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Diffstat (limited to 'tests/ui/traits/conditional-dispatch.rs')
-rw-r--r-- | tests/ui/traits/conditional-dispatch.rs | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/tests/ui/traits/conditional-dispatch.rs b/tests/ui/traits/conditional-dispatch.rs new file mode 100644 index 000000000..dd882dce6 --- /dev/null +++ b/tests/ui/traits/conditional-dispatch.rs @@ -0,0 +1,34 @@ +// run-pass +// Test that we are able to resolve conditional dispatch. Here, the +// blanket impl for T:Copy coexists with an impl for Box<T>, because +// Box does not impl Copy. + + +trait Get { + fn get(&self) -> Self; +} + +trait MyCopy { fn copy(&self) -> Self; } +impl MyCopy for u16 { fn copy(&self) -> Self { *self } } +impl MyCopy for u32 { fn copy(&self) -> Self { *self } } +impl MyCopy for i32 { fn copy(&self) -> Self { *self } } +impl<T:Copy> MyCopy for Option<T> { fn copy(&self) -> Self { *self } } + +impl<T:MyCopy> Get for T { + fn get(&self) -> T { self.copy() } +} + +impl Get for Box<i32> { + fn get(&self) -> Box<i32> { Box::new(get_it(&**self)) } +} + +fn get_it<T:Get>(t: &T) -> T { + (*t).get() +} + +fn main() { + assert_eq!(get_it(&1_u32), 1_u32); + assert_eq!(get_it(&1_u16), 1_u16); + assert_eq!(get_it(&Some(1_u16)), Some(1_u16)); + assert_eq!(get_it(&Box::new(1)), Box::new(1)); +} |