Related to #2275 (I opened a new issue per @charris request).

See this gist for a repro. Observed with numpy==1.13.1 in Python 3.6. The source causing a failure is:

function wat(x, y) result(z) bind(c, name='wat')
  integer, intent(in) :: x, y
  integer :: z

  z = x + y
end function wat