all: join some chained ifs to unindent code

Found with mvdan.cc/unindent. It skipped the cases where parentheses
would need to be added, where comments would have to be moved elsewhere,
or where actions and simple logic would mix.

One of them was of the form "err != nil && err == io.EOF", so the first
part was removed.

Change-Id: Ie504c2b03a2c87d10ecbca1b9270069be1171b91
Reviewed-on: https://go-review.googlesource.com/57690
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/crypto/cipher/io.go

@@ -37,10 +37,8 @@ func (w StreamWriter) Write(src []byte) (n int, err error) {
 	c := make([]byte, len(src))
 	w.S.XORKeyStream(c, src)
 	n, err = w.W.Write(c)
-	if n != len(src) {
-		if err == nil { // should never happen
-			err = io.ErrShortWrite
-		}
+	if n != len(src) && err == nil { // should never happen
+		err = io.ErrShortWrite
 	}
 	return
 }

src/encoding/gob/decoder.go

@@ -99,10 +99,8 @@ func (dec *Decoder) readMessage(nbytes int) {
 	// Read the data
 	dec.buf.Size(nbytes)
 	_, dec.err = io.ReadFull(dec.r, dec.buf.Bytes())
-	if dec.err != nil {
-		if dec.err == io.EOF {
-			dec.err = io.ErrUnexpectedEOF
-		}
+	if dec.err == io.EOF {
+		dec.err = io.ErrUnexpectedEOF
 	}
 }
 

src/net/http/fs.go

@@ -530,10 +530,8 @@ func checkPreconditions(w ResponseWriter, r *Request, modtime time.Time) (done b
 	}
 
 	rangeHeader = r.Header.get("Range")
-	if rangeHeader != "" {
-		if checkIfRange(w, r, modtime) == condFalse {
-			rangeHeader = ""
-		}
+	if rangeHeader != "" && checkIfRange(w, r, modtime) == condFalse {
+		rangeHeader = ""
 	}
 	return false, rangeHeader
 }

src/net/url/url.go

@@ -953,12 +953,10 @@ func (u *URL) ResolveReference(ref *URL) *URL {
 		url.Path = ""
 		return &url
 	}
-	if ref.Path == "" {
-		if ref.RawQuery == "" {
-			url.RawQuery = u.RawQuery
-			if ref.Fragment == "" {
-				url.Fragment = u.Fragment
-			}
+	if ref.Path == "" && ref.RawQuery == "" {
+		url.RawQuery = u.RawQuery
+		if ref.Fragment == "" {
+			url.Fragment = u.Fragment
 		}
 	}
 	// The "abs_path" or "rel_path" cases.

src/runtime/cgocall.go

@@ -580,10 +580,8 @@ func cgoCheckUnknownPointer(p unsafe.Pointer, msg string) (base, i uintptr) {
 				// No more possible pointers.
 				break
 			}
-			if hbits.isPointer() {
-				if cgoIsGoPointer(*(*unsafe.Pointer)(unsafe.Pointer(base + i))) {
-					panic(errorString(msg))
-				}
+			if hbits.isPointer() && cgoIsGoPointer(*(*unsafe.Pointer)(unsafe.Pointer(base + i))) {
+				panic(errorString(msg))
 			}
 			hbits = hbits.next()
 		}

src/runtime/proc.go

@@ -3568,13 +3568,11 @@ func procresize(nprocs int32) *p {
 	// free unused P's
 	for i := nprocs; i < old; i++ {
 		p := allp[i]
-		if trace.enabled {
-			if p == getg().m.p.ptr() {
-				// moving to p[0], pretend that we were descheduled
-				// and then scheduled again to keep the trace sane.
-				traceGoSched()
-				traceProcStop(p)
-			}
+		if trace.enabled && p == getg().m.p.ptr() {
+			// moving to p[0], pretend that we were descheduled
+			// and then scheduled again to keep the trace sane.
+			traceGoSched()
+			traceProcStop(p)
 		}
 		// move all runnable goroutines to the global queue
 		for p.runqhead != p.runqtail {

src/runtime/select.go

@@ -457,10 +457,8 @@ loop:
 		print("wait-return: sel=", sel, " c=", c, " cas=", cas, " kind=", cas.kind, "\n")
 	}
 
-	if cas.kind == caseRecv {
-		if cas.receivedp != nil {
-			*cas.receivedp = true
-		}
+	if cas.kind == caseRecv && cas.receivedp != nil {
+		*cas.receivedp = true
 	}
 
 	if raceenabled {

src/sync/waitgroup.go

@@ -63,13 +63,11 @@ func (wg *WaitGroup) Add(delta int) {
 	state := atomic.AddUint64(statep, uint64(delta)<<32)
 	v := int32(state >> 32)
 	w := uint32(state)
-	if race.Enabled {
-		if delta > 0 && v == int32(delta) {
-			// The first increment must be synchronized with Wait.
-			// Need to model this as a read, because there can be
-			// several concurrent wg.counter transitions from 0.
-			race.Read(unsafe.Pointer(&wg.sema))
-		}
+	if race.Enabled && delta > 0 && v == int32(delta) {
+		// The first increment must be synchronized with Wait.
+		// Need to model this as a read, because there can be
+		// several concurrent wg.counter transitions from 0.
+		race.Read(unsafe.Pointer(&wg.sema))
 	}
 	if v < 0 {
 		panic("sync: negative WaitGroup counter")

src/text/template/parse/lex.go

@@ -281,10 +281,9 @@ func (l *lexer) atRightDelim() (delim, trimSpaces bool) {
 		return true, false
 	}
 	// The right delim might have the marker before.
-	if strings.HasPrefix(l.input[l.pos:], rightTrimMarker) {
-		if strings.HasPrefix(l.input[l.pos+trimMarkerLen:], l.rightDelim) {
-			return true, true
-		}
+	if strings.HasPrefix(l.input[l.pos:], rightTrimMarker) &&
+		strings.HasPrefix(l.input[l.pos+trimMarkerLen:], l.rightDelim) {
+		return true, true
 	}
 	return false, false
 }