The linker would catch them if gc succeeded,
but too often the cycle manifests as making the
current package and the imported copy of itself
appear as different packages, which result in
type signature mismatches that confuse users.

As a crutch, add the -p flag to say 'if you see an
import of this package, give up early'.  Results in
messages like (during gotest in sort):

export_test.go:7: import "sort" while compiling that package (import cycle)
export_test.go:7: import "container/heap": package depends on "sort" (import cycle)

Fixes #2042.

R=ken
CC=bradfitz, dsymonds, golang-dev
https://golang.org/cl/4972057

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/4961069

Verified with objdump -W.

R=alex.brainman, rsc
CC=golang-dev
https://golang.org/cl/4974061

Also add exp/regexp to build (forgot before).

At this point I am very confident in exp/regexp's
behavior.  It should be usable as a drop-in
replacement for regexp now.

Later CLs could introduce a CompilePOSIX
to get at traditional POSIX ``extended regular expressions''
as in egrep and also an re.MatchLongest method to
change the matching mode to leftmost longest
instead of leftmost first.  On the other hand, I expect
very few people to use either.

R=r, r, gustavo
CC=golang-dev
https://golang.org/cl/4990041

Note that this CL will break your existing code which uses
ParseCIDR.

This CL changes ParseCIDR("172.16.253.121/28") to return
the IP address "172.16.253.121", the network implied by the
network number "172.16.253.112" and mask "255.255.255.240".

R=rsc, borman
CC=golang-dev
https://golang.org/cl/4749043

R=golang-dev
CC=golang-dev, rsc
https://golang.org/cl/4975055

See http://research.swtch.com/2008/01/killing-quicksort.html for more
info.
Fixes #467.

R=r, rsc
CC=golang-dev
https://golang.org/cl/4591051

Extract Windows filenames correctly.
Don't remove receivers from method names.

Fixes #2227.

R=rsc
CC=golang-dev
https://golang.org/cl/4969059

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/4964066

R=rsc
CC=golang-dev
https://golang.org/cl/4950060

R=nigeltao
CC=golang-dev
https://golang.org/cl/4987041

Fixes #2225

R=rsc, nigeltao, dave
CC=bradfitz, golang-dev, mikioh.mikioh
https://golang.org/cl/4972056

It actually occurred with the previous weekly snapshot.

R=golang-dev, adg
CC=golang-dev
https://golang.org/cl/4961066

R=r
CC=golang-dev
https://golang.org/cl/4984052

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/4951066

Fixes #2235

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/4967056

- func f(int,) is a legal signature
- func f(...int,) is a legal signature

Defer checking for correct use of "..." with last
paremeter type to type checker instead of parser.

R=rsc
CC=golang-dev
https://golang.org/cl/4973059

There may be more fine-tuning down the line,
but this CL fixes the most pressing issue at
hand.

Also: gofmt -w src misc

Fixes #1524.

R=rsc, bradfitz
CC=golang-dev
https://golang.org/cl/4975053

Most web frameworks allow ; as a synonym for &,
following a recommendation in some versions of
the HTML specification.  Do the same.

Remove overuse of Split.

Move ParseQuery tests from package http to package url.

Fixes #2210.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/4973062

allocparams + tempname + compactframe
all knew about how to place stack variables.

Now only compactframe, renamed to allocauto,
does the work.  Until the last minute, each PAUTO
variable is in its own space and has xoffset == 0.

This might break 5g.  I get failures in concurrent
code running under qemu and I can't tell whether
it's 5g's fault or qemu's.  We'll see what the real
ARM builders say.

R=ken2
CC=golang-dev
https://golang.org/cl/4973057

Fixes #2129.

R=rsc
CC=golang-dev
https://golang.org/cl/4934049

Fixes #2232.

R=ken2
CC=golang-dev
https://golang.org/cl/4960054

- fixed performance bug that could lead to O(n^2) behavior
- performance improvement for ASCII case

R=r, r
CC=golang-dev
https://golang.org/cl/4956060

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/4950064

R=fullung, golang-dev, rsc
CC=golang-dev
https://golang.org/cl/4986041

R=golang-dev, rsc
CC=golang-dev, mike.rosset
https://golang.org/cl/4950062

There was a time (in the past) when this wasn't robust.

R=rsc, dvyukov
CC=golang-dev
https://golang.org/cl/4965058

Fixes #2219.

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/4950063

R=n13m3y3r
CC=golang-dev
https://golang.org/cl/4918050

R=golang-dev, dsymonds
CC=golang-dev
https://golang.org/cl/4963059

Fixes #2219.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/4960052

There's some ambiguity in the U{url: url} case as it could be
both a map or a struct literal, but given context it's more
likely a struct, so U{url: url_} rather than U{url_: url_}.
At least that was the case for me.

R=golang-dev, rsc, adg
CC=golang-dev
https://golang.org/cl/4972052

Fixes #2194.

R=rsc, alex.brainman, vcc.163, jp
CC=golang-dev
https://golang.org/cl/4977044

R=mikesamuel
CC=golang-dev
https://golang.org/cl/4968063

R=ken2
CC=golang-dev
https://golang.org/cl/4967052

Fixes Han-Wen's termite bug.

R=lvd
CC=golang-dev
https://golang.org/cl/4977052

- read search index files in groutine to avoid
  start-up failure on app engine because reading
  the files takes too long
- permit usage of search index files and indexer
- minor cosmetic cleanups

R=dsymonds
CC=golang-dev
https://golang.org/cl/4952050

Needed to ensure that finding the last boundary does not result in O(n^2)-like behavior.
Now prevents lookbacks beyond 31 characters across the board (starter + 30 non-starters).
composition.go:
- maxCombiningCharacters now means exactly that.
- Bug fix.
- Small performance improvement/ made code consistent with other code.
forminfo.go:
- Bug fix: ccc needs to be 0 for inert runes.
normalize.go:
- A few bug fixes.
- Limit the amount of combining characters considered in FirstBoundary.
- Ditto for LastBoundary.
- Changed semantics of LastBoundary to not consider trailing illegal runes a boundary
  as long as adding bytes might still make them legal.
trie.go:
- As utf8.UTFMax is 4, we should treat UTF-8 encodings of size 5 or greater as illegal.
  This has no impact on the normalization process, but it prevents buffer overflows
  where we expect at most UTFMax bytes.

R=r
CC=golang-dev
https://golang.org/cl/4963041

Interesting that Fprintf can do zero mallocs.
(Sprintf must allocate the returned string.)

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/4977049

No need for lexInsideAction to loop.
Fixes #2217.

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/4963054