correct IDate-days

Author: MichaelChirico

R/IDateTime.R

@@ -129,8 +129,12 @@ chooseOpsMethod.IDate = function(x, y, mx, my, cl, reverse) inherits(y, "Date")
     # ii) .Date was newly exposed in R some time after 3.4.4
   }
   ans = as.integer(unclass(e1) - unclass(e2))
-  setattr(ans, "class", "difftime")
-  setattr(ans, "units", "days")
+  if (inherits(e2, "Date")) {
+    setattr(ans, "class", "difftime")
+    setattr(ans, "units", "days")
+  } else {
+    setattr(ans, "class", c("IDate", "Date"))
+  }
   ans
 }
 

inst/tests/tests.Rraw

@@ -10342,7 +10342,7 @@ test(1673.1, TT + 4L, as.IDate("2016-04-29"))
 test(1673.2, TT + 4, as.IDate("2016-04-29"))
 test(1673.3, TT - 3, as.IDate("2016-04-22"))
 test(1673.4, TT - 3L, as.IDate("2016-04-22"))
-test(1673.5, as.IDate("2016-04-28") - as.IDate("2016-04-20"), 8L)
+test(1673.5, all.equal(as.IDate("2016-04-28") - as.IDate("2016-04-20"), as.difftime(8, units='days')))
 
 
 # test for radix integer order when MAXINT is present AND decreasing=TRUE AND na.last=FALSE