go/doc/go1.18.html
Robert Griesemer ba83aa7caa doc/go1.18: add documentation for changes to go/constant
Updates #47694

Change-Id: I2ce5aaa4493259790712a8a49e5b03472c8a7400
Reviewed-on: https://go-review.googlesource.com/c/go/+/369094
Trust: Robert Griesemer <gri@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
2021-12-04 01:07:10 +00:00

644 lines
25 KiB
HTML
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

<!--{
"Title": "Go 1.18 Release Notes",
"Path": "/doc/go1.18"
}-->
<!--
NOTE: In this document and others in this directory, the convention is to
set fixed-width phrases with non-fixed-width spaces, as in
<code>hello</code> <code>world</code>.
Do not send CLs removing the interior tags from such phrases.
-->
<style>
main ul li { margin: 0.5em 0; }
</style>
<h2 id="introduction">DRAFT RELEASE NOTES — Introduction to Go 1.18</h2>
<p>
<strong>
Go 1.18 is not yet released. These are work-in-progress
release notes. Go 1.18 is expected to be released in February 2022.
</strong>
</p>
<h2 id="language">Changes to the language</h2>
<p>
TODO: complete this section
</p>
<h3 id="bug_fixes">Bug fixes</h3>
<p>
The Go 1.18 compiler now correctly reports <code>declared but not used</code> errors
for variables that are set inside a function literal but are never used. Before Go 1.18,
the compiler did not report an error in such cases. This fixes long-outstanding compiler
issue <a href="https://golang.org/issue/8560">#8560</a>. As a result of this change,
(possibly incorrect) programs may not compile anymore. The necessary fix is
straightforward: fix the program if it was in fact incorrect, or use the offending
variable, for instance by assigning it to the blank identifier <code>_</code>.
Since <code>go vet</code> always pointed out this error, the number of affected
programs is likely very small.
</p>
<p>
The Go 1.18 compiler now reports an overflow when passing a rune constant expression
such as <code>'1' << 32</code> as an argument to the predeclared functions
<code>print</code> and <code>println</code>, consistent with the behavior of
user-defined functions. Before Go 1.18, the compiler did not report an error
in such cases but silently accepted such constant arguments if they fit into an
<code>int64</code>. As a result of this change, (possibly incorrect) programs
may not compile anymore. The necessary fix is straightforward: fix the program if it
was in fact incorrect, or explicitly convert the offending argument to the correct type.
Since <code>go vet</code> always pointed out this error, the number of affected
programs is likely very small.
</p>
<h3 id="generics">Generics</h3>
<p>
Go 1.18 includes an implementation of generics as described
by <a href="https://go.googlesource.com/proposal/+/refs/heads/master/design/43651-type-parameters.md">the
generics proposal</a>.
</p>
<p>
The current generics implementation has the following limitations:
<ul>
<li><!-- issue 47631 -->
The Go compiler cannot currently handle type declarations inside generic functions
or methods. We hope to provide support for this feature in Go 1.19.
</li>
</ul>
</p>
<h3 id="fuzzing">Fuzzing</h3>
<p>
Go 1.18 includes an implementation of fuzzing as described by
<a href="https://golang.org/issue/44551">the fuzzing proposal</a>.
</p>
<p>
See the <a href="https://go.dev/doc/fuzz">fuzzing landing page</a> to get
started.
</p>
<p>
Please be aware that fuzzing can consume a lot of memory and may impact your
machines performance while it runs. Also be aware that the fuzzing engine
writes values that expand test coverage to a fuzz cache directory within
<code>$GOCACHE/fuzz</code> while it runs. There is currently no limit to the
number of files or total bytes that may be written to the fuzz cache, so it
may occupy a large amount of storage (possibly several GBs).
</p>
<h2 id="ports">Ports</h2>
<h3 id="amd64">AMD64</h3>
<p><!-- CL 349595 -->
Go 1.18 introduces the new <code>GOAMD64</code> environment variable which selects
a version of the AMD64 architecture. Allowed values are <code>v1</code>,
<code>v2</code>, <code>v3</code>, or <code>v4</code>. Each higher level requires,
and takes advantage of, additional processor features. A detailed description of the
versions is <a href="https://en.wikipedia.org/wiki/X86-64#Microarchitecture_levels">here</a>.
</p>
<p>
The <code>GOAMD64</code> environment variable defaults to <code>v1</code>.
</p>
<h3 id="riscv">RISC-V</h3>
<p><!-- golang.org/issue/47100, CL 334872 -->
The 64-bit RISC-V architecture on Linux (the <code>linux/riscv64</code> port)
now supports the <code>c-archive</code> and <code>c-shared</code> build modes.
</p>
<h3 id="windows">Windows</h3>
<p><!-- https://golang.org/issue/49759 -->
The <code>windows/arm</code> and <code>windows/arm64</code> ports now support
non-cooperative preemption, bringing that capability to all four Windows
ports, which should hopefully address subtle bugs encountered when calling
into Win32 functions that block for extended periods of time.
</p>
<h3 id="ios">iOS</h3>
<p><!-- golang.org/issue/48076, golang.org/issue/49616 -->
On iOS (the <code>ios/arm64</code> port)
and iOS simulator running on AMD64-based macOS (the <code>ios/amd64</code> port),
Go 1.18 now requires iOS 12 or later; support for previous versions has been discontinued.
</p>
<h3 id="freebsd">FreeBSD</h3>
<p>
Go 1.18 is the last release that is supported on FreeBSD 11.x, which has
already reached end-of-life. Go 1.19 will require FreeBSD 12.2+ or FreeBSD
13.0+.
FreeBSD 13.0+ will require a kernel with the COMPAT_FREEBSD12 option set (this is the default).
</p>
<h2 id="tools">Tools</h2>
<h3 id="go-command">Go command</h3>
<p><!-- golang.org/issue/43684 -->
<code>go</code> <code>get</code> no longer builds or installs packages in
module-aware mode. <code>go</code> <code>get</code> is now dedicated to
adjusting dependencies in <code>go.mod</code>. Effectively, the
<code>-d</code> flag is always enabled. To install the latest version
of an executable outside the context of the current module, use
<a href="https://golang.org/ref/mod#go-install"><code>go</code>
<code>install</code> <code>example.com/cmd@latest</code></a>. Any
<a href="https://golang.org/ref/mod#version-queries">version query</a>
may be used instead of <code>latest</code>. This form of <code>go</code>
<code>install</code> was added in Go 1.16, so projects supporting older
versions may need to provide install instructions for both <code>go</code>
<code>install</code> and <code>go</code> <code>get</code>. <code>go</code>
<code>get</code> now reports an error when used outside a module, since there
is no <code>go.mod</code> file to update. In GOPATH mode (with
<code>GO111MODULE=off</code>), <code>go</code> <code>get</code> still builds
and installs packages, as before.
</p>
<p><!-- golang.org/issue/37475 -->
The <code>go</code> command now embeds version control information in
binaries including the currently checked-out revision, commit time, and a
flag indicating whether edited or untracked files are present. Version
control information is embedded if the <code>go</code> command is invoked in
a directory within a Git, Mercurial, Fossil, or Bazaar repository, and the
<code>main</code> package and its containing main module are in the same
repository. This information may be omitted using the flag
<code>-buildvcs=false</code>.
</p>
<p><!-- golang.org/issue/37475 -->
Additionally, the <code>go</code> command embeds information about the build
including build and tool tags (set with <code>-tags</code>), compiler,
assembler, and linker flags (like <code>-gcflags</code>), whether cgo was
enabled, and if it was, the values of the cgo environment variables
(like <code>CGO_CFLAGS</code>). This information may be omitted using the
flag <code>-buildinfo=false</code>. Both VCS and build information may be
read together with module information using <code>go</code>
<code>version</code> <code>-m</code> <code>file</code> or
<code>runtime/debug.ReadBuildInfo</code> (for the currently running binary)
or the new <a href="#debug/buildinfo"><code>debug/buildinfo</code></a>
package.
</p>
<p><!-- https://golang.org/issue/44435 -->
If the main module's <code>go.mod</code> file
specifies <a href="/ref/mod#go-mod-file-go"><code>go</code> <code>1.17</code></a>
or higher, <code>go</code> <code>mod</code> <code>download</code> without
arguments now downloads source code for only the modules
explicitly <a href="/ref/mod#go-mod-file-require">required</a> in the main
module's <code>go.mod</code> file. (In a <code>go</code> <code>1.17</code> or
higher module, that set already includes all dependencies needed to build the
packages and tests in the main module.)
To also download source code for transitive dependencies, use
<code>go</code> <code>mod</code> <code>download</code> <code>all</code>.
</p>
<p><!-- https://golang.org/issue/47327 -->
The <code>go</code> <code>mod</code> <code>vendor</code> subcommand now
supports a <code>-o</code> flag to set the output directory.
(Other <code>go</code> commands still read from the <code>vendor</code>
directory at the module root when loading packages
with <code>-mod=vendor</code>, so the main use for this flag is for
third-party tools that need to collect package source code.)
</p>
<p><!-- CL 298612 -->
The <code>go</code> <code>build</code> command and related commands
now support an <code>-asan</code> flag that enables interoperation
with C (or C++) code compiled with the address sanitizer (C compiler
option <code>-fsanitize=address</code>).
</p>
<h3 id="gofmt"><code>gofmt</code></h3>
<p><!-- https://golang.org/issue/43566 -->
<code>gofmt</code> now reads and formats input files concurrently, with a
memory limit proportional to <code>GOMAXPROCS</code>. On a machine with
multiple CPUs, <code>gofmt</code> should now be significantly faster.
</p>
<h2 id="runtime">Runtime</h2>
<p><!-- https://golang.org/issue/44167 -->
The garbage collector now includes non-heap sources of garbage collector work
(e.g., stack scanning) when determining how frequently to run. As a result,
garbage collector overhead is more predictable when these sources are
significant. For most applications these changes will be negligible; however,
some Go applications may now use less memory and spend more time on garbage
collection, or vice versa, than before. The intended workaround is to tweak
<code>GOGC</code> where necessary.
</p>
<p>
The runtime now returns memory to the operating system more efficiently and has
been tuned to work more aggressively as a result.
</p>
<p><!-- CL 352057, https://golang.org/issue/45728 -->
Go 1.17 generally improved the formatting of arguments in stack traces,
but could print inaccurate values for arguments passed in registers.
This is improved in Go 1.18 by printing a question mark (<code>?</code>)
after each value that may be inaccurate.
</p>
<h2 id="compiler">Compiler</h2>
<p><!-- https://golang.org/issue/40724 -->
Go 1.17 <a href="go1.17#compiler">implemented</a> a new way of passing
function arguments and results using registers instead of the stack
on 64-bit x86 architecture on selected operating systems.
Go 1.18 expands the supported platforms to include 64-bit ARM (<code>GOARCH=arm64</code>),
big- and little-endian 64-bit PowerPC (<code>GOARCH=ppc64</code>, <code>ppc64le</code>),
as well as 64-bit x86 architecture (<code>GOARCH=amd64</code>)
on all operating systems.
On 64-bit ARM and 64-bit PowerPC systems, benchmarking shows
typical performance improvements of 10% or more.
</p>
<p>
As <a href="go1.17#compiler">mentioned</a> in the Go 1.17 release notes,
this change does not affect the functionality of any safe Go code and
is designed to have no impact on most assembly code. See the
<a href="go1.17#compiler">Go 1.17 release notes</a> for more details.
</p>
<p><!-- CL 355497, CL 356869 -->
The compiler now can inline functions that contain range loops or
labeled for loops.
</p>
<p><!-- CL 298611 -->
The new compiler <code>-asan</code> option supports the
new <code>go</code> command <code>-asan</code> option.
</p>
<p>
TODO: Mention build speed impact.
</p>
<h2 id="linker">Linker</h2>
<p><!-- CL 298610 -->
The new linker <code>-asan</code> option supports the
new <code>go</code> command <code>-asan</code> option.
</p>
<h2 id="library">Core library</h2>
<h3 id="constraints">New <code>constraints</code> package</h3>
<p><!-- CL 349709 -->
The new <a href="/pkg/constraints/"><code>constraints</code></a> package
defines a set of useful constraints that can be used with type parameters of
generic functions.
</p>
<h3 id="netip">New <code>net/netip</code> package</h3>
<p>
The new <a href="/pkg/net/netip/"><code>net/netip</code></a>
package defines a new IP address type, <a href="/pkg/net/netip/#Addr"><code>Addr</code></a>.
Compared to the existing
<a href="/pkg/net/#IP"><code>net.IP</code></a> type, the <code>netip.Addr</code> type takes less
memory, is immutable, and is comparable so it supports <code>==</code>
and can be used as a map key.
</p>
<p>
In addition to <code>Addr</code>, the package defines
<a href="/pkg/net/netip/#AddrPort"><code>AddrPort</code></a>, representing
an IP and port, and
<a href="/pkg/net/netip/#Prefix"><code>Prefix</code></a>, representing
a network CIDR prefix.
</p>
<p>
The <code>net</code> package now has methods to send and receive UDP packets
using <code>netip.Addr</code> values instead of the relatively heavy
<code>*net.UDPAddr</code> values.
</p>
<h3>TODO</h3>
<p>
TODO: complete this section
</p>
<h3 id="minor_library_changes">Minor changes to the library</h3>
<p>
As always, there are various minor changes and updates to the library,
made with the Go 1 <a href="/doc/go1compat">promise of compatibility</a>
in mind.
</p>
<p>
TODO: complete this section
</p>
<dl id="bufio"><dt><a href="/pkg/bufio/">bufio</a></dt>
<dd>
<p><!-- CL 345569 -->
The new <a href="/pkg/bufio#Writer.AvailableBuffer"><code>Writer.AvailableBuffer</code></a>
method returns an empty buffer with a possibly non-empty capacity for use
with append-like APIs. After appending, the buffer can be provided to a
succeeding <code>Write</code> call and possibly avoid any copying.
</p>
<p><!-- CL 345570 -->
The methods <a href="/pkg/bufio#Reader.Reset"><code>Reader.Reset</code></a> and
<a href="/pkg/bufio#Writer.Reset"><code>Writer.Reset</code></a>
now use the default buffer size when called on objects with a
<code>nil</code> buffer.
</p>
</dd>
</dl><!-- bufio -->
<dl id="bytes"><dt><a href="/pkg/bytes/">bytes</a></dt>
<dd>
<p><!-- CL 323318, CL 332771 -->
<a href="/pkg/bytes/#Trim"><code>Trim</code></a>, <a href="/pkg/bytes/#TrimLeft"><code>TrimLeft</code></a>,
and <a href="/pkg/bytes/#TrimRight"><code>TrimRight</code></a> are now allocation free and, especially for
small ASCII cutsets, up to 10 times faster.
</p>
<p><!-- CL 359485 -->
The <a href="/pkg/bytes/#Title"><code>Title</code></a> function is now deprecated. It doesn't
handle Unicode punctuation and language-specific capitalization rules, and is superseded by the
<a href="https://golang.org/x/text/cases">golang.org/x/text/cases</a> package.
</p>
<p><!-- CL 351710 -->
TODO: bytes.Cut.
</p>
</dd>
</dl><!-- bytes -->
<dl id="crypto/tls"><dt><a href="/pkg/crypto/tls/">crypto/tls</a></dt>
<dd>
<p><!-- CL 325250 -->
The new <a href="/pkg/crypto/tls/#Conn.NetConn"><code>Conn.NetConn</code></a>
method allows access to the underlying
<a href="/pkg/net#Conn"><code>net.Conn</code></a>.
</p>
</dd>
</dl><!-- crypto/tls -->
<dl id="debug/buildinfo"><dt><a href="/pkg/debug/buildinfo">debug/buildinfo</a></dt>
<dd>
<p><!-- golang.org/issue/39301 -->
This new package provides access to module versions, version control
information, and build flags embedded in executable files built by
the <code>go</code> command. The same information is also available via
<a href="/pkg/runtime/debug#ReadBuildInfo"><code>runtime/debug.ReadBuildInfo</code></a>
for the currently running binary and via <code>go</code>
<code>version</code> <code>-m</code> on the command line.
</p>
</dd>
</dl>
<dl id="go/constant"><dt><a href="/pkg/go/constant/">go/constant</a></dt>
<dd>
<p><!-- https://golang.org/issue/46211, CL 320491 -->
The new <a href="/pkg/go/constant/#Kind.String"><code>Kind.String</code></a>
method returns a human-readable name for the receiver kind.
</p>
</dd>
</dl>
<dl id="image/draw"><dt><a href="/pkg/image/draw/">image/draw</a></dt>
<dd>
<p><!-- CL 340049 -->
The <code>Draw</code> and <code>DrawMask</code> fallback implementations
(used when the arguments are not the most common image types) are now
faster when those arguments implement the optional
<a href="/pkg/image/draw/#RGBA64Image"><code>draw.RGBA64Image</code></a>
and <a href="/pkg/image/#RGBA64Image"><code>image.RGBA64Image</code></a>
interfaces that were added in Go 1.17.
</p>
</dd>
</dl><!-- image/draw -->
<dl id="net"><dt><a href="/pkg/net/">net</a></dt>
<dd>
<p><!-- CL 340261 -->
<a href="/pkg/net#Error"><code>net.Error.Temporary</code></a> has been deprecated.
</p>
</dd>
<dd>
<p>
TODO: Several new net APIs.
</p>
</dd>
</dl><!-- net -->
<dl id="net/http"><dt><a href="/pkg/net/http/">net/http</a></dt>
<dd>
<p><!-- CL 330852 -->
On WebAssembly targets, the <code>Dial</code>, <code>DialContext</code>,
<code>DialTLS</code> and <code>DialTLSContext</code> method fields in
<a href="/pkg/net/http/#Transport"><code>Transport</code></a>
will now be correctly used, if specified, for making HTTP requests.
</p>
<p><!-- CL 338590 -->
The new
<a href="/pkg/net/http#Cookie.Valid"><code>Cookie.Valid</code></a>
method reports whether the cookie is valid.
</p>
</dd>
</dl><!-- net/http -->
<dl id="os/user"><dt><a href="/pkg/os/user/">os/user</a></dt>
<dd>
<p><!-- CL 330753 -->
<a href="/pkg/os/user#User.GroupIds"><code>User.GroupIds</code></a>.
now uses a Go native implementation when cgo is not available.
</p>
</dd>
</dl><!-- os/user -->
<dl id="reflect"><dt><a href="/pkg/reflect/">reflect</a></dt>
<dd>
<p><!-- CL 356049, CL 320929 -->
The new
<a href="/pkg/reflect/#Value.SetIterKey"><code>Value.SetIterKey</code></a>
and <a href="/pkg/reflect/#Value.SetIterValue"><code>Value.SetIterValue</code></a>
methods set a Value using a map iterator as the source. They are equivalent to
<code>Value.Set(iter.Key())</code> and <code>Value.Set(iter.Value())</code> but
do fewer allocations.
</p>
<p><!-- CL 350691 -->
The new
<a href="/pkg/reflect/#Value.UnsafePointer"><code>Value.UnsafePointer</code></a>
method returns the Value's value as an <a href="/pkg/unsafe/#Pointer"><code>unsafe.Pointer</code></a>.
This allows callers to migrate from <a href="/pkg/reflect/#Value.UnsafeAddr"><code>Value.UnsafeAddr</code></a>
and <a href="/pkg/reflect/#Value.Pointer"><code>Value.Pointer</code></a>
to eliminate the need to perform uintptr to unsafe.Pointer conversions at the callsite (as unsafe.Pointer rules require).
</p>
<p><!-- CL 321891 -->
The new
<a href="/pkg/reflect/#MapIter.Reset"><code>MapIter.Reset</code></a>
method changes its receiver to iterate over a
different map. The use of
<a href="/pkg/reflect/#MapIter.Reset"><code>MapIter.Reset</code></a>
allows allocation-free iteration
over many maps.
</p>
<p><!-- CL 352131 -->
A number of methods (
<a href="/pkg/reflect#Value.CanInt"><code>Value.CanInt</code></a>,
<a href="/pkg/reflect#Value.CanUint"><code>Value.CanUint</code></a>,
<a href="/pkg/reflect#Value.CanFloat"><code>Value.CanFloat</code></a>,
<a href="/pkg/reflect#Value.CanComplex"><code>Value.CanComplex</code></a>
)
have been added to
<a href="/pkg/reflect#Value"><code>Value</code></a>
to test if a conversion is safe.
</p>
<p><!-- CL 357962 -->
<a href="/pkg/reflect#Value.FieldByIndexErr"><code>Value.FieldByIndexErr</code></a>
has been added to avoid the panic that occurs in
<a href="/pkg/reflect#Value.FieldByIndex"><code>Value.FieldByIndex</code></a>
when stepping through a nil pointer to an embedded struct.
</p>
<p><!-- CL 341333 -->
<a href="/pkg/reflect#Ptr"><code>reflect.Ptr</code></a> and
<a href="/pkg/reflect#PtrTo"><code>reflect.PtrTo</code></a>
have been renamed to
<a href="/pkg/reflect#Pointer"><code>reflect.Pointer</code></a> and
<a href="/pkg/reflect#Pointer"><code>reflect.PointerTo</code></a>,
respectively, for consistency with the rest of the reflect package.
The old names will continue to work, but will be deprecated in a
future Go release.
</p>
</dd>
</dl><!-- reflect -->
<dl id="regexp"><dt><a href="/pkg/regexp/">regexp</a></dt>
<dd>
<p><!-- CL 354569 -->
TODO: <a href="https://golang.org/cl/354569">https://golang.org/cl/354569</a>: document and implement that invalid UTF-8 bytes are the same as U+FFFD
</p>
</dd>
</dl><!-- regexp -->
<dl id="strconv"><dt><a href="/pkg/strconv/">strconv</a></dt>
<dd>
<p><!-- CL 343877 -->
TODO: <a href="https://golang.org/cl/343877">https://golang.org/cl/343877</a>: reject surrogate halves in Unquote
</p>
</dd>
</dl><!-- strconv -->
<dl id="strings"><dt><a href="/pkg/strings/">strings</a></dt>
<dd>
<p><!-- CL 345849 -->
The new <a href="/pkg/strings/#Clone"><code>Clone</code></a> function copies the input
<code>string</code> without the returned cloned <code>string</code> referencing
the input string's memory.
</p>
<p><!-- CL 323318, CL 332771 -->
<a href="/pkg/strings/#Trim"><code>Trim</code></a>, <a href="/pkg/strings/#TrimLeft"><code>TrimLeft</code></a>,
and <a href="/pkg/strings/#TrimRight"><code>TrimRight</code></a> are now allocation free and, especially for
small ASCII cutsets, up to 10 times faster.
</p>
<p><!-- CL 359485 -->
The <a href="/pkg/strings/#Title"><code>Title</code></a> function is now deprecated. It doesn't
handle Unicode punctuation and language-specific capitalization rules, and is superseded by the
<a href="https://golang.org/x/text/cases">golang.org/x/text/cases</a> package.
</p>
<p><!-- CL 351710 -->
TODO: strings.Cut.
</p>
</dd>
</dl><!-- strings -->
<dl id="sync"><dt><a href="/pkg/sync/">sync</a></dt>
<dd>
<p><!-- CL 319769 -->
TODO: <a href="https://golang.org/cl/319769">https://golang.org/cl/319769</a>: add Mutex.TryLock, RWMutex.TryLock, RWMutex.TryRLock
</p>
</dd>
</dl><!-- sync -->
<dl id="syscall"><dt><a href="/pkg/syscall/">syscall</a></dt>
<dd>
<p><!-- CL 336550 -->
The new function <a href="/pkg/syscall/?GOOS=windows#SyscallN"><code>SyscallN</code></a>
has been introduced for Windows, allowing for calls with arbitrary number
of arguments. As a result,
<a href="/pkg/syscall/?GOOS=windows#Syscall"><code>Syscall</code></a>,
<a href="/pkg/syscall/?GOOS=windows#Syscall6"><code>Syscall6</code></a>,
<a href="/pkg/syscall/?GOOS=windows#Syscall9"><code>Syscall9</code></a>,
<a href="/pkg/syscall/?GOOS=windows#Syscall12"><code>Syscall12</code></a>,
<a href="/pkg/syscall/?GOOS=windows#Syscall15"><code>Syscall15</code></a>, and
<a href="/pkg/syscall/?GOOS=windows#Syscall18"><code>Syscall18</code></a> are
deprecated in favor of <a href="/pkg/syscall/?GOOS=windows#SyscallN"><code>SyscallN</code></a>.
</p>
<p><!-- CL 355570 -->
TODO: <a href="https://golang.org/cl/355570">https://golang.org/cl/355570</a>: add support for SysProcAttr.Pdeathsig on FreeBSD
</p>
</dd>
</dl><!-- syscall -->
<dl id="syscall/js"><dt><a href="/pkg/syscall/js/">syscall/js</a></dt>
<dd>
<p><!-- CL 356430 -->
TODO: <a href="https://golang.org/cl/356430">https://golang.org/cl/356430</a>: remove Wrapper interface
</p>
</dd>
</dl><!-- syscall/js -->
<dl id="testing"><dt><a href="/pkg/testing/">testing</a></dt>
<dd>
<p><!-- CL 343883 -->
TODO: <a href="https://golang.org/cl/343883">https://golang.org/cl/343883</a>: increase alternation precedence
</p>
<p><!-- CL 356669 -->
TODO: <a href="https://golang.org/cl/356669">https://golang.org/cl/356669</a>: skip extra -count iterations if there are no tests
</p>
</dd>
</dl><!-- testing -->
<dl id="text/template"><dt><a href="/pkg/text/template/">text/template</a></dt>
<dd>
<p><!-- CL 321490 -->
The <code>and</code> function no longer always evaluates all arguments; it
stops evaluating arguments after the first argument that evaluates to
false. Similarly, the <code>or</code> function now stops evaluating
arguments after the first argument that evaluates to true. This makes a
difference if any of the arguments is a function call.
</p>
</dd>
</dl><!-- text/template -->
<dl id="unicode/utf8"><dt><a href="/pkg/unicode/utf8/">unicode/utf8</a></dt>
<dd>
<p><!-- CL 345571 -->
The <a href="/pkg/unicode/utf8/#AppendRune"><code>AppendRune</code></a> function appends the UTF-8 new
encoding of a <code>rune</code> to a <code>[]byte</code>.
</p>
</dd>
</dl><!-- unicode/utf8 -->