75 |     #[derive(Debug, Snafu)]
   |              ^^^^^ unsatisfied trait bound introduced in this `derive` macro
note: required for `GenericError<T, U>` to implement `snafu::Error`
  --> tests/transparent.rs:75:21
   |
75 |     #[derive(Debug, Snafu)]
   |                     ^^^^^ unsatisfied trait bound introduced in this `derive` macro
   = note: required for the cast from `&GenericError<T, U>` to `&dyn snafu::Error`
   = note: this error originates in the derive macro `Snafu` (in Nightly builds, run with -Z macro-backtrace for more info)
help: consider restricting type parameter `T` with trait `Debug`
   |
76 |     enum GenericError<T: std::fmt::Debug, U = i32> {
   |                        +++++++++++++++++

error[E0277]: `U` doesn't implement `Debug`
  --> tests/transparent.rs:75:21
   |
75 |     #[derive(Debug, Snafu)]
   |                     ^^^^^ the trait `Debug` is not implemented for `U`
   |
note: required for `GenericError<T, U>` to implement `Debug`
  --> tests/transparent.rs:75:14
   |
75 |     #[derive(Debug, Snafu)]
   |              ^^^^^ unsatisfied trait bound introduced in this `derive` macro
note: required for `GenericError<T, U>` to implement `snafu::Error`
  --> tests/transparent.rs:75:21
   |
75 |     #[derive(Debug, Snafu)]
   |                     ^^^^^ unsatisfied trait bound introduced in this `derive` macro
   = note: required for the cast from `&GenericError<T, U>` to `&dyn snafu::Error`
   = note: this error originates in the derive macro `Snafu` (in Nightly builds, run with -Z macro-backtrace for more info)
help: consider restricting type parameter `U` with trait `Debug`
   |
76 |     enum GenericError<T, U: std::fmt::Debug = i32> {
   |                           +++++++++++++++++

error[E0308]: mismatched types
  --> tests/transparent.rs:80:21
   |
80 |     #[derive(Debug, Snafu)]
   |                     ^^^^^ expected `()`, found `Result<(), Error>`
   |
   = note: expected unit type `()`
                   found enum `Result<(), std::fmt::Error>`
   = note: this error originates in the derive macro `Snafu` (in Nightly builds, run with -Z macro-backtrace for more info)
help: use the `?` operator to extract the `Result<(), std::fmt::Error>` value, propagating a `Result::Err` value to the caller
   |
80 |     #[derive(Debug, Snafu?)]
   |                          +

Some errors have detailed explanations: E0277, E0308.
For more information about an error, try `rustc --explain E0277`.
error: could not compile `snafu` (test "transparent") due to 5 previous errors

Exit status: 101