Including all remaining variables via "." operator gives error in stan_gamm4

I get the following error if I use the "." operator to include all remaining variables in stan_gamm4:

Error in terms.formula(gf, specials = c("s", "te", "ti", "t2", extra.special)) : 
  '.' in formula and no 'data' argument

Reproducible example:

dat <- mgcv::gamSim(1, n = 400, scale = 2) ## simulate 4 term additive truth

dat$fac <- fac <- as.factor(sample(1:20, 400, replace = TRUE))
dat$y <- dat$y + model.matrix(~ fac - 1) %*% rnorm(20) * .5

br <- stan_gamm4(y ~ s(x0) + s(x2) + . , 
               data = dat, random = ~ (1 | fac),
                chains = 1, iter = 200) # for example speed

I checked for other functions such as stan_glm and the error does not happen. Is any version of rstanarm where this error is resolved?

Start with the supplied stan_gamm4 reproducible example and trace how its formula is processed when the data argument contains '.'. Compare the behavior with stan_glm, which does not reproduce the error. Done means the example runs successfully with the '.' operator without the terms.formula error.