The new eFuse API implemented in #847 is a bit misleading to use, and in fact many of the generated EfuseField definitions that it included lead to a panic if you try to read them using Chip::read_efuse.
EfuseField appears to support defining fields that are wider than a single 32-bit word, and many of the generated definitions do exactly that, but Chip::read_efuse only supports reading fields of at most 32 bits. Passing in a field wider than that leads to a "attempt to shift left with overflow" panic.