| use std::ops::Index; | |
| pub trait Array2D: Index<usize> { | |
| fn rows(&self) -> usize; | |
| fn columns(&self) -> usize; | |
| fn get<'a>(&'a self, y: usize, x: usize) -> Option<&'a <Self as Index<usize>>::Output> { | |
| if y >= self.rows() || x >= self.columns() { | |
| return None; | |
| } | |
| let i = y * self.columns() + x; | |
| let indexer = &(*self as &dyn Index<usize, Output = <Self as Index<usize>>::Output>); | |
| //~^ERROR non-primitive cast | |
| Some(indexer.index(i)) | |
| } | |
| } | |
| fn main() {} |