[nomaster] teaches toolbox about -Yrangepos

Unlike in master, in 2.10.x enabling -Yrangepos requires instantiating
Global with mixed in RangePositions trait.

Same story for toolboxes. Just setting Yrangepos is not enough - one
needs to mix in RangePositions into ToolboxGlobal. I didn’t know that
back then, so now I’m fixing the oversight.

The commit is marked as [nomaster], because -Yrangepos doesn’t need
special treatment in master.
Deprecates Par*View and Gen*View

In 2.12, this gives us the option to move the code from
Gen*View down into *View. If we don't do something more
drastic with views, which inertia and history suggests
is a real possibility, we can at least shed a little of
the implementation.

These abstractions are *only* used to share implementation;
there is no `view` method available on, for instance, `GenSeq`
that lets one abstract over parallel/sequential collections
while spawning views.

  scala> (List(1): collection.GenSeq[Int]).view
  <console>:8: error: value view is not a member of scala.collection.GenSeq[Int]
                (List(1): collection.GenSeq[Int]).view
                                                  ^
Let's keep it that way.

I suspect that views over parallel collections exist not because
they were the most sought after feature, but rather because the
initial incarnatin of parallel collections used to live undernead
TraversableOnce, and hence were obligated to implement `def view`.

This change will give us deprecation warnings in the non deprecated
places that extend `Gen*View` (three, by my count) in the interim.
There are ways to avoid this, but they aren't particularly appealing.
Removes Gen*View and Par*View

 - code that used to be inherited in *View is now inlined
 - the `view` methods on `ParIteratoa` and `ParSeq` now
   convert to sequential collections, and are deprecated
   asking the user to do this explicitly in the future.

Should be largely source compatible with 2.10.x, on the assumption
that the removed classes, while being public, were internal
implementation details.

A few tests used now-removed classes to demonstrate compiler crashes.
I managed to confirm that after my decoupling, t4365 still exercises
the bug:

	% qbin/scalac test/files/pos/t4365/*.scala
	warning: there were 2 deprecation warning(s); re-run with -deprecation for details
	one warning found
	% scalac-hash 7b4e450 test/files/pos/t4365/*.scala
	warning: there were 2 deprecation warning(s); re-run with -deprecation for details
	one warning found
	% scalac-hash 7b4e450~1 test/files/pos/t4365/*.scala 2<&1 | grep -i wrong
	error: something is wrong: cannot make sense of type application
	something is wrong: cannot make sense of type application
	something is wrong: cannot make sense of type application

I didn't manage to do the same for specializes-sym-crash.scala,
and instead just made it compile.
Merge pull request #3196 from retronym/topic/3190-fixup

Corrects positions for Dynamic calls
Merge pull request #3180 from xeno-by/topic/toolbox-rangepos

teaches toolbox about -Yrangepos
SI-7548 askTypeAt returns the same type whether the source was fully or targeted type-checked

When asking for targeted typecheck, the located tree may have overloaded types
is the source isn't yet fully typechecked (e.g., a select tree for an
overloaded method). This is problematic as it can lead to unknown 'hovers',
broken hyperlinking that suddenly starts working, unresolved ScalaDoc comments,
and similar, in the Scala IDE.

With this commit we are hardening the contract of `askTypeAt` to return the
same type whether the file was fully type-checked or targeted type-checked.
This is done by preventing the typechecker to stop too early if the `located`
tree has an overloaded type. Furthermore, I'm assuming that if `located.tpe`
is of type `OverloadedType`, by letting the compiler carry-on the typechecking,
the `located.tpe` will eventually be resolved to a non-overloaded type. Said
otherwise, I expect the targeted typechecking will always terminate (if my
reasoning isn't sound, please say so).

The test provided with this commit demonstrates the new behavior (the position
used to execute the test is resolved to the `foo` method's call). In fact,
before this commit, executing the test returned the following:

    (x: Int, y: String)Unit <and> (x: String)Unit <and> (x: Int)Unit

Showing that the tree's type is an overloaded type. The ambiguity is fixed by
this commit, and in fact the test's output is now:

    (x: Int)Unit
SI-7548 Test to demonstrate residual exploratory typing bug

We shouldn't observe tree types under silent mode.

The enclosed test is a standalone version of `1 + BigInt(2)`,
a standard example of exploratory typing in Scala. Once we determine
that none of the `+` methods in `Int` accepts (possibly implicitly
coerced `BigInt`), we have to backtrack and look for a view from
`Int => { +(_: BigInt): ? }`.

The next commit will correct the problem.
SI-7458 Pres. compiler must not observe trees in silent mode

Otherwise we can think that `+` in `1 + BigInt(2)` refers
to a method in `Int`.

In general, this protects the IDE from observing results from
"exploratory" typing which is discarded as the compiler backtracks
to another possibility.

This protection subsumes the condition that checked for overloaded
types: presentation/t7458 now passes without this.
Merge pull request #3208 from dotta/si-7548-on-2.10

 askTypeAt returns the same type for full/ targeted typecheck (2.10.x)
SI-6913 Fixing semantics of Future fallbackTo to be according to docs

Origin: viktorklang@1bbe854
Merge pull request #3181 from heathermiller/issue/6913

SI-6913 Reapplies a lost fix by @viktorklang
SI-7982 Changed contract of askLoadedType to unload units by default

The rationale for not keeping units loaded by default is that the more
units are loaded, the slower is background compilation. For instance, in
the Scala IDE for Eclipse (which uses the presentation compiler),
typechecking occurs every time the reconciler kicks-in (~500millis after
you stop typing), hence it is important that units are not kept loaded
unless strictly necessary (for some extra information about this, see
https://www.assembla.com/spaces/scala-ide/tickets/1001388)

While I agree that using a boolean argument (`keepLoaded`) for deciding
if a unit should be loaded isn't a great design, other methods in
`CompilerControl` also have a keepLoaded parameter, so at least we have
some consistency. For the future, I'm thinking we should be able to
remove the `keepLoaded` flag altogether, and change the implementation
of `askLoadedType` to preserve the same units loaded in the presentation
compiler before and after its execution. Basically, if you want a unit
to be kept loaded, you should call `askReload` first, and then
`askLoadedType`. However, to reduce impact, I think the changes carried
by this commit will help us estimate if the solution I just outlined is
viable (because `askLoadeType` won't be keeping units loaded by default,
which wasn't the case with the former implementation).

(While the patch was mostly contributed by @huitseeker, @dotta has edited the
commit message to preserve the comments in the PR
https://github.com/scala/scala/pull/3209)
Merge commit 'da73950' into merge-2.10.x-to-master
Merge commit '7c1d114' into merge-2.10.x-to-master

Conflicts:
	src/compiler/scala/tools/nsc/interactive/Global.scala
Merge commit '7d74884' into merge-2.10.x-to-master

Conflicts:
	test/files/jvm/scala-concurrent-tck.scala
Merge commit '7d41094' into merge/2.10.x-and-pr-3209-to-master

Conflicts:
	src/interactive/scala/tools/nsc/interactive/CompilerControl.scala
Merge pull request #3191 from retronym/ticket/deprecate-par-view

Remove parallel collection views and, with them, Gen*View
Merge pull request #3228 from retronym/merge/2.10.x-and-pr-3209-to-master

Merge #3209 and 2.10.x to master
undeprecates c.parse

We never thought that c.parse is going to be completely subsumed by
quasiquotes, but hoped that the use cases that are going to be lost
aren’t going to be noticed by anyone.

Unfortunately, this isn’t the case, so I’m undeprecating c.parse until
we get a better story for those for whom quasiquotes are not enough.
Merge pull request #3231 from xeno-by/topic/undeprecate-parse

undeprecates c.parse