try different method

src/ext.rs

@@ -94,10 +94,15 @@ impl<T> VecExt<T> for Vec<T>
 	    (0, Some(0)) | (0, None) => (),
 	    (_, Some(bound)) | (bound, _) => self.reserve(bound),
 	};
+
+	let splice = self.split_off(location);
+	self.extend(slice.chain(splice.into_iter()));
+	/*
 	// shift everything across, replacing with the new values
 	let splice: Vec<_> = self.splice(location.., slice).collect();
+	//            ^ -- this allocation bugs me, but we violate aliasing rules if we don't somehow collect it before adding it back in so...
 	// add tail back
-	self.extend(splice);
+	self.extend(splice);*/
     }
 }