fix: support non-receiver lifetimes in trait functions

stabby-macros/src/traits.rs

@@ -679,10 +679,10 @@ impl DynTraitDescription<'_> {
             .map(|fn_ptr | {
                 let DynTraitFn {
                     ident,
-                    generics: _,
+                    generics,
                     abi,
                     unsafety,
-                    receiver: syn::Receiver {mutability, reference: Some((_, lt)), self_token, ..},
+                    receiver: syn::Receiver {mutability, reference: Some((_, receiver_lt)), self_token, ..},
                     inputs,
                     output,
                 } = fn_ptr else {panic!("Only references and mutable references are supported")};
@@ -697,15 +697,22 @@ impl DynTraitDescription<'_> {
                     .zip(arg_tys.iter())
                     .map(|(name, ty)| quote!(#name: #ty))
                     .collect::<Vec<_>>();
+                let mut arg_lts = generics.lifetimes().cloned().collect::<Vec<_>>();
                 let output = output.as_ref().map(|ty| {
                     let ty = self.self_dependent_types.unselfed(ty);
                     quote!(-> #ty)
                 });
-                let lt = lt.clone().unwrap_or_else(|| Lifetime::new("'stabby_receiver_lt", self_token.span()));
+                let receiver_lt = if let Some(lt) = receiver_lt {
+                    lt.clone()
+                } else {
+                    let default_lt = Lifetime::new("'stabby_receiver_lt", self_token.span());
+                    arg_lts.push(syn::LifetimeDef::new(default_lt.clone()));
+                    default_lt
+                };
                 let receiver = if mutability.is_some() {
-                    quote!(#st::AnonymRefMut<#lt>)
+                    quote!(#st::AnonymRefMut<#receiver_lt>)
                 } else {
-                    quote!(#st::AnonymRef<#lt>)
+                    quote!(#st::AnonymRef<#receiver_lt>)
                 };
                 let as_ref = if mutability.is_some() {
                     quote!(as_mut())
@@ -715,13 +722,13 @@ impl DynTraitDescription<'_> {
                 let mut ctor = quote!(#st::StableLike::new({
                     #unsafety #abi fn #ext_ident <
                         'stabby_local_lt,
-                        #lt,
                         #(#trait_lts,)*
+                        #(#arg_lts,)*
                         StabbyArbitraryType: 'stabby_local_lt,
                         #(#dyntrait_types,)*
                         #(#trait_types,)*
                         #(#trait_consts,)*
-                    >(this: #receiver, _lt_proof: ::core::marker::PhantomData<&#lt &'stabby_local_lt ()>, #(#args,)*) #output
+                    >(this: #receiver, _lt_proof: ::core::marker::PhantomData<&#receiver_lt &'stabby_local_lt ()>, #(#args,)*) #output
                     where
                         StabbyArbitraryType: #trait_id <#(#unbound_trait_lts,)* #(#unbound_trait_types,)* #(#unbound_trait_consts,)* #(#trait_to_vt_bindings,)* >,
                         #(#vt_bounds)*
@@ -735,9 +742,9 @@ impl DynTraitDescription<'_> {
                         }
                     }
                     #ext_ident :: < StabbyArbitraryType, #(#dyntrait_types,)* #(#unbound_trait_types,)* #(#unbound_trait_consts,)*  > as for <
-                    #lt,
                     #(#trait_lts,)*
-                > #unsafety #abi fn (#receiver, ::core::marker::PhantomData<&#lt &'stabby_vt_lt ()>, #(#arg_tys,)*) #output
+                    #(#arg_lts,)*
+                > #unsafety #abi fn (#receiver, ::core::marker::PhantomData<&#receiver_lt &'stabby_vt_lt ()>, #(#arg_tys,)*) #output
                 }));
                 if self.check_bounds {
                     ctor = quote!(#st::StableIf::new(#ctor))

stabby/src/tests/traits.rs

@@ -24,6 +24,7 @@ pub trait MyTrait {
     type Output;
     extern "C" fn do_stuff<'a>(&'a self, with: &'a Self::Output) -> &'a u8;
     extern "C" fn gen_stuff(&mut self) -> Self::Output;
+    extern "C" fn filter_stuff<'a>(&self, source: &'a u8) -> &'a u8;
 }
 
 // IMPL
@@ -36,6 +37,9 @@ impl MyTrait for u8 {
     extern "C" fn gen_stuff(&mut self) -> Self::Output {
         *self
     }
+    extern "C" fn filter_stuff<'a>(&self, source: &'a u8) -> &'a u8 {
+        source
+    }
 }
 impl MyTrait for u16 {
     type Output = u8;
@@ -45,6 +49,9 @@ impl MyTrait for u16 {
     extern "C" fn gen_stuff(&mut self) -> Self::Output {
         *self as u8
     }
+    extern "C" fn filter_stuff<'a>(&self, source: &'a u8) -> &'a u8 {
+        source
+    }
 }
 
 // MYTRAIT2
@@ -141,6 +148,8 @@ fn dyn_traits() {
     )>::from(boxed);
     assert_eq!(dyned.do_stuff(&0), &6);
     assert_eq!(dyned.gen_stuff(), 6);
+    let value = 33u8;
+    assert_eq!(&value as *const _, dyned.filter_stuff(&value) as *const _);
     assert_eq!(dyned.gen_stuff3(Box::new(())), 6);
     // assert_eq!(unsafe { dyned.downcast_ref::<u8>() }, Some(&6));
     // assert!(unsafe { dyned.downcast_ref::<u16>() }.is_none());