Multiple error types
The previous examples have always been very convenient; Result
s interact
with other Result
s and Option
s interact with other Option
s.
Sometimes an Option
needs to interact with a Result
, or a
Result<T, Error1>
needs to interact with a Result<T, Error2>
. In those
cases, we want to manage our different error types in a way that makes them
composable and easy to interact with.
In the following code, two instances of unwrap
generate different error
types. Vec::first
returns an Option
, while parse::<i32>
returns a
Result<i32, ParseIntError>
:
Over the next sections, we'll see several strategies for handling these kind of problems.