func (f *File) saveRef(n *ast.Expr, context astContext) {
	sel := (*n).(*ast.SelectorExpr)
	// For now, assume that the only instance of capital C is when
	// used as the imported package identifier.
	// The parser should take care of scoping in the future, so
	// that we will be able to distinguish a "top-level C" from a
	// local C.
	if l, ok := sel.X.(*ast.Ident); !ok || l.Name != "C" {
		return
	}
	if context == ctxAssign2 {

unmodified environments. Flags obtained from environment variables
are not subject to the security limitations described above.

All the cgo CPPFLAGS and CFLAGS directives in a package are concatenated and
used to compile C files in that package. All the CPPFLAGS and CXXFLAGS
directives in a package are concatenated and used to compile C++ files in that
package. All the CPPFLAGS and FFLAGS directives in a package are concatenated

	{"(R1, R3)", "(R1, R3)"},
	{"[R0,R1,g,R15", ""}, // Issue 11764 - asm hung parsing ']' missing register lists.
	{"[):[o-FP", ""},     // Issue 12469 - there was no infinite loop for ARM; these are just sanity checks.
	{"[):[R0-FP", ""},
	{"(", ""}, // Issue 12466 - backed up before beginning of line.
}

var ppc64OperandTests = []operandTest{
	{"$((1<<63)-1)", "$9223372036854775807"},

	// Type '7' is reserved.
	TypeCont = '7'

	// Type 'x' is used by the PAX format to store key-value records that
	// are only relevant to the next file.
	// This package transparently handles these types.
	TypeXHeader = 'x'

	// Type 'g' is used by the PAX format to store key-value records that
	// are relevant to all subsequent files.
	// This package only supports parsing and composing such headers,

type Buffer struct {
	buf      []byte // contents are the bytes buf[off : len(buf)]
	off      int    // read at &buf[off], write at &buf[len(buf)]
	lastRead readOp // last read operation, so that Unread* can work correctly.
}

// The readOp constants describe the last action performed on
// the buffer, so that UnreadRune and UnreadByte can check for
// invalid usage. opReadRuneX constants are chosen such that

			},
			Format: FormatPAX,
		}},
	}, {
		// Both BSD and GNU tar truncate long names at first NUL even
		// if there is data following that NUL character.
		// This is reasonable as GNU long names are C-strings.
		file: "testdata/gnu-long-nul.tar",
		headers: []*Header{{
			Name:     "0123456789",
			Mode:     0644,
			Uid:      1000,
			Gid:      1000,
			ModTime:  time.Unix(1486082191, 0),

// Copyright 2017 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// The cases are auto-generated by disassembler.
// The uncommented cases means they can be handled by assembler
// and they are consistent with disassembler decoding.
// TODO means they cannot be handled by current assembler.

#include "../../../../../runtime/textflag.h"

// dropped from the byte slice with no replacement. The characters in s and the
// output are interpreted as UTF-8-encoded code points.
func Map(mapping func(r rune) rune, s []byte) []byte {
	// In the worst case, the slice can grow when mapped, making
	// things unpleasant. But it's so rare we barge in assuming it's
	// fine. It could also shrink but that falls out naturally.
	b := make([]byte, 0, len(s))

Package builtin provides documentation for Go's predeclared identifiers.
The items documented here are not actually in package builtin
but their descriptions here allow godoc to present documentation
for the language's special identifiers.
*/
package builtin

import "cmp"

// bool is the set of boolean values, true and false.
type bool bool

// true and false are the two untyped boolean values.
const (
	true  = 0 == 0 // Untyped bool.

next:
	// Skip newlines.
	var tok lex.ScanToken
	for {
		tok = p.nextToken()
		// We save the line number here so error messages from this instruction
		// are labeled with this line. Otherwise we complain after we've absorbed
		// the terminating newline and the line numbers are off by one in errors.
		p.lineNum = p.lex.Line()
		switch tok {
		case '\n', ';':
			continue
		case scanner.EOF:
			return "", "", nil, false
		}