diff options
Diffstat (limited to 'sources/scalac/ast/parser/PatternNormalizer.java')
| -rw-r--r-- | sources/scalac/ast/parser/PatternNormalizer.java | 12 |
1 files changed, 10 insertions, 2 deletions
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; } |