numpy
diff --git a/‎numpy/core/multiarray.py
Lines changed: 23 additions & 0 deletions b/‎numpy/core/multiarray.py
Lines changed: 23 additions & 0 deletions
diff --git a/‎numpy/core/overrides.py
Lines changed: 11 additions & 2 deletions b/‎numpy/core/overrides.py
Lines changed: 11 additions & 2 deletions
diff --git a/‎numpy/tests/test_public_api.py
Lines changed: 16 additions & 0 deletions b/‎numpy/tests/test_public_api.py
Lines changed: 16 additions & 0 deletions
@@ -79,6 +79,7 @@
 def empty_like(prototype, dtype=None, order=None, subok=None, shape=None):
     """
     empty_like(prototype, dtype=None, order='K', subok=True, shape=None)
+    --
 
     Return a new array with the same shape and type as a given array.
 
@@ -147,6 +148,7 @@ def empty_like(prototype, dtype=None, order=None, subok=None, shape=None):
 def concatenate(arrays, axis=None, out=None, *, dtype=None, casting=None):
     """
     concatenate((a1, a2, ...), axis=0, out=None, dtype=None, casting="same_kind")
+    --
 
     Join a sequence of arrays along an existing axis.
 
@@ -248,6 +250,7 @@ def concatenate(arrays, axis=None, out=None, *, dtype=None, casting=None):
 def inner(a, b):
     """
     inner(a, b, /)
+    --
 
     Inner product of two arrays.
 
@@ -340,6 +343,7 @@ def inner(a, b):
 def where(condition, x=None, y=None):
     """
     where(condition, [x, y], /)
+    --
 
     Return elements chosen from `x` or `y` depending on `condition`.
 
@@ -415,6 +419,7 @@ def where(condition, x=None, y=None):
 def lexsort(keys, axis=None):
     """
     lexsort(keys, axis=-1)
+    --
 
     Perform an indirect stable sort using a sequence of keys.
 
@@ -497,6 +502,7 @@ def lexsort(keys, axis=None):
 def can_cast(from_, to, casting=None):
     """
     can_cast(from_, to, casting='safe')
+    --
 
     Returns True if cast between data types can occur according to the
     casting rule.  If from is a scalar or array scalar, also returns
@@ -612,6 +618,7 @@ def can_cast(from_, to, casting=None):
 def min_scalar_type(a):
     """
     min_scalar_type(a, /)
+    --
 
     For scalar ``a``, returns the data type with the smallest size
     and smallest scalar kind which can hold its value.  For non-scalar
@@ -663,6 +670,7 @@ def min_scalar_type(a):
 def result_type(*arrays_and_dtypes):
     """
     result_type(*arrays_and_dtypes)
+    --
 
     Returns the type that results from applying the NumPy
     type promotion rules to the arguments.
@@ -735,6 +743,7 @@ def result_type(*arrays_and_dtypes):
 def dot(a, b, out=None):
     """
     dot(a, b, out=None)
+    --
 
     Dot product of two arrays. Specifically,
 
@@ -824,6 +833,7 @@ def dot(a, b, out=None):
 def vdot(a, b):
     """
     vdot(a, b, /)
+    --
 
     Return the dot product of two vectors.
 
@@ -882,6 +892,7 @@ def vdot(a, b):
 def bincount(x, weights=None, minlength=None):
     """
     bincount(x, /, weights=None, minlength=0)
+    --
 
     Count number of occurrences of each value in array of non-negative ints.
 
@@ -959,6 +970,7 @@ def bincount(x, weights=None, minlength=None):
 def ravel_multi_index(multi_index, dims, mode=None, order=None):
     """
     ravel_multi_index(multi_index, dims, mode='raise', order='C')
+    --
 
     Converts a tuple of index arrays into an array of flat
     indices, applying boundary modes to the multi-index.
@@ -1020,6 +1032,7 @@ def ravel_multi_index(multi_index, dims, mode=None, order=None):
 def unravel_index(indices, shape=None, order=None):
     """
     unravel_index(indices, shape, order='C')
+    --
 
     Converts a flat index or array of flat indices into a tuple
     of coordinate arrays.
@@ -1070,6 +1083,7 @@ def unravel_index(indices, shape=None, order=None):
 def copyto(dst, src, casting=None, where=None):
     """
     copyto(dst, src, casting='same_kind', where=True)
+    --
 
     Copies values from one array to another, broadcasting as necessary.
 
@@ -1105,6 +1119,7 @@ def copyto(dst, src, casting=None, where=None):
 def putmask(a, mask, values):
     """
     putmask(a, mask, values)
+    --
 
     Changes elements of an array based on conditional and input values.
 
@@ -1150,6 +1165,7 @@ def putmask(a, mask, values):
 def packbits(a, axis=None, bitorder='big'):
     """
     packbits(a, /, axis=None, bitorder='big')
+    --
 
     Packs the elements of a binary-valued array into bits in a uint8 array.
 
@@ -1208,6 +1224,7 @@ def packbits(a, axis=None, bitorder='big'):
 def unpackbits(a, axis=None, count=None, bitorder='big'):
     """
     unpackbits(a, /, axis=None, count=None, bitorder='big')
+    --
 
     Unpacks elements of a uint8 array into a binary-valued output array.
 
@@ -1292,6 +1309,7 @@ def unpackbits(a, axis=None, count=None, bitorder='big'):
 def shares_memory(a, b, max_work=None):
     """
     shares_memory(a, b, /, max_work=None)
+    --
 
     Determine if two arrays share memory.
 
@@ -1367,6 +1385,7 @@ def shares_memory(a, b, max_work=None):
 def may_share_memory(a, b, max_work=None):
     """
     may_share_memory(a, b, /, max_work=None)
+    --
 
     Determine if two arrays might share memory
 
@@ -1408,6 +1427,7 @@ def may_share_memory(a, b, max_work=None):
 def is_busday(dates, weekmask=None, holidays=None, busdaycal=None, out=None):
     """
     is_busday(dates, weekmask='1111100', holidays=None, busdaycal=None, out=None)
+    --
 
     Calculates which of the given dates are valid days, and which are not.
 
@@ -1463,6 +1483,7 @@ def busday_offset(dates, offsets, roll=None, weekmask=None, holidays=None,
                   busdaycal=None, out=None):
     """
     busday_offset(dates, offsets, roll='raise', weekmask='1111100', holidays=None, busdaycal=None, out=None)
+    --
 
     First adjusts the date to fall on a valid day according to
     the ``roll`` rule, then applies offsets to the given dates
@@ -1557,6 +1578,7 @@ def busday_count(begindates, enddates, weekmask=None, holidays=None,
                  busdaycal=None, out=None):
     """
     busday_count(begindates, enddates, weekmask='1111100', holidays=[], busdaycal=None, out=None)
+    --
 
     Counts the number of valid days between `begindates` and
     `enddates`, not including the day of `enddates`.
@@ -1625,6 +1647,7 @@ def busday_count(begindates, enddates, weekmask=None, holidays=None,
 def datetime_as_string(arr, unit=None, timezone=None, casting=None):
     """
     datetime_as_string(arr, unit=None, timezone='naive', casting='same_kind')
+    --
 
     Convert an array of datetimes into an array of strings.
 
 
@@ -2,6 +2,7 @@
 import collections
 import functools
 import os
+import textwrap
 
 from numpy.core._multiarray_umath import (
     add_docstring, implement_array_function, _get_implementing_args)
@@ -85,6 +86,14 @@ def set_array_function_like_doc(public_api):
 ArgSpec = collections.namedtuple('ArgSpec', 'args varargs keywords defaults')
 
 
+def add_docstring_from_dispatcher(implementation, dispatcher):
+    """Use dispatcher to populate doc and text signature of implementation"""
+    doc = dispatcher.__doc__
+    if doc is None:
+        return
+    add_docstring(implementation, textwrap.dedent(doc).lstrip())
+
+
 def verify_matching_signatures(implementation, dispatcher):
     """Verify that a dispatcher function has the right signature."""
     implementation_spec = ArgSpec(*getargspec(implementation))
@@ -161,7 +170,7 @@ def array_function_dispatch(dispatcher, module=None, verify=True,
     if not ARRAY_FUNCTION_ENABLED:
         def decorator(implementation):
             if docs_from_dispatcher:
-                add_docstring(implementation, dispatcher.__doc__)
+                add_docstring_from_dispatcher(implementation, dispatcher)
             if module is not None:
                 implementation.__module__ = module
             return implementation
@@ -172,7 +181,7 @@ def decorator(implementation):
             verify_matching_signatures(implementation, dispatcher)
 
         if docs_from_dispatcher:
-            add_docstring(implementation, dispatcher.__doc__)
+            add_docstring_from_dispatcher(implementation, dispatcher)
 
         @functools.wraps(implementation)
         def public_api(*args, **kwargs):
 
@@ -2,6 +2,7 @@
 import subprocess
 import pkgutil
 import types
+import inspect
 import importlib
 import warnings
 
@@ -459,3 +460,18 @@ def check_importable(module_name):
         raise AssertionError("Modules that are not really public but looked "
                              "public and can not be imported: "
                              "{}".format(module_names))
+
+
+@pytest.mark.skipif(sys.flags.optimize >= 2, reason='docstring stripped')
+def test_all_function_have_signature():
+    allowlist = {'concatenate', 'where'}
+
+    for key, value in inspect.getmembers(numpy):
+        if not inspect.isfunction(value):
+            continue
+        if key in allowlist:
+            continue
+        try:
+            inspect.signature(value)
+        except ValueError:
+            raise AssertionError("No signature found for {}".format(key))