error in stat_smooth because object is not found

I would like to use stat_smooth and the number of points at which to evaluate smoother should be the number of rows in the dataset.

data <- tibble(x=runif(20), y=runif(20))

data %>% 
  mutate(m=n()) %>% 
  ggplot(data=.) + 
  geom_point(aes(x = x, y = y), colour = 'red') +
  geom_smooth(aes(x = x, y = y), method = NULL, se = TRUE) +
  stat_smooth(aes(x = x, y = x), n=min(m))

Unfortunately I will get the error

Error: object 'm' not found

Thanks for any hints!

This is an issue with the scope of ggplot2 in general. ggplot is not able to see variables from your dataframe outside of aes().
I can think of three options to resolve your issue:

1. Do what @nightstand already recommended in a comment (and what I'd recommend as well).

data %>%
ggplot() + 
  geom_point(aes(x = x, y = y), colour = 'red') +
  geom_smooth(aes(x = x, y = y), method = NULL, se = TRUE) +
  stat_smooth(aes(x = x, y = y), n=nrow(data))

2. If you are really attached to your m-variable you can call make a reference to the dataframe.

data <- data %>%
  mutate(m=n())
ggplot(data = data) + 
  geom_point(aes(x = x, y = y), colour = 'red') +
  geom_smooth(aes(x = x, y = y), method = NULL, se = TRUE) +
  stat_smooth(aes(x = x, y = y), n=min(data$m))

3. Or one possibility if you really just want min(m) without data$m would be to calculate m first, then use with() use it in ggplot.

data <- data %>%
  mutate(m=n())
with(data,
ggplot() + 
  geom_point(aes(x = x, y = y), colour = 'red') +
  geom_smooth(aes(x = x, y = y), method = NULL, se = TRUE) +
  stat_smooth(aes(x = x, y = y), n=min(m))
)