  Identifying planets around O-type and B-type stars is inherently difficult;
the most massive known planet host has a mass of only about $3M_{\odot}$.
However, planetary systems which survive the transformation of their host stars
into white dwarfs can be detected via photospheric trace metals, circumstellar
dusty and gaseous discs, and transits of planetary debris crossing our
line-of-sight. These signatures offer the potential to explore the efficiency
of planet formation for host stars with masses up to the core-collapse boundary
at $\approx 8M_{\odot}$, a mass regime rarely investigated in planet formation
theory. Here, we establish limits on where both major and minor planets must
reside around $\approx 6M_{\odot}-8M_{\odot}$ stars in order to survive into
the white dwarf phase. For this mass range, we find that intact terrestrial or
giant planets need to leave the main sequence beyond approximate minimum
star-planet separations of respectively about 3 and 6 au. In these systems,
rubble pile minor planets of radii 10, 1.0, and 0.1 km would have been shorn
apart by giant branch radiative YORP spin-up if they formed and remained
within, respectively, tens, hundreds and thousands of au. These boundary values
would help distinguish the nature of the progenitor of metal-pollution in white
dwarf atmospheres. We find that planet formation around the highest mass white
dwarf progenitors may be feasible, and hence encourage both dedicated planet
formation investigations for these systems and spectroscopic analyses of the
highest mass white dwarfs.
