Suppress cast_possible_truncation lint in generated Hash shim

macro/src/expand.rs

@@ -259,6 +259,7 @@ fn expand_struct_operators(strct: &Struct) -> TokenStream {
                 operators.extend(quote_spanned! {span=>
                     #[doc(hidden)]
                     #[export_name = #link_name]
+                    #[allow(clippy::cast_possible_truncation)]
                     extern "C" fn #local_name(this: &#ident) -> usize {
                         let mut hasher = ::std::collections::hash_map::DefaultHasher::new();
                         ::std::hash::Hash::hash(this, &mut hasher);

tests/ffi/lib.rs

@@ -1,6 +1,5 @@
 #![allow(
     clippy::boxed_local,
-    clippy::cast_possible_truncation,
     clippy::just_underscores_and_digits,
     clippy::let_underscore_drop,
     clippy::must_use_candidate,