ENH: __array_function__ updates for NumPy 1.17.0

- Always enable __array_function__ overrides.
- Remove special cases for Python 2 compatibility.
- Document these changes in 1.17.0-notes.rst.

It will be good to see ASV numbers to understand the performance implications
of these changes. If need be, we can speed up NumPy functions internally by
using non-dispatched functions (with ``.__wrapped__``).

2 files changed, 2 insertions, 9 deletions

diff --git a/numpy/lib/shape_base.py b/numpy/lib/shape_base.py
index e088a6c4a..ac2a25604 100644
--- a/numpy/lib/shape_base.py
+++ b/numpy/lib/shape_base.py
@@ -11,8 +11,7 @@ from numpy.core.fromnumeric import product, reshape, transpose
 from numpy.core.multiarray import normalize_axis_index
 from numpy.core import overrides
 from numpy.core import vstack, atleast_3d
-from numpy.core.shape_base import (
-    _arrays_for_stack_dispatcher, _warn_for_nonsequence)
+from numpy.core.shape_base import _arrays_for_stack_dispatcher
 from numpy.lib.index_tricks import ndindex
 from numpy.matrixlib.defmatrix import matrix  # this raises all the right alarm bells
 
@@ -630,7 +629,6 @@ def column_stack(tup):
            [3, 4]])
 
     """
-    _warn_for_nonsequence(tup)
     arrays = []
     for v in tup:
         arr = array(v, copy=False, subok=True)
@@ -695,7 +693,6 @@ def dstack(tup):
            [[3, 4]]])
 
     """
-    _warn_for_nonsequence(tup)
     return _nx.concatenate([atleast_3d(_m) for _m in tup], 2)
 
 
diff --git a/numpy/lib/ufunclike.py b/numpy/lib/ufunclike.py
index 5c411e8c8..8452604d9 100644
--- a/numpy/lib/ufunclike.py
+++ b/numpy/lib/ufunclike.py
@@ -8,7 +8,7 @@ from __future__ import division, absolute_import, print_function
 __all__ = ['fix', 'isneginf', 'isposinf']
 
 import numpy.core.numeric as nx
-from numpy.core.overrides import array_function_dispatch, ENABLE_ARRAY_FUNCTION
+from numpy.core.overrides import array_function_dispatch
 import warnings
 import functools
 
@@ -55,10 +55,6 @@ def _fix_out_named_y(f):
     return func
 
 
-if not ENABLE_ARRAY_FUNCTION:
-    _fix_out_named_y = _deprecate_out_named_y
-
-
 @_deprecate_out_named_y
 def _dispatcher(x, out=None):
     return (x, out)