diff options
Diffstat (limited to 'src/test/ui/self/object-safety-sized-self-return-Self.rs')
-rw-r--r-- | src/test/ui/self/object-safety-sized-self-return-Self.rs | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/src/test/ui/self/object-safety-sized-self-return-Self.rs b/src/test/ui/self/object-safety-sized-self-return-Self.rs new file mode 100644 index 000000000..222c75439 --- /dev/null +++ b/src/test/ui/self/object-safety-sized-self-return-Self.rs @@ -0,0 +1,39 @@ +// run-pass +// Check that a trait is still object-safe (and usable) if it has +// methods that return `Self` so long as they require `Self : Sized`. + + +trait Counter { + fn new() -> Self where Self : Sized; + fn tick(&mut self) -> u32; +} + +struct CCounter { + c: u32 +} + +impl Counter for CCounter { + fn new() -> CCounter { CCounter { c: 0 } } + fn tick(&mut self) -> u32 { self.c += 1; self.c } +} + +fn preticked<C:Counter>() -> C { + let mut c: C = Counter::new(); + tick(&mut c); + c +} + +fn tick(c: &mut dyn Counter) { + tick_generic(c); +} + +fn tick_generic<C:?Sized+Counter>(c: &mut C) { + c.tick(); + c.tick(); +} + +fn main() { + let mut c = preticked::<CCounter>(); + tick(&mut c); + assert_eq!(c.tick(), 5); +} |