Add tests for specialization on associated types

src/test/compile-fail/specialization-default-projection.rs

@@ -0,0 +1,32 @@
+// 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.
+
+// Make sure we can't project defaulted associated types
+
+trait Foo {
+    type Assoc;
+}
+
+impl<T> Foo for T {
+    default type Assoc = ();
+}
+
+impl Foo for u8 {
+    type Assoc = String;
+}
+
+fn generic<T>() -> <T as Foo>::Assoc {
+    () //~ ERROR
+}
+
+fn main() {
+    let s: String = generic::<u8>();
+    println!("{}", s); // bad news
+}

src/test/compile-fail/specialization-default-types.rs

@@ -0,0 +1,43 @@
+// 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.
+
+// It should not be possible to use the concrete value of a defaulted
+// associated type in the impl defining it -- otherwise, what happens
+// if it's overridden?
+
+trait Example {
+    type Output;
+    fn generate(self) -> Self::Output;
+}
+
+impl<T> Example for T {
+    default type Output = Box<T>;
+    default fn generate(self) -> Self::Output {
+        Box::new(self) //~ ERROR
+    }
+}
+
+impl Example for bool {
+    type Output = bool;
+    fn generate(self) -> bool { self }
+}
+
+fn trouble<T>(t: T) -> Box<T> {
+    Example::generate(t) //~ ERROR
+}
+
+fn weaponize() -> bool {
+    let b: Box<bool> = trouble(true);
+    *b
+}
+
+fn main() {
+    weaponize();
+}

src/test/run-pass/specialization-on-projection.rs

@@ -0,0 +1,27 @@
+// 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.
+
+trait Foo<T> {}
+
+trait Assoc {
+    type Item;
+}
+
+impl<T: Assoc> Foo<T::Item> for T {}
+
+struct Struct;
+
+impl Assoc for Struct {
+    type Item = u8;
+}
+
+impl Foo<u8> for Struct {}
+
+fn main() {}

src/test/run-pass/specialization-projection.rs

@@ -0,0 +1,27 @@
+// 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.
+
+// Make sure we *can* project non-defaulted associated types
+// cf compile-fail/specialization-default-projection.rs
+
+trait Foo {
+    type Assoc;
+}
+
+impl<T> Foo for T {
+    type Assoc = ();
+}
+
+fn generic<T>() -> <T as Foo>::Assoc {
+    ()
+}
+
+fn main() {
+}

src/test/run-pass/specialization-translate-projections-with-params.rs

@@ -0,0 +1,34 @@
+// 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.
+
+trait Trait<T> {
+    fn convert(&self) -> T;
+}
+trait WithAssoc {
+    type Item;
+    fn as_item(&self) -> &Self::Item;
+}
+
+impl<T, U> Trait<U> for T where T: WithAssoc<Item=U>, U: Clone {
+    fn convert(&self) -> U {
+        self.as_item().clone()
+    }
+}
+
+impl WithAssoc for u8 {
+    type Item = u8;
+    fn as_item(&self) -> &u8 { self }
+}
+
+impl Trait<u8> for u8 {}
+
+fn main() {
+    assert!(3u8.convert() == 3u8);
+}

src/test/run-pass/specialization-translate-projections.rs

@@ -0,0 +1,36 @@
+// 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.
+
+use std::convert::Into;
+
+trait Trait {
+    fn to_u8(&self) -> u8;
+}
+trait WithAssoc {
+    type Item;
+    fn to_item(&self) -> Self::Item;
+}
+
+impl<T, U> Trait for T where T: WithAssoc<Item=U>, U: Into<u8> {
+    fn to_u8(&self) -> u8 {
+        self.to_item().into()
+    }
+}
+
+impl WithAssoc for u8 {
+    type Item = u8;
+    fn to_item(&self) -> u8 { *self }
+}
+
+impl Trait for u8 {}
+
+fn main() {
+    assert!(3u8.to_u8() == 3u8);
+}