Add some type ascription

aya/src/programs/links.rs

@@ -107,7 +107,7 @@ impl<T: Link> Links<T> {
 
 impl<T: Link> Drop for Links<T> {
     fn drop(&mut self) {
-        let _ = self.remove_all();
+        let _: Result<(), ProgramError> = self.remove_all();
     }
 }
 
@@ -510,7 +510,7 @@ macro_rules! define_link_wrapper {
                 use $crate::programs::links::Link as _;
 
                 if let Some(base) = self.0.take() {
-                    let _ = base.detach();
+                    let _: Result<(), ProgramError> = base.detach();
                 }
             }
         }

aya/src/programs/mod.rs

@@ -788,7 +788,7 @@ macro_rules! impl_program_unload {
 
             impl Drop for $struct_name {
                 fn drop(&mut self) {
-                    let _ = self.unload();
+                    let _: Result<(), ProgramError> = self.unload();
                 }
             }
         )+

aya/src/programs/xdp.rs

@@ -262,7 +262,8 @@ impl Link for NlLink {
         };
         // SAFETY: TODO(https://github.com/aya-rs/aya/issues/612): make this safe by not holding `RawFd`s.
         let prog_fd = unsafe { BorrowedFd::borrow_raw(self.prog_fd) };
-        let _ = unsafe { netlink_set_xdp_fd(self.if_index, None, Some(prog_fd), flags) };
+        let _: Result<(), NetlinkError> =
+            unsafe { netlink_set_xdp_fd(self.if_index, None, Some(prog_fd), flags) };
         Ok(())
     }
 }