error messages include paths that cannot possibly resolve when used

[whitequark]

E.g. let's say in src/wire/mod.rs I have:

pub use self::arp::Packet as ArpPacket;

If I now misuse a value of this type, I get an error like this:

error[E0277]: the trait bound `smoltcp::wire::Packet<&[u8]>: std::fmt::Display` is not satisfied
  --> examples/smoltcpdump.rs:22:28
   |
22 |             println!("{}", packet);
   |                            ^^^^^^ the trait `std::fmt::Display` is not implemented for `smoltcp::wire::Packet<&[u8]>`
   |
   = note: `smoltcp::wire::Packet<&[u8]>` cannot be formatted with the default formatter; try using `:?` instead if you are using a format string
   = note: required by `std::fmt::Display::fmt`

which of course does not refer to a path that exists.

[estebank]

Related to #21934.

[Mark-Simulacrum]

Duplicate, I think, not related. Closing in favor of #21934.