  We study the interplay of disorder and bandstructure topology in a Weyl
semimetal with a tilted conical spectrum around the Weyl points. The spectrum
of particles is given by the eigenvalues of a non-Hermitian matrix, which
contains contributions from a Weyl Hamiltonian and complex self-energy due to
electron elastic scattering on disorder. We find that the tilt-induced matrix
structure of the self-energy gives rise to either a flat band or a nodal line
segment at the interface of the electron and hole pockets in the bulk
bandstructure of type-II Weyl semimetals depending on the Weyl cone
inclination. For the tilt in a single direction in momentum space, each Weyl
point expands into a flat band lying on the plane, which is transverse to the
direction of the tilt. The spectrum of the flat band is fully imaginary and is
separated from the in-plane dispersive part of the spectrum by the "exceptional
nodal ring" where the matrix of the Green function in momentum-frequency space
is defective. The tilt in two directions might shrink a flat band into a nodal
line segment with "exceptional edge points". We discuss the connection to the
non-Hermitian topological theory.
