| // Copyright 2015 The Rust Project Developers. See the COPYRIGHT |
| // file at the top-level directory of this distribution and at |
| // http://rust-lang.org/COPYRIGHT. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| // run-pass |
| |
| #![feature(specialization)] |
| |
| // 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> |
| |
| // use the provided method |
| impl<T> Bar for T {} |
| |
| 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(); |
| } |