Cannot create summary object with null values in generated quantities

Summary:

If there are null values in an object from the generated quantities, stan cannot create a summary.

Description:

When attempted, you see an error like this

Error in quantile.default(chain, probs = probs) :
  missing values and NaN's not allowed if 'na.rm' is FALSE

Reproducible Steps:

R script

library(rstan)
outcome <- c(1,1,1,1,1,1,1,1,0,1,1,1,1,0,0,1,0,1,1,1,0,1,0,1,0,1,0,0,1,1,1,1,1,1,1,0,0,1,0,1,1,0,0,1,0,1,0,1,1,1,0,1,0,0,1,1,0,1,1,1,1,1,1,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,0,1,1,1,1,1,1,1,1,1,0,0,1,1,0,0,1,1,1)
treat <- c(rep(0,50),rep(1,50))
fake_chai_data <- data.frame(outcome, treat)

chai_dat <- list(N = length(fake_chai_data$outcome), 
                    y = fake_chai_data$outcome,
                    treat = fake_chai_data$treat) 

mod <- stan_model("model.stan")
fit <- sampling(mod, data = chai_dat, iter = 10, chains = 2)
summary(fit)$summary

Stan model:

data {
    int<lower=0> N;  
    int<lower=0,upper=1> y[N]; 
    vector[N] treat;  
}
parameters {
    real alpha;
    real beta;
}
model {
    alpha ~ normal(0,10);  
    beta ~ normal(0,10); 
    y ~ bernoulli_logit(alpha + beta*treat);
}
generated quantities {
    real effect;
    vector[N] y_with_nulls = treat;
    effect = inv_logit(alpha+beta)-inv_logit(alpha);
    y_with_nulls = treat /0;
}

Current Output:

Error in quantile.default(chain, probs = probs) :
  missing values and NaN's not allowed if 'na.rm' is FALSE

RStan Version:

R> packageVersion("rstan")
[1] ‘2.18.2’

R Version:

R> R.version.string
[1] "R version 3.5.2 (2018-12-20)"

Operating System:

OS X 10.12.6

Start with the summary(fit)$summary entry point, using the reproducible R script and model.stan as the first test case. Trace how generated-quantity values reach quantile.default; done means summary(fit)$summary completes for the shown model with missing generated-quantity values while existing summaries remain valid.