Rust 1.81 lint fixes

Cargo.toml

@@ -77,6 +77,9 @@ internal-tests = [
     "tokio/rt-multi-thread",
 ]
 
+[lints.rust]
+unexpected_cfgs = { level = "warn", check-cfg = ['cfg(docs)'] }
+
 [dev-dependencies]
 safer-ffi.path = "."
 safer-ffi.features = ["internal-tests"]
@@ -110,7 +113,7 @@ scopeguard.default-features = false
 
 serde.version = "1.0.204"
 serde.optional = true
-serde.default_features = false
+serde.default-features = false
 
 stabby.version = "36.1.1"
 stabby.optional = true

src/proc_macro/derives/c_type/struct_.rs

@@ -2,6 +2,7 @@
 
 use super::*;
 
+#[allow(unexpected_cfgs)]
 pub(in crate)
 fn derive (
     args: Args,

src/proc_macro/derives/dyn_trait/args.rs

@@ -28,6 +28,7 @@ define_kws! {$
 
 pub
 struct Args {
+    #[allow(dead_code)]
     pub dyn_: sym![dyn],
     pub clone: Option<sym![Clone]>,
 }

src/proc_macro/derives/dyn_trait/coercions.rs

@@ -283,6 +283,7 @@ match_! {(
     struct Env<'r> {
         // quote-interpolable/friendly stuff from the caller.
     $(
+        #[allow(dead_code)]
         pub
         $field : &'r dyn ToTokens,
     )*

src/proc_macro/ffi_export/const_.rs

@@ -42,6 +42,7 @@ impl Parse for Args {
 }
 
 
+#[allow(unexpected_cfgs)]
 pub(in super)
 fn handle (
     Args { untyped }: Args,

src/proc_macro/ffi_export/fn_/args.rs

@@ -21,7 +21,7 @@ pub(in crate)
 struct Executor {
     pub(in crate) kw: kw::executor,
     pub(in crate) _eq: Token![=],
-    #[cfg_attr(not(feature = "async_fn"),
+    #[cfg_attr(not(feature = "async-fn"),
         allow(dead_code),
     )]
     pub(in crate) block_on: Expr,

src/proc_macro/ffi_export/static_.rs

@@ -6,6 +6,5 @@ fn handle (
     _input: ItemStatic,
 ) -> Result<TokenStream2>
 {
-    #[cfg(not(TODO))]
     todo!("`#[ffi_export]`ing a `static`");
 }