SI-4438 FindAll implicits after error

Fix cross talk between candidates in ImplicitComputation#findAll.

Haoyi reported that he couldn't get the presentation compiler
to offer completion suggestions for extension methods on primitive
arrays.

Turns out that an error in typechecking the previous candidate
had not been cleared, and this was taken to mean that `arrayIntOps`
was itself ineligible.

After this patch:
```
scala> Array(1, 2, 3) reverse
reverseIterator   reverse   reverseMap   reversed

scala> Array(1,2,3).reverse //print
   scala.Predef.intArrayOps(scala.Array.apply(1, 2, 3)).reverse

scala> Array(1, 2, 3) to
toString   toCollection   toSeq      toIterator   to              toMap      toSet          toList
toArray    toBuffer       toStream   toIterable   toTraversable   toVector   toIndexedSeq

scala> Array(1, 2, 3) toSeq
   override def toSeq: Seq[Int]
```

1 files changed, 1 insertions, 1 deletions

diff --git a/src/compiler/scala/tools/nsc/typechecker/Implicits.scala b/src/compiler/scala/tools/nsc/typechecker/Implicits.scala
index 098653fd1f..494e1e49b7 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Implicits.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Implicits.scala
@@ -920,7 +920,7 @@ trait Implicits {
 
       /** Returns all eligible ImplicitInfos and their SearchResults in a map.
        */
-      def findAll() = linkedMapFrom(eligible)(typedImplicit(_, ptChecked = false, isLocalToCallsite))
+      def findAll() = linkedMapFrom(eligible)(x => try typedImplicit(x, ptChecked = false, isLocalToCallsite) finally context.reporter.clearAll())
 
       /** Returns the SearchResult of the best match.
        */