C source.

Cgo first invokes gcc -E -dM on the preamble, in order to find out
about simple #defines for constants and the like. These are recorded
for later use.

Next, cgo needs to identify the kinds for each identifier. For the
identifiers C.foo, cgo generates this C program:

	<preamble>
	#line 1 "not-declared"
	void __cgo_f_1_1(void) { __typeof__(foo) *__cgo_undefined__1; }
	#line 1 "not-type"

same kind; that is, a boolean, integer, floating-point, complex, or string
constant.
If the untyped operands of a binary operation (other than a shift) are of
different kinds, the result is of the operand's kind that appears later in this
list: integer, rune, floating-point, complex.
For example, an untyped integer constant divided by an
untyped complex constant yields an untyped complex constant.

		return
	}
	hiName := p.next().String()
	hi, ok := p.arch.Register[hiName]
	if !ok {
		p.errorf("register list: bad high register in `[%s-%s`", loName, hiName)
		return
	}
	if tok := p.next().ScanToken; tok != ']' {
		p.errorf("register list: expected ']' after `[%s-%s`, found %s", loName, hiName, tok)
	}

	a.Type = obj.TYPE_REGLIST
	a.Reg = lo

	The type argument for <code>P<sub>k</sub></code> is the
	<a href="#Constants">default type</a> for the determined constant kind.
	If a constant kind cannot be determined due to conflicting constant kinds,
	type inference fails.
	</p>
</li>
</ol>

<p>
If not all type arguments have been found after these two phases, type inference fails.
</p>

<p>

pkg database/sql, method (IsolationLevel) String() string
pkg database/sql, type DBStats struct, Idle int
pkg database/sql, type DBStats struct, InUse int
pkg database/sql, type DBStats struct, MaxIdleClosed int64
pkg database/sql, type DBStats struct, MaxLifetimeClosed int64
pkg database/sql, type DBStats struct, MaxOpenConnections int

	return time.FixedZone("", int(offset/time.Second))
}

// msDosTimeToTime converts an MS-DOS date and time into a time.Time.
// The resolution is 2s.
// See: https://learn.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-dosdatetimetofiletime
func msDosTimeToTime(dosDate, dosTime uint16) time.Time {
	return time.Date(
		// date bits 0-4: day of month; 5-8: month; 9-15: years since 1980
		int(dosDate>>9+1980),

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
connecting to servers with buggy HTTP/2 implementations.
These kinds of changes are unavoidable and
[permitted by the Go 1 compatibility rules](/doc/go1compat).
Even so, Go provides a mechanism called GODEBUG to
reduce the impact such changes have on Go developers

// guessKinds tricks gcc into revealing the kind of each
// name xxx for the references C.xxx in the Go input.
// The kind is either a constant, type, or variable.
func (p *Package) guessKinds(f *File) []*Name {
	// Determine kinds for names we already know about,
	// like #defines or 'struct foo', before bothering with gcc.
	var names, needType []*Name
	optional := map[*Name]bool{}
	for _, key := range nameKeys(f.Name) {
		n := f.Name[key]