>`?` uses the `From` trait which means you often don't need `.map_err`. 1. `From` is a global solution to a local problem. All `std::io::Error` must necessaril

>`?` uses the `From` trait which means you often don't need `.map_err`. 1. `From` is a global solution to a local problem. All `std::io::Error` must necessarily be converted to the same enum variant regardless of what caused them. Failing to open a file and failing to write to a network socket will create the same variant. 2. `From` does not have access to context anyway. A `From<std::io::Error>` is not going to know that the error was hit specifically when "parsing the /etc/foo.conf file", and a `From<std::string::ParseError>` is not going to know the error was hit when "parsing the bar field of the /etc/foo.conf file because it is set to `baz` which is not an integer". >as long as your error types implement std::error::Error, you shouldn't need an explicit .map_err to box them: This only works when you want your function to return `Box<dyn Error>` itself without any additional context. The conversation was about needing to add context like in the golang example.