Fix and test output type of min(uint*).

theano/tensor/basic.py

@@ -1717,7 +1717,8 @@ def min(x, axis=None, keepdims=False):
         return -max(-x, axis=axis, keepdims=keepdims)
     elif str_x_type in uint_dtypes:
         itype = np.iinfo(x.dtype)
-        return itype.max - max(itype.max - x, axis=axis, keepdims=keepdims)
+        max_val = np.array(itype.max, dtype=itype.dtype)
+        return max_val - max(max_val - x, axis=axis, keepdims=keepdims)
     elif str_x_type == 'bool':
         return ~max(~x, axis=axis, keepdims=keepdims)
     else:

theano/tensor/tests/test_basic.py

@@ -3609,16 +3609,20 @@ class T_min_max(unittest.TestCase):
             itype = np.iinfo(dtype)
             data = np.array([itype.min + 3, itype.min, itype.max - 5, itype.max], dtype)
             n = as_tensor_variable(data)
+            self.assertEqual(min(n).dtype, dtype)
             i = eval_outputs(min(n))
             self.assertEqual(i, itype.min)
+            self.assertEqual(max(n).dtype, dtype)
             i = eval_outputs(max(n))
             self.assertEqual(i, itype.max)
 
     def test_bool(self):
         data = np.array([True, False], 'bool')
         n = as_tensor_variable(data)
+        self.assertEqual(min(n).dtype, 'bool')
         i = eval_outputs(min(n))
         self.assertEqual(i, False)
+        self.assertEqual(max(n).dtype, 'bool')
         i = eval_outputs(max(n))
         self.assertEqual(i, True)