diff --git a/spec/ruby/core/time/localtime_spec.rb b/spec/ruby/core/time/localtime_spec.rb
index 6f682b0b34..2fc8a2d56a 100644
--- a/spec/ruby/core/time/localtime_spec.rb
+++ b/spec/ruby/core/time/localtime_spec.rb
@@ -90,6 +90,19 @@ describe "Time#localtime" do
 
       t.utc_offset.should == -18000
     end
+
+    it "does nothing if already in a local time zone" do
+      time = with_timezone("America/New_York") do
+        break Time.new(2005, 2, 27, 22, 50, 0)
+      end
+      zone = time.zone
+
+      with_timezone("Europe/Amsterdam") do
+        time.localtime
+      end
+
+      time.zone.should == zone
+    end
   end
 
   describe "with an argument that responds to #to_str" do
diff --git a/test/ruby/test_time_tz.rb b/test/ruby/test_time_tz.rb
index 51fc968e9b..8be7294440 100644
--- a/test/ruby/test_time_tz.rb
+++ b/test/ruby/test_time_tz.rb
@@ -107,6 +107,18 @@ class TestTimeTZ < Test::Unit::TestCase
     assert_equal(expected, real, m)
   end
 
+  def test_localtime_zone
+    t = with_tz("America/Los_Angeles") {
+      Time.local(2000, 1, 1)
+    }
+    skip "force_tz_test is false on this environment" unless t
+    z1 = t.zone
+    z2 = with_tz(tz="Asia/Singapore") {
+      t.localtime.zone
+    }
+    assert_equal(z2, z1)
+  end
+
   def test_america_los_angeles
     with_tz(tz="America/Los_Angeles") {
       assert_time_constructor(tz, "2007-03-11 03:00:00 -0700", :local, [2007,3,11,2,0,0])
diff --git a/time.c b/time.c
index 672a794efe..2e77bda630 100644
--- a/time.c
+++ b/time.c
@@ -3410,6 +3410,9 @@ time_localtime(VALUE time)
  *
  *     t.localtime("+09:00")                   #=> 2000-01-02 05:15:01 +0900
  *     t.utc?                                  #=> false
+ *
+ *  If +utc_offset+ is not given and _time_ is local time, just return
+ *  the receiver.
  */
 
 static VALUE
diff --git a/version.h b/version.h
index ebc3f21d32..08f64ff5f7 100644
--- a/version.h
+++ b/version.h
@@ -1,6 +1,6 @@
 #define RUBY_VERSION "2.5.4"
 #define RUBY_RELEASE_DATE "2019-01-10"
-#define RUBY_PATCHLEVEL 126
+#define RUBY_PATCHLEVEL 127
 
 #define RUBY_RELEASE_YEAR 2019
 #define RUBY_RELEASE_MONTH 1