  Mass loss remains a major uncertainty in stellar modelling. In low-mass
stars, mass loss is most significant on the red giant branch (RGB), and will
impact the star's evolutionary path and final stellar remnant. Directly
measuring the mass difference of stars in various phases of evolution
represents one of the best ways to quantify integrated mass loss. Globular
clusters (GCs) are ideal objects for this. M4 is currently the only GC for
which asteroseismic data exists for stars in multiple phases of evolution.
Using K2 photometry, we report asteroseismic masses for 75 red giants in M4,
the largest seismic sample in a GC to date. We find an integrated RGB mass loss
of $\Delta\bar{M} = 0.17 \pm 0.01 ~\mathrm{M}_{\odot}$, equivalent to a
Reimers' mass-loss coefficient of $\eta_R = 0.39$. Our results for initial
mass, horizontal branch mass, $\eta_R$, and integrated RGB mass loss show
remarkable agreement with previous studies, but with higher precision using
asteroseismology. We also report the first detections of solar-like
oscillations in early asymptotic giant branch (EAGB) stars in GCs. We find an
average mass of $\bar{M}_{\text{EAGB}}=0.54 \pm 0.01 ~\mathrm{M}_{\odot}$,
significantly lower than predicted by models. This suggests
larger-than-expected mass loss on the horizontal branch. Alternatively, it
could indicate unknown systematics in seismic scaling relations for the EAGB.
We discover a tentative mass bi-modality in the RGB sample, possibly due to the
multiple populations. In our red horizontal branch sample, we find a mass
distribution consistent with a single value. We emphasise the importance of
seismic studies of GCs since they could potentially resolve major uncertainties
in stellar theory.
