  The low-temperature thermal expansion of CeCoIn5 single crystals measured
parallel and perpendicular to magnetic fields B oriented along the c axis
yields the volume thermal-expansion coefficient $\beta$. Considerable
deviations of $\beta(T)$ from Fermi-liquid behavior occur already within the
superconducting region of the (B, T) phase diagram and become maximal at the
upper critical field $B^0_{c2}$. However, $\beta(T)$ and the Gr\"uneisen
parameter $\Gamma$ are incompatible with a quantum critical point (QCP) at
$B^0_{c2}$, but allow for a QCP shielded by superconductivity and extending to
negative pressures for $B < B^0_{c2}$. Together with literature data we
construct a tentative (p, B, T) phase diagram of CeCoIn5 suggesting a quantum
critical line in the (p, B) plane.
