add FixedSizeTable trait

Author: Luro02

src/raw/array_table/table.rs

@@ -3,7 +3,7 @@ use core::{array, fmt, iter, mem, slice};
 use super::{DrainIter, IterMut};
 
 use crate::errors::{CapacityError, UnavailableMutError};
-use crate::raw::{RawTable, RawTableIter, TableIndex};
+use crate::raw::{FixedSizeTable, RawTable, RawTableIter, TableIndex};
 use crate::utils::{self, unwrap_unchecked, ArrayExt, IterCircular};
 use crate::{invariant, unreachable_unchecked};
 
@@ -248,6 +248,8 @@ impl<T, const N: usize> RawTable<T> for ArrayTable<T, N> {
     }
 }
 
+impl<T, const N: usize> FixedSizeTable<T, N> for ArrayTable<T, N> {}
+
 impl<'a, T, const N: usize> IntoIterator for &'a ArrayTable<T, N> {
     type IntoIter = iter::Flatten<slice::Iter<'a, Option<T>>>;
     type Item = &'a T;

src/raw/raw_table.rs

@@ -153,3 +153,6 @@ pub trait RawTableIter<T>: RawTable<T> {
     /// Returns an immutable iterator over the table.
     fn iter(&self) -> Self::Iter<'_>;
 }
+
+/// A trait implemented by [`RawTable`]s with a fixed capacity.
+pub trait FixedSizeTable<T, const N: usize>: RawTable<T> {}