directlyAssignable invoked rtype.Name() just to compare its result
to empty string. We really only need to check whether rtype has
name. It can be done much cheaper, by checking tflagNamed.

Benchmark: https://play.golang.org/p/V2BzESPuf2w
name                   old time/op  new time/op  delta
DirectlyAssignable-12  32.7ns ± 6%   6.6ns ± 6%  -79.80%  (p=0.008 n=5+5)

Fixes #32186

Change-Id: I1a2a167dbfddf319fba3015cb6a011bf010f99a8
Reviewed-on: https://go-review.googlesource.com/c/go/+/178518
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Don't skip closing parentheses of any kind after a missing
expression. They are likely part of the lexical construct
enclosing the expression.

Fixes #33386.

Change-Id: Ic0abc2037ec339a345ec357ccc724b7ad2a64c00
Reviewed-on: https://go-review.googlesource.com/c/go/+/188502Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Some constants were added above the initial copyright blurb, and then
later a new copyright blurb was added on top of that. So we wound up
with two header sections, one of which contained a useful comment that
became obscured. This commit fixes up that mistake.

Change-Id: I8b9b8c34495cdceae959e151e8ccdee3137f6ca4
Reviewed-on: https://go-review.googlesource.com/c/go/+/191841
Run-TryBot: Jason A. Donenfeld <Jason@zx2c4.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Quietly drop duplicate methods inherited from embedded interfaces if
they have an identical signature to existing methods.

Updates #6977.

Change-Id: I144151cb7d99695f12b555c0db56207993c56284
Reviewed-on: https://go-review.googlesource.com/c/go/+/187519
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

Move checkdupfields call into expandiface, and inline/simplify offmod.
More prep work for implementing #6977.

Change-Id: I958ae87f761ec25a8fa7298a2a3019eeca5b25ba
Reviewed-on: https://go-review.googlesource.com/c/go/+/187518Reviewed-by: Robert Griesemer <gri@golang.org>

Allows avoiding the Type.Fields call, which affects prevents
checkdupfields from being called at the more natural point during
dowidth.

Change-Id: I724789c860e7fffba1e8e876e2d74dcfba85d75c
Reviewed-on: https://go-review.googlesource.com/c/go/+/187517Reviewed-by: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Updates #33738

Change-Id: If0856d7c57ecfde08341c1aecb5e92361fd64f2b
Reviewed-on: https://go-review.googlesource.com/c/go/+/191217Reviewed-by: Andrew Bonventre <andybons@golang.org>
Run-TryBot: Andrew Bonventre <andybons@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes #33796

Change-Id: I9f6837be96410e96d004523c48bef95ee1427484
Reviewed-on: https://go-review.googlesource.com/c/go/+/191746Reviewed-by: Bryan C. Mills <bcmills@google.com>

The stack of delayed actions is grown by pushing a new action
on top with Checker.later. Checker.processDelayed processes
all actions above a top watermark and then resets the stack
to top.

Until now, pushed actions above the watermark were processed
in LIFO order. This change processes them in FIFO order, which
seems more natural (if an action A was delayed before an action
B, A should be processed before B for that stack segment).

(With this change, Checker.later could be used instead of
Checker.atEnd to postpone interface method type comparison
and then the specific example in issue #33656 does type-check.
However, in general we want interface method type comparisons
to run after all interfaces are completed. With Checker.later
we may still end up mixing interface completions and interface
method type comparisons in ways leading to other errors for
sufficiently convoluted code.)

Also, move Checker.processDelayed from resolver.go to check.go.

Change-Id: Id31254605e6944c490eab410553fff907630cc64
Reviewed-on: https://go-review.googlesource.com/c/go/+/191458Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Updates #6977.

Change-Id: I6eda4be550e7c7ea1e1bac3222850002d90a81a8
Reviewed-on: https://go-review.googlesource.com/c/go/+/190378Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Introduce a new list of final actions that is executed at the
end of type checking and use it to collect method type comparisons
and also map key checks.

Fixes #33656.

Change-Id: Ia77a35a45a9d7eaa7fc3e9e19f41f32dcd6ef9d9
Reviewed-on: https://go-review.googlesource.com/c/go/+/191418Reviewed-by: Alan Donovan <adonovan@google.com>

When creating a new interface via the exported API calls, a shared
empty and completed Interface value is returned if there are no
methods or embedded interfaces. This is a minor optimization and
matches the internal behavior when creating empty interfaces.

Since calling Interface.Complete is idempotent, and since there
are no other legitimate ways to create Interface values externally
but via NewInterface/NewInterfaceType calls, and completed Interfaces
are considered "immutable", this change is not expected to affect
clients. The only observable behavior that changed is the string
value for empty interfaces created via the above API calls; those
empty interfaces now don't show "incomplete" anymore even before
Interface.Complete is called. Except in special test cases, this
behavior is unlikely to affect clients.

Change-Id: Idf7f2cd112241c5b81a43b4544bbe3f2e003d8d8
Reviewed-on: https://go-review.googlesource.com/c/go/+/191417Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Quietly drop duplicate methods from embedded interfaces
if they have an identical signature to existing methods.

Instead of adjusting the prior syntax-based only method set
computation where methods don't have signature information
(and thus where de-duplication according to the new rules
would have been somewhat tricky to get right), this change
completely rewrites interface method set computation, taking
a page from the cmd/compiler's implementation. In a first
pass, when type-checking interfaces, explicit methods and
embedded interfaces are collected, but the interfaces are
not "expanded", that is the final method set computation
is done lazily, either when needed for method lookup, or
at the end of type-checking.

While this is a substantial rewrite, it allows us to get
rid of the separate (duplicate and delicate) syntactical
method set computation and generally simplifies checking
of interface types significantly. A few (esoteric) test
cases now have slightly different error messages but all
tests that are accepted by cmd/compile are also accepted
by go/types.

(This is a replacement for golang.org/cl/190258.)

Updates #6977.

Change-Id: Ic8b9321374ab4f617498d97c12871b69d1119735
Reviewed-on: https://go-review.googlesource.com/c/go/+/191257Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Specifying -halt in `go test -run Check$ -halt` causes a panic
upon encountering the first error. The stack trace is useful to
determine what code path issued the error.

Change-Id: I2e17e0014ba87505b01786980b98565f468065bf
Reviewed-on: https://go-review.googlesource.com/c/go/+/190257Reviewed-by: Matthew Dempsky <mdempsky@google.com>

The doc comments of both ServerContextKey and LocalAddrContextKey both suggest that context.WithValue can be used to access (get) properties of the server or connection. This PR fixes those comments to refer to Context.Value instead.

Change-Id: I4ed383ef97ba1951f90c555243007469cfc18d4d
GitHub-Last-Rev: 05bc3acf82322e3dc77abc7fa0412efe01a77eac
GitHub-Pull-Request: golang/go#33833
Reviewed-on: https://go-review.googlesource.com/c/go/+/191838Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

This reverts commit 739123c3.

Reason for revert: broke Windows and Plan 9 builders

Fixes #33828

Change-Id: I1d85c81549b1b34924fdd0ade8bf9406e5cf6555
Reviewed-on: https://go-review.googlesource.com/c/go/+/191742
Run-TryBot: Andrew Bonventre <andybons@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jonathan Amsterdam <jba@google.com>

This saves a redirect and makes the document more consistent.

Change-Id: Ib7f68b1967275c0c676a044314919449680297f3
Reviewed-on: https://go-review.googlesource.com/c/go/+/191537Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>

Change-Id: I7db3ad060773c9396fbe34e7bd52e7ccf6e5e52c
Reviewed-on: https://go-review.googlesource.com/c/go/+/191797Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>

Change-Id: I2bddee9b460d3875911859b49528a00d318f37fc
Reviewed-on: https://go-review.googlesource.com/c/go/+/184237Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>

Update vendored x/arch repo to pick up the fix of issue #33802.

This is done with the following commands:

$ cd $GOROOT/src/cmd
$ go get -d golang.org/x/arch@latest
go: finding golang.org/x/arch latest
go: downloading golang.org/x/arch v0.0.0-20190815191158-8a70ba74b3a1
go: extracting golang.org/x/arch v0.0.0-20190815191158-8a70ba74b3a1
$ go mod tidy
$ go mod vendor

Fixes #33802.

Change-Id: I0a44f1d83d6f573124cea1f099378b1c851f3feb
Reviewed-on: https://go-review.googlesource.com/c/go/+/191619
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>

Fixes #32815

Change-Id: Ia8ac9943a920a056ba7dbc69c1c70fa188f7aca8
Reviewed-on: https://go-review.googlesource.com/c/go/+/191578Reviewed-by: Robert Griesemer <gri@golang.org>

The -m flag is removed in Go 1.13. -d should be used instead.

Change-Id: Ia53764748309f16cb231e5ac6770400a73804484
Reviewed-on: https://go-review.googlesource.com/c/go/+/191621
Run-TryBot: Jay Conrod <jayconrod@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Update golang.org/x/net to v0.0.0-20190813141303-74dc4d7220e7 to import
the following security fix.

    commit 74dc4d7220e7acc4e100824340f3e66577424772
    Author: Filippo Valsorda <filippo@golang.org>
    Date:   Sun Aug 11 02:12:18 2019 -0400

    http2: limit number of control frames in server send queue

    An attacker could cause servers to queue an unlimited number of PING
    ACKs or RST_STREAM frames by soliciting them and not reading them, until
    the program runs out of memory.

    Limit control frames in the queue to a few thousands (matching the limit
    imposed by other vendors) by counting as they enter and exit the scheduler,
    so the protection will work with any WriteScheduler.

    Once the limit is exceeded, close the connection, as we have no way to
    communicate with the peer.

    Change-Id: I842968fc6ed3eac654b497ade8cea86f7267886b
    Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/525552Reviewed-by: Brad Fitzpatrick <bradfitz@google.com>

This change was generated with cmd/go and cmd/bundle:

$ go get -u golang.org/x/net
$ go mod tidy
$ go mod vendor
$ go generate net/http

Fixes CVE-2019-9512 and CVE-2019-9514
Fixes #33606

Change-Id: I464baf96175006aa101d65d3b0f6494f28a626ab
Reviewed-on: https://go-review.googlesource.com/c/go/+/190137Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>

Followon from a review comment in https://golang.org/cl/191078

Change-Id: If115b2ae0df5e5cb9babd60802947ddb687d56c2
Reviewed-on: https://go-review.googlesource.com/c/go/+/191219Reviewed-by: Ian Lance Taylor <iant@golang.org>

- Add doc to syscall.Errno (and syscall.ErrorString for plan9).

- Mention under `syscall` in release notes.

Fixes #33436.

Change-Id: I032ffebaa76ed67eb9d748e7645ca73f26144ea0
Reviewed-on: https://go-review.googlesource.com/c/go/+/191337Reviewed-by: Ian Lance Taylor <iant@golang.org>

As of Go 1.13rc1, TimeoutHandler supports the Flusher and Pusher interfaces and
this change corrects its documentation to say that.

Fixes #33769
Updates #29193

Change-Id: Ia0523f7f2e3dc1f8f0b68950b85a7bf81c4abe60
GitHub-Last-Rev: 5310d2c9608a1af2d3030a9573e920906c76744e
GitHub-Pull-Request: golang/go#33770
Reviewed-on: https://go-review.googlesource.com/c/go/+/191237Reviewed-by: Andrew Bonventre <andybons@golang.org>
Run-TryBot: Andrew Bonventre <andybons@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes #33750.
Updates #31197.

Change-Id: I26f63cef57e5f0eec85b84554c82f6d47b4f41a1
Reviewed-on: https://go-review.googlesource.com/c/go/+/191078Reviewed-by: Robert Griesemer <gri@golang.org>

Document that:
* math/big.Float.Parse
* math/big.Int.SetString
* strconv.ParseFloat
* strconv.ParseInt
* strconv.ParseUint
now accept underscores to group digits only if base = 0,
as per the Go 2 language changes.

Updates #32815

Change-Id: Id45bd803a18442436419739297e8aed0d32ca56c
Reviewed-on: https://go-review.googlesource.com/c/go/+/191077Reviewed-by: Robert Griesemer <gri@golang.org>

This reverts CL 151157.

CL 151157 introduced a crash when decoding into ",string" fields. It
came with a moderate speedup, so at this stage of the release cycle
let's just revert it, and reapply it in Go 1.14 with the fix in CL 190659.

Also applied the test cases from CL 190659.

Updates #33728

Change-Id: Ie46e2bc15224b251888580daf6b79d5865f3878e
Reviewed-on: https://go-review.googlesource.com/c/go/+/190909
Run-TryBot: Andrew Bonventre <andybons@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Andrew Bonventre <andybons@golang.org>

This CL makes the go command understand that
GOSUMDB=sum.golang.google.cn should connect
to that domain but expect to find a checksum database
signed by sum.golang.org there.

The host sum.golang.google.cn is not yet completely
configured; we hope it will be available in a few weeks.

Change-Id: Ie0fc4323f0c7084dda59bd3b45fc406717fa16d9
Reviewed-on: https://go-review.googlesource.com/c/go/+/191137
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Andrew Bonventre <andybons@golang.org>

Fixes #33720
Updates #14295

Change-Id: I9cb6e02bcaccd7971057315163d8810157d465bd
Reviewed-on: https://go-review.googlesource.com/c/go/+/190907
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>

The docs refer to "the last two paragraphs", but in fact should refer to
the first two of the previous three paragraphs. Moved up the out of place
paragraph.

Updates #14295

Change-Id: I066da7a665bc6754d246782b941af214a385017a
Reviewed-on: https://go-review.googlesource.com/c/go/+/190839Reviewed-by: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: I75619feced842b8ca509ee08e01b63258c5e87ca
Reviewed-on: https://go-review.googlesource.com/c/go/+/190757Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Currently test build fails with:

$ go test -tags=gofuzz encoding/json
encoding/json/fuzz.go:36:4: Println call has possible formatting directive %s
FAIL	encoding/json [build failed]

Change-Id: I23aef44a421ed0e7bcf48b74ac5a8c6768a4841b
Reviewed-on: https://go-review.googlesource.com/c/go/+/190698
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

CL 131196 optimized Time.Sub, but was reverted because
it incorrectly computed the nanoseconds in some edge cases.
This CL adds a test case to enforce the correct behavior
so that a future optimization does not break this again.

Updates #17858
Updates #33677

Change-Id: I596d8302ca6bf721cf7ca11cc6f939639fcbdd43
Reviewed-on: https://go-review.googlesource.com/c/go/+/190524
Run-TryBot: Joe Tsai <thebrokentoaster@gmail.com>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Andrew Bonventre <andybons@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

CL 162337 changed go/ast to better handle block comments,
but was reverted because it introduced an off-by-one bug.
This CL adds a test case to enforce the correct behavior
so that future changes do not break this again.

Updates #18929
Updates #33538

Change-Id: I2d25c139d007f8db1091b7a48b1dd20c584e2699
Reviewed-on: https://go-review.googlesource.com/c/go/+/190523
Run-TryBot: Joe Tsai <thebrokentoaster@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

This reverts commit CL 131196 because there is a bug
in the calculation of nanoseconds.

Fixes #33677

Change-Id: Ic8e94c547ee29b8aeda1b9a5cb9764dbf47b14b4
Reviewed-on: https://go-review.googlesource.com/c/go/+/190497
Run-TryBot: Andrew Bonventre <andybons@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Reviewed-by: Andrew Bonventre <andybons@golang.org>

Change-Id: I88b7e085fc70f9c021788d364099f5bc6b705ba8
Reviewed-on: https://go-review.googlesource.com/c/go/+/190438Reviewed-by: Filippo Valsorda <filippo@golang.org>

Change-Id: I0daab6cd347e1fc0066e516f02c33f1b63e3f1a3
Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/526992Reviewed-by: Filippo Valsorda <valsorda@google.com>
(cherry picked from commit 305f6dc3)
Reviewed-on: https://go-review.googlesource.com/c/go/+/190437Reviewed-by: Filippo Valsorda <filippo@golang.org>

When calling a function obtained from reflect.Value.Method (or
MethodByName), we copy the arguments from the caller frame, which
does not include the receiver, to a new frame to call the actual
method, which does include the receiver. Here we need to align
the first (non-receiver) argument. As the receiver is pointer
sized, it is generally naturally aligned, except on amd64p32,
where the argument can have larger alignment, and this aligning
becomes necessary.

Fixes #33628.

Change-Id: I5bea0e20173f06d1602c5666d4f334e3d0de5c1e
Reviewed-on: https://go-review.googlesource.com/c/go/+/190297
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>