controlled by the cgocheck setting of the GODEBUG environment
variable. The default setting is GODEBUG=cgocheck=1, which implements
reasonably cheap dynamic checks. These checks may be disabled
entirely using GODEBUG=cgocheck=0. Complete checking of pointer
handling, at some cost in run time, is available by setting
GOEXPERIMENT=cgocheck2 at build time.

It is possible to defeat this enforcement by using the unsafe package,

pkg go/types, method (*Info) ObjectOf(*ast.Ident) Object
pkg go/types, method (*Info) TypeOf(ast.Expr) Type
pkg go/types, method (*Initializer) String() string
pkg go/types, method (*Interface) Complete() *Interface
pkg go/types, method (*Interface) Embedded(int) *Named
pkg go/types, method (*Interface) Empty() bool
pkg go/types, method (*Interface) ExplicitMethod(int) *Func

unlike with a regular call, program execution does not wait
for the invoked function to complete.
Instead, the function begins executing independently
in a new goroutine.
When the function terminates, its goroutine also terminates.
If the function has any return values, they are discarded when the
function completes.
</p>

<pre>
go Server()

+ The PR title is formatted as follows: `net/http: frob the quux before blarfing`
  + The package name goes before the colon
  + The part after the colon uses the verb tense + phrase that completes the blank in,
    "This change modifies Go to ___________"
  + Lowercase verb after the colon
  + No trailing period
  + Keep the title as short as possible. ideally under 76 characters or shorter
+ No Markdown

			}
			continue
		}

		switch filename {
		case "completed":
			// Strictly speaking, there is no guarantee that seeing the error at completed:1
			// (at the end of the file) means we've seen all the errors from earlier in the file,
			// but usually it does. Certainly if we don't see the completed:1 error, we did
			// not get all the errors we expected.
			completed = true

		case "not-declared":
			sniff[i] |= notDeclared

which are tied to a specific release.
-->

## Introduction {#intro}

Go's emphasis on backwards compatibility is one of its key strengths.
There are, however, times when we cannot maintain complete compatibility.
If code depends on buggy (including insecure) behavior,
then fixing the bug will break that code.
New features can also have similar impacts:
enabling the HTTP/2 use by the HTTP client broke programs

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// This input was created by taking the instruction productions in
// the old assembler's (5a's) grammar and hand-writing complete
// instructions for each rule, to guarantee we cover the same space.

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

TEXT	foo(SB), DUPOK|NOSPLIT, $0

// ADD
//
//	LTYPE1 cond imsr ',' spreg ',' reg
//	{

// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// This input was created by taking the instruction productions in
// the old assembler's (7a's) grammar and hand-writing complete
// instructions for each rule, to guarantee we cover the same space.

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

TEXT	foo(SB), DUPOK|NOSPLIT, $-8

// arithmetic operations
	ADDW	$1, R2, R3
	ADDW	R1, R2, R3

// the [Scanner] returns it to the user. If the token is nil, the
// Scanner reads more data and continues scanning; if there is no more
// data--if atEOF was true--the [Scanner] returns. If the data does not
// yet hold a complete token, for instance if it has no newline while
// scanning lines, a [SplitFunc] can return (0, nil, nil) to signal the
// [Scanner] to read more data into the slice and try again with a

	extraLen := int(b.uint16())
	return int64(fileHeaderLen + filenameLen + extraLen), nil
}

// readDirectoryHeader attempts to read a directory header from r.
// It returns io.ErrUnexpectedEOF if it cannot read a complete header,
// and ErrFormat if it doesn't find a valid header signature.
func readDirectoryHeader(f *File, r io.Reader) error {
	var buf [directoryHeaderLen]byte
	if _, err := io.ReadFull(r, buf[:]); err != nil {