Added ability to compare date/time with infinity

Date, DateTime, Time and TimeWithZone can now be compared to infinity,
  so it's now possible to create ranges with one infinite bound and
  date/time object as another bound.

  Ex.: @range = Range.new(Date.today, Float::INFINITY)

Also it's possible to check inclusion of date/time in range with
  conversion.

  Ex.: @range.include?(Time.now + 1.year) # => true
       @range.include?(DateTime.now + 1.year) # => true

Ability to create date/time ranges with infinite bound is required
  for handling postgresql range types.

2 files changed, 5 insertions, 7 deletions

diff --git a/activesupport/lib/active_support/core_ext/date_time/calculations.rb b/activesupport/lib/active_support/core_ext/date_time/calculations.rb
index fca5d4d679..4e4852a5e6 100644
--- a/activesupport/lib/active_support/core_ext/date_time/calculations.rb
+++ b/activesupport/lib/active_support/core_ext/date_time/calculations.rb
@@ -142,11 +142,4 @@ class DateTime
   def utc_offset
     (offset * 86400).to_i
   end
-
-  # Layers additional behavior on DateTime#<=> so that Time and
-  # ActiveSupport::TimeWithZone instances can be compared with a DateTime.
-  def <=>(other)
-    super other.to_datetime
-  end
-
 end
diff --git a/activesupport/lib/active_support/core_ext/date_time/infinite_comparable.rb b/activesupport/lib/active_support/core_ext/date_time/infinite_comparable.rb
new file mode 100644
index 0000000000..8a282b19f2
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/date_time/infinite_comparable.rb
@@ -0,0 +1,5 @@
+require 'active_support/core_ext/infinite_comparable'
+
+class DateTime
+  include InfiniteComparable
+end