88 lines
1.6 KiB
Rust
88 lines
1.6 KiB
Rust
//@ run-pass
|
|
|
|
#![feature(specialization)] //~ WARN the feature `specialization` is incomplete
|
|
|
|
// Test that default methods are cascaded correctly
|
|
|
|
// First, test only use of explicit `default` items:
|
|
|
|
trait Foo {
|
|
fn foo(&self) -> bool;
|
|
}
|
|
|
|
// Specialization tree for Foo:
|
|
//
|
|
// T
|
|
// / \
|
|
// i32 i64
|
|
|
|
impl<T> Foo for T {
|
|
default fn foo(&self) -> bool { false }
|
|
}
|
|
|
|
impl Foo for i32 {}
|
|
|
|
impl Foo for i64 {
|
|
fn foo(&self) -> bool { true }
|
|
}
|
|
|
|
fn test_foo() {
|
|
assert!(!0i8.foo());
|
|
assert!(!0i32.foo());
|
|
assert!(0i64.foo());
|
|
}
|
|
|
|
// Next, test mixture of explicit `default` and provided methods:
|
|
|
|
trait Bar {
|
|
fn bar(&self) -> i32 { 0 }
|
|
}
|
|
|
|
// Specialization tree for Bar.
|
|
// Uses of $ designate that method is provided
|
|
//
|
|
// $Bar (the trait)
|
|
// |
|
|
// T
|
|
// /|\
|
|
// / | \
|
|
// / | \
|
|
// / | \
|
|
// / | \
|
|
// / | \
|
|
// $i32 &str $Vec<T>
|
|
// /\
|
|
// / \
|
|
// Vec<i32> $Vec<i64>
|
|
|
|
impl<T> Bar for T {
|
|
default fn bar(&self) -> i32 { 0 }
|
|
}
|
|
|
|
impl Bar for i32 {
|
|
fn bar(&self) -> i32 { 1 }
|
|
}
|
|
impl<'a> Bar for &'a str {}
|
|
|
|
impl<T> Bar for Vec<T> {
|
|
default fn bar(&self) -> i32 { 2 }
|
|
}
|
|
impl Bar for Vec<i32> {}
|
|
impl Bar for Vec<i64> {
|
|
fn bar(&self) -> i32 { 3 }
|
|
}
|
|
|
|
fn test_bar() {
|
|
assert!(0u8.bar() == 0);
|
|
assert!(0i32.bar() == 1);
|
|
assert!("hello".bar() == 0);
|
|
assert!(vec![()].bar() == 2);
|
|
assert!(vec![0i32].bar() == 2);
|
|
assert!(vec![0i64].bar() == 3);
|
|
}
|
|
|
|
fn main() {
|
|
test_foo();
|
|
test_bar();
|
|
}
|