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Diffstat (limited to '')
-rw-r--r-- | src/test/ui/issues/issue-15734.rs | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/src/test/ui/issues/issue-15734.rs b/src/test/ui/issues/issue-15734.rs new file mode 100644 index 000000000..be5820606 --- /dev/null +++ b/src/test/ui/issues/issue-15734.rs @@ -0,0 +1,58 @@ +// run-pass +// If `Index` used an associated type for its output, this test would +// work more smoothly. + +use std::ops::Index; + +struct Mat<T> { data: Vec<T>, cols: usize, } + +impl<T> Mat<T> { + fn new(data: Vec<T>, cols: usize) -> Mat<T> { + Mat { data: data, cols: cols } + } + fn row<'a>(&'a self, row: usize) -> Row<&'a Mat<T>> { + Row { mat: self, row: row, } + } +} + +impl<T> Index<(usize, usize)> for Mat<T> { + type Output = T; + + fn index<'a>(&'a self, (row, col): (usize, usize)) -> &'a T { + &self.data[row * self.cols + col] + } +} + +impl<'a, T> Index<(usize, usize)> for &'a Mat<T> { + type Output = T; + + fn index<'b>(&'b self, index: (usize, usize)) -> &'b T { + (*self).index(index) + } +} + +struct Row<M> { mat: M, row: usize, } + +impl<T, M: Index<(usize, usize), Output=T>> Index<usize> for Row<M> { + type Output = T; + + fn index<'a>(&'a self, col: usize) -> &'a T { + &self.mat[(self.row, col)] + } +} + +fn main() { + let m = Mat::new(vec![1, 2, 3, 4, 5, 6], 3); + let r = m.row(1); + + assert_eq!(r.index(2), &6); + assert_eq!(r[2], 6); + assert_eq!(r[2], 6); + assert_eq!(6, r[2]); + + let e = r[2]; + assert_eq!(e, 6); + + let e: usize = r[2]; + assert_eq!(e, 6); +} |