Stats imports

[klin333]

Add utils:: and stats:: in front of functions not explicitly imported.

Fixes #5186

[teunbrand]

Thanks for the PR, the proposed changed look good to me.
Can I just quickly check in that these changes have resolved the issue that you were experiencing?

[klin333]

yes, this use to complain about approxfun not found if stats package is not in namespace: tibble(x = seq(10), y = seq(10)) %>% ggplot() + geom_area(aes(x = x, y = y)). But it works now.

[klin333]

also note that utils::head and utils::tail are used in various places in ggplot2. i didn't prepend utils:: to them as i didn't want to make too many file changes. probably best to explicitly import these 2 functions in ggplot2-package.R?

naked head and tail calls may be in the files below based on regex search, though i didn't manually check for false positives.
1 R/guide-colorsteps.R
2 R/guide-legend.R
3 R/guides-.R
4 R/scale-.R

[teunbrand]

probably best to explicitly import these 2 functions in ggplot2-package.R?

Yeah that might be wise. You could use usethis::use_import_from("utils", c("head", "tail")) to automatically write the namespace as well.

[teunbrand]

Great, thanks for the contribution!