Set the size of a new enumerator created by Enumerator#each with arguments to nil

When each() takes arguments, it is never safe to assume that the iteration
would repeat the same number of times as with each() without any
argument.  Actually, there is no way to get the exact number, so the
size should be set to nil to denote that.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65302 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

enumerator.c

@@ -550,6 +550,8 @@ enumerator_each(int argc, VALUE *argv, VALUE obj)
 	    args = rb_ary_new4(argc, argv);
 	}
 	e->args = args;
+	e->size = Qnil;
+	e->size_fn = 0;
     }
     if (!rb_block_given_p()) return obj;
     return enumerator_block_call(obj, 0, obj);

test/ruby/test_enumerator.rb

@@ -301,8 +301,11 @@ class TestEnumerator < Test::Unit::TestCase
       yield
     end
     ary = []
-    e = o.to_enum.each(ary)
-    e.next
+    e = o.to_enum { 1 }
+    assert_equal(1, e.size)
+    e_arg = e.each(ary)
+    assert_equal(nil, e_arg.size)
+    e_arg.next
     assert_equal([1], ary)
   end