Fix Range#overlaps? for beginless ranges

activesupport/lib/active_support/core_ext/range/overlaps.rb

@@ -5,6 +5,6 @@ class Range
   #  (1..5).overlaps?(4..6) # => true
   #  (1..5).overlaps?(7..9) # => false
   def overlaps?(other)
-    cover?(other.first) || other.cover?(first)
+    other.begin == self.begin || cover?(other.begin) || other.cover?(self.begin)
   end
 end

activesupport/test/core_ext/range_ext_test.rb

@@ -65,6 +65,14 @@ def test_overlaps_first_exclusive
     assert_not (5..10).overlaps?(1...5)
   end
 
+  def test_overlaps_with_beginless_range
+    assert((1..5).overlaps?(..10))
+  end
+
+  def test_overlaps_with_two_beginless_ranges
+    assert((..5).overlaps?(..10))
+  end
+
   def test_should_include_identical_inclusive
     assert((1..10).include?(1..10))
   end