Macro salsa::database_storage

macro_rules! database_storage {
    (
        $(#[$attr:meta])*
        $v:vis struct $Storage:ident for $Database:ty {
            $(
                impl $TraitName:path {
                    $(
                        fn $query_method:ident() for $QueryType:path;
                    )*
                }
            )*
        }
    ) => { ... };
}

This macro generates the “query storage” that goes into your query context.