Fix binned scaled not accepting function-limits if there are transformations

NEWS.md

@@ -1,5 +1,7 @@
 # ggplot2 (development version)
 
+* Fixed bug where binned scales wouldn't simultaneously accept transformations
+  and function-limits (@teunbrand, #6144).
 * Fixed bug where the `ggplot2::`-prefix did not work with `stage()` 
   (@teunbrand, #6104).
 * New `get_labs()` function for retrieving completed plot labels 

R/scale-.R

@@ -319,7 +319,7 @@ binned_scale <- function(aesthetics, scale_name = deprecated(), palette, name =
   }
 
   transform <- as.transform(transform)
-  if (!is.null(limits)) {
+  if (!is.null(limits) && !is.function(limits)) {
     limits <- transform$transform(limits)
   }
 

tests/testthat/test-scale-binned.R

@@ -44,6 +44,16 @@ test_that("binned limits should not compute out-of-bounds breaks", {
   ))
 })
 
+test_that("binned scales can use limits and transformations simultaneously (#6144)", {
+  s <- scale_x_binned(
+    limits = function(x) x + 1,
+    trans = transform_log10()
+  )
+  s$train(c(0, 1)) # c(1, 10) in untransformed space
+  out <- s$get_limits()
+  expect_equal(s$get_limits(), log10(c(2, 11)))
+})
+
 test_that("binned scales can use NAs in limits", {
   scale <- scale_x_binned(limits = c(NA, 10))
   scale$train(c(-20, 20))