SI-6448 Collecting the spoils of PartialFun#runWith

Avoids calling both `isDefinedAt` and `apply`. This pathological
case that would benefit the most looks like:

  xs collect {
    case x if {expensive(); true} => x
  }

The typical change looks like:

-    for (x <- this) if (pf.isDefinedAt(x)) b += pf(x)
+    foreach(pf.runWith(b += _))

Incorporates feedback provided by Pavel Pavlov:

  https://github.com/retronym/scala/commit/ef5430

A few more opportunities for optimization are noted in the
`Pending` section of the enclosed test. `Iterator.collect`
would be nice, but a solution eludes me.

Calling the guard less frequently does change the behaviour
of these functions in an obervable way, but not contravene
the documented semantics. That said, there is an alternative
opinion on the comment of the ticket:

  https://issues.scala-lang.org/browse/SI-6448
Merge pull request #1574 from jsuereth/merge-2.10.0

Merge 2.10.0-RC2 into 2.10.x
SI-6616 Check that unsafe operations are only called on the presentation compiler thread.

The method that checks the actual constraint is @elidable, expecting it to be used
for nightly builds but stripped-off in release builds. This way we don't lose any
performance, but 'fail-fast' in IDE nightlies.

This assumes that release builds will have at least `-Xelide-below ASSERTION`, but
this pull request does not do that.
comment / question in typers
SI-6539 Annotation for methods unfit for post-typer ASTs

Motivated by the `.value` method in the SBT task-syntax branch,
which should only be called within the context of the argument
to a setting initialization macro.

The facility is akin to a fatal deprecation.
Optimize primitive Array(e1, ..., en)

Expands an existing optimization for reference arrays to
apply to primitives, as well.

Fixes one aspect of SI-6247.
More principled tree copying.

Canonical > home-spun.
Refine @compileTimeOnly

 - Don't default the message, and show it exclusively.
 - Fix cut-and-pasto in the @since tag
 - Be tolerant if the annotaion class is missing, as seems to
   have been the case compiling the continuations plugin.
 - s/\t/  / in the test file to show the errors are positioned
   correctly.
 - Use defensive getOrElse
show developer guidelines on opening pull request

Includes "Improvements and typo fixes to CONTRIBUTING.md" by @heathercmiller
as well as feedback from @retronym.
show developer guidelines on opening pull request

Includes "Improvements and typo fixes to CONTRIBUTING.md" by @heathercmiller
as well as feedback from @retronym.
Associate correct names to e-mails, correct or not

This is used by git log to produce names with certain formats, and
is used by the release notes tool as well. Helpful if you have commits
with Author not set correctly, as did I.

I'm also including Aleksandar Prokopec and his friend Aleksandar Pokopec,
as well as Pavel Pavlov, both of whom have commits appearing under more
than one name.

I'm not including others who have not set a full name, but don't have
commits appearing under more than one name.
Update tools/epfl-publish

Currently, during each Scala nightly build, the epfl-publish script rsyncs the resulting dists/archives to the repository machine (chara).

Now, as a result of a change introduced a while back, dists/archives/ now also contains a symbolic link, created at the end of the build when the targets "pack-archives.latest.*" are invoked (in src/build/pack.xml). That was introduced in:

scala/scala@506bcfe71c93160ebfa0ca9b8b170b4b54e844e9
scala/scala@cb99853c8655686dae1288cbcd44a42cf1ea6609

This link, created in dists/archives/, is copied over as-is at the end of the rsync to chara by epfl-publish. On chara, however, the link points to an invalid target (the path is absolute).

Separately, the repository directory on chara is rsync'd every 30 minutes over to the machine that serves www.scala-lang.org, via cron. Rsynch finds that the link target does not exist, and generates an email with the crontab log, which is then duly sent to a system mailbox. Every 30 minutes. Since March. Needless to say, the mailbox is pretty large by now.

The fix is trivial, but this needs to be included in all the branches that are tested during the nightly. Since RC2 has just been cut, and the code frozen, I'm not sure how this change can be included without disruption; therefore, I'll just send a pull request on 2.10.0-wip, and let Josh/Paul take the appropriate steps.
Fix type of the custom `ClassTag` in `PatternMatching.scala`

In fb315772 custom ClassTags were introduced to optimize array
creation in hot places. The idea was that if `Array[T]` is allocated
through `ClassTag[T]` (which is essentially a factory for Array[T])
we would introduce a custom class implementing `ClassTag[T]` interface
and would have specialized array allocation instruction instead of
having reflective call as it's being done with default (compiler
synthesized) implementation of `ClassTag[T]`.

In case of `PatternMatching.scala` I made a mistake of providing
`ClassTag[Array[Clause]]` instead of `ClassTag[Clause]` so that value
would never be used and compiler still would resolve implicit through
default mechanism. This has been discovered thanks to @paulp's work
on unused value detection.

Review by @paulp.
SI-6632 SI-6633 Fixes issues and data corruption in ListBuffer

 - Disallow negative positions for ListBuffer#insert/insertAll/update
 - Fix data corruption issue in ListBuffer#insert
SI-6646 Fix regression in for desugaring.

The early check in the parser of pattern irrefutability,
added in c82ecab, failed to consider InitCaps and
`backquoted` identifiers.
SI-6644 Account for varargs in extmethod forwarder

Which sounded difficult, so instead I offshored the work
to the friendly republic of TreeGen.
SI-6640 Better reporting of deficient classpaths.

In a55788e, StubSymbols were introduced to fail-slow when
the classpath was deficient. This allowed compilation to
succeed in cases when one didn't actually use the part of
class A which referred to some missing class B.

But a few problems were introduced.

Firstly, when the deferred error eventually happened, it was
signalled with abort(msg), rather than through a thrown
MissingRequirementError. The latter is desirable, as it doesn't
lead to printing a stack trace.

Second, the actual error message changed, and no longer
included the name of the class file that refers to the missing
class.

Finally, it seems that we can end up with a stub term symbol
in a situation where a class symbol is desired. An assertion
in the constructor of ThisType throws trips when calling .isClass,
before the useful error message from StubSymbol can be emitted.

This commit addresses these points, and rewords the error
a little to be more accessible. The last point is the most fragile
in this arrangement, there might be some whack-a-mole
required to find other places that also need this.
I don't see a clean solution for this, but am open to suggestions.

We should really build a facility in partest to delete
specified classfiles between groups in separate compilation
tests, in order to have tests for this. I'll work on that as a followup.

For now, here's the result of my manual testing:

[info] Set current project to default-821d14 (in build file:/Users/jason/code/scratch1/)
> compile

[info] Compiling 1 Scala source to /Users/jason/code/scratch1/target/scala-2.10/classes...
[error]
[error]      while compiling: /Users/jason/code/scratch1/test.scala
[error]         during phase: typer
[error]      library version: version 2.10.0-RC2
[error]     compiler version: version 2.10.0-RC2
...
[error]   last tree to typer: Ident(SwingWorker)
[error]               symbol: <none> (flags: )
[error]    symbol definition: <none>
[error]        symbol owners:
[error]       context owners: object Test -> package <empty>
 ...
[error] uncaught exception during compilation: java.lang.AssertionError
[trace] Stack trace suppressed: run last compile:compile for the full output.
[error] (compile:compile) java.lang.AssertionError: assertion failed: value actors
[error] Total time: 2 s, completed Nov 10, 2012 3:18:34 PM
>
> set scalaHome := Some(file("/Users/jason/code/scala/build/pack"))
[info] Defining *:scala-home
[info] The new value will be used by no settings or tasks.
[info] Reapplying settings...
[info] Set current project to default-821d14 (in build file:/Users/jason/code/scratch1/)
^[compile
[info] Compiling 1 Scala source to /Users/jason/code/scratch1/target/scala-2.10/classes...
[error] /Users/jason/code/scratch1/test.scala:4: A signature in SwingWorker.class refers to term actors in package scala which is missing from the classpath.
[error] object Test extends SwingWorker
[error]                     ^
[error] one error found
[error] (compile:compile) Compilation failed
[error] Total time: 2 s, completed Nov 10, 2012 3:18:45 PM
Refine the message and triggering of MissingRequirementError.

 - To force a failure of the stub, call a new method `failIfStub`
   rather than `info`.
 - Offer a broader range of potential root causes in the
   error message.
-Yshow-trees-compact respects other options

The aforementioned tree printer now respects other tree printing
options such as -uniqid and -Xprint-types.

This helps debugging reify, which uses `nodePrinters`, not `showRaw`
to print its trees, because back then `showRaw` didn't exist yet.
Merge pull request #1602 from gkossakowski/wrong-implicit-classTag

Fix type of the custom `ClassTag` in `PatternMatching.scala`