go/printer, gofmt: fix printing of labels,

apply gofmt to src, misc

Fixes #752.

R=rsc
CC=golang-dev
https://golang.org/cl/1240044

src/pkg/exp/draw/draw_test.go

@@ -134,7 +134,8 @@ func makeGolden(dst image.Image, t drawTest) image.Image {
 }
 
 func TestDraw(t *testing.T) {
-loop: for _, test := range drawTests {
+loop:
+	for _, test := range drawTests {
 		dst := hgradRed(255)
 		// Draw the (src, mask, op) onto a copy of dst using a slow but obviously correct implementation.
 		golden := makeGolden(dst, test)

src/pkg/fmt/print.go

@@ -795,7 +795,8 @@ func (p *pp) doprintf(format string, a []interface{}) {
 		i++
 		// flags and widths
 		p.fmt.clearflags()
-	F: for ; i < end; i++ {
+	F:
+		for ; i < end; i++ {
 			switch format[i] {
 			case '#':
 				p.fmt.sharp = true

src/pkg/go/parser/parser.go

@@ -1224,7 +1224,8 @@ func (p *parser) parsePrimaryExpr() ast.Expr {
 	}
 
 	x := p.parseOperand()
-L: for {
+L:
+	for {
 		switch p.tok {
 		case token.PERIOD:
 			x = p.parseSelectorOrTypeAssertion(p.checkExpr(x))

src/pkg/go/printer/nodes.go

@@ -1030,14 +1030,17 @@ func (p *printer) stmt(stmt ast.Stmt, nextIsRBrace bool, multiLine *bool) {
 		// a "correcting" unindent immediately following a line break
 		// is applied before the line break if there is no comment
 		// between (see writeWhitespace)
-		p.print(unindent)
+		p.print(unindent, s.Pos())
 		p.expr(s.Label, multiLine)
-		p.print(token.COLON, vtab, indent)
-		if _, isEmpty := s.Stmt.(*ast.EmptyStmt); isEmpty && !nextIsRBrace {
-			p.print(token.SEMICOLON)
-			break
+		p.print(token.COLON, indent)
+		if _, isEmpty := s.Stmt.(*ast.EmptyStmt); isEmpty {
+			if !nextIsRBrace {
+				p.print(newline, s.Stmt.Pos(), token.SEMICOLON)
+				break
+			}
+		} else {
+			p.print(newline)
 		}
-		p.linebreak(s.Stmt.Pos().Line, 0, 1, ignore, true)
 		p.stmt(s.Stmt, nextIsRBrace, multiLine)
 
 	case *ast.ExprStmt:

src/pkg/go/printer/testdata/statements.golden

@@ -247,7 +247,6 @@ func _() {
 // Formatting around labels.
 func _() {
 L:
-
 }
 
 
@@ -260,36 +259,50 @@ L:	// no semicolon needed
 func _() {
 	switch 0 {
 	case 0:
-	L0:	;	// semicolon required
+	L0:	// semicolon required
+		;
 	case 1:
-	L1:	;	// semicolon required
+	L1:	// semicolon required
+		;
 	default:
 	L2:	// no semicolon needed
 	}
 }
 
 
+func _() {
+	f()
+L1:
+	f()
+L2:
+	;
+L3:
+}
+
+
 func _() {
 	// this comment should be indented
 L:
-
 }
 
 
 func _() {
-L:	_ = 0
+L:
+	_ = 0
 }
 
 
 func _() {
 	// this comment should be indented
-L:	_ = 0
+L:
+	_ = 0
 }
 
 
 func _() {
 	for {
-	L1:	_ = 0
+	L1:
+		_ = 0
 	L2:
 		_ = 0
 	}
@@ -299,7 +312,8 @@ func _() {
 func _() {
 	// this comment should be indented
 	for {
-	L1:	_ = 0
+	L1:
+		_ = 0
 	L2:
 		_ = 0
 	}
@@ -319,5 +333,6 @@ AnOverlongLabel:
 	}
 	_ = 0
 
-L:	_ = 0
+L:
+	_ = 0
 }

src/pkg/go/printer/testdata/statements.input

@@ -205,6 +205,16 @@ func _() {
 }
 
 
+func _() {
+	f()
+L1:
+	f()
+L2:
+	;
+L3:
+}
+
+
 func _() {
 	// this comment should be indented
 	L:

src/pkg/net/ip.go

@@ -346,7 +346,8 @@ func parseIPv6(s string) IP {
 
 	// Loop, parsing hex numbers followed by colon.
 	j := 0
-L: for j < IPv6len {
+L:
+	for j < IPv6len {
 		// Hex number.
 		n, i1, ok := xtoi(s, i)
 		if !ok || n > 0xFFFF {

src/pkg/reflect/type.go

@@ -518,7 +518,8 @@ func (t *StructType) fieldByNameFunc(match func(string) bool, mark map[*StructTy
 
 	var fi int // field index
 	n := 0     // number of matching fields at depth fd
-L: for i, _ := range t.fields {
+L:
+	for i, _ := range t.fields {
 		f := t.Field(i)
 		d := inf
 		switch {