  We analyze the chemical composition of the planetary nebula (PN) NGC 5315,
through high-resolution (R = 40000) optical spectroscopy with UVES at the Very
Large Telescope, and medium-resolution (R = 4800) near-infrared spectroscopy
with FIRE at Magellan Baade Telescope, covering a wide spectral range from 0.31
to 2.50 micron. The main aim of this work is to investigate neutron (n)-capture
element abundances to study the operation of the slow n-capture ("s-process")
in the AGB progenitor of NGC 5315. We detect more than 700 emission lines,
including ions of the n-capture elements Se, Kr, Xe, and possibly Br. We
compute physical conditions from a large number of diagnostic line ratios, and
derive ionic abundances for species with available atomic data. The total
abundances are computed using recent ionization correction factors (ICFs) or by
summing ionic abundances. Total abundances of common elements are in good
agreement with previous work on this object. Based on our abundance analysis of
NGC 5315, including the lack of s-process enrichment, we speculate that the
most probable scenario is that the progenitor star is in a binary system as
hinted at by radial velocity studies, and interactions with its companion
truncated the AGB before s-process enrichment could occur. However there are
other two possible scenarios for its evolution, that cannot be ruled out: i)
the progenitor is a low-mass single star that did not undergo third dredge-up;
ii) the progenitor star of NGC 5315 had an initial mass of 4--6 solar masses,
and any s-process enhancements were heavily diluted by the massive envelope
during the AGB phase.
