Nothing plotted or lines and dots are Grey with manual_scale when a named vector is used as the input. about ggplot2 HOT 3 CLOSED

colors_named_vector <- c(
  red = "red",
  blue = "blue",
  green = "green"
)

library(ggplot2)

ggplot(iris, aes(x=Sepal.Length, y=Sepal.Width, color=Species)) +
  geom_point() +
  scale_color_manual(values=colors_named_vector)
#> Warning: No shared levels found between `names(values)` of the manual scale and the
#> data's colour values.
#> No shared levels found between `names(values)` of the manual scale and the
#> data's colour values.

colors_named_vector <- c(
    setosa = "red",
    versicolor = "blue",
    virginica = "green"
)


library(ggplot2)

ggplot(iris, aes(x=Sepal.Length, y=Sepal.Width, color=Species)) +
    geom_point() +
    scale_color_manual(values=colors_named_vector)