Derive Debug.

src/backends/appkit.rs

@@ -9,7 +9,7 @@ use objc::*;
 
 use crate::{Backend, BackendId, Error, Features, UtteranceId};
 
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub(crate) struct AppKit(*mut Object, *mut Object);
 
 impl AppKit {

src/backends/av_foundation.rs

@@ -11,7 +11,7 @@ use objc::{class, declare::ClassDecl, msg_send, sel, sel_impl};
 
 use crate::{Backend, BackendId, Error, Features, UtteranceId, CALLBACKS};
 
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub(crate) struct AvFoundation {
     id: BackendId,
     delegate: *mut Object,

src/backends/speech_dispatcher.rs

@@ -8,7 +8,7 @@ use speech_dispatcher::*;
 
 use crate::{Backend, BackendId, Error, Features, UtteranceId, CALLBACKS};
 
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub(crate) struct SpeechDispatcher(Connection);
 
 lazy_static! {

src/backends/tolk.rs

@@ -4,7 +4,7 @@ use tolk::Tolk as TolkPtr;
 
 use crate::{Backend, BackendId, Error, Features, UtteranceId};
 
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub(crate) struct Tolk(TolkPtr);
 
 impl Tolk {

src/backends/web.rs

@@ -12,7 +12,7 @@ use web_sys::{
 
 use crate::{Backend, BackendId, Error, Features, UtteranceId, CALLBACKS};
 
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub struct Web {
     id: BackendId,
     rate: f32,

src/backends/winrt.rs

@@ -21,7 +21,7 @@ impl From<winrt::Error> for Error {
     }
 }
 
-#[derive(Clone)]
+#[derive(Clone, Debug)]
 pub struct WinRT {
     id: BackendId,
     synth: SpeechSynthesizer,

src/lib.rs

@@ -110,7 +110,7 @@ pub enum Error {
 }
 
 #[clonable]
-trait Backend: Clone {
+trait Backend: Clone + std::fmt::Debug {
     fn id(&self) -> Option<BackendId>;
     fn supported_features(&self) -> Features;
     fn speak(&mut self, text: &str, interrupt: bool) -> Result<Option<UtteranceId>, Error>;