Keeping errorbars solid while showing color AND linetype in the legend for lines in ggplot2

solution_to_lineplot.R

library(ggplot2)

set.seed(1)
test_df <- data.frame(models = rep(paste("Model", LETTERS[1:3]), 3),
                      x = c(rep(1, 3),
                            rep(2, 3),
                            rep(3, 3)),
                      y = c(1:3,1:3+1+rnorm(3,0,.2),1:3+2)+rnorm(3,0,.3))
test_df$ymax <- test_df$y + .3
test_df$ymin <- test_df$y - .3

ggplot(test_df, aes(x=x, y=y, color=models)) +
  geom_errorbar(aes(ymax=ymax, ymin=ymin), 
                show.legend = FALSE, 
                lwd=1.2, width=.5) +
  geom_line(aes(linetype=models))