diff options
Diffstat (limited to 'tests/ui/marker_trait_attr/overlap-marker-trait.rs')
-rw-r--r-- | tests/ui/marker_trait_attr/overlap-marker-trait.rs | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/tests/ui/marker_trait_attr/overlap-marker-trait.rs b/tests/ui/marker_trait_attr/overlap-marker-trait.rs new file mode 100644 index 000000000..67e551797 --- /dev/null +++ b/tests/ui/marker_trait_attr/overlap-marker-trait.rs @@ -0,0 +1,29 @@ +// Test for RFC 1268: we allow overlapping impls of marker traits, +// that is, traits with #[marker]. In this case, a type `T` is +// `MyMarker` if it is either `Debug` or `Display`. This test just +// checks that we don't consider **all** types to be `MyMarker`. + +#![feature(marker_trait_attr)] + +use std::fmt::{Debug, Display}; + +#[marker] +trait Marker {} + +impl<T: Debug> Marker for T {} +impl<T: Display> Marker for T {} + +fn is_marker<T: Marker>() { } + +struct NotDebugOrDisplay; + +fn main() { + // Debug && Display: + is_marker::<i32>(); + + // Debug && !Display: + is_marker::<Vec<i32>>(); + + // !Debug && !Display + is_marker::<NotDebugOrDisplay>(); //~ ERROR +} |