Error if not diagonal

Author: charleskawczynski

src/Fields/fieldvector.jl

@@ -284,7 +284,10 @@ function Base.Broadcast.instantiate(
         # So, let's statically elide this when we have "diagonal"
         # broadcast expressions:
         if !is_diagonal_bc(bc)
-            Base.Broadcast.check_broadcast_axes(axes, bc.args...)
+            error(
+                "Broadcasting over different FieldVector types is unsupported.",
+            )
+            # Base.Broadcast.check_broadcast_axes(axes, bc.args...)
         end
     end
     return Base.Broadcast.Broadcasted(bc.style, bc.f, bc.args, axes)