScanComments)
 
 		// if the input ended in newlines, the input must tokenize the
 		// same with or without those newlines
 		for i := len(line) - 1; i >= 0 && line[i] == '\n'; i-- {
-			checkSemi(t, line[0:i], InsertSemis)
-			checkSemi(t, line[0:i], InsertSemis|ScanComments)
+			checkSemi(t, line[0:i], 0)
+			checkSemi(t, line[0:i], ScanComments)
 		}
 	}
 }
@@ -492,7 +492,7 @@ func TestLineComments(t *testing.T) {
 	// verify scan
 	var S Scanner
 	file := fset.AddFile(filepath.Join("dir", "TestLineComments"), fset.Base(), len(src))
-	S.Init(file, []byte(src), nil, 0)
+	S.Init(file, []byte(src), nil, dontInsertSemis)
 	for _, s := range segs {
 		p, _, lit := S.Scan()
 		pos := file.Position(p)
@@ -511,7 +511,7 @@ func TestInit(t *testing.T) {
 	// 1st init
 	src1 := "if true { }"
 	f1 := fset.AddFile("src1", fset.Base(), len(src1))
-	s.Init(f1, []byte(src1), nil, 0)
+	s.Init(f1, []byte(src1), nil, dontInsertSemis)
 	if f1.Size() != len(src1) {
 		t.Errorf("bad file size: got %d, expected %d", f1.Size(), len(src1))
 	}
@@ -525,7 +525,7 @@ func TestInit(t *testing.T) {
 	// 2nd init
 	src2 := "go true { ]"
 	f2 := fset.AddFile("src2", fset.Base(), len(src2))
-	s.Init(f2, []byte(src2), nil, 0)
+	s.Init(f2, []byte(src2), nil, dontInsertSemis)
 	if f2.Size() != len(src2) {
 		t.Errorf("bad file size: got %d, expected %d", f2.Size(), len(src2))
 	}
@@ -551,7 +551,7 @@ func TestStdErrorHander(t *testing.T) {
 
 	v := new(ErrorVector)
 	var s Scanner
-	s.Init(fset.AddFile("File1", fset.Base(), len(src)), []byte(src), v, 0)
+	s.Init(fset.AddFile("File1", fset.Base(), len(src)), []byte(src), v, dontInsertSemis)
 	for {
 		if _, tok, _ := s.Scan(); tok == token.EOF {
 			break
@@ -596,7 +596,7 @@ func (h *errorCollector) Error(pos token.Position, msg string) {
 func checkError(t *testing.T, src string, tok token.Token, pos int, err string) {
 	var s Scanner
 	var h errorCollector
-	s.Init(fset.AddFile("", fset.Base(), len(src)), []byte(src), &h, ScanComments)
+	s.Init(fset.AddFile("", fset.Base(), len(src)), []byte(src), &h, ScanComments|dontInsertSemis)
 	_, tok0, _ := s.Scan()
 	_, tok1, _ := s.Scan()
 	if tok0 != tok {