Warning from examples on oldrel

[MichaelChirico]

As of now, oldrel is throwing a warning:

https://www.r-project.org/nosvn/R.check/r-oldrel-macos-arm64/lintr-00check.html

checking examples ... [1s/1s] WARNING
Found the following significant warnings:

  Warning: 'all.equal.default(<function>)' is deprecated.
  Warning: 'all.equal.default(<function>)' is deprecated.
  Warning: 'all.equal.default(<function>)' is deprecated.
  Warning: 'all.equal.default(<function>)' is deprecated.
  Warning: 'all.equal.default(<function>)' is deprecated.
  Warning: 'all.equal.default(<function>)' is deprecated.
  Warning: 'all.equal.default(<function>)' is deprecated.
  Warning: 'all.equal.default(<function>)' is deprecated.
  Warning: 'all.equal.default(<function>)' is deprecated.
  Warning: 'all.equal.default(<function>)' is deprecated.
  Warning: 'all.equal.default(<function>)' is deprecated.
  Warning: 'all.equal.default(<function>)' is deprecated.
  Warning: 'all.equal.default(<function>)' is deprecated.
  Warning: 'all.equal.default(<function>)' is deprecated.
  Warning: 'all.equal.default(<function>)' is deprecated.
  Warning: 'all.equal.default(<function>)' is deprecated.
  Warning: 'all.equal.default(<function>)' is deprecated.
  Warning: 'all.equal.default(<function>)' is deprecated.
  Warning: 'all.equal.default(<function>)' is deprecated.
  Warning: 'all.equal.default(<function>)' is deprecated.
  Warning: 'all.equal.default(<function>)' is deprecated.
  Warning: 'all.equal.default(<function>)' is deprecated.
  Warning: 'all.equal.default(<function>)' is deprecated.
  Warning: 'all.equal.default(<function>)' is deprecated.
Deprecated functions may be defunct as soon as of the next release of
R.
See ?Deprecated.

AFAICT, it's due to this line:

lintr/R/with.R

Line 76 in 5a0b54e

#' all.equal(linters_with_defaults(), linters_with_tags("default"))

which, because Linter() doesn't add "function" to the class winds up dispatching to all.equal.default() instead of all.equal.function().

I'm not sure why it's not showing up for GHA -- maybe there's some tweak in S3 dispatch that uses mode() (which is correctly "function") instead of class() for some versions?

Anyway, is there any reason not to change this line:

lintr/R/utils.R

Line 181 in 5a0b54e

structure(fun, class = "linter", name = name)

To set the Linter() output class to c("linter", "lintr_function", "function")? It seems like the better approach in general. It would also improve this line:

lintr/R/with.R

Lines 49 to 51 in 5a0b54e

	if (is.function(x) && !inherits(x, "lintr_function")) {
	class(x) <- c(prev_class, "lintr_function")
	}

Where we apparently always add "lintr_function" to the class later, to do so up-front.

[MichaelChirico]

Actually, it looks like this recent change is why it's not showing up in r-devel/current release. But still don't know why it's not showing up in GHA oldrel:

r-devel/r-svn@5490269