Debug for the ErrorKind

One small improvement is to fix the debug output of Func1ErrorKind. As you probably noticed, the output doesn't say much of the enum.

Debug Error:
src/main.rs:35: Func2
[…]

As a lazy shortcut, we implement Debug by calling Display and end up with

Debug Error:
src/main.rs:40: func1 error calling func2
[…}

which gives us a lot more detail.

To create your own Errors, you might find crates which create enum Display+Debug via derive macros.

Also noteworthy is custom_error to define your custom errors, which can then be used with chainerror.

{{#include ../examples/tutorial11.rs}}
# #[allow(dead_code)]
# mod chainerror {
{{#rustdoc_include ../src/lib.rs:-1}}
# }