all: append(bytes, str...) works out of the box

From the append docs in the builtin package:

	As a special case, it is legal to append a string to a byte slice, like this:

	slice = append([]byte("hello "), "world"...)

Change-Id: Ib14039a7476873b12a3aefccd8863e8d628b9249
Reviewed-on: https://go-review.googlesource.com/c/go/+/425102
Reviewed-by: hopehook <hopehook@qq.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: David Chase <drchase@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>

src/cmd/go/internal/modindex/write.go

@@ -126,7 +126,7 @@ func (e *encoder) String(s string) {
 	e.strings[s] = pos
 	e.Int(pos)
 	e.stringTable = binary.AppendUvarint(e.stringTable, uint64(len(s)))
-	e.stringTable = append(e.stringTable, []byte(s)...)
+	e.stringTable = append(e.stringTable, s...)
 }
 
 func (e *encoder) Bool(b bool) {

src/cmd/internal/quoted/quoted.go

@@ -83,16 +83,16 @@ func Join(args []string) (string, error) {
 		}
 		switch {
 		case !sawSpace && !sawSingleQuote && !sawDoubleQuote:
-			buf = append(buf, []byte(arg)...)
+			buf = append(buf, arg...)
 
 		case !sawSingleQuote:
 			buf = append(buf, '\'')
-			buf = append(buf, []byte(arg)...)
+			buf = append(buf, arg...)
 			buf = append(buf, '\'')
 
 		case !sawDoubleQuote:
 			buf = append(buf, '"')
-			buf = append(buf, []byte(arg)...)
+			buf = append(buf, arg...)
 			buf = append(buf, '"')
 
 		default:

src/syscall/exec_linux.go

@@ -590,7 +590,7 @@ func forkExecPipe(p []int) (err error) {
 func formatIDMappings(idMap []SysProcIDMap) []byte {
 	var data []byte
 	for _, im := range idMap {
-		data = append(data, []byte(itoa.Itoa(im.ContainerID)+" "+itoa.Itoa(im.HostID)+" "+itoa.Itoa(im.Size)+"\n")...)
+		data = append(data, itoa.Itoa(im.ContainerID)+" "+itoa.Itoa(im.HostID)+" "+itoa.Itoa(im.Size)+"\n"...)
 	}
 	return data
 }

src/time/format.go

@@ -588,7 +588,7 @@ func (t Time) GoString() string {
 		// Of these, Location(loc.name) is the least disruptive. This is an edge
 		// case we hope not to hit too often.
 		buf = append(buf, `time.Location(`...)
-		buf = append(buf, []byte(quote(loc.name))...)
+		buf = append(buf, quote(loc.name)...)
 		buf = append(buf, ')')
 	}
 	buf = append(buf, ')')