Macro circuit_cache_key_unsized 

macro_rules! circuit_cache_key_unsized {
    ($constructor:ident$(<$($typearg:ident),*>)?($key_type:ty => $val_type:ty)) => { ... };
    (local $vis:vis $constructor:ident$(<$($typearg:ident),*>)?($key_type:ty => $val_type:ty)) => { ... };
    (@inner $vis:vis [$type_key:path] $constructor:ident$(<$($typearg:ident),*>)?($key_type:ty => $val_type:ty)) => { ... };
}