fix remaining issues before fixing tests

poulpy-hal/src/api/scratch.rs

@@ -28,6 +28,8 @@ pub trait TakeSlice {
     fn take_slice<T>(&mut self, len: usize) -> (&mut [T], &mut Self);
 }
 
+impl<B: Backend> ScratchTakeBasic for Scratch<B> where Self: TakeSlice {}
+
 pub trait ScratchTakeBasic
 where
     Self: TakeSlice,

poulpy-hal/src/delegates/module.rs

@@ -1,5 +1,5 @@
 use crate::{
-    api::ModuleNew,
+    api::{ModuleN, ModuleNew},
     layouts::{Backend, Module},
     oep::ModuleNewImpl,
 };
@@ -12,3 +12,12 @@ where
         B::new_impl(n)
     }
 }
+
+impl<B> ModuleN for Module<B>
+where
+    B: Backend,
+{
+    fn n(&self) -> usize {
+        self.n()
+    }
+}