From dcffa4f12c6bbc5330ab2b44d34b6fe3ee209852 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?D=C3=A1niel=20Buga?= <bugadani@gmail.com>
Date: Fri, 10 Jan 2025 13:11:13 +0100
Subject: [PATCH] Place unused_imports on unstable reexports

---
 example/src/lib.rs |  2 --
 src/item_like.rs   | 54 ++++++++++++++++++++++++++++++----------------
 src/unstable.rs    |  4 +++-
 3 files changed, 39 insertions(+), 21 deletions(-)

diff --git a/example/src/lib.rs b/example/src/lib.rs
index d2c1489..95ab695 100644
--- a/example/src/lib.rs
+++ b/example/src/lib.rs
@@ -265,7 +265,6 @@ pub use private::private_function as stable_reexport;
 ///
 /// This re-export is unstable.
 #[instability::unstable(feature = "reexport")]
-#[allow(unused_imports)]
 pub use private::private_function as unstable_reexport;
 
 // This does not work as the unstable_private_function is only public within the crate and cannot
@@ -281,5 +280,4 @@ pub use private::private_function as unstable_reexport;
 /// section of the unstable_private_function, which will look odd. Consider avoiding re-exporting
 /// unstable items like this, and instead only mark the re-export itself as unstable.
 #[instability::unstable(feature = "reexport")]
-#[allow(unused_imports)]
 pub use private::unstable_private_function as unstable_unstable_export;
diff --git a/src/item_like.rs b/src/item_like.rs
index e95d6fb..ca87939 100644
--- a/src/item_like.rs
+++ b/src/item_like.rs
@@ -15,34 +15,48 @@ pub trait ItemLike: Stability {
     fn is_public(&self) -> bool {
         matches!(self.visibility(), Visibility::Public(_))
     }
+
+    fn unused_category(&self) -> syn::Ident;
 }
 
 macro_rules! impl_has_visibility {
-($($ty:ty),+ $(,)?) => {
-    $(
-        impl Stability for $ty {
-            fn attrs(&self) -> &[syn::Attribute] {
-                &self.attrs
-            }
-
-            fn push_attr(&mut self, attr: syn::Attribute) {
-                self.attrs.push(attr);
-            }
+($ty:ty[$unused:ident]) => {
+    impl Stability for $ty {
+        fn attrs(&self) -> &[syn::Attribute] {
+            &self.attrs
+        }
+
+        fn push_attr(&mut self, attr: syn::Attribute) {
+            self.attrs.push(attr);
+        }
+    }
+
+    impl ItemLike for $ty {
+        fn visibility(&self) -> &Visibility {
+            &self.vis
         }
 
-        impl ItemLike for $ty {
-            fn visibility(&self) -> &Visibility {
-                &self.vis
-            }
+        fn set_visibility(&mut self, visibility: Visibility) {
+            self.vis = visibility;
+        }
 
-            fn set_visibility(&mut self, visibility: Visibility) {
-                self.vis = visibility;
-            }
+        fn unused_category(&self) -> syn::Ident {
+            syn::Ident::new(stringify!($unused), proc_macro2::Span::call_site())
         }
+    }
+};
+($ty:ty) => {
+    $crate::item_like::impl_has_visibility!($ty [dead_code]);
+};
+($($ty:ty $([$unused:ident])?),+ $(,)?) => {
+    $(
+        $crate::item_like::impl_has_visibility!($ty $([$unused])?);
     )*
 };
 }
 
+pub(crate) use impl_has_visibility;
+
 impl_has_visibility!(
     syn::ItemType,
     syn::ItemEnum,
@@ -51,7 +65,7 @@ impl_has_visibility!(
     syn::ItemTrait,
     syn::ItemConst,
     syn::ItemStatic,
-    syn::ItemUse,
+    syn::ItemUse[unused_imports],
 );
 
 impl Stability for syn::ItemStruct {
@@ -79,6 +93,10 @@ impl ItemLike for syn::ItemStruct {
 
         self.vis = visibility;
     }
+
+    fn unused_category(&self) -> syn::Ident {
+        syn::Ident::new("dead_code", proc_macro2::Span::call_site())
+    }
 }
 
 impl Stability for syn::ItemImpl {
diff --git a/src/unstable.rs b/src/unstable.rs
index 70bd595..4f7818c 100644
--- a/src/unstable.rs
+++ b/src/unstable.rs
@@ -59,13 +59,15 @@ impl UnstableAttribute {
         let mut hidden_item = item.clone();
         hidden_item.set_visibility(parse_quote! { pub(crate) });
 
+        let unused = item.unused_category();
+
         quote! {
             #[cfg(any(doc, feature = #feature_flag))]
             #[cfg_attr(docsrs, doc(cfg(feature = #feature_flag)))]
             #item
 
             #[cfg(not(any(doc, feature = #feature_flag)))]
-            #[allow(dead_code)]
+            #[allow(#unused)]
             #hidden_item
         }
     }