go/printer: forbid empty line before first comment in block

To improve readability when exported fields are removed,
forbid the printer from emitting an empty line before the first comment
in a const, var, or type block.
Also, when printing the "Has filtered or unexported fields." message,
add an empty line before it to separate the message from the struct
or interfact contents.

Before the change:
<<<
type NamedArg struct {

        // Name is the name of the parameter placeholder.
        //
        // If empty, the ordinal position in the argument list will be
        // used.
        //
        // Name must omit any symbol prefix.
        Name string

        // Value is the value of the parameter.
        // It may be assigned the same value types as the query
        // arguments.
        Value interface{}
        // contains filtered or unexported fields
}
>>>

After the change:
<<<
type NamedArg struct {
        // Name is the name of the parameter placeholder.
        //
        // If empty, the ordinal position in the argument list will be
        // used.
        //
        // Name must omit any symbol prefix.
        Name string

        // Value is the value of the parameter.
        // It may be assigned the same value types as the query
        // arguments.
        Value interface{}

        // contains filtered or unexported fields
}
>>>

Fixes #18264

Change-Id: I9fe17ca39cf92fcdfea55064bd2eaa784ce48c88
Reviewed-on: https://go-review.googlesource.com/71990
Run-TryBot: Joe Tsai <thebrokentoaster@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

30 files changed, 293 insertions, 26 deletions

diff --git a/misc/cgo/test/buildid_linux.go b/misc/cgo/test/buildid_linux.go
index 47dd87128f..d25a7ac434 100644
--- a/misc/cgo/test/buildid_linux.go
+++ b/misc/cgo/test/buildid_linux.go
@@ -39,7 +39,6 @@ func testBuildID(t *testing.T) {
 		}
 
 		for len(d) > 0 {
-
 			// ELF standards differ as to the sizes in
 			// note sections.  Both the GNU linker and
 			// gold always generate 32-bit sizes, so that
diff --git a/src/cmd/compile/internal/ssa/gen/rulegen.go b/src/cmd/compile/internal/ssa/gen/rulegen.go
index c23a54d9b5..5946b01f8e 100644
--- a/src/cmd/compile/internal/ssa/gen/rulegen.go
+++ b/src/cmd/compile/internal/ssa/gen/rulegen.go
@@ -659,7 +659,6 @@ func extract(val string) (op string, typ string, auxint string, aux string, args
 // It returns the op and unparsed strings for typ, auxint, and aux restrictions and for all args.
 // oparch is the architecture that op is located in, or "" for generic.
 func parseValue(val string, arch arch, loc string) (op opData, oparch string, typ string, auxint string, aux string, args []string) {
-
 	// Resolve the op.
 	var s string
 	s, typ, auxint, aux, args = extract(val)
diff --git a/src/cmd/internal/obj/ppc64/asm9.go b/src/cmd/internal/obj/ppc64/asm9.go
index 644cc65880..2b8efe846d 100644
--- a/src/cmd/internal/obj/ppc64/asm9.go
+++ b/src/cmd/internal/obj/ppc64/asm9.go
@@ -2468,7 +2468,6 @@ func (c *ctxt9) asmout(p *obj.Prog, o *Optab, out []uint32) {
 		d := c.vregoff(p.GetFrom3())
 		var a int
 		switch p.As {
-
 		// These opcodes expect a mask operand that has to be converted into the
 		// appropriate operand.  The way these were defined, not all valid masks are possible.
 		// Left here for compatibility in case they were used or generated.
diff --git a/src/cmd/internal/obj/x86/asm6.go b/src/cmd/internal/obj/x86/asm6.go
index dbdaebba8d..4e4cae6b44 100644
--- a/src/cmd/internal/obj/x86/asm6.go
+++ b/src/cmd/internal/obj/x86/asm6.go
@@ -1996,7 +1996,6 @@ func span6(ctxt *obj.Link, s *obj.LSym, newprog obj.ProgAlloc) {
 		c = 0
 		for p := s.Func.Text; p != nil; p = p.Link {
 			if ctxt.Headtype == objabi.Hnacl && p.Isize > 0 {
-
 				// pad everything to avoid crossing 32-byte boundary
 				if c>>5 != (c+int32(p.Isize)-1)>>5 {
 					c = naclpad(ctxt, s, c, -c&31)
diff --git a/src/cmd/link/internal/ld/data.go b/src/cmd/link/internal/ld/data.go
index 79b9ae1013..a6e03baafa 100644
--- a/src/cmd/link/internal/ld/data.go
+++ b/src/cmd/link/internal/ld/data.go
@@ -1857,7 +1857,6 @@ func assignAddress(ctxt *Link, sect *sym.Section, n int, s *sym.Symbol, va uint6
 	// Only break at outermost syms.
 
 	if ctxt.Arch.InFamily(sys.PPC64) && s.Outer == nil && ctxt.IsELF && ctxt.LinkMode == LinkExternal && va-sect.Vaddr+funcsize+maxSizeTrampolinesPPC64(s, isTramp) > 0x1c00000 {
-
 		// Set the length for the previous text section
 		sect.Length = va - sect.Vaddr
 
diff --git a/src/cmd/link/internal/ppc64/asm.go b/src/cmd/link/internal/ppc64/asm.go
index 4e277f9aa9..9b30e5f27c 100644
--- a/src/cmd/link/internal/ppc64/asm.go
+++ b/src/cmd/link/internal/ppc64/asm.go
@@ -523,7 +523,6 @@ func archrelocaddr(ctxt *ld.Link, r *sym.Reloc, s *sym.Symbol, val *int64) bool
 
 // resolve direct jump relocation r in s, and add trampoline if necessary
 func trampoline(ctxt *ld.Link, r *sym.Reloc, s *sym.Symbol) {
-
 	// Trampolines are created if the branch offset is too large and the linker cannot insert a call stub to handle it.
 	// For internal linking, trampolines are always created for long calls.
 	// For external linking, the linker can insert a call stub to handle a long call, but depends on having the TOC address in
@@ -542,7 +541,6 @@ func trampoline(ctxt *ld.Link, r *sym.Reloc, s *sym.Symbol) {
 		if (ctxt.LinkMode == ld.LinkExternal && s.Sect != r.Sym.Sect) || (ctxt.LinkMode == ld.LinkInternal && int64(int32(t<<6)>>6) != t) || (*ld.FlagDebugTramp > 1 && s.File != r.Sym.File) {
 			var tramp *sym.Symbol
 			for i := 0; ; i++ {
-
 				// Using r.Add as part of the name is significant in functions like duffzero where the call
 				// target is at some offset within the function.  Calls to duff+8 and duff+256 must appear as
 				// distinct trampolines.
diff --git a/src/encoding/base32/base32.go b/src/encoding/base32/base32.go
index e72ba74983..e0a6e04b1d 100644
--- a/src/encoding/base32/base32.go
+++ b/src/encoding/base32/base32.go
@@ -290,7 +290,6 @@ func (enc *Encoding) decode(dst, src []byte) (n int, end bool, err error) {
 		dlen := 8
 
 		for j := 0; j < 8; {
-
 			// We have reached the end and are missing padding
 			if len(src) == 0 && enc.padChar != NoPadding {
 				return n, false, CorruptInputError(olen - len(src) - j)
diff --git a/src/go/doc/testdata/blank.0.golden b/src/go/doc/testdata/blank.0.golden
index 70f2929f8a..29c30f6942 100644
--- a/src/go/doc/testdata/blank.0.golden
+++ b/src/go/doc/testdata/blank.0.golden
@@ -48,6 +48,7 @@ TYPES
 		H	uint32
 	
 		A	uint8
+	
 		// contains filtered or unexported fields
 	}
 
diff --git a/src/go/doc/testdata/blank.2.golden b/src/go/doc/testdata/blank.2.golden
index 70f2929f8a..29c30f6942 100644
--- a/src/go/doc/testdata/blank.2.golden
+++ b/src/go/doc/testdata/blank.2.golden
@@ -48,6 +48,7 @@ TYPES
 		H	uint32
 	
 		A	uint8
+	
 		// contains filtered or unexported fields
 	}
 
diff --git a/src/go/doc/testdata/testing.0.golden b/src/go/doc/testdata/testing.0.golden
index 83cf37cd3a..6bdf726efc 100644
--- a/src/go/doc/testdata/testing.0.golden
+++ b/src/go/doc/testdata/testing.0.golden
@@ -42,6 +42,7 @@ TYPES
 	// B is a type passed to Benchmark functions to manage benchmark ...
 	type B struct {
 		N int
+	
 		// contains filtered or unexported fields
 	}
 
diff --git a/src/go/doc/testdata/testing.2.golden b/src/go/doc/testdata/testing.2.golden
index 83cf37cd3a..6bdf726efc 100644
--- a/src/go/doc/testdata/testing.2.golden
+++ b/src/go/doc/testdata/testing.2.golden
@@ -42,6 +42,7 @@ TYPES
 	// B is a type passed to Benchmark functions to manage benchmark ...
 	type B struct {
 		N int
+	
 		// contains filtered or unexported fields
 	}
 
diff --git a/src/go/printer/nodes.go b/src/go/printer/nodes.go
index 37b5873b68..83c17fef5e 100644
--- a/src/go/printer/nodes.go
+++ b/src/go/printer/nodes.go
@@ -479,6 +479,7 @@ func (p *printer) fieldList(fields *ast.FieldList, isStruct, isIncomplete bool)
 		if isIncomplete {
 			if len(list) > 0 {
 				p.print(formfeed)
+				p.print(newline)
 			}
 			p.flush(p.posFor(rbrace), token.RBRACE) // make sure we don't lose the last line comment
 			p.setLineComment("// contains filtered or unexported fields")
@@ -506,6 +507,7 @@ func (p *printer) fieldList(fields *ast.FieldList, isStruct, isIncomplete bool)
 		if isIncomplete {
 			if len(list) > 0 {
 				p.print(formfeed)
+				p.print(newline)
 			}
 			p.flush(p.posFor(rbrace), token.RBRACE) // make sure we don't lose the last line comment
 			p.setLineComment("// contains filtered or unexported methods")
diff --git a/src/go/printer/printer.go b/src/go/printer/printer.go
index dbb4bbd90c..61723899d4 100644
--- a/src/go/printer/printer.go
+++ b/src/go/printer/printer.go
@@ -62,7 +62,7 @@ type printer struct {
 	mode        pmode        // current printer mode
 	impliedSemi bool         // if set, a linebreak implies a semicolon
 	lastTok     token.Token  // last token printed (token.ILLEGAL if it's whitespace)
-	prevOpen    token.Token  // previous non-brace "open" token (, [, or token.ILLEGAL
+	prevOpen    token.Token  // previous "open" token: (, [, {, or token.ILLEGAL
 	wsbuf       []whiteSpace // delayed white space
 
 	// Positions
@@ -426,6 +426,11 @@ func (p *printer) writeCommentPrefix(pos, next token.Position, prev *ast.Comment
 		n := 0
 		if pos.IsValid() && p.last.IsValid() {
 			n = pos.Line - p.last.Line
+			if n > 1 && p.prevOpen != token.ILLEGAL && prev == nil {
+				// Forbid multiple empty lines from appearing immediately
+				// following some type of open paren, bracket, or brace.
+				n = 1
+			}
 			if n < 0 { // should never happen
 				n = 0
 			}
@@ -879,7 +884,7 @@ func (p *printer) print(args ...interface{}) {
 		switch p.lastTok {
 		case token.ILLEGAL:
 			// ignore (white space)
-		case token.LPAREN, token.LBRACK:
+		case token.LPAREN, token.LBRACK, token.LBRACE:
 			p.prevOpen = p.lastTok
 		default:
 			// other tokens followed any opening token
diff --git a/src/go/printer/testdata/comments.golden b/src/go/printer/testdata/comments.golden
index 4d92e65327..d14d8d6cbb 100644
--- a/src/go/printer/testdata/comments.golden
+++ b/src/go/printer/testdata/comments.golden
@@ -97,6 +97,109 @@ type S3 struct {
 	f3	int	// f3 is not exported
 }
 
+type T struct {	// foo
+
+	// bar
+	x	int
+	X	int
+}
+
+type T struct {	/* foo */
+
+	// bar
+	x int
+}
+
+type T struct {	// foo
+
+	x	int
+
+	X	int
+}
+
+type T struct {	/* foo */
+
+	x int
+}
+
+type T struct {
+	x int
+}
+
+type T struct {
+	x int
+}
+
+type T struct{ x int }
+
+type T struct {
+	x int
+}
+
+type T struct {
+	x	int
+	X	int
+	x	int
+}
+
+type T struct {
+	// Comment
+	x	int
+	// X.
+	X	int
+	// Comment
+	x	int
+}
+
+const (	// foo
+
+	// bar
+	x	int	= 0
+	X	int	= 0
+)
+
+const (	/* foo */
+
+	// bar
+	x int = 0
+)
+
+const (	// foo
+
+	x	int	= 0
+
+	X	int	= 0
+)
+
+const (	/* foo */
+
+	x int = 0
+)
+
+const (
+	x int = 0
+)
+
+const (
+	x	int	= 0
+	X	int	= 0
+)
+
+const (
+	x	int	= 0
+	X	int	= 0
+	x	int	= 0
+)
+
+const (
+	// Comment
+	x	int	= 0
+	// X.
+	X	int	= 0
+	// Comment
+	x	int	= 0
+)
+
 // This comment group should be separated
 // with a newline from the next comment
 // group.
diff --git a/src/go/printer/testdata/comments.input b/src/go/printer/testdata/comments.input
index 40351eeef6..df98056a65 100644
--- a/src/go/printer/testdata/comments.input
+++ b/src/go/printer/testdata/comments.input
@@ -97,6 +97,113 @@ type S3 struct {
 	f3 int // f3 is not exported
 }
 
+type T struct { // foo
+
+   // bar
+   x int
+   X int
+}
+
+type T struct { /* foo */
+
+  			 // bar
+   x int
+}
+
+type T struct { // foo
+
+  				 x int
+
+   X int
+}
+
+type T struct { /* foo */
+
+
+
+x int
+}
+
+type T struct {x int
+}
+
+type T struct {
+					x int}
+
+type T struct {x int}
+
+type T struct {
+
+   x int
+}
+
+type T struct {
+   x int
+   X int
+   x int
+}
+
+type T struct {
+   // Comment
+   x int
+   // X.
+   X int
+   // Comment
+   x int
+}
+
+const ( // foo
+
+   // bar
+   x int = 0
+   X int = 0
+)
+
+const ( /* foo */
+
+   // bar
+   x int = 0
+)
+
+const ( // foo
+
+   x int = 0
+
+   X int = 0
+)
+
+const ( /* foo */
+
+   x int = 0
+)
+
+const (
+
+   x int = 0
+)
+
+const (
+
+   x int = 0
+   X int = 0
+
+)
+
+const (
+   x int = 0
+   X int = 0
+   x int = 0
+)
+
+const (
+   // Comment
+   x int = 0
+   // X.
+   X int = 0
+   // Comment
+   x int = 0
+)
+
 // This comment group should be separated
 // with a newline from the next comment
 // group.
diff --git a/src/go/printer/testdata/comments.x b/src/go/printer/testdata/comments.x
index ae7729286e..7178519b95 100644
--- a/src/go/printer/testdata/comments.x
+++ b/src/go/printer/testdata/comments.x
@@ -54,3 +54,73 @@ type S3 struct {
 	F2	int	// line comment for F2
 	// contains filtered or unexported fields
 }
+
+type T struct {
+	X int
+
+	// contains filtered or unexported fields
+}
+
+type T struct {
+	// contains filtered or unexported fields
+}
+
+type T struct {
+	X int
+
+	// contains filtered or unexported fields
+}
+
+type T struct {
+	// contains filtered or unexported fields
+}
+
+type T struct {
+	// contains filtered or unexported fields
+}
+
+type T struct {
+	// contains filtered or unexported fields
+}
+
+type T struct {
+	// contains filtered or unexported fields
+}
+
+type T struct {
+	// contains filtered or unexported fields
+}
+
+type T struct {
+	X int
+
+	// contains filtered or unexported fields
+}
+
+type T struct {
+	// X.
+	X int
+
+	// contains filtered or unexported fields
+}
+
+const (
+	X int = 0
+)
+
+const (
+	X int = 0
+)
+
+const (
+	X int = 0
+)
+
+const (
+	X int = 0
+)
+
+const (
+	// X.
+	X int = 0
+)
diff --git a/src/hash/crc32/crc32_ppc64le.go b/src/hash/crc32/crc32_ppc64le.go
index 686722761d..8e54d52b94 100644
--- a/src/hash/crc32/crc32_ppc64le.go
+++ b/src/hash/crc32/crc32_ppc64le.go
@@ -65,7 +65,6 @@ func archInitIEEE() {
 
 // archUpdateIEEE calculates the checksum of p using vectorizedIEEE.
 func archUpdateIEEE(crc uint32, p []byte) uint32 {
-
 	// Check if vector code should be used.  If not aligned, then handle those
 	// first up to the aligned bytes.
 
diff --git a/src/image/internal/imageutil/impl.go b/src/image/internal/imageutil/impl.go
index cfd5047879..4c6de742da 100644
--- a/src/image/internal/imageutil/impl.go
+++ b/src/image/internal/imageutil/impl.go
@@ -42,7 +42,6 @@ func DrawYCbCr(dst *image.RGBA, r image.Rectangle, src *image.YCbCr, sp image.Po
 
 			ci := (sy-src.Rect.Min.Y)*src.CStride + (sp.X - src.Rect.Min.X)
 			for x := x0; x != x1; x, yi, ci = x+4, yi+1, ci+1 {
-
 				// This is an inline version of image/color/ycbcr.go's func YCbCrToRGB.
 				yy1 := int32(src.Y[yi]) * 0x10101
 				cb1 := int32(src.Cb[ci]) - 128
@@ -212,7 +211,6 @@ func DrawYCbCr(dst *image.RGBA, r image.Rectangle, src *image.YCbCr, sp image.Po
 
 			ci := (sy/2-src.Rect.Min.Y/2)*src.CStride + (sp.X - src.Rect.Min.X)
 			for x := x0; x != x1; x, yi, ci = x+4, yi+1, ci+1 {
-
 				// This is an inline version of image/color/ycbcr.go's func YCbCrToRGB.
 				yy1 := int32(src.Y[yi]) * 0x10101
 				cb1 := int32(src.Cb[ci]) - 128
diff --git a/src/net/http/httputil/dump_test.go b/src/net/http/httputil/dump_test.go
index f881020fef..a403c88eaa 100644
--- a/src/net/http/httputil/dump_test.go
+++ b/src/net/http/httputil/dump_test.go
@@ -27,7 +27,6 @@ type dumpTest struct {
 }
 
 var dumpTests = []dumpTest{
-
 	// HTTP/1.1 => chunked coding; body; empty trailer
 	{
 		Req: http.Request{
diff --git a/src/net/http/httputil/persist.go b/src/net/http/httputil/persist.go
index cbedf25ad1..24c9c73474 100644
--- a/src/net/http/httputil/persist.go
+++ b/src/net/http/httputil/persist.go
@@ -173,7 +173,6 @@ func (sc *ServerConn) Pending() int {
 // Response.Close field to true. Write should be considered operational until
 // it returns an error, regardless of any errors returned on the Read side.
 func (sc *ServerConn) Write(req *http.Request, resp *http.Response) error {
-
 	// Retrieve the pipeline ID of this request/response pair
 	sc.mu.Lock()
 	id, ok := sc.pipereq[req]
diff --git a/src/net/http/internal/chunked.go b/src/net/http/internal/chunked.go
index 63f321d03b..7f83a56f1c 100644
--- a/src/net/http/internal/chunked.go
+++ b/src/net/http/internal/chunked.go
@@ -192,7 +192,6 @@ type chunkedWriter struct {
 // NOTE: Note that the corresponding chunk-writing procedure in Conn.Write has
 // a bug since it does not check for success of io.WriteString
 func (cw *chunkedWriter) Write(data []byte) (n int, err error) {
-
 	// Don't send 0-length data. It looks like EOF for chunked encoding.
 	if len(data) == 0 {
 		return 0, nil
diff --git a/src/net/http/requestwrite_test.go b/src/net/http/requestwrite_test.go
index eb65b9f736..74b01db6da 100644
--- a/src/net/http/requestwrite_test.go
+++ b/src/net/http/requestwrite_test.go
@@ -813,7 +813,6 @@ func TestRequestWriteError(t *testing.T) {
 // try to restore it. It always dumps the whole body.
 // And it doesn't support https.
 func dumpRequestOut(req *Request, onReadHeaders func()) ([]byte, error) {
-
 	// Use the actual Transport code to record what we would send
 	// on the wire, but not using TCP.  Use a Transport with a
 	// custom dialer that returns a fake net.Conn that waits
diff --git a/src/net/http/server.go b/src/net/http/server.go
index 91f481ed50..4329e61e60 100644
--- a/src/net/http/server.go
+++ b/src/net/http/server.go
@@ -2231,7 +2231,6 @@ func (mux *ServeMux) shouldRedirect(path string) bool {
 // If there is no registered handler that applies to the request,
 // Handler returns a ``page not found'' handler and an empty pattern.
 func (mux *ServeMux) Handler(r *Request) (h Handler, pattern string) {
-
 	// CONNECT requests are not canonicalized.
 	if r.Method == "CONNECT" {
 		// If r.URL.Path is /tree and its handler is not registered,
diff --git a/src/net/mail/message_test.go b/src/net/mail/message_test.go
index 5d5d6e4e9c..b1bb31e982 100644
--- a/src/net/mail/message_test.go
+++ b/src/net/mail/message_test.go
@@ -727,7 +727,6 @@ func TestAddressString(t *testing.T) {
 
 // Check if all valid addresses can be parsed, formatted and parsed again
 func TestAddressParsingAndFormatting(t *testing.T) {
-
 	// Should pass
 	tests := []string{
 		`<Bob@example.com>`,
diff --git a/src/regexp/syntax/parse.go b/src/regexp/syntax/parse.go
index 8c6d43a706..8b5b32a786 100644
--- a/src/regexp/syntax/parse.go
+++ b/src/regexp/syntax/parse.go
@@ -1626,7 +1626,6 @@ func (p *parser) parseClass(s string) (rest string, err error) {
 // cleanClass sorts the ranges (pairs of elements of r),
 // merges them, and eliminates duplicates.
 func cleanClass(rp *[]rune) []rune {
-
 	// Sort by lo increasing, hi decreasing to break ties.
 	sort.Sort(ranges{rp})
 
diff --git a/src/runtime/symtab.go b/src/runtime/symtab.go
index 2f426c7bf1..135fc1a7ad 100644
--- a/src/runtime/symtab.go
+++ b/src/runtime/symtab.go
@@ -642,7 +642,6 @@ func findfunc(pc uintptr) funcInfo {
 		idx = uint32(len(datap.ftab) - 1)
 	}
 	if pc < datap.ftab[idx].entry {
-
 		// With multiple text sections, the idx might reference a function address that
 		// is higher than the pc being searched, so search backward until the matching address is found.
 
@@ -653,7 +652,6 @@ func findfunc(pc uintptr) funcInfo {
 			throw("findfunc: bad findfunctab entry idx")
 		}
 	} else {
-
 		// linear search to find func with pc >= entry.
 		for datap.ftab[idx+1].entry <= pc {
 			idx++
diff --git a/src/syscall/syscall_netbsd.go b/src/syscall/syscall_netbsd.go
index c645b139b1..5545532bc9 100644
--- a/src/syscall/syscall_netbsd.go
+++ b/src/syscall/syscall_netbsd.go
@@ -52,7 +52,6 @@ func sysctlNodes(mib []_C_int) (nodes []Sysctlnode, err error) {
 }
 
 func nametomib(name string) (mib []_C_int, err error) {
-
 	// Split name into components.
 	var parts []string
 	last := 0
diff --git a/src/syscall/syscall_openbsd.go b/src/syscall/syscall_openbsd.go
index a43d88bf7a..8f58f7d341 100644
--- a/src/syscall/syscall_openbsd.go
+++ b/src/syscall/syscall_openbsd.go
@@ -29,7 +29,6 @@ type SockaddrDatalink struct {
 func Syscall9(num, a1, a2, a3, a4, a5, a6, a7, a8, a9 uintptr) (r1, r2 uintptr, err Errno)
 
 func nametomib(name string) (mib []_C_int, err error) {
-
 	// Perform lookup via a binary search
 	left := 0
 	right := len(sysctlMib) - 1
diff --git a/src/time/sleep_test.go b/src/time/sleep_test.go
index 9af39c0d03..ea29ac4489 100644
--- a/src/time/sleep_test.go
+++ b/src/time/sleep_test.go
@@ -82,7 +82,6 @@ func TestAfterStress(t *testing.T) {
 }
 
 func benchmark(b *testing.B, bench func(n int)) {
-
 	// Create equal number of garbage timers on each P before starting
 	// the benchmark.
 	var wg sync.WaitGroup
diff --git a/src/unicode/example_test.go b/src/unicode/example_test.go
index 50c5b18a48..a60dae4458 100644
--- a/src/unicode/example_test.go
+++ b/src/unicode/example_test.go
@@ -12,7 +12,6 @@ import (
 // Functions starting with "Is" can be used to inspect which table of range a
 // rune belongs to. Note that runes may fit into more than one range.
 func Example_is() {
-
 	// constant with mixed type runes
 	const mixed = "\b5Ὂg̀9! ℃ᾭG"
 	for _, c := range mixed {