2 files changed, 32 insertions, 0 deletions
diff --git a/range.c b/range.c
index a6ef8c9835..7c116d78c7 100644
--- a/range.c
+++ b/range.c
@@ -1820,6 +1820,7 @@ range_string_cover_internal(VALUE range, VALUE val)
             return r_cover_p(range, beg, end, val);
         }
         if (NIL_P(beg)) {
+unbounded_begin:;
             VALUE r = rb_funcall(val, id_cmp, 1, end);
             if (NIL_P(r)) return Qfalse;
             if (RANGE_EXCL(range)) {
@@ -1828,12 +1829,20 @@ range_string_cover_internal(VALUE range, VALUE val)
             return RBOOL(rb_cmpint(r, val, end) <= 0);
         }
         else if (NIL_P(end)) {
+unbounded_end:;
             VALUE r = rb_funcall(beg, id_cmp, 1, val);
             if (NIL_P(r)) return Qfalse;
             return RBOOL(rb_cmpint(r, beg, val) <= 0);
         }
     }
 
+    if (!NIL_P(beg) && NIL_P(end)) {
+        goto unbounded_end;
+    }
+    if (NIL_P(beg) && !NIL_P(end)) {
+        goto unbounded_begin;
+    }
+
     return range_include_fallback(beg, end, val);
 }
 
diff --git a/test/ruby/test_range.rb b/test/ruby/test_range.rb
index 8c01254d19..8c310b0bae 100644
--- a/test/ruby/test_range.rb
+++ b/test/ruby/test_range.rb
@@ -2,6 +2,7 @@
 require 'test/unit'
 require 'delegate'
 require 'timeout'
+require 'date'
 require 'rbconfig/sizeof'
 
 class TestRange < Test::Unit::TestCase
@@ -624,6 +625,28 @@ class TestRange < Test::Unit::TestCase
     assert_operator(c.new(0)..c.new(10), :===, c.new(5), bug12003)
   end
 
+  def test_eqq_unbounded_ruby_bug_19864
+    t1 = Date.today
+    t2 = t1 + 1
+    assert_equal(true, (..t1) === t1)
+    assert_equal(false, (..t1) === t2)
+    assert_equal(true, (..t2) === t1)
+    assert_equal(true, (..t2) === t2)
+    assert_equal(false, (...t1) === t1)
+    assert_equal(false, (...t1) === t2)
+    assert_equal(true, (...t2) === t1)
+    assert_equal(false, (...t2) === t2)
+
+    assert_equal(true, (t1..) === t1)
+    assert_equal(true, (t1..) === t2)
+    assert_equal(false, (t2..) === t1)
+    assert_equal(true, (t2..) === t2)
+    assert_equal(true, (t1...) === t1)
+    assert_equal(true, (t1...) === t2)
+    assert_equal(false, (t2...) === t1)
+    assert_equal(true, (t2...) === t2)
+  end
+
   def test_eqq_non_iteratable
     k = Class.new do
       include Comparable