all: join a few chained ifs

I had been finding these over a year or so, but none were big enough
changes to warrant CLs. They're a handful now, so clean them all up in a
single commit.

The smaller bodies get a bit simpler, but most importantly, the larger
bodies get unindented.

Change-Id: I5707a6fee27d4c9ff9efd3d363af575d7a4bf2aa
Reviewed-on: https://go-review.googlesource.com/c/go/+/165340
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/encoding/json/encode.go

@@ -392,19 +392,15 @@ func newTypeEncoder(t reflect.Type, allowAddr bool) encoderFunc {
 	if t.Implements(marshalerType) {
 		return marshalerEncoder
 	}
-	if t.Kind() != reflect.Ptr && allowAddr {
-		if reflect.PtrTo(t).Implements(marshalerType) {
-			return newCondAddrEncoder(addrMarshalerEncoder, newTypeEncoder(t, false))
-		}
+	if t.Kind() != reflect.Ptr && allowAddr && reflect.PtrTo(t).Implements(marshalerType) {
+		return newCondAddrEncoder(addrMarshalerEncoder, newTypeEncoder(t, false))
 	}
 
 	if t.Implements(textMarshalerType) {
 		return textMarshalerEncoder
 	}
-	if t.Kind() != reflect.Ptr && allowAddr {
-		if reflect.PtrTo(t).Implements(textMarshalerType) {
-			return newCondAddrEncoder(addrTextMarshalerEncoder, newTypeEncoder(t, false))
-		}
+	if t.Kind() != reflect.Ptr && allowAddr && reflect.PtrTo(t).Implements(textMarshalerType) {
+		return newCondAddrEncoder(addrTextMarshalerEncoder, newTypeEncoder(t, false))
 	}
 
 	switch t.Kind() {

src/net/http/server.go

@@ -749,10 +749,8 @@ func (cr *connReader) handleReadError(_ error) {
 // may be called from multiple goroutines.
 func (cr *connReader) closeNotify() {
 	res, _ := cr.conn.curReq.Load().(*response)
-	if res != nil {
-		if atomic.CompareAndSwapInt32(&res.didCloseNotify, 0, 1) {
-			res.closeNotifyCh <- true
-		}
+	if res != nil && atomic.CompareAndSwapInt32(&res.didCloseNotify, 0, 1) {
+		res.closeNotifyCh <- true
 	}
 }
 

src/runtime/chan.go

@@ -729,10 +729,8 @@ func (q *waitq) dequeue() *sudog {
 		// We use a flag in the G struct to tell us when someone
 		// else has won the race to signal this goroutine but the goroutine
 		// hasn't removed itself from the queue yet.
-		if sgp.isSelect {
-			if !atomic.Cas(&sgp.g.selectDone, 0, 1) {
-				continue
-			}
+		if sgp.isSelect && !atomic.Cas(&sgp.g.selectDone, 0, 1) {
+			continue
 		}
 
 		return sgp

src/runtime/signal_amd64x.go

@@ -46,21 +46,19 @@ func (c *sigctxt) fault() uintptr { return uintptr(c.sigaddr()) }
 
 // preparePanic sets up the stack to look like a call to sigpanic.
 func (c *sigctxt) preparePanic(sig uint32, gp *g) {
-	if GOOS == "darwin" {
-		// Work around Leopard bug that doesn't set FPE_INTDIV.
-		// Look at instruction to see if it is a divide.
-		// Not necessary in Snow Leopard (si_code will be != 0).
-		if sig == _SIGFPE && gp.sigcode0 == 0 {
-			pc := (*[4]byte)(unsafe.Pointer(gp.sigpc))
-			i := 0
-			if pc[i]&0xF0 == 0x40 { // 64-bit REX prefix
-				i++
-			} else if pc[i] == 0x66 { // 16-bit instruction prefix
-				i++
-			}
-			if pc[i] == 0xF6 || pc[i] == 0xF7 {
-				gp.sigcode0 = _FPE_INTDIV
-			}
+	// Work around Leopard bug that doesn't set FPE_INTDIV.
+	// Look at instruction to see if it is a divide.
+	// Not necessary in Snow Leopard (si_code will be != 0).
+	if GOOS == "darwin" && sig == _SIGFPE && gp.sigcode0 == 0 {
+		pc := (*[4]byte)(unsafe.Pointer(gp.sigpc))
+		i := 0
+		if pc[i]&0xF0 == 0x40 { // 64-bit REX prefix
+			i++
+		} else if pc[i] == 0x66 { // 16-bit instruction prefix
+			i++
+		}
+		if pc[i] == 0xF6 || pc[i] == 0xF7 {
+			gp.sigcode0 = _FPE_INTDIV
 		}
 	}
 

src/runtime/signal_unix.go

@@ -503,16 +503,14 @@ func raisebadsignal(sig uint32, c *sigctxt) {
 
 //go:nosplit
 func crash() {
-	if GOOS == "darwin" {
-		// OS X core dumps are linear dumps of the mapped memory,
-		// from the first virtual byte to the last, with zeros in the gaps.
-		// Because of the way we arrange the address space on 64-bit systems,
-		// this means the OS X core file will be >128 GB and even on a zippy
-		// workstation can take OS X well over an hour to write (uninterruptible).
-		// Save users from making that mistake.
-		if GOARCH == "amd64" {
-			return
-		}
+	// OS X core dumps are linear dumps of the mapped memory,
+	// from the first virtual byte to the last, with zeros in the gaps.
+	// Because of the way we arrange the address space on 64-bit systems,
+	// this means the OS X core file will be >128 GB and even on a zippy
+	// workstation can take OS X well over an hour to write (uninterruptible).
+	// Save users from making that mistake.
+	if GOOS == "darwin" && GOARCH == "amd64" {
+		return
 	}
 
 	dieFromSignal(_SIGABRT)

src/testing/testing.go

@@ -1303,20 +1303,18 @@ func toOutputDir(path string) string {
 	if *outputDir == "" || path == "" {
 		return path
 	}
-	if runtime.GOOS == "windows" {
-		// On Windows, it's clumsy, but we can be almost always correct
-		// by just looking for a drive letter and a colon.
-		// Absolute paths always have a drive letter (ignoring UNC).
-		// Problem: if path == "C:A" and outputdir == "C:\Go" it's unclear
-		// what to do, but even then path/filepath doesn't help.
-		// TODO: Worth doing better? Probably not, because we're here only
-		// under the management of go test.
-		if len(path) >= 2 {
-			letter, colon := path[0], path[1]
-			if ('a' <= letter && letter <= 'z' || 'A' <= letter && letter <= 'Z') && colon == ':' {
-				// If path starts with a drive letter we're stuck with it regardless.
-				return path
-			}
+	// On Windows, it's clumsy, but we can be almost always correct
+	// by just looking for a drive letter and a colon.
+	// Absolute paths always have a drive letter (ignoring UNC).
+	// Problem: if path == "C:A" and outputdir == "C:\Go" it's unclear
+	// what to do, but even then path/filepath doesn't help.
+	// TODO: Worth doing better? Probably not, because we're here only
+	// under the management of go test.
+	if runtime.GOOS == "windows" && len(path) >= 2 {
+		letter, colon := path[0], path[1]
+		if ('a' <= letter && letter <= 'z' || 'A' <= letter && letter <= 'Z') && colon == ':' {
+			// If path starts with a drive letter we're stuck with it regardless.
+			return path
 		}
 	}
 	if os.IsPathSeparator(path[0]) {