Enable rust_2018_idioms lint

This change enables the rust_2018_idioms lint which helps enforce the
usage of Rust 2018 code idioms. A while back the "impl trait" feature
stabilized and along with it trait objects are supposed to be prefixed
with "dyn".
This change adjusts the code accordingly.

1 files changed, 5 insertions, 2 deletions

diff --git a/nitrocli/src/main.rs b/nitrocli/src/main.rs
index 67a0a22..c598b8d 100644
--- a/nitrocli/src/main.rs
+++ b/nitrocli/src/main.rs
@@ -18,7 +18,10 @@
 // *************************************************************************
 
 #![deny(missing_docs)]
-#![warn(rust_2018_compatibility)]
+#![warn(
+  rust_2018_compatibility,
+  rust_2018_idioms,
+)]
 
 //! Nitrocli is a program providing a command line interface to certain
 //! commands of the Nitrokey Storage device.
@@ -40,7 +43,7 @@ use std::time;
 use crate::error::Error;
 
 type Result<T> = result::Result<T, Error>;
-type NitroFunc = Fn(&mut libhid::Handle) -> Result<()>;
+type NitroFunc = dyn Fn(&mut libhid::Handle) -> Result<()>;
 
 
 const PIN_TYPE: pinentry::PinType = pinentry::PinType::User;