Remove last bin if it lies outside of range (#4433)

Author: thomasp85

NEWS.md

@@ -1,5 +1,8 @@
 # ggplot2 (development version)
 
+* Fix a bug in `stat_summary_bin()` where one more than the requested number of
+  bins would be created (@thomasp85, #3824)
+  
 * Fix a bug in `geom_abline()` that resulted in `intercept` not being subjected
   to the transformation of the y scale (@thomasp85, #3741)
 

R/stat-bin2d.r

@@ -132,6 +132,12 @@ bin2d_breaks <- function(scale, breaks = NULL, origin = NULL, binwidth = NULL,
   if (!(is.numeric(origin) && length(origin) == 1)) abort("`origin` must be a numeric scalar")
 
   breaks <- seq(origin, range[2] + binwidth, binwidth)
+
+  # Check if the last bin lies fully outside the range
+  if (length(breaks) > 1 && breaks[length(breaks) - 1] >= range[2]) {
+    breaks <- breaks[-length(breaks)]
+  }
+
   adjust_breaks(breaks, right)
 }