Fix ProposalInfo specialization

- The specialization macro needs to be invoked after the impl block, so
  that macros generated for this block are available at the
  specialization point.
- Macro qualification is not supported in the crate where the macro is
  defined.

mls-rs/src/group/proposal_filter/bundle.rs

@@ -460,10 +460,8 @@ pub struct ProposalInfo<T> {
     pub source: ProposalSource,
 }
 
-safer_ffi_gen::specialize!(ProposalInfoFfi = crate::group::proposal_filter::ProposalInfo<Proposal>);
-
 #[cfg_attr(all(feature = "ffi", not(test)), ::safer_ffi_gen::safer_ffi_gen)]
-impl ProposalInfo<Proposal> {
+impl<T> ProposalInfo<T> {
     /// Create a new ProposalInfo.
     ///
     /// The resulting value will be either transmitted with a commit or
@@ -472,8 +470,8 @@ impl ProposalInfo<Proposal> {
     ///
     /// This function is useful when implementing custom
     /// [`MlsRules`](crate::MlsRules).
-    #[safer_ffi_gen::safer_ffi_gen_ignore]
-    pub fn new(proposal: Proposal, sender: Sender, can_transmit: bool) -> ProposalInfo<Proposal> {
+    #[cfg_attr(all(feature = "ffi", not(test)), safer_ffi_gen::safer_ffi_gen_ignore)]
+    pub fn new(proposal: T, sender: Sender, can_transmit: bool) -> Self {
         let source = if can_transmit {
             ProposalSource::ByValue
         } else {
@@ -487,20 +485,17 @@ impl ProposalInfo<Proposal> {
         }
     }
 
-    // TODO: Proposal has a lot of cases that we don't have FFI support for yet.
-
-    #[cfg(feature = "ffi")]
+    #[cfg(all(feature = "ffi", not(test)))]
     pub fn sender(&self) -> &Sender {
         &self.sender
     }
 
-    #[cfg(feature = "ffi")]
+    #[cfg(all(feature = "ffi", not(test)))]
     pub fn source(&self) -> &ProposalSource {
         &self.source
     }
-}
 
-impl<T> ProposalInfo<T> {
+    #[cfg_attr(all(feature = "ffi", not(test)), safer_ffi_gen::safer_ffi_gen_ignore)]
     pub fn map<U, F>(self, f: F) -> ProposalInfo<U>
     where
         F: FnOnce(T) -> U,
@@ -512,6 +507,7 @@ impl<T> ProposalInfo<T> {
         }
     }
 
+    #[cfg_attr(all(feature = "ffi", not(test)), safer_ffi_gen::safer_ffi_gen_ignore)]
     pub fn as_ref(&self) -> ProposalInfo<&T> {
         ProposalInfo {
             proposal: &self.proposal,
@@ -540,6 +536,9 @@ impl<T> ProposalInfo<T> {
     }
 }
 
+#[cfg(all(feature = "ffi", not(test)))]
+safer_ffi_gen::specialize!(ProposalInfoFfi = ProposalInfo<Proposal>);
+
 pub trait Proposable: Sized {
     const TYPE: ProposalType;