TokenTreeBuilder crash with conditional else

[Gama11]

class Foo
{
    function foo()
    {
        #if def
        if (true) {}
        else
        {
        #end

        trace("test");

        #if def
        }
        #end
    }
}

bad token Sharp(end) != BrClose
Stacktrace: 
Called from checkstyle.token.TokenStream::consumeTokenDef line 46
Called from checkstyle.token.TokenTreeBuilder::walkBlock line 736
Called from checkstyle.token.TokenTreeBuilder::walkIf line 850
Called from checkstyle.token.TokenTreeBuilder::walkKeyword line 651
Called from checkstyle.token.TokenTreeBuilder::walkIdentifier line 564
Called from checkstyle.token.TokenTreeBuilder::walkSharpExpr line 1261
Called from checkstyle.token.TokenTreeBuilder::walkSharpIf line 1175
Called from checkstyle.token.TokenTreeBuilder::walkSharp line 1154
Called from checkstyle.token.TokenTreeBuilder::walkStatement line 480
Called from checkstyle.token.TokenTreeBuilder::walkBlock line 734
Called from checkstyle.token.TokenTreeBuilder::walkFunction line 338
Called from checkstyle.token.TokenTreeBuilder::walkClass line 126
Called from checkstyle.token.TokenTreeBuilder::walkType line 49
Called from checkstyle.token.TokenTreeBuilder::walkFile line 38
Called from checkstyle.token.TokenTreeBuilder::buildTokenTree line 18
Called from checkstyle.Checker::getTokenTree line 53
Called from checkstyle.checks.whitespace.WhitespaceAfterCheck::checkTokens line 88
Called from checkstyle.checks.whitespace.WhitespaceAfterCheck::actualRun line 84
Called from checkstyle.checks.Check::run line 41