helper: split out ExactSizeArr into its own module

src/helper.rs

@@ -5,30 +5,6 @@ pub fn ordered<T: Ord, const N: usize>(mut xs: [T; N]) -> [T; N] {
     xs
 }
 
-/// An iterator adaptor (derived from ExactSizedIterator) which has a guaranteed
-/// compile time size, allowing for collection of an iterator into a stack
-/// allocated array.
-pub trait ExactSizedArr<I>: ExactSizeIterator<Item = I> + Sized
-where
-    I: Default,
-{
-    fn into_array<const N: usize>(mut self) -> Result<[Self::Item; N], Self> {
-        if self.len() < N {
-            Err(self)
-        } else {
-            Ok(std::array::from_fn(|_| self.next().unwrap()))
-        }
-    }
-}
-
-/// Default implementation of ExactSizedArr for any ExactSizeIterator.
-impl<T, I> ExactSizedArr<T> for I
-where
-    T: Default + Copy + Clone,
-    I: ExactSizeIterator<Item = T>,
-{
-}
-
 /// A macro which generates Eq, PartialEq, and PartialOrd implementations for
 /// some given type.  These implementations are dependent on Ord already being
 /// implemented for that type.