Fix non-exhaustive match in macro code parsing

Before:

```
⚡ qscala -deprecation
Welcome to Scala 2.12.0-20160126-000825-1e302b76aa (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_66).
Type in expressions for evaluation. Or try :help.

scala> import reflect.macros.blackbox.Context; import language.experimental.macros
import reflect.macros.blackbox.Context
import language.experimental.macros

scala> def impl(c: Context) = {println(c.universe.showRaw(c.parse("val then = 0"))); c.literalUnit}; def m: Unit = macro impl;
<console>:13: warning: method literalUnit in trait ExprUtils is deprecated: Use quasiquotes instead
       def impl(c: Context) = {println(c.universe.showRaw(c.parse("val then = 0"))); c.literalUnit}; def m: Unit = macro impl;
                                                                                       ^
impl: (c: scala.reflect.macros.blackbox.Context)c.Expr[Unit]
defined term macro m: Unit

scala> m
<console>:16: error: exception during macro expansion:
scala.MatchError: pos: source-<macro>,line-1,offset=4 then is now a reserved word; usage as an identifier is deprecated WARNING (of class scala.tools.nsc.reporters.StoreReporter$Info)
	at scala.reflect.macros.contexts.Parsers$class.scala$reflect$macros$contexts$Parsers$class$$$anonfun$1(Parsers.scala:17)
```

1 files changed, 2 insertions, 1 deletions

diff --git a/src/compiler/scala/reflect/macros/contexts/Parsers.scala b/src/compiler/scala/reflect/macros/contexts/Parsers.scala
index f4584f3627..cc3f01e53b 100644
--- a/src/compiler/scala/reflect/macros/contexts/Parsers.scala
+++ b/src/compiler/scala/reflect/macros/contexts/Parsers.scala
@@ -16,8 +16,9 @@ trait Parsers {
       val tree = gen.mkTreeOrBlock(parser.parseStatsOrPackages())
       sreporter.infos.foreach {
         case sreporter.Info(pos, msg, sreporter.ERROR) => throw ParseException(pos, msg)
+        case _ =>
       }
       tree
     } finally global.reporter = oldReporter
   }
-}
\ No newline at end of file
+}