Adds ndarray as rtype for T attribute.

Closes pylint-dev/pylint#3387

.gitignore

@@ -13,3 +13,4 @@ astroid.egg-info/
 .cache/
 .eggs/
 .pytest_cache/
+.mypy_cache/

ChangeLog

@@ -18,6 +18,10 @@ Release Date: TBA
 
 * Added a brain for ``hypothesis.strategies.composite``
 
+* The transpose of a ``numpy.ndarray`` is also a ``numpy.ndarray``
+
+  Fixes PyCQA/pylint#3387
+
 * Added a brain for ``sqlalchemy.orm.session``
 
 * Separate string and bytes classes patching

astroid/brain/brain_numpy_core_numerictypes.py

@@ -20,7 +20,7 @@ def numpy_core_numerictypes_transform():
     # different types defined in numerictypes.py
     class generic(object):
         def __init__(self, value):
-            self.T = None
+            self.T = np.ndarray([0, 0])
             self.base = None
             self.data = None
             self.dtype = None

astroid/brain/brain_numpy_ndarray.py

@@ -17,7 +17,7 @@ def infer_numpy_ndarray(node, context=None):
     class ndarray(object):
         def __init__(self, shape, dtype=float, buffer=None, offset=0,
                      strides=None, order=None):
-            self.T = None
+            self.T = numpy.ndarray([0, 0])
             self.base = None
             self.ctypes = None
             self.data = None

tests/unittest_brain_numpy_ndarray.py

@@ -154,7 +154,7 @@ def test_numpy_ndarray_attribute_inferred_as_ndarray(self):
         Test that some numpy ndarray attributes are inferred as numpy.ndarray
         """
         licit_array_types = ".ndarray"
-        for attr_ in ("real", "imag"):
+        for attr_ in ("real", "imag", "shape", "T"):
             with self.subTest(typ=attr_):
                 inferred_values = list(self._inferred_ndarray_attribute(attr_))
                 self.assertTrue(