SI-6502 Remove cp command as unworkable

People expect to change the class path midstream.

Let's disabuse them by removing the broken command.

The internals are deprecated.
SI-6502 Repl reset/replay take settings args

The reset and replay commands take arbitrary command line args.
When settings args are supplied, the compiler is recreated.

For uniformity, the settings command performs only the usual
arg parsing: use -flag:true instead of +flag, and clearing a
setting is promoted to the command line, so that -Xlint: is not
an error but clears the flags.

```
scala> maqicode.Test main null
<console>:8: error: not found: value maqicode
              maqicode.Test main null
              ^

scala> :reset -classpath/a target/scala-2.11/sample_2.11-1.0.jar
Resetting interpreter state.
Forgetting all expression results and named terms: $intp

scala> maqicode.Test main null
Hello, world.

scala> val i = 42
i: Int = 42

scala> s"$i is the loneliest numbah."
res1: String = 42 is the loneliest numbah.

scala> :replay -classpath ""
Replaying: maqicode.Test main null
Hello, world.

Replaying: val i = 42
i: Int = 42

Replaying: s"$i is the loneliest numbah."
res1: String = 42 is the loneliest numbah.

scala> :replay -classpath/a ""
Replaying: maqicode.Test main null
<console>:8: error: not found: value maqicode
              maqicode.Test main null
              ^

Replaying: val i = 42
i: Int = 42

Replaying: s"$i is the loneliest numbah."
res1: String = 42 is the loneliest numbah.
```

Clearing a clearable setting:
```
scala> :reset -Xlint:missing-interpolator
Resetting interpreter state.

scala> { val i = 42 ; "$i is the loneliest numbah." }
<console>:8: warning: possible missing interpolator: detected interpolated identifier `$i`
              { val i = 42 ; "$i is the loneliest numbah." }
                             ^
res0: String = $i is the loneliest numbah.

scala> :reset -Xlint:
Resetting interpreter state.
Forgetting this session history:

{ val i = 42 ; "$i is the loneliest numbah." }

scala> { val i = 42 ; "$i is the loneliest numbah." }
res0: String = $i is the loneliest numbah.

```
Add color to severity in REPL reporter

* Errors are red
* Warnings are yellow
SI-6192  Range: to, until and end are confusing

Added some documentation explaining what the role of `end` is.
SI-8870 Fix markup errors in the Types section of the spec

Bad: `T'_n`
Good: `T_n'`
Increase REPL startup timeout to avoid test failures

Under load on Jenkins, we've been seeing:

```
% diff /localhome/jenkins/a/workspace/scala-nightly-auxjvm-2.12.x/jdk/jdk7/label/auxjvm/test/files/run/t4542-run.log /localhome/jenkins/a/workspace/scala-nightly-auxjvm-2.12.x/jdk/jdk7/label/auxjvm/test/files/run/t4542.check
@@ -2,75 +2,14 @@ Type in expressions to have them evaluated.
 Type :help for more information.

 scala> @deprecated("foooo", "ReplTest version 1.0-FINAL") class Foo() {
 java.util.concurrent.TimeoutException: Futures timed out after [60 seconds]
 	at scala.concurrent.impl.Promise$DefaultPromise.ready(Promise.scala:219)
 	at scala.concurrent.impl.Promise$DefaultPromise.ready(Promise.scala:153)
 	at scala.concurrent.Await$$anonfun$ready$1.apply(package.scala:95)
 	at scala.concurrent.Await$$anonfun$ready$1.apply(package.scala:95)
 	at scala.concurrent.BlockContext$DefaultBlockContext$.blockOn(BlockContext.scala:53)
 	at scala.concurrent.Await$.ready(package.scala:95)
 	at scala.tools.nsc.interpreter.ILoop.processLine(ILoop.scala:431)
 	at scala.tools.nsc.interpreter.ILoop.loop(ILoop.scala:457)
 	at scala.tools.nsc.interpreter.ILoop$$anonfun$process$1.apply$mcZ$sp(ILoop.scala:875)
```

This commit bumps the timeout up be a factor of ten to try to
restore that comforting green glow to https://scala-webapps.epfl.ch/jenkins/view/2.N.x
SI-8845 Control flow pot-pourri crashes GenASM, but not -BCode

Given that we'll switch to GenBCode in 2.12, the test case
showing the bug is fixed under that option is all I plan to
offer for this bug.

The flags file contains `-Ynooptimize` to stay locked into
`GenBCode`.
SI-8217 allow abstract type members in objects

Previously, abstract type members were allowed in objects only when inherited,
but not when declared directly. This inconsistency was not intended. In dotty,
abstract type members are allowed in values and represent existentials; so upon
discussion, it was decided to fix things to conform to dotty and allow such type
members. Adriaan also asked to keep rejecting abstract type members in methods
even though they would conceivably make sense.

Discussions happened on #3407, scala/scala-dist#127.
This code is improved from #3442, keeps closer to the current logic, and passes tests.

Existing tests that have been converted to `pos` tests show that
this works, and a new test has been added to show that local
aliases (ie term-owned) without a RHS are still rejected.
SI-8267 Avoid existentials after polymorphic overload resolution

... which can be introduced by `memberType` for methods
with parameter types dependent on class type parameters.

Here's an example of such a type:

```
scala> class Bippy { trait Foo[A] }
defined class Bippy

scala> final class RichBippy[C <: Bippy with Singleton](val c1: C) {
     |   def g[A](x: A)(ev: c1.Foo[A]): Int = 2
     | }
defined class RichBippy

scala> :power
** Power User mode enabled - BEEP WHIR GYVE **
** :phase has been set to 'typer'.          **
** scala.tools.nsc._ has been imported      **
** global._, definitions._ also imported    **
** Try  :help, :vals, power.<tab>           **

scala> val g = typeOf[RichBippy[_]].member(TermName("g"))
g: $r.intp.global.Symbol = method g

scala> val c = new Bippy
c: Bippy = Bippy@92e2c93

scala> val memberType = typeOf[RichBippy[c.type]].memberType(g)
memberType: $r.intp.global.Type = ([A](x: A)(ev: _7.c1.Foo[A])Int) forSome { val _7: RichBippy[c.type] }

```

In this example, if we were to typecheck the selection
`new RichBippy[c.type].g` that existential type would be short lived.

Consider this approximation of `Typer#typedInternal`:

```scala
val tree1: Tree = typed1(tree, mode, ptWild)
val result = adapt(tree1, mode, ptPlugins, tree)
```

Given that `tree1.tpe` is not an overloaded, adapt will find its
way to:

```
  case tp if mode.typingExprNotLhs && isExistentialType(tp) =>
    adapt(tree setType tp.dealias.skolemizeExistential(context.owner, tree), mode, pt, original)
```

Which would open the existential as per:

```
scala> memberType.skolemizeExistential
res2: $r.intp.global.Type = [A](x: A)(ev: _7.c1.Foo[A])Int
```

However, if do have overloaded alternatives, as in the test case,
we have to remember to call `adapt` again *after* we have picked
the winning alternative.

We actually don't have a centralised place where overload resolution
occurs, as the process differs depending on the context of the
selection. (Are there explicit type arguments? Inferred type
arguments? Do we need to use the expected type to pick a winner?)

This commit finds the existing places that call adapt after
overloade resolution and routes those calls through a marker
method. It then adds one more call to this in `inferPolyAlternatives`,
which fixes the bug.
Revert "Disable flaky presentation compiler test."

This reverts commit 8986ee4fd56c53d563165d992185c6c532f35790.

Scaladoc seems to work reliably for 2.11.x. We are using it in the IDE builds and haven't noticed any
flakiness, so we'd like to get reinstate this test.
Make Scaladoc actually exit with non-zero exit code in case of errors,
as its docs say it does.
SI-8291 Fix implicitNotFound message with type aliases

This pattern of code is typically a bug:

    if (f(tp.typeSymbol)) {
       g(tp.typeArgs)
    }

Intead, one needs to take the base type of `tp` wrt `tp.typeSymbol`.

This commit does exactly that when formatting the `@implicitNotFound`
custom error message.

Patch found on the back of an envelope in the handwriting of @adriaanm
SI-7746 patmat: fix non-determinism, infeasible counter examples
Fixes non-determinism within the DPLL algorithm and disallows
infeasible counter examples directly in the formula.

The function to compute all solutions was flawed and thus only
returned a subset of the solutions. The algorithm would stop too soon
and thus depending on the ordering of the symbols return more or less
solutions. I also added printing a warning when the search was stopped
because the max recursion depth was reached. This is very useful as an
explanation of spuriously failing regression tests, since less counter
examples might be reported. In such a case the recursion depth should
be set to infinite by adding `-Ypatmat-exhaust-depth off`.

The mapping of the solutions of the DPLL algorithm to counter examples
has been adapted to take the additional solutions from the
solver into account:

Consider for example `t8430.scala`:

```Scala
sealed trait CL3Literal
case object IntLit extends CL3Literal
case object CharLit extends CL3Literal
case object BooleanLit extends CL3Literal
case object UnitLit extends CL3Literal

sealed trait Tree
case class LetL(value: CL3Literal) extends Tree
case object LetP extends Tree
case object LetC extends Tree
case object LetF extends Tree

object Test {
  (tree: Tree) => tree match {case LetL(CharLit) => ??? }
}
```

This test contains 2 domains,  `IntLit, CharLit, ...` and `LetL, LetP, ...`,
the corresponding formula to check exhaustivity looks like:

```
    V1=LetC.type#13    \/ V1=LetF.type#14 \/    V1=LetL#11     \/  V1=LetP.type#15    /\
 V2=BooleanLit.type#16 \/  V2=CharLit#12  \/ V2=IntLit.type#17 \/ V2=UnitLit.type#18  /\
      -V1=LetL#11      \/ -V2=CharLit#12  \/                   \/
```

The first two lines assign a value of the domain to the scrutinee (and
the correponding member in case of `LetL`) and prohibit the counter
example `LetL(CharLit)` since it's covered by the pattern match. The
used Boolean encoding allows that scrutinee `V1` can be equal to
`LetC` and `LetF` at the same time and thus, during enumeration of all
possible solutions of the formula, such a solution will be found,
since only one literal needs to be set to true, to  satisfy that
clause. That means, if at least one of the literals of such a clause
was in the `unassigned` list of the DPLL procedure, we will get
solutions where the scrutinee is equal to more than one element of the
domain.

A remedy would be to add constraints that forbid both literals
to be true at the same time. His is infeasible for big domains (see
`pos/t8531.scala`), since we would have to add a quadratic number of
clauses (one clause for each pair in the domain). A much simpler
solution is to just filter the invalid results. Since both values for
`unassigned` literals are explored, we will eventually find a valid
counter example.
Cleanup `LinkedHashSet` fixes and replace them with `Set` (i.e., back
to initial implementation).

Assuming that the DPLL procedure does not run into max recursion
depth, that workaround is not needed anymore, since the non-
determinism has been fixed.
SI-8843 AbsFileCL acts like a CL

Let the AbstractFileClassLoader override just the usual suspects.

Normal delegation behavior should ensue.

That's instead of overriding `getResourceAsStream`, which was intended
that "The repl classloader now works more like you'd expect a classloader to."
(Workaround for "Don't know how to construct an URL for something which exists
only in memory.")

Also override `findResources` so that `getResources` does the obvious thing,
namely, return one iff `getResource` does.

The translating class loader for REPL only special-cases `foo.class`: as
a fallback, take `foo` as `$line42.$read$something$foo` and try that class file.
That's the use case for "works like you'd expect it to."

There was a previous fix to ensure `getResource` doesn't take a class name.
The convenience behavior, that `classBytes` takes either a class name or a resource
path ending in ".class", has been promoted to `ScalaClassLoader`.
SI-8731 warning if @switch is ignored

For matches with two or fewer cases, @switch is ignored. This should
not happen silently.
SI-8888 Avoid ClassFormatError under -Ydelambdafy:method

The pattern matcher phase (conceivably, among others) can generate
code that binds local `Ident`s symbolically, rather than according
to the lexical scope. This means that a lambda can capture more than
one local of the same name.

In the enclosed test case, this ends up creating the following
tree after delambdafy

    [[syntax trees at end of                delambdafy]] // delambday-patmat-path-dep.scala
    matchEnd4({
      case <synthetic> val x1: Object = (x2: Object);
      case5(){
        if (x1.$isInstanceOf[C]())
          {
            <synthetic> val x2#19598: C = (x1.$asInstanceOf[C](): C);
            matchEnd4({
              {
                (new resume$1(x2#19598, x2#19639): runtime.AbstractFunction0)
              };
              scala.runtime.BoxedUnit.UNIT
            })
          }
        else
          case6()
      };
      ...
    })
    ...
    <synthetic> class resume$1 extends AbstractFunction0 {
      <synthetic> var x2: C = null;
      <synthetic> var x2: C = null;
      ...
    }

After this commit, the var members of `resume$1` are given fresh
names, rather than directly using the name of the captured var:

    <synthetic> var x2$3: C = null;
    <synthetic> var x2$4: C = null;
Update stripPrefix/StringLike docs to talk about no op case

Incorporate review comments by Som Snytt.
Avoid ClassfileAnnotation warning for @SerialVersionUID

@SerialVersionUID is special-cased, the warning doesn't apply.

Related to SI-7041.
SI-4788/SI-5948 Respect RetentionPolicy of Java annotations

Note that I removed the check to ignore @deprecated:
- @deprecated extends StaticAnnotation, so they aren't
  supposed to show up in the RuntimeInvisibleAnnotation
  attribute anyway, and the earlier check for "extends
  ClassfileAnnotationClass" makes this check superflous
  anyway.
- Otherwise, if @deprecated was extending
  ClassfileAnnotationClass it would seem inconsistent
  that we don't emit @deprecated, but would do so for
  @deprecatedOverriding, @deprecatedInheritance, etc.
  Anyway, due to ClassfileAnnotation not working in
  Scala, and the additional check which only allows
  Java-defined annotations, this is pretty pointless
  from every perspective.