static boolean lambda_expression_head(PsiBuilder b, int l) {
    if (!recursion_guard_(b, l, "lambda_expression_head")) return false;
    if (!nextTokenIsFast(b, T_LPAREN)) return false;
    boolean r;
    Marker m = enter_section_(b);
    r = lambda_parameter_list(b, l + 1);
    r = r && mb_nl(b, l + 1);
    r = r && consumeToken(b, T_ARROW);
    exit_section_(b, m, null, r);
    return r;
  }
static boolean lambda_expression_head(PsiBuilder b, int l)