all: fix article typos

a -> an

Change-Id: I7362bdc199e83073a712be657f5d9ba16df3077e
Reviewed-on: https://go-review.googlesource.com/63850Reviewed-by: Rob Pike <r@golang.org>

src/archive/zip/reader.go

@@ -94,7 +94,7 @@ func (z *Reader) init(r io.ReaderAt, size int64) error {
 
 	// The count of files inside a zip is truncated to fit in a uint16.
 	// Gloss over this by reading headers until we encounter
-	// a bad one, and then only report a ErrFormat or UnexpectedEOF if
+	// a bad one, and then only report an ErrFormat or UnexpectedEOF if
 	// the file count modulo 65536 is incorrect.
 	for {
 		f := &File{zip: z, zipr: r, zipsize: size}

src/cmd/cgo/main.go

@@ -106,7 +106,7 @@ func (n *Name) IsConst() bool {
 	return strings.HasSuffix(n.Kind, "const")
 }
 
-// A ExpFunc is an exported function, callable from C.
+// An ExpFunc is an exported function, callable from C.
 // Such functions are identified in the Go input file
 // by doc comments containing the line //export ExpName
 type ExpFunc struct {

src/cmd/compile/internal/gc/walk.go

@@ -1767,7 +1767,7 @@ func ascompatee1(l *Node, r *Node, init *Nodes) *Node {
 
 func ascompatee(op Op, nl, nr []*Node, init *Nodes) []*Node {
 	// check assign expression list to
-	// a expression list. called in
+	// an expression list. called in
 	//	expr-list = expr-list
 
 	// ensure order of evaluation for function calls
@@ -1819,7 +1819,7 @@ func fncall(l *Node, rt *types.Type) bool {
 }
 
 // check assign type list to
-// a expression list. called in
+// an expression list. called in
 //	expr-list = func()
 func ascompatet(nl Nodes, nr *types.Type) []*Node {
 	if nl.Len() != nr.NumFields() {

src/cmd/compile/internal/ssa/loopreschedchecks.go

@@ -17,7 +17,7 @@ type edgeMem struct {
 	m *Value // phi for memory at dest of e
 }
 
-// a rewriteTarget is a a value-argindex pair indicating
+// a rewriteTarget is a value-argindex pair indicating
 // where a rewrite is applied.  Note that this is for values,
 // not for block controls, because block controls are not targets
 // for the rewrites performed in inserting rescheduling checks.

src/cmd/internal/obj/arm64/obj7.go

@@ -632,7 +632,7 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
 				//	B    end
 				//
 				// The NOP is needed to give the jumps somewhere to land.
-				// It is a liblink NOP, not a ARM64 NOP: it encodes to 0 instruction bytes.
+				// It is a liblink NOP, not an ARM64 NOP: it encodes to 0 instruction bytes.
 				q = q1
 
 				// MOV g_panic(g), R1

src/cmd/link/internal/ld/dwarf.go

@@ -123,7 +123,7 @@ func getattr(die *dwarf.DWDie, attr uint16) *dwarf.DWAttr {
 	return nil
 }
 
-// Every DIE has at least a AT_name attribute (but it will only be
+// Every DIE has at least an AT_name attribute (but it will only be
 // written out if it is listed in the abbrev).
 func newdie(ctxt *Link, parent *dwarf.DWDie, abbrev int, name string, version int) *dwarf.DWDie {
 	die := new(dwarf.DWDie)

src/compress/gzip/gunzip.go

@@ -66,7 +66,7 @@ type Header struct {
 // Only the first header is recorded in the Reader fields.
 //
 // Gzip files store a length and checksum of the uncompressed data.
-// The Reader will return a ErrChecksum when Read
+// The Reader will return an ErrChecksum when Read
 // reaches the end of the uncompressed data if it does not
 // have the expected length or checksum. Clients should treat data
 // returned by Read as tentative until they receive the io.EOF

src/context/example_test.go

@@ -52,7 +52,7 @@ func ExampleWithCancel() {
 	// 5
 }
 
-// This example passes a context with a arbitrary deadline to tell a blocking
+// This example passes a context with an arbitrary deadline to tell a blocking
 // function that it should abandon its work as soon as it gets to it.
 func ExampleWithDeadline() {
 	d := time.Now().Add(50 * time.Millisecond)

src/crypto/dsa/dsa.go

@@ -37,7 +37,7 @@ type PrivateKey struct {
 // this error must be handled.
 var ErrInvalidPublicKey = errors.New("crypto/dsa: invalid public key")
 
-// ParameterSizes is a enumeration of the acceptable bit lengths of the primes
+// ParameterSizes is an enumeration of the acceptable bit lengths of the primes
 // in a set of DSA parameters. See FIPS 186-3, section 4.2.
 type ParameterSizes int
 

src/crypto/ecdsa/ecdsa.go

@@ -49,7 +49,7 @@ type PublicKey struct {
 	X, Y *big.Int
 }
 
-// PrivateKey represents a ECDSA private key.
+// PrivateKey represents an ECDSA private key.
 type PrivateKey struct {
 	PublicKey
 	D *big.Int

src/crypto/tls/key_agreement.go

@@ -172,7 +172,7 @@ func curveForCurveID(id CurveID) (elliptic.Curve, bool) {
 }
 
 // ecdheRSAKeyAgreement implements a TLS key agreement where the server
-// generates a ephemeral EC public/private key pair and signs it. The
+// generates an ephemeral EC public/private key pair and signs it. The
 // pre-master secret is then calculated using ECDH. The signature may
 // either be ECDSA or RSA.
 type ecdheKeyAgreement struct {

src/encoding/asn1/asn1.go

@@ -374,7 +374,7 @@ func parseGeneralizedTime(bytes []byte) (ret time.Time, err error) {
 
 // PrintableString
 
-// parsePrintableString parses a ASN.1 PrintableString from the given byte
+// parsePrintableString parses an ASN.1 PrintableString from the given byte
 // array and returns it.
 func parsePrintableString(bytes []byte) (ret string, err error) {
 	for _, b := range bytes {
@@ -406,7 +406,7 @@ func isPrintable(b byte) bool {
 
 // IA5String
 
-// parseIA5String parses a ASN.1 IA5String (ASCII string) from the given
+// parseIA5String parses an ASN.1 IA5String (ASCII string) from the given
 // byte slice and returns it.
 func parseIA5String(bytes []byte) (ret string, err error) {
 	for _, b := range bytes {
@@ -421,7 +421,7 @@ func parseIA5String(bytes []byte) (ret string, err error) {
 
 // T61String
 
-// parseT61String parses a ASN.1 T61String (8-bit clean string) from the given
+// parseT61String parses an ASN.1 T61String (8-bit clean string) from the given
 // byte slice and returns it.
 func parseT61String(bytes []byte) (ret string, err error) {
 	return string(bytes), nil
@@ -429,7 +429,7 @@ func parseT61String(bytes []byte) (ret string, err error) {
 
 // UTF8String
 
-// parseUTF8String parses a ASN.1 UTF8String (raw UTF-8) from the given byte
+// parseUTF8String parses an ASN.1 UTF8String (raw UTF-8) from the given byte
 // array and returns it.
 func parseUTF8String(bytes []byte) (ret string, err error) {
 	if !utf8.Valid(bytes) {
@@ -992,7 +992,7 @@ func setDefaultValue(v reflect.Value, params fieldParameters) (ok bool) {
 //
 // The following tags on struct fields have special meaning to Unmarshal:
 //
-//	application specifies that a APPLICATION tag is used
+//	application specifies that an APPLICATION tag is used
 //	default:x   sets the default value for optional integer fields (only used if optional is also present)
 //	explicit    specifies that an additional, explicit tag wraps the implicit one
 //	optional    marks the field as ASN.1 OPTIONAL

src/encoding/asn1/marshal.go

@@ -18,7 +18,7 @@ var (
 	byteFFEncoder encoder = byteEncoder(0xff)
 )
 
-// encoder represents a ASN.1 element that is waiting to be marshaled.
+// encoder represents an ASN.1 element that is waiting to be marshaled.
 type encoder interface {
 	// Len returns the number of bytes needed to marshal this element.
 	Len() int

src/image/color/color.go

@@ -200,7 +200,7 @@ func nrgbaModel(c Color) Color {
 	if a == 0 {
 		return NRGBA{0, 0, 0, 0}
 	}
-	// Since Color.RGBA returns a alpha-premultiplied color, we should have r <= a && g <= a && b <= a.
+	// Since Color.RGBA returns an alpha-premultiplied color, we should have r <= a && g <= a && b <= a.
 	r = (r * 0xffff) / a
 	g = (g * 0xffff) / a
 	b = (b * 0xffff) / a
@@ -218,7 +218,7 @@ func nrgba64Model(c Color) Color {
 	if a == 0 {
 		return NRGBA64{0, 0, 0, 0}
 	}
-	// Since Color.RGBA returns a alpha-premultiplied color, we should have r <= a && g <= a && b <= a.
+	// Since Color.RGBA returns an alpha-premultiplied color, we should have r <= a && g <= a && b <= a.
 	r = (r * 0xffff) / a
 	g = (g * 0xffff) / a
 	b = (b * 0xffff) / a

src/net/http/server.go

@@ -1213,7 +1213,7 @@ func (cw *chunkWriter) writeHeader(p []byte) {
 		}
 	}
 
-	// Check for a explicit (and valid) Content-Length header.
+	// Check for an explicit (and valid) Content-Length header.
 	hasCL := w.contentLength != -1
 
 	if w.wants10KeepAlive && (isHEAD || hasCL || !bodyAllowedForStatus(w.status)) {

src/os/sys_windows.go

@@ -24,7 +24,7 @@ func hostname() (name string, err error) {
 			return "", NewSyscallError("ComputerNameEx", err)
 		}
 
-		// If we received a ERROR_MORE_DATA, but n doesn't get larger,
+		// If we received an ERROR_MORE_DATA, but n doesn't get larger,
 		// something has gone wrong and we may be in an infinite loop
 		if n <= uint32(len(b)) {
 			return "", NewSyscallError("ComputerNameEx", err)

src/reflect/value.go

@@ -176,7 +176,7 @@ type emptyInterface struct {
 	word unsafe.Pointer
 }
 
-// nonEmptyInterface is the header for a interface value with methods.
+// nonEmptyInterface is the header for an interface value with methods.
 type nonEmptyInterface struct {
 	// see ../runtime/iface.go:/Itab
 	itab *struct {

src/regexp/exec.go

@@ -16,7 +16,7 @@ type queue struct {
 	dense  []entry
 }
 
-// A entry is an entry on a queue.
+// An entry is an entry on a queue.
 // It holds both the instruction pc and the actual thread.
 // Some queue entries are just place holders so that the machine
 // knows it has considered that pc. Such entries have t == nil.

src/runtime/cgocall.go

@@ -340,7 +340,7 @@ func unwindm(restore *bool) {
 	// Call endcgo to do the accounting that cgocall will not have a
 	// chance to do during an unwind.
 	//
-	// In the case where a a Go call originates from C, ncgo is 0
+	// In the case where a Go call originates from C, ncgo is 0
 	// and there is no matching cgocall to end.
 	if mp.ncgo > 0 {
 		endcgo(mp)

src/runtime/mheap.go

@@ -863,7 +863,7 @@ HaveSpan:
 // Large spans have a minimum size of 1MByte. The maximum number of large spans to support
 // 1TBytes is 1 million, experimentation using random sizes indicates that the depth of
 // the tree is less that 2x that of a perfectly balanced tree. For 1TByte can be referenced
-// by a perfectly balanced tree with a a depth of 20. Twice that is an acceptable 40.
+// by a perfectly balanced tree with a depth of 20. Twice that is an acceptable 40.
 func (h *mheap) isLargeSpan(npages uintptr) bool {
 	return npages >= uintptr(len(h.free))
 }

src/strconv/extfloat.go

@@ -641,7 +641,7 @@ func (f *extFloat) ShortestDecimal(d *decimalSlice, lower, upper *extFloat) bool
 // adjustLastDigit modifies d = x-currentDiff*ε, to get closest to
 // d = x-targetDiff*ε, without becoming smaller than x-maxDiff*ε.
 // It assumes that a decimal digit is worth ulpDecimal*ε, and that
-// all data is known with a error estimate of ulpBinary*ε.
+// all data is known with an error estimate of ulpBinary*ε.
 func adjustLastDigit(d *decimalSlice, currentDiff, targetDiff, maxDiff, ulpDecimal, ulpBinary uint64) bool {
 	if ulpDecimal < 2*ulpBinary {
 		// Approximation is too wide.

test/chan/sendstmt.go

@@ -5,7 +5,7 @@
 // license that can be found in the LICENSE file.
 
 // Test various parsing cases that are a little
-// different now that send is a statement, not a expression.
+// different now that send is a statement, not an expression.
 
 package main
 

test/fixedbugs/issue15747b.go

@@ -4,7 +4,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Issue 15747: If a ODCL is dropped, for example when inlining,
+// Issue 15747: If an ODCL is dropped, for example when inlining,
 // then it's easy to end up not initializing the '&x' pseudo-variable
 // to point to an actual allocation. The liveness analysis will detect
 // this and abort the computation, so this test just checks that the