diff --git a/enum.c b/enum.c
index 2e78d08a9a..6c68240f0e 100644
--- a/enum.c
+++ b/enum.c
@@ -319,17 +319,17 @@ limit_by_enum_size(VALUE obj, long n)
 {
     unsigned long limit;
     VALUE size = rb_check_funcall(obj, id_size, 0, 0);
-    if (size == Qundef) return n;
-    limit = NUM2ULONG(size);
-    return ((unsigned long)n > limit) ? limit : n;
+    if (!FIXNUM_P(size)) return n;
+    limit = FIX2ULONG(size);
+    return ((unsigned long)n > limit) ? (long)limit : n;
 }
 
 static int
 enum_size_over_p(VALUE obj, long n)
 {
     VALUE size = rb_check_funcall(obj, id_size, 0, 0);
-    if (size == Qundef) return 0;
-    return ((unsigned long)n > NUM2ULONG(size));
+    if (!FIXNUM_P(size)) return 0;
+    return ((unsigned long)n > FIX2ULONG(size));
 }
 
 /*
diff --git a/test/ruby/test_lazy_enumerator.rb b/test/ruby/test_lazy_enumerator.rb
index 75f24580ca..952a773d58 100644
--- a/test/ruby/test_lazy_enumerator.rb
+++ b/test/ruby/test_lazy_enumerator.rb
@@ -483,6 +483,18 @@ EOS
     assert_equal Enumerator::Lazy, [].lazy.slice_when{}.class, bug7507
   end
 
+  def test_each_cons_limit
+    n = 1 << 120
+    assert_equal([1, 2], (1..n).lazy.each_cons(2).first)
+    assert_equal([[1, 2], [2, 3]], (1..n).lazy.each_cons(2).first(2))
+  end
+
+  def test_each_slice_limit
+    n = 1 << 120
+    assert_equal([1, 2], (1..n).lazy.each_slice(2).first)
+    assert_equal([[1, 2], [3, 4]], (1..n).lazy.each_slice(2).first(2))
+  end
+
   def test_no_warnings
     le = (1..3).lazy
     assert_warning("") {le.zip([4,5,6]).force}