I think the original bug is due to line 535 of numpy/core/src/multiarray/ctors.c (svn) that should be: intp numcopies, nbytes; instead of: int numcopies, nbytes; To resume: in line 535 of numpy/core/src/multiarray/ctors.c and in line 209 of numpy/core/src/multiarray/item_selection.c int should be replaced with intp.