fix 781, nullpointerexcs in matcherror

2 files changed, 10 insertions, 5 deletions

diff --git a/src/compiler/scala/tools/nsc/matching/PatternMatchers.scala b/src/compiler/scala/tools/nsc/matching/PatternMatchers.scala
index 27c5792069..145190f1ed 100644
--- a/src/compiler/scala/tools/nsc/matching/PatternMatchers.scala
+++ b/src/compiler/scala/tools/nsc/matching/PatternMatchers.scala
@@ -366,7 +366,9 @@ trait PatternMatchers requires (transform.ExplicitOuter with PatternNodes) {
     //Console.println("tree.getClass() "+tree.getClass());
     tree match {
       case Bind(name, Typed(Ident( nme.WILDCARD ), tpe)) => // x@_:Type
-        if (isSubType(header.getTpe(),tpe.tpe)) {
+        if (false && isSubType(header.getTpe(),tpe.tpe)) {
+          // this optimization is not correct, because
+          //  null.isInstanceOf will return false
           val node = pDefaultPat(tree.pos, tpe.tpe)
           env.newBoundVar(tree.symbol, tree.tpe, header.selector)
           node
@@ -1002,7 +1004,7 @@ trait PatternMatchers requires (transform.ExplicitOuter with PatternNodes) {
             ); // forward jump
           if (guard(i) != EmptyTree)
             res0 = And(guard(i), res0);
-          res = Or(Block(ts.toList, res0), res);
+          res = Or(squeezedBlock(ts.toList, res0), res);
           i = i - 1
         }
       if (_b.or != null)
diff --git a/src/library/scala/MatchError.scala b/src/library/scala/MatchError.scala
index a26c5087ce..6ef969b97c 100644
--- a/src/library/scala/MatchError.scala
+++ b/src/library/scala/MatchError.scala
@@ -23,13 +23,16 @@ import Predef._
  */
 object MatchError {
 
+  def string(obj: Any) =
+    if(obj != null) obj.toString() else "null"
+
   // todo: change pattern matcher so that dummy type parameter T can be removed.
   def fail[T](source: String, line: Int): Nothing =
     throw new MatchError(source, line)
 
   def report(source: String, line: Int, obj: Any) =
     try {
-      throw new MatchError(source, line, obj.toString())
+      throw new MatchError(source, line, string(obj))
     } catch {
       case e: MatchError => throw e
       case e: Throwable => throw new MatchError(source, line)
@@ -43,6 +46,6 @@ final class MatchError(msg: String) extends Error(msg) {
   def this(source: String, line: Int, obj: String) =
     this("for object " + obj + " in '" + source + "' at line " + line)
 
-  def this(ob: Any) =
-    this(ob.toString())
+  def this(obj: Any) =
+    this(MatchError.string(obj))
 }