Add tests, fix remaining bug in label implementation, make label implementation strictly more flexible using to_owned over clone

Signed-off-by: Justus Fluegel <justusfluegel@gmail.com>
Signed-off-by: Justus Flügel <justusfluegel@gmail.com>

miette-derive/src/label.rs

@@ -208,10 +208,14 @@ impl Labels {
             Some(quote! {
                 miette::macro_helpers::OptionalWrapper::<#ty>::new().to_option(&self.#span)
                 .as_ref()
-                .map(|#var| #ctor(
-                    #display,
-                    (*#var).clone(),
-                ))
+                .map(|#var| {
+                    use ::std::borrow::ToOwned;
+
+                    #ctor(
+                        #display,
+                        (*#var).to_owned(),
+                    )
+                })
             })
         });
         let collections_chain = self.0.iter().filter_map(|label| {
@@ -236,7 +240,8 @@ impl Labels {
                     let display = #display;
                     ::std::iter::IntoIterator::into_iter(&self.#span).map(move |span| {
                         use miette::macro_helpers::{ToLabelSpanWrapper,ToLabeledSpan};
-                        let mut labeled_span = ToLabelSpanWrapper::to_labeled_span(span.clone());
+                        use ::std::borrow::ToOwned;
+                        let mut labeled_span = ToLabelSpanWrapper::to_labeled_span(span.to_owned());
                         if display.is_some() && labeled_span.label().is_none() {
                             labeled_span.set_label(display.clone())
                         }
@@ -296,10 +301,15 @@ impl Labels {
 
                         Some(quote! {
                             miette::macro_helpers::OptionalWrapper::<#ty>::new().to_option(#field)
-                            .map(|#var| #ctor(
-                                #display,
-                                #var.clone(),
-                            ))
+                            .as_ref()
+                            .map(|#var| {
+                                use ::std::borrow::ToOwned;
+
+                                #ctor(
+                                    #display,
+                                    (*#var).to_owned(),
+                                )
+                            })
                         })
                     });
                     let collections_chain = labels.0.iter().filter_map(|label| {
@@ -322,9 +332,12 @@ impl Labels {
                         Some(quote! {
                             .chain({
                                 let display = #display;
-                                #field.iter().map(move |span| {
+                                ::std::iter::IntoIterator::into_iter(#field).map(move |span| {
                                     use miette::macro_helpers::{ToLabelSpanWrapper,ToLabeledSpan};
-                                    let mut labeled_span = ToLabelSpanWrapper::to_labeled_span(span.clone());
+                                    use ::std::borrow::ToOwned;
+                                    let mut labeled_span = ToLabelSpanWrapper::to_labeled_span(
+                                        span.to_owned()
+                                    );
                                     if display.is_some() && labeled_span.label().is_none() {
                                         labeled_span.set_label(display.clone());
                                     }

miette-derive/src/trait_bounds.rs

@@ -20,7 +20,8 @@ pub struct RequiredTraitBound {
     source_code: bool,
     into_source_span: bool,
     std_into_iter: bool,
-    std_clone: bool,
+    std_deref: bool,
+    std_to_owned: bool,
 }
 
 impl RequiredTraitBound {
@@ -56,9 +57,13 @@ impl RequiredTraitBound {
             )))
         }
 
-        if self.std_clone {
+        if self.std_deref {
+            bounds.push(TypeParamBound::Trait(syn::parse_quote!(::std::ops::Deref)))
+        }
+
+        if self.std_to_owned {
             bounds.push(TypeParamBound::Trait(syn::parse_quote!(
-                ::std::clone::Clone
+                ::std::borrow::ToOwned
             )))
         }
 
@@ -80,7 +85,6 @@ impl RequiredTraitBound {
 
     fn register_label_usage(&mut self) {
         self.into_source_span = true;
-        self.std_clone = true;
     }
 
     fn register_collection_usage(&mut self) {
@@ -95,6 +99,14 @@ impl RequiredTraitBound {
         self.miette_diagnostic = true;
         self.r#static = true;
     }
+
+    fn register_deref_usage(&mut self) {
+        self.std_deref = true;
+    }
+
+    fn register_to_owned_usage(&mut self) {
+        self.std_to_owned = true;
+    }
 }
 
 pub struct TraitBoundStore(HashMap<(Option<BoundLifetimes>, Type), RequiredTraitBound>);
@@ -354,12 +366,22 @@ impl TraitBoundStore {
     pub fn register_label_usage(&mut self, r#type: &Type) {
         let r#type = Self::extract_option(r#type).unwrap_or(r#type);
 
-        let Some(r#type) = self.check_generic_usage(r#type) else {
+        let Some(ty) = self.check_generic_usage(r#type) else {
             return;
         };
 
-        let type_opts = self.0.entry((None, r#type.clone())).or_default();
-        type_opts.register_label_usage()
+        let type_opts = self.0.entry((None, ty.clone())).or_default();
+
+        type_opts.register_to_owned_usage();
+
+        let type_opts_to_owned = self
+            .0
+            .entry((
+                None,
+                syn::parse_quote!(<#ty as ::std::borrow::ToOwned>::Owned),
+            ))
+            .or_default();
+        type_opts_to_owned.register_label_usage();
     }
 
     pub fn register_label_collection_usage(&mut self, r#type: &Type) {
@@ -385,7 +407,25 @@ impl TraitBoundStore {
                 syn::parse_quote!(<#ty as ::std::iter::IntoIterator>::Item),
             ))
             .or_default();
-        type_opts_item.register_label_usage();
+        type_opts_item.register_deref_usage();
+
+        let type_opts_deref_item = self
+            .0
+            .entry((
+                Some(syn::parse_quote!(for<'__miette_internal_lt>)),
+                syn::parse_quote!(<<#ty as ::std::iter::IntoIterator>::Item as ::std::ops::Deref>::Target),
+            ))
+            .or_default();
+        type_opts_deref_item.register_to_owned_usage();
+
+        let type_opts_deref_to_owned_item = self
+            .0
+            .entry((
+                Some(syn::parse_quote!(for<'__miette_internal_lt>)),
+                syn::parse_quote!(<<<#ty as ::std::iter::IntoIterator>::Item as ::std::ops::Deref>::Target as ::std::borrow::ToOwned>::Owned),
+            ))
+            .or_default();
+        type_opts_deref_to_owned_item.register_label_usage();
     }
 
     pub fn register_related_usage(&mut self, r#type: &Type) {

tests/test_derive_attr.rs

@@ -145,3 +145,133 @@ fn attr_not_required() {
     let expectation = LabeledSpan::new(Some("this bit here".into()), 9usize, 4usize);
     assert_eq!(err_span, expectation);
 }
+
+fn assert_impl_diagnostic<T: Diagnostic>() {}
+
+#[test]
+fn transparent_generic() {
+    #[derive(Debug, Diagnostic, Error)]
+    enum Combined<T> {
+        #[error(transparent)]
+        #[diagnostic(transparent)]
+        Other(T),
+        #[error("foo")]
+        Custom,
+    }
+
+    assert_impl_diagnostic::<Combined<miette::MietteDiagnostic>>();
+}
+
+#[test]
+fn generic_label() {
+    #[derive(Debug, Diagnostic, Error)]
+    #[error("foo")]
+    struct Combined<T> {
+        #[label]
+        label: T,
+    }
+
+    assert_impl_diagnostic::<Combined<SourceSpan>>();
+    assert_impl_diagnostic::<Combined<(usize, usize)>>();
+}
+
+#[test]
+fn generic_source_code() {
+    #[derive(Debug, Diagnostic, Error)]
+    #[error("foo")]
+    struct Combined<T> {
+        #[source_code]
+        label: T,
+    }
+
+    assert_impl_diagnostic::<Combined<String>>();
+}
+
+#[test]
+fn generic_optional_source_code() {
+    #[derive(Debug, Diagnostic, Error)]
+    #[error("foo")]
+    struct Combined<T> {
+        #[source_code]
+        label: Option<T>,
+    }
+
+    assert_impl_diagnostic::<Combined<String>>();
+}
+
+#[test]
+fn generic_label_primary() {
+    #[derive(Debug, Diagnostic, Error)]
+    #[error("foo")]
+    struct Combined<T> {
+        #[label(primary)]
+        label: T,
+    }
+
+    assert_impl_diagnostic::<Combined<SourceSpan>>();
+    assert_impl_diagnostic::<Combined<(usize, usize)>>();
+}
+
+#[test]
+fn generic_label_collection() {
+    #[derive(Debug, Diagnostic, Error)]
+    #[error("foo")]
+    struct Combined<T> {
+        #[label(collection)]
+        label: Vec<T>,
+    }
+
+    assert_impl_diagnostic::<Combined<SourceSpan>>();
+    assert_impl_diagnostic::<Combined<(usize, usize)>>();
+}
+
+#[test]
+fn generic_label_generic_collection() {
+    #[derive(Debug, Diagnostic, Error)]
+    #[error("foo")]
+    struct Combined<T> {
+        #[label(collection)]
+        label: T,
+    }
+
+    assert_impl_diagnostic::<Combined<Vec<SourceSpan>>>();
+    assert_impl_diagnostic::<Combined<Vec<(usize, usize)>>>();
+}
+
+#[test]
+fn generic_related() {
+    #[derive(Debug, Diagnostic, Error)]
+    #[error("foo")]
+    struct Combined<T> {
+        #[related]
+        label: Vec<T>,
+    }
+
+    assert_impl_diagnostic::<Combined<miette::MietteDiagnostic>>();
+}
+
+#[test]
+fn generic_diagnostic_source() {
+    #[derive(Debug, Diagnostic, Error)]
+    enum Combined<T> {
+        #[error(transparent)]
+        Other(#[diagnostic_source] T),
+        #[error("foo")]
+        Custom,
+    }
+
+    assert_impl_diagnostic::<Combined<miette::MietteDiagnostic>>();
+}
+
+#[test]
+fn generic_not_influencing_default() {
+    #[derive(Debug, Diagnostic, Error)]
+    enum Combined<T> {
+        #[error("bar")]
+        Other(T),
+        #[error("foo")]
+        Custom,
+    }
+
+    assert_impl_diagnostic::<Combined<i32>>();
+}