Lots of libraries we depend on throw exceptions, e.g. yojson, postgresql, or even just the stdlib (`Invalid_argument`, anyone?). Because the exceptions aren't

Lots of libraries we depend on throw exceptions, e.g. yojson, postgresql, or even just the stdlib (`Invalid_argument`, anyone?). Because the exceptions aren't statically shown at each usage point, it's hard to know what failure modes you should be watching for.