clean up some instances of suboffsets handling in memoryview code

Cython/Utility/MemoryView.pyx

@@ -526,7 +526,7 @@ cdef class memoryview(object):
         @cname('__pyx_memoryview_get_suboffsets')
         def __get__(self):
             if self.view.suboffsets == NULL:
-                return [-1] * self.view.ndim
+                return (-1,) * self.view.ndim
 
             return tuple([suboffset for suboffset in self.view.suboffsets[:self.view.ndim]])
 
@@ -654,9 +654,8 @@ cdef tuple _unellipsify(object index, int ndim):
     return have_slices or nslices, tuple(result)
 
 cdef assert_direct_dimensions(Py_ssize_t *suboffsets, int ndim):
-    cdef int i
-    for i in range(ndim):
-        if suboffsets[i] >= 0:
+    for suboffset in suboffsets[:ndim]:
+        if suboffset >= 0:
             raise ValueError("Indirect dimensions not supported")
 
 #
@@ -1024,10 +1023,7 @@ cdef void slice_copy(memoryview memview, {{memviewslice_name}} *dst):
     for dim in range(memview.view.ndim):
         dst.shape[dim] = shape[dim]
         dst.strides[dim] = strides[dim]
-        if suboffsets == NULL:
-            dst.suboffsets[dim] = -1
-        else:
-            dst.suboffsets[dim] = suboffsets[dim]
+        dst.suboffsets[dim] = suboffsets[dim] if suboffsets else -1
 
 @cname('__pyx_memoryview_copy_object')
 cdef memoryview_copy(memoryview memview):
@@ -1291,21 +1287,21 @@ cdef int memoryview_copy_contents({{memviewslice_name}} src,
     return 0
 
 @cname('__pyx_memoryview_broadcast_leading')
-cdef void broadcast_leading({{memviewslice_name}} *slice,
+cdef void broadcast_leading({{memviewslice_name}} *mslice,
                             int ndim,
                             int ndim_other) nogil:
     cdef int i
     cdef int offset = ndim_other - ndim
 
     for i in range(ndim - 1, -1, -1):
-        slice.shape[i + offset] = slice.shape[i]
-        slice.strides[i + offset] = slice.strides[i]
-        slice.suboffsets[i + offset] = slice.suboffsets[i]
+        mslice.shape[i + offset] = mslice.shape[i]
+        mslice.strides[i + offset] = mslice.strides[i]
+        mslice.suboffsets[i + offset] = mslice.suboffsets[i]
 
     for i in range(offset):
-        slice.shape[i] = 1
-        slice.strides[i] = slice.strides[0]
-        slice.suboffsets[i] = -1
+        mslice.shape[i] = 1
+        mslice.strides[i] = mslice.strides[0]
+        mslice.suboffsets[i] = -1
 
 #
 ### Take care of refcounting the objects in slices. Do this seperately from any copying,