Add more tests.

Author: Alexander Regueiro

src/test/run-pass/traits/trait-alias-bounds.rs

@@ -10,9 +10,14 @@
 
 #![feature(trait_alias)]
 
+use std::marker::PhantomData;
+
 trait SimpleAlias = Default;
-trait GenericAlias<T> = Iterator<Item=T>;
-trait Partial<T> = IntoIterator<Item=T>;
+trait GenericAlias<T> = Iterator<Item = T>;
+trait Partial<T> = IntoIterator<Item = T>;
+trait SpecificAlias = GenericAlias<i32>;
+trait PartialEqRef<'a, T> = PartialEq<&'a T>;
+trait StaticAlias = 'static;
 
 trait Things<T> {}
 trait Romeo {}
@@ -26,19 +31,54 @@ impl<T> Romeo for Fore<T> {}
 trait WithWhere<Art, Thou> = Romeo + Romeo where Fore<(Art, Thou)>: Romeo;
 trait BareWhere<Wild, Are> = where The<Wild>: Things<Are>;
 
-trait CD = Clone + Default;
+trait Empty {}
+trait EmptyAlias = Empty;
+trait CloneDefault = Clone + Default;
+trait SendSyncAlias = Send + Sync;
+trait WhereSendAlias = where Self: Send;
+trait SendEqAlias<T> = Send where T: PartialEq<Self>;
+trait I32Iterator = Iterator<Item = i32>;
+
+#[allow(dead_code)]
+struct Foo<T: SendSyncAlias>(PhantomData<T>);
+#[allow(dead_code)]
+struct Bar<T>(PhantomData<T>) where T: SendSyncAlias;
+
+impl EmptyAlias {}
+
+impl<T: SendSyncAlias> Empty for T {}
 
-fn foo<T: CD>() -> (T, T) {
+fn a<T: CloneDefault>() -> (T, T) {
     let one = T::default();
     let two = one.clone();
     (one, two)
 }
 
+fn b(x: &impl SendEqAlias<i32>) -> bool {
+    22_i32 == *x
+}
+
+fn c<T: I32Iterator>(x: &mut T) -> Option<i32> {
+    x.next()
+}
+
+fn d<T: SendSyncAlias>() {
+    is_send_and_sync::<T>();
+}
+
+fn is_send_and_sync<T: Send + Sync>() {}
+
 fn main() {
-    let both = foo::<i32>();
+    let both = a::<i32>();
     assert_eq!(both.0, 0);
     assert_eq!(both.1, 0);
-    let both: (i32, i32) = foo();
+    let both: (i32, i32) = a();
     assert_eq!(both.0, 0);
     assert_eq!(both.1, 0);
+
+    assert!(b(&22));
+
+    assert_eq!(c(&mut vec![22].into_iter()), Some(22));
+
+    d::<i32>();
 }

src/test/run-pass/traits/trait-alias-object-type.rs

@@ -13,9 +13,15 @@
 trait Foo = PartialEq<i32> + Send;
 trait Bar = Foo + Sync;
 
+trait I32Iterator = Iterator<Item = i32>;
+
 pub fn main() {
-    let a: &Bar = &123;
+    let a: &dyn Bar = &123;
     assert!(*a == 123);
     let b = Box::new(456) as Box<dyn Foo>;
     assert!(*b == 456);
+
+    // FIXME(alexreg): associated type should be gotten from trait alias definition
+    // let c: &dyn I32Iterator = &vec![123].into_iter();
+    // assert_eq!(c.next(), Some(123));
 }

src/test/ui/traits/trait-alias-fail.stderr

@@ -10,11 +10,12 @@
 
 // gate-test-trait_alias
 
-trait Alias1<T> = Default where T: Clone;
-trait Alias2<T: Clone = ()> = Default;
+trait CloneDefault<T> = Default where T: Clone;
+trait BoundedAlias<T: Clone = ()> = Default;
 
-impl Alias1 {}
+trait A<T: Send> {}
+trait B<T> = A<T>; // FIXME: parameter T should need a bound here, or semantics should be changed
 
-impl Alias1 for () {}
+impl CloneDefault for () {}
 
 fn main() {}

src/test/ui/traits/trait-alias-fail.rs renamed to src/test/ui/traits/trait-alias-fail1.rs

@@ -0,0 +1,46 @@
+error: type parameters on the left side of a trait alias cannot be bounded
+  --> $DIR/trait-alias-fail1.rs:14:20
+   |
+LL | trait BoundedAlias<T: Clone = ()> = Default;
+   |                    ^
+
+error: type parameters on the left side of a trait alias cannot have defaults
+  --> $DIR/trait-alias-fail1.rs:14:20
+   |
+LL | trait BoundedAlias<T: Clone = ()> = Default;
+   |                    ^
+
+error[E0404]: expected trait, found trait alias `CloneDefault`
+  --> $DIR/trait-alias-fail1.rs:19:6
+   |
+LL | impl CloneDefault for () {}
+   |      ^^^^^^^^^^^^ not a trait
+
+error[E0658]: trait aliases are experimental (see issue #41517)
+  --> $DIR/trait-alias-fail1.rs:13:1
+   |
+LL | trait CloneDefault<T> = Default where T: Clone;
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(trait_alias)] to the crate attributes to enable
+
+error[E0658]: trait aliases are experimental (see issue #41517)
+  --> $DIR/trait-alias-fail1.rs:14:1
+   |
+LL | trait BoundedAlias<T: Clone = ()> = Default;
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(trait_alias)] to the crate attributes to enable
+
+error[E0658]: trait aliases are experimental (see issue #41517)
+  --> $DIR/trait-alias-fail1.rs:17:1
+   |
+LL | trait B<T> = A<T>; // FIXME: this should not work... or should it?
+   | ^^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(trait_alias)] to the crate attributes to enable
+
+error: aborting due to 6 previous errors
+
+Some errors occurred: E0404, E0658.
+For more information about an error, try `rustc --explain E0404`.

src/test/ui/traits/trait-alias-fail1.stderr

@@ -0,0 +1,19 @@
+// Copyright 2018 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.
+
+// gate-test-trait_alias
+
+trait EqAlias = Eq;
+trait IteratorAlias = Iterator;
+
+fn main() {
+    let _: &dyn EqAlias = &123;
+    let _: &dyn IteratorAlias = &vec![123].into_iter();
+}

src/test/ui/traits/trait-alias-fail2.rs

@@ -0,0 +1,19 @@
+error[E0658]: trait aliases are experimental (see issue #41517)
+  --> $DIR/trait-alias-fail2.rs:13:1
+   |
+LL | trait EqAlias = Eq;
+   | ^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(trait_alias)] to the crate attributes to enable
+
+error[E0658]: trait aliases are experimental (see issue #41517)
+  --> $DIR/trait-alias-fail2.rs:14:1
+   |
+LL | trait IteratorAlias = Iterator;
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: add #![feature(trait_alias)] to the crate attributes to enable
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0658`.