Added appropiate cfg(use_alloc) for combinations_with_replacement

(and its dependencies)

Author: mendelsshop

src/combinations.rs

@@ -1,3 +1,5 @@
+#[cfg(feature = "use_alloc")]
+use alloc::boxed::Box;
 use core::array;
 use core::borrow::BorrowMut;
 use std::fmt;
@@ -52,6 +54,7 @@ pub trait PoolIndex<T>: BorrowMut<[usize]> {
         self.borrow().len()
     }
 }
+#[cfg(feature = "use_alloc")]
 impl<T> PoolIndex<T> for Box<[usize]> {
     type Item = Vec<T>;
 

src/combinations_with_replacement.rs

@@ -1,3 +1,4 @@
+#[cfg(feature = "use_alloc")]
 use alloc::boxed::Box;
 use std::fmt;
 use std::iter::FusedIterator;
@@ -21,6 +22,7 @@ where
     first: bool,
 }
 
+#[cfg(feature = "use_alloc")]
 /// Iterator for `Box<[I]>` valued combinations_with_replacement returned by [`.combinations_with_replacement()`](crate::Itertools::combinations_with_replacement)
 pub type CombinationsWithReplacement<I> = CombinationsWithReplacementGeneric<I, Box<[usize]>>;
 /// Iterator for const generic combinations_with_replacement returned by [`.array_combinations_with_replacement()`](crate::Itertools::array_combinations_with_replacement)
@@ -45,6 +47,7 @@ where
 {
     ArrayCombinationsWithReplacement::new(iter, [0; K])
 }
+#[cfg(feature = "use_alloc")]
 /// Create a new `CombinationsWithReplacement` from a clonable iterator.
 pub fn combinations_with_replacement<I>(iter: I, k: usize) -> CombinationsWithReplacement<I>
 where