diff --git a/lib/yaml/__init__.py b/lib/yaml/__init__.py
index e7a419dd2..7b8d7d8f6 100644
--- a/lib/yaml/__init__.py
+++ b/lib/yaml/__init__.py
@@ -329,7 +329,7 @@ def add_path_resolver(tag, path, kind=None, Loader=Loader, Dumper=Dumper):
     Loader.add_path_resolver(tag, path, kind)
     Dumper.add_path_resolver(tag, path, kind)
 
-def add_constructor(tag, constructor, Loader=Loader):
+def add_constructor(tag, constructor, Loader=FullLoader):
     """
     Add a constructor for the given tag.
     Constructor is a function that accepts a Loader instance
diff --git a/lib3/yaml/__init__.py b/lib3/yaml/__init__.py
index 5df0bb5fd..bd96246c1 100644
--- a/lib3/yaml/__init__.py
+++ b/lib3/yaml/__init__.py
@@ -326,7 +326,7 @@ def add_path_resolver(tag, path, kind=None, Loader=Loader, Dumper=Dumper):
     Loader.add_path_resolver(tag, path, kind)
     Dumper.add_path_resolver(tag, path, kind)
 
-def add_constructor(tag, constructor, Loader=Loader):
+def add_constructor(tag, constructor, Loader=FullLoader):
     """
     Add a constructor for the given tag.
     Constructor is a function that accepts a Loader instance
diff --git a/tests/lib/test_constructor.py b/tests/lib/test_constructor.py
index beee7b0a7..ffdc35b33 100644
--- a/tests/lib/test_constructor.py
+++ b/tests/lib/test_constructor.py
@@ -19,7 +19,7 @@ def _make_objects():
             NewArgs, NewArgsWithState, Reduce, ReduceWithState, MyInt, MyList, MyDict,  \
             FixedOffset, today, execute
 
-    class MyLoader(yaml.Loader):
+    class MyLoader(yaml.FullLoader):
         pass
     class MyDumper(yaml.Dumper):
         pass
diff --git a/tests/lib3/test_constructor.py b/tests/lib3/test_constructor.py
index 427f53c30..8a556c024 100644
--- a/tests/lib3/test_constructor.py
+++ b/tests/lib3/test_constructor.py
@@ -16,7 +16,7 @@ def _make_objects():
             NewArgs, NewArgsWithState, Reduce, ReduceWithState, MyInt, MyList, MyDict,  \
             FixedOffset, today, execute
 
-    class MyLoader(yaml.Loader):
+    class MyLoader(yaml.FullLoader):
         pass
     class MyDumper(yaml.Dumper):
         pass