private static void parseBracketExpression(PsiBuilder builder) {
    final PsiBuilder.Marker marker = builder.mark();
    builder.advanceLexer();
    if (builder.getTokenType() == RegExpTT.CARET) {
      builder.advanceLexer();
    }
    checkMatches(builder, RegExpTT.NAME, RegExpBundle.message("parse.error.posix.character.class.name.expected"));
    checkMatches(builder, RegExpTT.BRACKET_EXPRESSION_END, RegExpBundle.message("parse.error.unclosed.posix.bracket.expression"));
    marker.done(RegExpElementTypes.POSIX_BRACKET_EXPRESSION);
  }
private static void parseBracketExpression(PsiBuilder builder)