diff options
Diffstat (limited to 'tests/ui/dynamically-sized-types/dst-deref-mut.rs')
-rw-r--r-- | tests/ui/dynamically-sized-types/dst-deref-mut.rs | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/tests/ui/dynamically-sized-types/dst-deref-mut.rs b/tests/ui/dynamically-sized-types/dst-deref-mut.rs new file mode 100644 index 000000000..1d62f42bd --- /dev/null +++ b/tests/ui/dynamically-sized-types/dst-deref-mut.rs @@ -0,0 +1,35 @@ +// run-pass +// Test that a custom deref with a fat pointer return type does not ICE + + +use std::ops::{Deref, DerefMut}; + +pub struct Arr { + ptr: Box<[usize]> +} + +impl Deref for Arr { + type Target = [usize]; + + fn deref(&self) -> &[usize] { + panic!(); + } +} + +impl DerefMut for Arr { + fn deref_mut(&mut self) -> &mut [usize] { + &mut *self.ptr + } +} + +pub fn foo(arr: &mut Arr) { + let x: &mut [usize] = &mut **arr; + assert_eq!(x[0], 1); + assert_eq!(x[1], 2); + assert_eq!(x[2], 3); +} + +fn main() { + let mut a = Arr { ptr: Box::new([1, 2, 3]) }; + foo(&mut a); +} |