  Among the so-called classical tests of general relativity (GR), light bending
has been confirmed with an accuracy that increases as times goes by. Here we
study the gravitational deflection of photons within the framework of classical
and semiclassical higher-derivative gravity (HDG) -- the only version of GR
that is known up to now to be renormalizable along with its matter couplings.
Since our computations are restricted to scales much below the Planck cut-off
we need not be afraid of the massive spin-2 ghost that haunts HDG. An upper
bound on the constant related to the $R^2_{\mu \nu}$-sector of the theory is
then found by analyzing -- from a classical and semiclassical viewpoint -- the
deflection angle of a photon passing by the Sun. This upper limit greatly
improves that available in the literature.
