Demonstration - BroadcastShape<Self> as "supertrait" for Dimension

src/dimension/broadcast.rs

@@ -41,7 +41,7 @@ where
     Ok(out)
 }
 
-pub trait BroadcastShape<Other: Dimension>: Dimension {
+pub trait BroadcastShape<Other: Dimension> {
     /// The resulting dimension type after broadcasting.
     type BroadcastOutput: Dimension;
 
@@ -52,7 +52,8 @@ pub trait BroadcastShape<Other: Dimension>: Dimension {
     /// Uses the [NumPy broadcasting rules]
     /// (https://docs.scipy.org/doc/numpy/user/basics.broadcasting.html#general-broadcasting-rules).
     fn broadcast_shape(&self, other: &Other) -> Result<Self::BroadcastOutput, ShapeError> {
-        broadcast_shape::<Self, Other, Self::BroadcastOutput>(self, other)
+        panic!()
+        //broadcast_shape::<Self, Other, Self::BroadcastOutput>(self, other)
     }
 }
 

src/dimension/dimension_trait.rs

@@ -20,6 +20,7 @@ use crate::IntoDimension;
 use crate::RemoveAxis;
 use crate::{ArrayView1, ArrayViewMut1};
 use crate::{Dim, Ix, Ix0, Ix1, Ix2, Ix3, Ix4, Ix5, Ix6, IxDyn, IxDynImpl, Ixs, SliceOrIndex};
+use crate::dimension::broadcast::BroadcastShape;
 
 /// Array shape and index trait.
 ///
@@ -46,6 +47,8 @@ pub trait Dimension:
     + MulAssign
     + for<'x> MulAssign<&'x Self>
     + MulAssign<usize>
+    + BroadcastShape<Self, BroadcastOutput=Self>
+    + BroadcastShape<Ix0, BroadcastOutput=Self>
 {
     /// For fixed-size dimension representations (e.g. `Ix2`), this should be
     /// `Some(ndim)`, and for variable-size dimension representations (e.g.

src/numeric/impl_numeric.rs

@@ -283,11 +283,10 @@ where
     ///     a.mean_axis(Axis(0)).unwrap().mean_axis(Axis(0)).unwrap() == aview0(&3.5)
     /// );
     /// ```
-    pub fn mean_axis(&self, axis: Axis) -> Option<Array<A, <D::Smaller as BroadcastShape<Ix0>>::BroadcastOutput>>
+    pub fn mean_axis(&self, axis: Axis) -> Option<Array<A, D::Smaller>>
     where
         A: Clone + Zero + FromPrimitive + Add<Output = A> + Div<Output = A>,
         D: RemoveAxis,
-        D::Smaller: BroadcastShape<Ix0>,
     {
         let axis_length = self.len_of(axis);
         if axis_length == 0 {