diff --git a/NEWS.md b/NEWS.md
index ae87adecd9..869f9b2f85 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -188,8 +188,8 @@ Note: We're only listing outstanding class updates.
 
 * Range
 
-    * `Range#to_set` and `Enumerator#to_set` now perform size checks to prevent
-      issues with endless ranges. [[Bug #21654]]
+    * `Range#to_set` now performs size checks to prevent issues with
+      endless ranges. [[Bug #21654]]
 
     * `Range#overlap?` now correctly handles infinite (unbounded) ranges.
       [[Bug #21185]]
diff --git a/enumerator.c b/enumerator.c
index c2b2bfa9a0..93671dfe71 100644
--- a/enumerator.c
+++ b/enumerator.c
@@ -3366,24 +3366,6 @@ enumerator_plus(VALUE obj, VALUE eobj)
     return new_enum_chain(rb_ary_new_from_args(2, obj, eobj));
 }
 
-/*
- * call-seq:
- *   e.to_set -> set
- *
- * Returns a set generated from this enumerator.
- *
- *   e = Enumerator.new { |y| y << 1 << 1 << 2 << 3 << 5 }
- *   e.to_set #=> #<Set: {1, 2, 3, 5}>
- */
-static VALUE enumerator_to_set(int argc, VALUE *argv, VALUE obj)
-{
-    VALUE size = rb_funcall(obj, id_size, 0);
-    if (RB_TYPE_P(size, T_FLOAT) && RFLOAT_VALUE(size) == INFINITY) {
-        rb_raise(rb_eArgError, "cannot convert an infinite enumerator to a set");
-    }
-    return rb_call_super(argc, argv);
-}
-
 /*
  * Document-class: Enumerator::Product
  *
@@ -4540,7 +4522,6 @@ InitVM_Enumerator(void)
     rb_define_method(rb_cEnumerator, "rewind", enumerator_rewind, 0);
     rb_define_method(rb_cEnumerator, "inspect", enumerator_inspect, 0);
     rb_define_method(rb_cEnumerator, "size", enumerator_size, 0);
-    rb_define_method(rb_cEnumerator, "to_set", enumerator_to_set, -1);
     rb_define_method(rb_cEnumerator, "+", enumerator_plus, 1);
     rb_define_method(rb_mEnumerable, "chain", enum_chain, -1);
 
diff --git a/test/ruby/test_enumerator.rb b/test/ruby/test_enumerator.rb
index 5fabea645d..177d7c04fa 100644
--- a/test/ruby/test_enumerator.rb
+++ b/test/ruby/test_enumerator.rb
@@ -1070,13 +1070,4 @@ class TestEnumerator < Test::Unit::TestCase
     enum = ary.each
     assert_equal(35.0, enum.sum)
   end
-
-  def test_to_set
-    e = Enumerator.new { it << 1 << 1 << 2 << 3 << 5 }
-    set = e.to_set
-    assert_equal(Set[1, 2, 3, 5], set)
-
-    ei = Enumerator.new(Float::INFINITY) { it << 1 << 1 << 2 << 3 << 5 }
-    assert_raise(ArgumentError) { ei.to_set }
-  end
 end
diff --git a/test/ruby/test_set.rb b/test/ruby/test_set.rb
index e8ac3e329e..70a61aa3b5 100644
--- a/test/ruby/test_set.rb
+++ b/test/ruby/test_set.rb
@@ -1003,6 +1003,12 @@ class TC_Enumerable < Test::Unit::TestCase
     set = assert_nothing_raised { enum.to_set }
     assert(set.is_a?(Set))
     assert_equal(Set[1,2,3], set)
+
+    enumerator = enum.to_enum
+
+    set = assert_nothing_raised { enumerator.to_set }
+    assert(set.is_a?(Set))
+    assert_equal(Set[1,2,3], set)
   end
 end