fixed bug in patterns()

2 files changed, 15 insertions, 6 deletions

diff --git a/sources/scalac/ast/parser/Parser.java b/sources/scalac/ast/parser/Parser.java
index a25b219d3b..ff36b2c4fc 100644
--- a/sources/scalac/ast/parser/Parser.java
+++ b/sources/scalac/ast/parser/Parser.java
@@ -1198,7 +1198,8 @@ public class Parser implements Tokens {
 		s.nextToken();
 		choices.append( pattern1() );
 	    }
-	    TreeList ts = pN.flattenAlternativeChildren( choices.toArray() );
+	    Tree[] tarr = choices.toArray();
+	    TreeList ts = pN.flattenAlternativeChildren( tarr );
 	    return pN.flattenAlternative( make.Alternative( pos, ts.toArray() ) );
 	}
 	return first;
@@ -1335,10 +1336,10 @@ public class Parser implements Tokens {
 	    Tree[] ts = Tree.EMPTY_ARRAY;
 	    if( s.token!= RPAREN )
 		ts = patterns();
-            Tree t;
-            if (ts.length == 1)
+            Tree t = null;
+            if ((ts.length == 1)&&!( ts[0] instanceof Tree.Alternative ))  {
                 t = ts[0];
-            else {
+            } else {
                 t = pN.flattenSequence(make.Sequence(s.pos, ts));
                 t = pN.elimSequence(t);
             }
diff --git a/sources/scalac/ast/parser/PatternNormalizer.java b/sources/scalac/ast/parser/PatternNormalizer.java
index 70dc2fe789..8b69ef84ae 100644
--- a/sources/scalac/ast/parser/PatternNormalizer.java
+++ b/sources/scalac/ast/parser/PatternNormalizer.java
@@ -245,18 +245,26 @@ public class PatternNormalizer {
 
     // main algo for (1), precondition: choices are children of an Alternative node
     TreeList flattenAlternativeChildren( Tree[] choices ) {
+	boolean allEmpty = true;
 	TreeList cs = new TreeList();
 	for( int j = 0; j < choices.length; j++ ) {
 	    Tree tree = flattenAlternative( choices[ j ] ); // flatten child
 	    switch( tree ) {
 	    case Alternative( Tree[] child_choices ):
+		int tmp = cs.length();
 		appendNonEmpty( cs, child_choices );
+		if( cs.length() != tmp )
+		    allEmpty = false;
 		break;
 	    default:
-		appendNonEmpty( cs, tree );
+		cs.append( tree );
+		allEmpty = allEmpty && TreeInfo.isEmptySequence( tree );
 	    }
 	}
-	//System.out.println( cs.length() );
+	if( allEmpty ) {
+	    cs.clear();
+	    cs.append(make.Sequence(choices[0].pos, Tree.EMPTY_ARRAY));
+	}
 	return cs;
     }