Macro setup_interned_struct 

macro_rules! setup_interned_struct {
    (
        // Attributes on the struct
        attrs: [$(#[$attr:meta]),*],

        // Visibility of the struct
        vis: $vis:vis,

        // Name of the struct
        Struct: $Struct:ident,

        // Name of the struct data. This is a parameter because `std::concat_idents`
        // is unstable and taking an additional dependency is unnecessary.
        StructData: $StructDataIdent:ident,

        // Name of the struct type with a `'static` argument (unless this type has no db lifetime,
        // in which case this is the same as `$Struct`)
        StructWithStatic: $StructWithStatic:ty,

        // Name of the `'db` lifetime that the user gave
        db_lt: $db_lt:lifetime,

        // optional db lifetime argument.
        db_lt_arg: $($db_lt_arg:lifetime)?,

        // the salsa ID
        id: $Id:path,

        // The minimum number of revisions to keep the value interned.
        revisions: $($revisions:expr)?,

        // the lifetime used in the desugared interned struct.
        // if the `db_lt_arg`, is present, this is `db_lt_arg`, but otherwise,
        // it is `'static`.
        interior_lt: $interior_lt:lifetime,

        // Name user gave for `new`
        new_fn: $new_fn:ident,

        // A series of option tuples; see `setup_tracked_struct` macro
        field_options: [$($field_option:tt),*],

        // Field names
        field_ids: [$($field_id:ident),*],

        // Names for field setter methods (typically `set_foo`)
        field_getters: [$($field_getter_vis:vis $field_getter_id:ident),*],

        // Field types
        field_tys: [$($field_ty:ty),*],

        // Indices for each field from 0..N -- must be unsuffixed (e.g., `0`, `1`).
        field_indices: [$($field_index:tt),*],

        // Indexed types for each field (T0, T1, ...)
        field_indexed_tys: [$($indexed_ty:ident),*],

        // Attrs for each field.
        field_attrs: [$([$(#[$field_attr:meta]),*]),*],

        // Number of fields
        num_fields: $N:literal,

        // If true, generate a debug impl.
        generate_debug_impl: $generate_debug_impl:tt,

        // The function used to implement `C::heap_size`.
        heap_size_fn: $($heap_size_fn:path)?,

        // If `true`, `serialize_fn` and `deserialize_fn` have been provided.
        persist: $persist:tt,

        // The path to the `serialize` function for the value's fields.
        serialize_fn: $($serialize_fn:path)?,

        // The path to the `serialize` function for the value's fields.
        deserialize_fn: $($deserialize_fn:path)?,

        assert_types_are_update: {$($assert_types_are_update:tt)*},

        // Annoyingly macro-rules hygiene does not extend to items defined in the macro.
        // We have the procedural macro generate names for those items that are
        // not used elsewhere in the user's code.
        unused_names: [
            $zalsa:ident,
            $zalsa_struct:ident,
            $Configuration:ident,
            $CACHE:ident,
            $Db:ident,
        ]
    ) => { ... };
}

Macro for setting up a function that must intern its arguments.