diff options
Diffstat (limited to 'src/test/ui/traits/alias')
38 files changed, 2042 insertions, 0 deletions
diff --git a/src/test/ui/traits/alias/ambiguous.rs b/src/test/ui/traits/alias/ambiguous.rs new file mode 100644 index 000000000..28409e0c6 --- /dev/null +++ b/src/test/ui/traits/alias/ambiguous.rs @@ -0,0 +1,24 @@ +#![feature(trait_alias)] + +mod inner { + pub trait A { fn foo(&self); } + pub trait B { fn foo(&self); } + + impl A for u8 { + fn foo(&self) {} + } + impl B for u8 { + fn foo(&self) {} + } + + pub trait C = A + B; +} + +use inner::C; + +fn main() { + let t = 1u8; + t.foo(); //~ ERROR E0034 + + inner::A::foo(&t); // ok +} diff --git a/src/test/ui/traits/alias/ambiguous.stderr b/src/test/ui/traits/alias/ambiguous.stderr new file mode 100644 index 000000000..0fe1a7967 --- /dev/null +++ b/src/test/ui/traits/alias/ambiguous.stderr @@ -0,0 +1,28 @@ +error[E0034]: multiple applicable items in scope + --> $DIR/ambiguous.rs:21:7 + | +LL | t.foo(); + | ^^^ multiple `foo` found + | +note: candidate #1 is defined in an impl of the trait `A` for the type `u8` + --> $DIR/ambiguous.rs:8:9 + | +LL | fn foo(&self) {} + | ^^^^^^^^^^^^^ +note: candidate #2 is defined in an impl of the trait `B` for the type `u8` + --> $DIR/ambiguous.rs:11:9 + | +LL | fn foo(&self) {} + | ^^^^^^^^^^^^^ +help: disambiguate the associated function for candidate #1 + | +LL | A::foo(&t); + | ~~~~~~~~~~ +help: disambiguate the associated function for candidate #2 + | +LL | B::foo(&t); + | ~~~~~~~~~~ + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0034`. diff --git a/src/test/ui/traits/alias/auxiliary/greeter.rs b/src/test/ui/traits/alias/auxiliary/greeter.rs new file mode 100644 index 000000000..9e4122155 --- /dev/null +++ b/src/test/ui/traits/alias/auxiliary/greeter.rs @@ -0,0 +1,13 @@ +#![feature(trait_alias)] + +pub trait Hello { + fn hello(&self); +} + +pub struct Hi; + +impl Hello for Hi { + fn hello(&self) {} +} + +pub trait Greet = Hello; diff --git a/src/test/ui/traits/alias/auxiliary/send_sync.rs b/src/test/ui/traits/alias/auxiliary/send_sync.rs new file mode 100644 index 000000000..9e56b87e0 --- /dev/null +++ b/src/test/ui/traits/alias/auxiliary/send_sync.rs @@ -0,0 +1,3 @@ +#![feature(trait_alias)] + +pub trait SendSync = Send + Sync; diff --git a/src/test/ui/traits/alias/basic.rs b/src/test/ui/traits/alias/basic.rs new file mode 100644 index 000000000..d8168f299 --- /dev/null +++ b/src/test/ui/traits/alias/basic.rs @@ -0,0 +1,8 @@ +// run-pass + +#![feature(trait_alias)] + +pub trait Foo {} +pub trait FooAlias = Foo; + +fn main() {} diff --git a/src/test/ui/traits/alias/bounds.rs b/src/test/ui/traits/alias/bounds.rs new file mode 100644 index 000000000..b97eb38c5 --- /dev/null +++ b/src/test/ui/traits/alias/bounds.rs @@ -0,0 +1,57 @@ +// run-pass + +#![feature(trait_alias)] + +use std::marker::PhantomData; + +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 dyn EmptyAlias {} + +impl<T: SendSyncAlias> Empty for 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 = a::<i32>(); + assert_eq!(both.0, 0); + assert_eq!(both.1, 0); + 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>(); +} diff --git a/src/test/ui/traits/alias/cross-crate.rs b/src/test/ui/traits/alias/cross-crate.rs new file mode 100644 index 000000000..8919c6434 --- /dev/null +++ b/src/test/ui/traits/alias/cross-crate.rs @@ -0,0 +1,17 @@ +// aux-build:send_sync.rs + +#![feature(trait_alias)] + +extern crate send_sync; + +use std::rc::Rc; +use send_sync::SendSync; + +fn use_alias<T: SendSync>() {} + +fn main() { + use_alias::<u32>(); + use_alias::<Rc<u32>>(); + //~^ ERROR `Rc<u32>` cannot be sent between threads safely [E0277] + //~^^ ERROR `Rc<u32>` cannot be shared between threads safely [E0277] +} diff --git a/src/test/ui/traits/alias/cross-crate.stderr b/src/test/ui/traits/alias/cross-crate.stderr new file mode 100644 index 000000000..d0d00c97e --- /dev/null +++ b/src/test/ui/traits/alias/cross-crate.stderr @@ -0,0 +1,31 @@ +error[E0277]: `Rc<u32>` cannot be sent between threads safely + --> $DIR/cross-crate.rs:14:17 + | +LL | use_alias::<Rc<u32>>(); + | ^^^^^^^ `Rc<u32>` cannot be sent between threads safely + | + = help: the trait `Send` is not implemented for `Rc<u32>` + = note: required because of the requirements on the impl of `SendSync` for `Rc<u32>` +note: required by a bound in `use_alias` + --> $DIR/cross-crate.rs:10:17 + | +LL | fn use_alias<T: SendSync>() {} + | ^^^^^^^^ required by this bound in `use_alias` + +error[E0277]: `Rc<u32>` cannot be shared between threads safely + --> $DIR/cross-crate.rs:14:17 + | +LL | use_alias::<Rc<u32>>(); + | ^^^^^^^ `Rc<u32>` cannot be shared between threads safely + | + = help: the trait `Sync` is not implemented for `Rc<u32>` + = note: required because of the requirements on the impl of `SendSync` for `Rc<u32>` +note: required by a bound in `use_alias` + --> $DIR/cross-crate.rs:10:17 + | +LL | fn use_alias<T: SendSync>() {} + | ^^^^^^^^ required by this bound in `use_alias` + +error: aborting due to 2 previous errors + +For more information about this error, try `rustc --explain E0277`. diff --git a/src/test/ui/traits/alias/impl.rs b/src/test/ui/traits/alias/impl.rs new file mode 100644 index 000000000..6e35793a0 --- /dev/null +++ b/src/test/ui/traits/alias/impl.rs @@ -0,0 +1,7 @@ +#![feature(trait_alias)] + +trait DefaultAlias = Default; + +impl DefaultAlias for () {} //~ ERROR expected trait, found trait alias + +fn main() {} diff --git a/src/test/ui/traits/alias/impl.stderr b/src/test/ui/traits/alias/impl.stderr new file mode 100644 index 000000000..cedcd1021 --- /dev/null +++ b/src/test/ui/traits/alias/impl.stderr @@ -0,0 +1,9 @@ +error[E0404]: expected trait, found trait alias `DefaultAlias` + --> $DIR/impl.rs:5:6 + | +LL | impl DefaultAlias for () {} + | ^^^^^^^^^^^^ not a trait + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0404`. diff --git a/src/test/ui/traits/alias/import-cross-crate.rs b/src/test/ui/traits/alias/import-cross-crate.rs new file mode 100644 index 000000000..868585cd0 --- /dev/null +++ b/src/test/ui/traits/alias/import-cross-crate.rs @@ -0,0 +1,14 @@ +// run-pass +// aux-build:greeter.rs + +#![feature(trait_alias)] + +extern crate greeter; + +// Import only the alias, not the real trait. +use greeter::{Greet, Hi}; + +fn main() { + let hi = Hi; + hi.hello(); // From `Hello`, via `Greet` alias. +} diff --git a/src/test/ui/traits/alias/import.rs b/src/test/ui/traits/alias/import.rs new file mode 100644 index 000000000..802a8f156 --- /dev/null +++ b/src/test/ui/traits/alias/import.rs @@ -0,0 +1,40 @@ +// run-pass + +#![feature(trait_alias)] + +mod inner { + pub trait Foo { + fn foo(&self); + } + + pub struct Qux; + + impl Foo for Qux { + fn foo(&self) {} + } + + pub trait Bar = Foo; +} + +mod two { + pub trait A { + fn foo(); + } + + impl A for u8 { + fn foo() {} + } +} + +// Import only the alias, not the `Foo` trait. +use inner::{Bar, Qux}; + +// Declaring an alias also brings in aliased methods. +trait Two = two::A; + +fn main() { + let q = Qux; + q.foo(); // From Bar. + + u8::foo(); // From A. +} diff --git a/src/test/ui/traits/alias/issue-60021-assoc-method-resolve.rs b/src/test/ui/traits/alias/issue-60021-assoc-method-resolve.rs new file mode 100644 index 000000000..5e27ed3c6 --- /dev/null +++ b/src/test/ui/traits/alias/issue-60021-assoc-method-resolve.rs @@ -0,0 +1,19 @@ +// check-pass + +#![feature(trait_alias)] + +trait SomeTrait { + fn map(&self) {} +} + +impl<T> SomeTrait for Option<T> {} + +trait SomeAlias = SomeTrait; + +fn main() { + let x = Some(123); + // This should resolve to the trait impl for Option + Option::map(x, |z| z); + // This should resolve to the trait impl for SomeTrait + SomeTrait::map(&x); +} diff --git a/src/test/ui/traits/alias/issue-72415-assoc-const-resolve.rs b/src/test/ui/traits/alias/issue-72415-assoc-const-resolve.rs new file mode 100644 index 000000000..e49125d10 --- /dev/null +++ b/src/test/ui/traits/alias/issue-72415-assoc-const-resolve.rs @@ -0,0 +1,14 @@ +// check-pass + +#![feature(trait_alias)] + +trait Bounded { const MAX: Self; } + +impl Bounded for u32 { + // This should correctly resolve to the associated const in the inherent impl of u32. + const MAX: Self = u32::MAX; +} + +trait Num = Bounded + Copy; + +fn main() {} diff --git a/src/test/ui/traits/alias/issue-75983.rs b/src/test/ui/traits/alias/issue-75983.rs new file mode 100644 index 000000000..f9a7f36de --- /dev/null +++ b/src/test/ui/traits/alias/issue-75983.rs @@ -0,0 +1,17 @@ +// check-pass + +#![feature(trait_alias)] + +struct Bar; +trait Foo {} +impl Foo for Bar {} + +trait Baz = Foo where Bar: Foo; + +fn new() -> impl Baz { + Bar +} + +fn main() { + let _ = new(); +} diff --git a/src/test/ui/traits/alias/issue-83613.rs b/src/test/ui/traits/alias/issue-83613.rs new file mode 100644 index 000000000..04320e720 --- /dev/null +++ b/src/test/ui/traits/alias/issue-83613.rs @@ -0,0 +1,13 @@ +#![feature(type_alias_impl_trait)] +trait OpaqueTrait {} +impl<T> OpaqueTrait for T {} +type OpaqueType = impl OpaqueTrait; +fn mk_opaque() -> OpaqueType { + || 0 +} +trait AnotherTrait {} +impl<T: Send> AnotherTrait for T {} +impl AnotherTrait for OpaqueType {} +//~^ ERROR conflicting implementations of trait `AnotherTrait` for type `OpaqueType` +//~| ERROR cannot implement trait on type alias impl trait +fn main() {} diff --git a/src/test/ui/traits/alias/issue-83613.stderr b/src/test/ui/traits/alias/issue-83613.stderr new file mode 100644 index 000000000..b9d931601 --- /dev/null +++ b/src/test/ui/traits/alias/issue-83613.stderr @@ -0,0 +1,23 @@ +error[E0119]: conflicting implementations of trait `AnotherTrait` for type `OpaqueType` + --> $DIR/issue-83613.rs:10:1 + | +LL | impl<T: Send> AnotherTrait for T {} + | -------------------------------- first implementation here +LL | impl AnotherTrait for OpaqueType {} + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `OpaqueType` + +error: cannot implement trait on type alias impl trait + --> $DIR/issue-83613.rs:10:23 + | +LL | impl AnotherTrait for OpaqueType {} + | ^^^^^^^^^^ + | +note: type alias impl trait defined here + --> $DIR/issue-83613.rs:4:19 + | +LL | type OpaqueType = impl OpaqueTrait; + | ^^^^^^^^^^^^^^^^ + +error: aborting due to 2 previous errors + +For more information about this error, try `rustc --explain E0119`. diff --git a/src/test/ui/traits/alias/maybe-bound.rs b/src/test/ui/traits/alias/maybe-bound.rs new file mode 100644 index 000000000..284baa481 --- /dev/null +++ b/src/test/ui/traits/alias/maybe-bound.rs @@ -0,0 +1,29 @@ +// build-pass (FIXME(62277): could be check-pass?) + +// Test that `dyn ... + ?Sized + ...` resulting from the expansion of trait aliases is okay. + +#![feature(trait_alias)] + +trait Foo {} + +trait S = ?Sized; + +// Nest a couple of levels deep: +trait _0 = S; +trait _1 = _0; + +// Straight list expansion: +type _T0 = dyn _1 + Foo; + +// In second position: +type _T1 = dyn Foo + _1; + +// ... and with an auto trait: +type _T2 = dyn Foo + Send + _1; + +// Twice: +trait _2 = _1 + _1; + +type _T3 = dyn _2 + Foo; + +fn main() {} diff --git a/src/test/ui/traits/alias/no-duplicates.rs b/src/test/ui/traits/alias/no-duplicates.rs new file mode 100644 index 000000000..88feb8917 --- /dev/null +++ b/src/test/ui/traits/alias/no-duplicates.rs @@ -0,0 +1,126 @@ +// The purpose of this test is to demonstrate that duplicating object safe traits +// that are not auto traits is rejected with trait aliases even though one could +// reasonably accept this. + +#![feature(trait_alias)] + +use std::marker::Unpin; + +// Some arbitrary object-safe trait: +trait Obj {} + +// Nest a few levels deep: +trait _0 = Obj; +trait _1 = _0; + +type _T00 = dyn _0 + _0; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T01 = dyn _1 + _0; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T02 = dyn _1 + _1; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T03 = dyn Obj + _1; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T04 = dyn _1 + Obj; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +// Nest some more and in weird ways: + +trait _2 = _0 + _1; +trait _3 = Obj; +trait _4 = _3; + +type _T10 = dyn _2 + _3; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T11 = dyn _3 + _2; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T12 = dyn Obj + _2; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T13 = dyn _2 + Obj; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T14 = dyn _1 + _3; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T15 = dyn _3 + _1; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T16 = dyn _1 + _4; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T17 = dyn _4 + _1; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +// Include auto traits: + +trait _5 = Obj + Send; + +type _T20 = dyn _5 + _5; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T21 = dyn Obj + _5; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T22 = dyn _5 + Obj; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T23 = dyn _5 + Send + Sync + Obj; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +// Also nest: + +trait _6 = _5 + _5; // ==> Obj + Send + Obj + Send + +type _T30 = dyn _6; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T31 = dyn _6 + Send; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T32 = dyn Send + _6; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +// Nest some more: + +trait _7 = _5 + Sync; +trait _8 = Unpin + _7; + +type _T40 = dyn _8 + Obj; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T41 = dyn Obj + _8; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T42 = dyn _8 + _4; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T43 = dyn _4 + _8; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T44 = dyn _4 + Send + Sync + _8; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +// Take higher ranked types into account. + +// Note that `'a` and `'b` are intentionally different to make sure we consider +// them semantically the same. +trait ObjL<'l> {} +trait _9 = for<'a> ObjL<'a>; +trait _10 = for<'b> ObjL<'b>; +type _T50 = dyn _9 + _10; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +trait ObjT<T> {} +trait _11 = ObjT<for<'a> fn(&'a u8)>; +trait _12 = ObjT<for<'b> fn(&'b u8)>; +type _T60 = dyn _11 + _12; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +fn main() {} diff --git a/src/test/ui/traits/alias/no-duplicates.stderr b/src/test/ui/traits/alias/no-duplicates.stderr new file mode 100644 index 000000000..bf244b97e --- /dev/null +++ b/src/test/ui/traits/alias/no-duplicates.stderr @@ -0,0 +1,527 @@ +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-duplicates.rs:16:22 + | +LL | trait _0 = Obj; + | --- + | | + | additional non-auto trait + | first non-auto trait +... +LL | type _T00 = dyn _0 + _0; + | -- ^^ trait alias used in trait object type (additional use) + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Obj + Obj {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-duplicates.rs:19:22 + | +LL | trait _0 = Obj; + | --- + | | + | additional non-auto trait + | first non-auto trait +LL | trait _1 = _0; + | -- referenced here (first use) +... +LL | type _T01 = dyn _1 + _0; + | -- ^^ trait alias used in trait object type (additional use) + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Obj + Obj {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-duplicates.rs:22:22 + | +LL | trait _0 = Obj; + | --- + | | + | additional non-auto trait + | first non-auto trait +LL | trait _1 = _0; + | -- + | | + | referenced here (additional use) + | referenced here (first use) +... +LL | type _T02 = dyn _1 + _1; + | -- ^^ trait alias used in trait object type (additional use) + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Obj + Obj {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-duplicates.rs:25:23 + | +LL | trait _0 = Obj; + | --- additional non-auto trait +LL | trait _1 = _0; + | -- referenced here (additional use) +... +LL | type _T03 = dyn Obj + _1; + | --- ^^ trait alias used in trait object type (additional use) + | | + | first non-auto trait + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Obj + Obj {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-duplicates.rs:28:22 + | +LL | trait _0 = Obj; + | --- first non-auto trait +LL | trait _1 = _0; + | -- referenced here (first use) +... +LL | type _T04 = dyn _1 + Obj; + | -- ^^^ additional non-auto trait + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Obj + Obj {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-duplicates.rs:37:17 + | +LL | trait _0 = Obj; + | --- + | | + | additional non-auto trait + | first non-auto trait +LL | trait _1 = _0; + | -- referenced here (additional use) +... +LL | trait _2 = _0 + _1; + | -- -- referenced here (additional use) + | | + | referenced here (first use) +... +LL | type _T10 = dyn _2 + _3; + | ^^ + | | + | trait alias used in trait object type (additional use) + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Obj + Obj + Obj {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-duplicates.rs:40:22 + | +LL | trait _0 = Obj; + | --- additional non-auto trait +... +LL | trait _2 = _0 + _1; + | -- referenced here (additional use) +LL | trait _3 = Obj; + | --- first non-auto trait +... +LL | type _T11 = dyn _3 + _2; + | -- ^^ trait alias used in trait object type (additional use) + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Obj + Obj + Obj {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-duplicates.rs:43:23 + | +LL | trait _0 = Obj; + | --- additional non-auto trait +... +LL | trait _2 = _0 + _1; + | -- referenced here (additional use) +... +LL | type _T12 = dyn Obj + _2; + | --- ^^ trait alias used in trait object type (additional use) + | | + | first non-auto trait + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Obj + Obj + Obj {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-duplicates.rs:46:17 + | +LL | trait _0 = Obj; + | --- + | | + | additional non-auto trait + | first non-auto trait +LL | trait _1 = _0; + | -- referenced here (additional use) +... +LL | trait _2 = _0 + _1; + | -- -- referenced here (additional use) + | | + | referenced here (first use) +... +LL | type _T13 = dyn _2 + Obj; + | ^^ + | | + | trait alias used in trait object type (additional use) + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Obj + Obj + Obj {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-duplicates.rs:49:22 + | +LL | trait _0 = Obj; + | --- first non-auto trait +LL | trait _1 = _0; + | -- referenced here (first use) +... +LL | trait _3 = Obj; + | --- additional non-auto trait +... +LL | type _T14 = dyn _1 + _3; + | -- ^^ trait alias used in trait object type (additional use) + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Obj + Obj {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-duplicates.rs:52:22 + | +LL | trait _0 = Obj; + | --- additional non-auto trait +LL | trait _1 = _0; + | -- referenced here (additional use) +... +LL | trait _3 = Obj; + | --- first non-auto trait +... +LL | type _T15 = dyn _3 + _1; + | -- ^^ trait alias used in trait object type (additional use) + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Obj + Obj {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-duplicates.rs:55:22 + | +LL | trait _0 = Obj; + | --- first non-auto trait +LL | trait _1 = _0; + | -- referenced here (first use) +... +LL | trait _3 = Obj; + | --- additional non-auto trait +LL | trait _4 = _3; + | -- referenced here (additional use) +... +LL | type _T16 = dyn _1 + _4; + | -- ^^ trait alias used in trait object type (additional use) + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Obj + Obj {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-duplicates.rs:58:22 + | +LL | trait _0 = Obj; + | --- additional non-auto trait +LL | trait _1 = _0; + | -- referenced here (additional use) +... +LL | trait _3 = Obj; + | --- first non-auto trait +LL | trait _4 = _3; + | -- referenced here (first use) +... +LL | type _T17 = dyn _4 + _1; + | -- ^^ trait alias used in trait object type (additional use) + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Obj + Obj {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-duplicates.rs:65:22 + | +LL | trait _5 = Obj + Send; + | --- + | | + | additional non-auto trait + | first non-auto trait +LL | +LL | type _T20 = dyn _5 + _5; + | -- ^^ trait alias used in trait object type (additional use) + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Obj + Obj {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-duplicates.rs:68:23 + | +LL | trait _5 = Obj + Send; + | --- additional non-auto trait +... +LL | type _T21 = dyn Obj + _5; + | --- ^^ trait alias used in trait object type (additional use) + | | + | first non-auto trait + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Obj + Obj {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-duplicates.rs:71:22 + | +LL | trait _5 = Obj + Send; + | --- first non-auto trait +... +LL | type _T22 = dyn _5 + Obj; + | -- ^^^ additional non-auto trait + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Obj + Obj {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-duplicates.rs:74:36 + | +LL | trait _5 = Obj + Send; + | --- first non-auto trait +... +LL | type _T23 = dyn _5 + Send + Sync + Obj; + | -- ^^^ additional non-auto trait + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Obj + Obj {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-duplicates.rs:81:17 + | +LL | trait _5 = Obj + Send; + | --- + | | + | additional non-auto trait + | first non-auto trait +... +LL | trait _6 = _5 + _5; // ==> Obj + Send + Obj + Send + | -- -- referenced here (additional use) + | | + | referenced here (first use) +LL | +LL | type _T30 = dyn _6; + | ^^ + | | + | trait alias used in trait object type (additional use) + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Obj + Obj {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-duplicates.rs:84:17 + | +LL | trait _5 = Obj + Send; + | --- + | | + | additional non-auto trait + | first non-auto trait +... +LL | trait _6 = _5 + _5; // ==> Obj + Send + Obj + Send + | -- -- referenced here (additional use) + | | + | referenced here (first use) +... +LL | type _T31 = dyn _6 + Send; + | ^^ + | | + | trait alias used in trait object type (additional use) + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Obj + Obj {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-duplicates.rs:87:24 + | +LL | trait _5 = Obj + Send; + | --- + | | + | additional non-auto trait + | first non-auto trait +... +LL | trait _6 = _5 + _5; // ==> Obj + Send + Obj + Send + | -- -- referenced here (additional use) + | | + | referenced here (first use) +... +LL | type _T32 = dyn Send + _6; + | ^^ + | | + | trait alias used in trait object type (additional use) + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Obj + Obj {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-duplicates.rs:95:22 + | +LL | trait _5 = Obj + Send; + | --- first non-auto trait +... +LL | trait _7 = _5 + Sync; + | -- referenced here (first use) +LL | trait _8 = Unpin + _7; + | -- referenced here (first use) +LL | +LL | type _T40 = dyn _8 + Obj; + | -- ^^^ additional non-auto trait + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Obj + Obj {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-duplicates.rs:98:23 + | +LL | trait _5 = Obj + Send; + | --- additional non-auto trait +... +LL | trait _7 = _5 + Sync; + | -- referenced here (additional use) +LL | trait _8 = Unpin + _7; + | -- referenced here (additional use) +... +LL | type _T41 = dyn Obj + _8; + | --- ^^ trait alias used in trait object type (additional use) + | | + | first non-auto trait + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Obj + Obj {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-duplicates.rs:101:22 + | +LL | trait _3 = Obj; + | --- additional non-auto trait +LL | trait _4 = _3; + | -- referenced here (additional use) +... +LL | trait _5 = Obj + Send; + | --- first non-auto trait +... +LL | trait _7 = _5 + Sync; + | -- referenced here (first use) +LL | trait _8 = Unpin + _7; + | -- referenced here (first use) +... +LL | type _T42 = dyn _8 + _4; + | -- ^^ trait alias used in trait object type (additional use) + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Obj + Obj {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-duplicates.rs:104:22 + | +LL | trait _3 = Obj; + | --- first non-auto trait +LL | trait _4 = _3; + | -- referenced here (first use) +... +LL | trait _5 = Obj + Send; + | --- additional non-auto trait +... +LL | trait _7 = _5 + Sync; + | -- referenced here (additional use) +LL | trait _8 = Unpin + _7; + | -- referenced here (additional use) +... +LL | type _T43 = dyn _4 + _8; + | -- ^^ trait alias used in trait object type (additional use) + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Obj + Obj {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-duplicates.rs:107:36 + | +LL | trait _3 = Obj; + | --- first non-auto trait +LL | trait _4 = _3; + | -- referenced here (first use) +... +LL | trait _5 = Obj + Send; + | --- additional non-auto trait +... +LL | trait _7 = _5 + Sync; + | -- referenced here (additional use) +LL | trait _8 = Unpin + _7; + | -- referenced here (additional use) +... +LL | type _T44 = dyn _4 + Send + Sync + _8; + | -- ^^ trait alias used in trait object type (additional use) + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: Obj + Obj {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-duplicates.rs:117:22 + | +LL | trait _9 = for<'a> ObjL<'a>; + | ---------------- first non-auto trait +LL | trait _10 = for<'b> ObjL<'b>; + | ---------------- additional non-auto trait +LL | type _T50 = dyn _9 + _10; + | -- ^^^ trait alias used in trait object type (additional use) + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: for<'a> ObjL<'a> + for<'b> ObjL<'b> {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-duplicates.rs:123:23 + | +LL | trait _11 = ObjT<for<'a> fn(&'a u8)>; + | ------------------------ first non-auto trait +LL | trait _12 = ObjT<for<'b> fn(&'b u8)>; + | ------------------------ additional non-auto trait +LL | type _T60 = dyn _11 + _12; + | --- ^^^ trait alias used in trait object type (additional use) + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: ObjT<for<'a> fn(&'a u8)> + ObjT<for<'b> fn(&'b u8)> {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error: aborting due to 27 previous errors + +For more information about this error, try `rustc --explain E0225`. diff --git a/src/test/ui/traits/alias/no-extra-traits.rs b/src/test/ui/traits/alias/no-extra-traits.rs new file mode 100644 index 000000000..4dad8c0f8 --- /dev/null +++ b/src/test/ui/traits/alias/no-extra-traits.rs @@ -0,0 +1,121 @@ +// The purpose of this test is to demonstrate that trait alias expansion +// preserves the rule that `dyn Trait` may only reference one non-auto trait. + +#![feature(trait_alias)] + +use std::marker::Unpin; + +// Some arbitrary object-safe traits: +trait ObjA {} +trait ObjB {} + +// Nest a few levels deep: +trait _0 = ObjA; +trait _1 = _0; + +type _T00 = dyn _0 + ObjB; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T01 = dyn ObjB + _0; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T02 = dyn ObjB + _1; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T03 = dyn _1 + ObjB; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +// Nest some more and in weird ways: + +trait _2 = ObjB; +trait _3 = _2; +trait _4 = _3; + +type _T10 = dyn _2 + _3; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T11 = dyn _3 + _2; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T12 = dyn _2 + _4; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T13 = dyn _4 + _2; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +// Include auto traits: + +trait _5 = Sync + ObjB + Send; + +type _T20 = dyn _5 + _1; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T21 = dyn _1 + _5; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T22 = dyn _5 + ObjA; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T23 = dyn ObjA + _5; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T24 = dyn Send + _5 + _1 + Sync; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T25 = dyn _1 + Sync + _5 + Send; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T26 = dyn Sync + Send + _5 + ObjA; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T27 = dyn Send + Sync + ObjA + _5; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +// Also nest: + +trait _6 = _1 + _5; +trait _7 = _6; +trait _8 = _7; + +type _T30 = dyn _6; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T31 = dyn _6 + Send; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T32 = dyn Send + _6; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T33 = dyn _8; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T34 = dyn _8 + Send; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T35 = dyn Send + _8; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +// Nest some more: + +trait _9 = _5 + Sync; +trait _10 = Unpin + _9; + +type _T40 = dyn _10 + ObjA; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T41 = dyn ObjA + _10; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T42 = dyn _10 + _1; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T43 = dyn Send + _10 + Sync + ObjA; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T44 = dyn ObjA + _10 + Send + Sync; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +type _T45 = dyn Sync + Send + _10 + _1; +//~^ ERROR only auto traits can be used as additional traits in a trait object [E0225] + +fn main() {} diff --git a/src/test/ui/traits/alias/no-extra-traits.stderr b/src/test/ui/traits/alias/no-extra-traits.stderr new file mode 100644 index 000000000..4b1ddf684 --- /dev/null +++ b/src/test/ui/traits/alias/no-extra-traits.stderr @@ -0,0 +1,579 @@ +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-extra-traits.rs:16:22 + | +LL | trait _0 = ObjA; + | ---- first non-auto trait +... +LL | type _T00 = dyn _0 + ObjB; + | -- ^^^^ additional non-auto trait + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: ObjA + ObjB {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-extra-traits.rs:19:24 + | +LL | trait _0 = ObjA; + | ---- additional non-auto trait +... +LL | type _T01 = dyn ObjB + _0; + | ---- ^^ trait alias used in trait object type (additional use) + | | + | first non-auto trait + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: ObjB + ObjA {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-extra-traits.rs:22:24 + | +LL | trait _0 = ObjA; + | ---- additional non-auto trait +LL | trait _1 = _0; + | -- referenced here (additional use) +... +LL | type _T02 = dyn ObjB + _1; + | ---- ^^ trait alias used in trait object type (additional use) + | | + | first non-auto trait + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: ObjB + ObjA {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-extra-traits.rs:25:22 + | +LL | trait _0 = ObjA; + | ---- first non-auto trait +LL | trait _1 = _0; + | -- referenced here (first use) +... +LL | type _T03 = dyn _1 + ObjB; + | -- ^^^^ additional non-auto trait + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: ObjA + ObjB {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-extra-traits.rs:34:22 + | +LL | trait _2 = ObjB; + | ---- + | | + | additional non-auto trait + | first non-auto trait +LL | trait _3 = _2; + | -- referenced here (additional use) +... +LL | type _T10 = dyn _2 + _3; + | -- ^^ trait alias used in trait object type (additional use) + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: ObjB + ObjB {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-extra-traits.rs:37:22 + | +LL | trait _2 = ObjB; + | ---- + | | + | additional non-auto trait + | first non-auto trait +LL | trait _3 = _2; + | -- referenced here (first use) +... +LL | type _T11 = dyn _3 + _2; + | -- ^^ trait alias used in trait object type (additional use) + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: ObjB + ObjB {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-extra-traits.rs:40:22 + | +LL | trait _2 = ObjB; + | ---- + | | + | additional non-auto trait + | first non-auto trait +LL | trait _3 = _2; + | -- referenced here (additional use) +LL | trait _4 = _3; + | -- referenced here (additional use) +... +LL | type _T12 = dyn _2 + _4; + | -- ^^ trait alias used in trait object type (additional use) + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: ObjB + ObjB {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-extra-traits.rs:43:22 + | +LL | trait _2 = ObjB; + | ---- + | | + | additional non-auto trait + | first non-auto trait +LL | trait _3 = _2; + | -- referenced here (first use) +LL | trait _4 = _3; + | -- referenced here (first use) +... +LL | type _T13 = dyn _4 + _2; + | -- ^^ trait alias used in trait object type (additional use) + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: ObjB + ObjB {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-extra-traits.rs:50:22 + | +LL | trait _0 = ObjA; + | ---- additional non-auto trait +LL | trait _1 = _0; + | -- referenced here (additional use) +... +LL | trait _5 = Sync + ObjB + Send; + | ---- first non-auto trait +LL | +LL | type _T20 = dyn _5 + _1; + | -- ^^ trait alias used in trait object type (additional use) + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: ObjB + ObjA {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-extra-traits.rs:53:22 + | +LL | trait _0 = ObjA; + | ---- first non-auto trait +LL | trait _1 = _0; + | -- referenced here (first use) +... +LL | trait _5 = Sync + ObjB + Send; + | ---- additional non-auto trait +... +LL | type _T21 = dyn _1 + _5; + | -- ^^ trait alias used in trait object type (additional use) + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: ObjA + ObjB {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-extra-traits.rs:56:22 + | +LL | trait _5 = Sync + ObjB + Send; + | ---- first non-auto trait +... +LL | type _T22 = dyn _5 + ObjA; + | -- ^^^^ additional non-auto trait + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: ObjB + ObjA {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-extra-traits.rs:59:24 + | +LL | trait _5 = Sync + ObjB + Send; + | ---- additional non-auto trait +... +LL | type _T23 = dyn ObjA + _5; + | ---- ^^ trait alias used in trait object type (additional use) + | | + | first non-auto trait + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: ObjA + ObjB {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-extra-traits.rs:62:29 + | +LL | trait _0 = ObjA; + | ---- additional non-auto trait +LL | trait _1 = _0; + | -- referenced here (additional use) +... +LL | trait _5 = Sync + ObjB + Send; + | ---- first non-auto trait +... +LL | type _T24 = dyn Send + _5 + _1 + Sync; + | -- ^^ trait alias used in trait object type (additional use) + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: ObjB + ObjA {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-extra-traits.rs:65:29 + | +LL | trait _0 = ObjA; + | ---- first non-auto trait +LL | trait _1 = _0; + | -- referenced here (first use) +... +LL | trait _5 = Sync + ObjB + Send; + | ---- additional non-auto trait +... +LL | type _T25 = dyn _1 + Sync + _5 + Send; + | -- ^^ trait alias used in trait object type (additional use) + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: ObjA + ObjB {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-extra-traits.rs:68:36 + | +LL | trait _5 = Sync + ObjB + Send; + | ---- first non-auto trait +... +LL | type _T26 = dyn Sync + Send + _5 + ObjA; + | -- ^^^^ additional non-auto trait + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: ObjB + ObjA {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-extra-traits.rs:71:38 + | +LL | trait _5 = Sync + ObjB + Send; + | ---- additional non-auto trait +... +LL | type _T27 = dyn Send + Sync + ObjA + _5; + | ---- ^^ trait alias used in trait object type (additional use) + | | + | first non-auto trait + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: ObjA + ObjB {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-extra-traits.rs:80:17 + | +LL | trait _0 = ObjA; + | ---- first non-auto trait +LL | trait _1 = _0; + | -- referenced here (first use) +... +LL | trait _5 = Sync + ObjB + Send; + | ---- additional non-auto trait +... +LL | trait _6 = _1 + _5; + | -- -- referenced here (additional use) + | | + | referenced here (first use) +... +LL | type _T30 = dyn _6; + | ^^ + | | + | trait alias used in trait object type (additional use) + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: ObjA + ObjB {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-extra-traits.rs:83:17 + | +LL | trait _0 = ObjA; + | ---- first non-auto trait +LL | trait _1 = _0; + | -- referenced here (first use) +... +LL | trait _5 = Sync + ObjB + Send; + | ---- additional non-auto trait +... +LL | trait _6 = _1 + _5; + | -- -- referenced here (additional use) + | | + | referenced here (first use) +... +LL | type _T31 = dyn _6 + Send; + | ^^ + | | + | trait alias used in trait object type (additional use) + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: ObjA + ObjB {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-extra-traits.rs:86:24 + | +LL | trait _0 = ObjA; + | ---- first non-auto trait +LL | trait _1 = _0; + | -- referenced here (first use) +... +LL | trait _5 = Sync + ObjB + Send; + | ---- additional non-auto trait +... +LL | trait _6 = _1 + _5; + | -- -- referenced here (additional use) + | | + | referenced here (first use) +... +LL | type _T32 = dyn Send + _6; + | ^^ + | | + | trait alias used in trait object type (additional use) + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: ObjA + ObjB {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-extra-traits.rs:89:17 + | +LL | trait _0 = ObjA; + | ---- first non-auto trait +LL | trait _1 = _0; + | -- referenced here (first use) +... +LL | trait _5 = Sync + ObjB + Send; + | ---- additional non-auto trait +... +LL | trait _6 = _1 + _5; + | -- -- referenced here (additional use) + | | + | referenced here (first use) +LL | trait _7 = _6; + | -- + | | + | referenced here (additional use) + | referenced here (first use) +LL | trait _8 = _7; + | -- + | | + | referenced here (additional use) + | referenced here (first use) +... +LL | type _T33 = dyn _8; + | ^^ + | | + | trait alias used in trait object type (additional use) + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: ObjA + ObjB {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-extra-traits.rs:92:17 + | +LL | trait _0 = ObjA; + | ---- first non-auto trait +LL | trait _1 = _0; + | -- referenced here (first use) +... +LL | trait _5 = Sync + ObjB + Send; + | ---- additional non-auto trait +... +LL | trait _6 = _1 + _5; + | -- -- referenced here (additional use) + | | + | referenced here (first use) +LL | trait _7 = _6; + | -- + | | + | referenced here (additional use) + | referenced here (first use) +LL | trait _8 = _7; + | -- + | | + | referenced here (additional use) + | referenced here (first use) +... +LL | type _T34 = dyn _8 + Send; + | ^^ + | | + | trait alias used in trait object type (additional use) + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: ObjA + ObjB {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-extra-traits.rs:95:24 + | +LL | trait _0 = ObjA; + | ---- first non-auto trait +LL | trait _1 = _0; + | -- referenced here (first use) +... +LL | trait _5 = Sync + ObjB + Send; + | ---- additional non-auto trait +... +LL | trait _6 = _1 + _5; + | -- -- referenced here (additional use) + | | + | referenced here (first use) +LL | trait _7 = _6; + | -- + | | + | referenced here (additional use) + | referenced here (first use) +LL | trait _8 = _7; + | -- + | | + | referenced here (additional use) + | referenced here (first use) +... +LL | type _T35 = dyn Send + _8; + | ^^ + | | + | trait alias used in trait object type (additional use) + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: ObjA + ObjB {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-extra-traits.rs:103:23 + | +LL | trait _5 = Sync + ObjB + Send; + | ---- first non-auto trait +... +LL | trait _9 = _5 + Sync; + | -- referenced here (first use) +LL | trait _10 = Unpin + _9; + | -- referenced here (first use) +LL | +LL | type _T40 = dyn _10 + ObjA; + | --- ^^^^ additional non-auto trait + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: ObjB + ObjA {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-extra-traits.rs:106:24 + | +LL | trait _5 = Sync + ObjB + Send; + | ---- additional non-auto trait +... +LL | trait _9 = _5 + Sync; + | -- referenced here (additional use) +LL | trait _10 = Unpin + _9; + | -- referenced here (additional use) +... +LL | type _T41 = dyn ObjA + _10; + | ---- ^^^ trait alias used in trait object type (additional use) + | | + | first non-auto trait + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: ObjA + ObjB {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-extra-traits.rs:109:23 + | +LL | trait _0 = ObjA; + | ---- additional non-auto trait +LL | trait _1 = _0; + | -- referenced here (additional use) +... +LL | trait _5 = Sync + ObjB + Send; + | ---- first non-auto trait +... +LL | trait _9 = _5 + Sync; + | -- referenced here (first use) +LL | trait _10 = Unpin + _9; + | -- referenced here (first use) +... +LL | type _T42 = dyn _10 + _1; + | --- ^^ trait alias used in trait object type (additional use) + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: ObjB + ObjA {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-extra-traits.rs:112:37 + | +LL | trait _5 = Sync + ObjB + Send; + | ---- first non-auto trait +... +LL | trait _9 = _5 + Sync; + | -- referenced here (first use) +LL | trait _10 = Unpin + _9; + | -- referenced here (first use) +... +LL | type _T43 = dyn Send + _10 + Sync + ObjA; + | --- ^^^^ additional non-auto trait + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: ObjB + ObjA {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-extra-traits.rs:115:24 + | +LL | trait _5 = Sync + ObjB + Send; + | ---- additional non-auto trait +... +LL | trait _9 = _5 + Sync; + | -- referenced here (additional use) +LL | trait _10 = Unpin + _9; + | -- referenced here (additional use) +... +LL | type _T44 = dyn ObjA + _10 + Send + Sync; + | ---- ^^^ trait alias used in trait object type (additional use) + | | + | first non-auto trait + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: ObjA + ObjB {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error[E0225]: only auto traits can be used as additional traits in a trait object + --> $DIR/no-extra-traits.rs:118:37 + | +LL | trait _0 = ObjA; + | ---- additional non-auto trait +LL | trait _1 = _0; + | -- referenced here (additional use) +... +LL | trait _5 = Sync + ObjB + Send; + | ---- first non-auto trait +... +LL | trait _9 = _5 + Sync; + | -- referenced here (first use) +LL | trait _10 = Unpin + _9; + | -- referenced here (first use) +... +LL | type _T45 = dyn Sync + Send + _10 + _1; + | --- ^^ trait alias used in trait object type (additional use) + | | + | trait alias used in trait object type (first use) + | + = help: consider creating a new trait with all of these as supertraits and using that trait here instead: `trait NewTrait: ObjB + ObjA {}` + = note: auto-traits like `Send` and `Sync` are traits that have special properties; for more information on them, visit <https://doc.rust-lang.org/reference/special-types-and-traits.html#auto-traits> + +error: aborting due to 28 previous errors + +For more information about this error, try `rustc --explain E0225`. diff --git a/src/test/ui/traits/alias/object-fail.rs b/src/test/ui/traits/alias/object-fail.rs new file mode 100644 index 000000000..5c753ff20 --- /dev/null +++ b/src/test/ui/traits/alias/object-fail.rs @@ -0,0 +1,11 @@ +#![feature(trait_alias)] + +trait EqAlias = Eq; +trait IteratorAlias = Iterator; + +fn main() { + let _: &dyn EqAlias = &123; + //~^ ERROR the trait `Eq` cannot be made into an object [E0038] + let _: &dyn IteratorAlias = &vec![123].into_iter(); + //~^ ERROR must be specified +} diff --git a/src/test/ui/traits/alias/object-fail.stderr b/src/test/ui/traits/alias/object-fail.stderr new file mode 100644 index 000000000..325bc6d28 --- /dev/null +++ b/src/test/ui/traits/alias/object-fail.stderr @@ -0,0 +1,22 @@ +error[E0038]: the trait `Eq` cannot be made into an object + --> $DIR/object-fail.rs:7:13 + | +LL | let _: &dyn EqAlias = &123; + | ^^^^^^^^^^^ `Eq` cannot be made into an object + | +note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety> + --> $SRC_DIR/core/src/cmp.rs:LL:COL + | +LL | pub trait Eq: PartialEq<Self> { + | ^^^^^^^^^^^^^^^ the trait cannot be made into an object because it uses `Self` as a type parameter + +error[E0191]: the value of the associated type `Item` (from trait `Iterator`) must be specified + --> $DIR/object-fail.rs:9:17 + | +LL | let _: &dyn IteratorAlias = &vec![123].into_iter(); + | ^^^^^^^^^^^^^ help: specify the associated type: `IteratorAlias<Item = Type>` + +error: aborting due to 2 previous errors + +Some errors have detailed explanations: E0038, E0191. +For more information about an error, try `rustc --explain E0038`. diff --git a/src/test/ui/traits/alias/object-wf.rs b/src/test/ui/traits/alias/object-wf.rs new file mode 100644 index 000000000..1440f02df --- /dev/null +++ b/src/test/ui/traits/alias/object-wf.rs @@ -0,0 +1,85 @@ +// check-pass + +// This test checks that trait objects involving trait aliases are well-formed. + +#![feature(trait_alias)] + +trait Obj {} + +trait _0 = Send + Sync; + +// Just auto traits: + +trait _1 = _0 + Send + Sync; + +use std::marker::Unpin; + +fn _f0() { + let _: Box<dyn _0>; + let _: Box<dyn _1>; + let _: Box<dyn Unpin + _1 + Send + Sync>; +} + +// Include object safe traits: + +fn _f1() { + let _: Box<dyn Obj + _0>; + let _: Box<dyn Obj + _1>; + let _: Box<dyn Obj + _1 + _0>; +} + +// And when the object safe trait is in a trait alias: + +trait _2 = Obj; + +fn _f2() { + let _: Box<dyn _2 + _0>; + let _: Box<dyn _2 + _1>; + let _: Box<dyn _2 + _1 + _0>; +} + +// And it should also work when that trait is has auto traits to the right of it. + +trait _3 = Obj + Unpin; + +fn _f3() { + let _: Box<dyn _3 + _0>; + let _: Box<dyn _3 + _1>; + let _: Box<dyn _3 + _1 + _0>; +} + +// Nest the trait deeply: + +trait _4 = _3; +trait _5 = _4 + Sync + _0 + Send; +trait _6 = _5 + Send + _1 + Sync; + +fn _f4() { + let _: Box<dyn _6 + _0>; + let _: Box<dyn _6 + _1>; + let _: Box<dyn _6 + _1 + _0>; +} + +// Just nest the trait alone: + +trait _7 = _2; +trait _8 = _7; +trait _9 = _8; + +fn _f5() { + let _: Box<dyn _9>; +} + +// First bound is auto trait: + +trait _10 = Send + Obj; +trait _11 = Obj + Send; +trait _12 = Sync + _11; +trait _13 = Send + _12; + +fn f6() { + let _: Box<dyn _10>; + let _: Box<dyn _13>; +} + +fn main() {} diff --git a/src/test/ui/traits/alias/object.rs b/src/test/ui/traits/alias/object.rs new file mode 100644 index 000000000..12177cd82 --- /dev/null +++ b/src/test/ui/traits/alias/object.rs @@ -0,0 +1,18 @@ +// run-pass + +#![feature(trait_alias)] + +trait Foo = PartialEq<i32> + Send; +trait Bar = Foo + Sync; + +trait I32Iterator = Iterator<Item = i32>; + +pub fn main() { + let a: &dyn Bar = &123; + assert!(*a == 123); + let b = Box::new(456) as Box<dyn Foo>; + assert!(*b == 456); + + let c: &mut dyn I32Iterator = &mut vec![123].into_iter(); + assert_eq!(c.next(), Some(123)); +} diff --git a/src/test/ui/traits/alias/only-maybe-bound.rs b/src/test/ui/traits/alias/only-maybe-bound.rs new file mode 100644 index 000000000..e4abf314e --- /dev/null +++ b/src/test/ui/traits/alias/only-maybe-bound.rs @@ -0,0 +1,22 @@ +// Test that `dyn ?Sized` (i.e., a trait object with only a maybe buond) is not allowed, when just +// `?Sized` results from trait alias expansion. + +#![feature(trait_alias)] + +trait S = ?Sized; + +// Nest a couple of levels deep: +trait _0 = S; +trait _1 = _0; + +// Straight list expansion: +type _T0 = dyn _1; +//~^ ERROR at least one trait is required for an object type [E0224] + +// Twice: +trait _2 = _1 + _1; + +type _T1 = dyn _2; +//~^ ERROR at least one trait is required for an object type [E0224] + +fn main() {} diff --git a/src/test/ui/traits/alias/only-maybe-bound.stderr b/src/test/ui/traits/alias/only-maybe-bound.stderr new file mode 100644 index 000000000..175ec8120 --- /dev/null +++ b/src/test/ui/traits/alias/only-maybe-bound.stderr @@ -0,0 +1,21 @@ +error[E0224]: at least one trait is required for an object type + --> $DIR/only-maybe-bound.rs:13:12 + | +LL | trait _1 = _0; + | -------- this alias does not contain a trait +... +LL | type _T0 = dyn _1; + | ^^^^^^ + +error[E0224]: at least one trait is required for an object type + --> $DIR/only-maybe-bound.rs:19:12 + | +LL | trait _2 = _1 + _1; + | -------- this alias does not contain a trait +LL | +LL | type _T1 = dyn _2; + | ^^^^^^ + +error: aborting due to 2 previous errors + +For more information about this error, try `rustc --explain E0224`. diff --git a/src/test/ui/traits/alias/style_lint.rs b/src/test/ui/traits/alias/style_lint.rs new file mode 100644 index 000000000..33be20054 --- /dev/null +++ b/src/test/ui/traits/alias/style_lint.rs @@ -0,0 +1,8 @@ +// check-pass + +#![feature(trait_alias)] + +trait Foo = std::fmt::Display + std::fmt::Debug; +trait bar = std::fmt::Display + std::fmt::Debug; //~WARN trait alias `bar` should have an upper camel case name + +fn main() {} diff --git a/src/test/ui/traits/alias/style_lint.stderr b/src/test/ui/traits/alias/style_lint.stderr new file mode 100644 index 000000000..91e2ea90e --- /dev/null +++ b/src/test/ui/traits/alias/style_lint.stderr @@ -0,0 +1,10 @@ +warning: trait alias `bar` should have an upper camel case name + --> $DIR/style_lint.rs:6:7 + | +LL | trait bar = std::fmt::Display + std::fmt::Debug; + | ^^^ help: convert the identifier to upper camel case: `Bar` + | + = note: `#[warn(non_camel_case_types)]` on by default + +warning: 1 warning emitted + diff --git a/src/test/ui/traits/alias/suggest-trait-alias-instead-of-type.fixed b/src/test/ui/traits/alias/suggest-trait-alias-instead-of-type.fixed new file mode 100644 index 000000000..8a94abaeb --- /dev/null +++ b/src/test/ui/traits/alias/suggest-trait-alias-instead-of-type.fixed @@ -0,0 +1,13 @@ +// Regression test of #43913. + +// run-rustfix + +#![feature(trait_alias)] +#![allow(bare_trait_objects, dead_code)] + +trait Strings = Iterator<Item=String>; + +struct Struct<S: Strings>(S); +//~^ ERROR: expected trait, found type alias `Strings` + +fn main() {} diff --git a/src/test/ui/traits/alias/suggest-trait-alias-instead-of-type.rs b/src/test/ui/traits/alias/suggest-trait-alias-instead-of-type.rs new file mode 100644 index 000000000..40c678c28 --- /dev/null +++ b/src/test/ui/traits/alias/suggest-trait-alias-instead-of-type.rs @@ -0,0 +1,13 @@ +// Regression test of #43913. + +// run-rustfix + +#![feature(trait_alias)] +#![allow(bare_trait_objects, dead_code)] + +type Strings = Iterator<Item=String>; + +struct Struct<S: Strings>(S); +//~^ ERROR: expected trait, found type alias `Strings` + +fn main() {} diff --git a/src/test/ui/traits/alias/suggest-trait-alias-instead-of-type.stderr b/src/test/ui/traits/alias/suggest-trait-alias-instead-of-type.stderr new file mode 100644 index 000000000..6e03eeada --- /dev/null +++ b/src/test/ui/traits/alias/suggest-trait-alias-instead-of-type.stderr @@ -0,0 +1,14 @@ +error[E0404]: expected trait, found type alias `Strings` + --> $DIR/suggest-trait-alias-instead-of-type.rs:10:18 + | +LL | struct Struct<S: Strings>(S); + | ^^^^^^^ type aliases cannot be used as traits + | +help: you might have meant to use `#![feature(trait_alias)]` instead of a `type` alias + | +LL | trait Strings = Iterator<Item=String>; + | + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0404`. diff --git a/src/test/ui/traits/alias/syntax-fail.rs b/src/test/ui/traits/alias/syntax-fail.rs new file mode 100644 index 000000000..039bbce8c --- /dev/null +++ b/src/test/ui/traits/alias/syntax-fail.rs @@ -0,0 +1,10 @@ +#![feature(trait_alias)] + +trait Foo {} +auto trait A = Foo; //~ ERROR trait aliases cannot be `auto` +unsafe trait B = Foo; //~ ERROR trait aliases cannot be `unsafe` + +trait C: Ord = Eq; //~ ERROR bounds are not allowed on trait aliases +trait D: = Eq; //~ ERROR bounds are not allowed on trait aliases + +fn main() {} diff --git a/src/test/ui/traits/alias/syntax-fail.stderr b/src/test/ui/traits/alias/syntax-fail.stderr new file mode 100644 index 000000000..748b92056 --- /dev/null +++ b/src/test/ui/traits/alias/syntax-fail.stderr @@ -0,0 +1,26 @@ +error: trait aliases cannot be `auto` + --> $DIR/syntax-fail.rs:4:1 + | +LL | auto trait A = Foo; + | ^^^^^^^^^^^^^^^^^^^ trait aliases cannot be `auto` + +error: trait aliases cannot be `unsafe` + --> $DIR/syntax-fail.rs:5:1 + | +LL | unsafe trait B = Foo; + | ^^^^^^^^^^^^^^^^^^^^^ trait aliases cannot be `unsafe` + +error: bounds are not allowed on trait aliases + --> $DIR/syntax-fail.rs:7:8 + | +LL | trait C: Ord = Eq; + | ^^^^^ + +error: bounds are not allowed on trait aliases + --> $DIR/syntax-fail.rs:8:8 + | +LL | trait D: = Eq; + | ^ + +error: aborting due to 4 previous errors + diff --git a/src/test/ui/traits/alias/syntax.rs b/src/test/ui/traits/alias/syntax.rs new file mode 100644 index 000000000..17557a51a --- /dev/null +++ b/src/test/ui/traits/alias/syntax.rs @@ -0,0 +1,24 @@ +// run-pass + +#![feature(trait_alias)] + +trait SimpleAlias = Default; +trait GenericAlias<T> = Iterator<Item = T>; +trait Partial<T> = IntoIterator<Item = T>; +trait SpecificAlias = GenericAlias<i32>; +trait PartialEqRef<'a, T: 'a> = PartialEq<&'a T>; +trait StaticAlias = 'static; + +trait Things<T> {} +trait Romeo {} +#[allow(dead_code)] +struct The<T>(T); +#[allow(dead_code)] +struct Fore<T>(T); +impl<T, U> Things<T> for The<U> {} +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>; + +fn main() {} diff --git a/src/test/ui/traits/alias/wf.rs b/src/test/ui/traits/alias/wf.rs new file mode 100644 index 000000000..d10e2abb0 --- /dev/null +++ b/src/test/ui/traits/alias/wf.rs @@ -0,0 +1,7 @@ +#![feature(trait_alias)] + +trait Foo {} +trait A<T: Foo> {} +trait B<T> = A<T>; //~ ERROR `T: Foo` is not satisfied + +fn main() {} diff --git a/src/test/ui/traits/alias/wf.stderr b/src/test/ui/traits/alias/wf.stderr new file mode 100644 index 000000000..7172008d3 --- /dev/null +++ b/src/test/ui/traits/alias/wf.stderr @@ -0,0 +1,19 @@ +error[E0277]: the trait bound `T: Foo` is not satisfied + --> $DIR/wf.rs:5:14 + | +LL | trait B<T> = A<T>; + | ^^^^ the trait `Foo` is not implemented for `T` + | +note: required by a bound in `A` + --> $DIR/wf.rs:4:12 + | +LL | trait A<T: Foo> {} + | ^^^ required by this bound in `A` +help: consider restricting type parameter `T` + | +LL | trait B<T: Foo> = A<T>; + | +++++ + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0277`. |