  Fractons are gapped point-like excitations in $d=3$ topological ordered
phases whose motion is constrained. They have been discovered in several gapped
models but a unifying physical mechanism for generating them is still missing.
It has been noticed that in symmetric-tensor ${\rm U}(1)$ gauge theories,
charges are fractons and cannot move freely due to, for example, the
conservation of not only the charge but also the dipole moment. To connect
these theories with fully gapped fracton models, we study Higgs and partial
confinement mechanisms in rank-2 symmetric-tensor gauge theories, where charges
or magnetic excitations, respectively, are condensed. Specifically, we describe
two different routes from the rank-2 ${\rm U}(1)$ scalar charge theory to the
X-cube fracton topological order, finding that a combination of Higgs and
partial confinement mechanisms is necessary to obtain the fully gapped fracton
model. On the other hand, the rank-2 $\mathbb{Z}_2$ scalar charge theory, which
is obtained from the former theory upon condensing charge-2 matter, is
equivalent to four copies of the $d=3$ toric code and does not support fracton
excitations. We also explain how the checkerboard fracton model can be viewed
as a rank-2 $\mathbb{Z}_2$ gauge theory with two different Gauss' law
constraints on different lattice sites.
