Wigner negativity is equivalent to contextuality for generalised position and momentum measurements
Understanding what differentiates a quantum system from a classical one is a crucial question, both foundationally and for quantum information applications. In this work, we consider two non-classical features of quantum systems: negativity of the Wigner function and contextuality. We prove that these two notions coincide when one considers measurements of linear combinations of position and momentum operators. Amongst other consequences, our result implies that contextuality is a crucial resource for continuous-variable quantum computations.