`try!(foo)` is roughly equivalent to this (invalid) code: foo().unwrap_or_else({ |e| return Err(e) }) Or in Go terms: a := try!(foo) is equivalent t

`try!(foo)` is roughly equivalent to this (invalid) code: foo().unwrap_or_else({ |e| return Err(e) }) Or in Go terms: a := try!(foo) is equivalent to: a, err := foo() if err != nil { return nil, err } Basically it will take the result of foo, and if foo returns an error it will return the error itself. https://doc.rust-lang.org/beta/std/result/ https://doc.rust-lang.org/beta/std/result/ has lots of examples of alternative ways you can deal with the error case, or the Ok() case of a result.