diff options
Diffstat (limited to 'tests')
5 files changed, 188 insertions, 0 deletions
diff --git a/tests/ui/traits/next-solver/cycles/normalizes-to-is-not-productive-2.rs b/tests/ui/traits/next-solver/cycles/normalizes-to-is-not-productive-2.rs new file mode 100644 index 00000000000..bb3540f9a21 --- /dev/null +++ b/tests/ui/traits/next-solver/cycles/normalizes-to-is-not-productive-2.rs @@ -0,0 +1,24 @@ +//@ revisions: current next +//@ ignore-compare-mode-next-solver (explicit revisions) +//@[next] compile-flags: -Znext-solver +//@ check-pass + +// Regression test for trait-system-refactor-initiative#176. +// +// Normalizing `<Vec<T> as IntoIterator>::IntoIter` has two candidates +// inside of the function: +// - `impl<T> IntoIterator for Vec<T>` which trivially applies +// - `impl<I: Iterator> IntoIterator for I` +// - requires `Vec<T>: Iterator` +// - where-clause requires `<Vec<T> as IntoIterator>::IntoIter eq Vec<T>` +// - normalize `<Vec<T> as IntoIterator>::IntoIter` again, cycle +// +// We need to treat this cycle as an error to be able to use the actual impl. + +fn test<T>() +where + <Vec<T> as IntoIterator>::IntoIter: Iterator, +{ +} + +fn main() {} diff --git a/tests/ui/traits/next-solver/cycles/normalizes-to-is-not-productive.current.stderr b/tests/ui/traits/next-solver/cycles/normalizes-to-is-not-productive.current.stderr new file mode 100644 index 00000000000..0a5b90f3d12 --- /dev/null +++ b/tests/ui/traits/next-solver/cycles/normalizes-to-is-not-productive.current.stderr @@ -0,0 +1,48 @@ +error[E0277]: the trait bound `Foo: Bound` is not satisfied + --> $DIR/normalizes-to-is-not-productive.rs:41:1 + | +LL | / fn generic<T>() +LL | | where +LL | | <Foo as Trait<T>>::Assoc: Bound, + | |____________________________________^ the trait `Bound` is not implemented for `Foo` + | + = help: the trait `Bound` is implemented for `u32` +note: required for `Foo` to implement `Trait<T>` + --> $DIR/normalizes-to-is-not-productive.rs:24:19 + | +LL | impl<T: Bound, U> Trait<U> for T { + | ----- ^^^^^^^^ ^ + | | + | unsatisfied trait bound introduced here + +error[E0277]: the trait bound `Foo: Bound` is not satisfied + --> $DIR/normalizes-to-is-not-productive.rs:41:4 + | +LL | fn generic<T>() + | ^^^^^^^ the trait `Bound` is not implemented for `Foo` + | + = help: the trait `Bound` is implemented for `u32` +note: required for `Foo` to implement `Trait<T>` + --> $DIR/normalizes-to-is-not-productive.rs:24:19 + | +LL | impl<T: Bound, U> Trait<U> for T { + | ----- ^^^^^^^^ ^ + | | + | unsatisfied trait bound introduced here + +error[E0277]: the trait bound `Foo: Bound` is not satisfied + --> $DIR/normalizes-to-is-not-productive.rs:48:19 + | +LL | impls_bound::<Foo>(); + | ^^^ the trait `Bound` is not implemented for `Foo` + | + = help: the trait `Bound` is implemented for `u32` +note: required by a bound in `impls_bound` + --> $DIR/normalizes-to-is-not-productive.rs:28:19 + | +LL | fn impls_bound<T: Bound>() { + | ^^^^^ required by this bound in `impls_bound` + +error: aborting due to 3 previous errors + +For more information about this error, try `rustc --explain E0277`. diff --git a/tests/ui/traits/next-solver/cycles/normalizes-to-is-not-productive.next.stderr b/tests/ui/traits/next-solver/cycles/normalizes-to-is-not-productive.next.stderr new file mode 100644 index 00000000000..d888fbf9db1 --- /dev/null +++ b/tests/ui/traits/next-solver/cycles/normalizes-to-is-not-productive.next.stderr @@ -0,0 +1,31 @@ +error[E0277]: the trait bound `Foo: Bound` is not satisfied + --> $DIR/normalizes-to-is-not-productive.rs:43:31 + | +LL | <Foo as Trait<T>>::Assoc: Bound, + | ^^^^^ the trait `Bound` is not implemented for `Foo` + | + = help: the trait `Bound` is implemented for `u32` +note: required for `Foo` to implement `Trait<T>` + --> $DIR/normalizes-to-is-not-productive.rs:24:19 + | +LL | impl<T: Bound, U> Trait<U> for T { + | ----- ^^^^^^^^ ^ + | | + | unsatisfied trait bound introduced here + +error[E0277]: the trait bound `Foo: Bound` is not satisfied + --> $DIR/normalizes-to-is-not-productive.rs:48:19 + | +LL | impls_bound::<Foo>(); + | ^^^ the trait `Bound` is not implemented for `Foo` + | + = help: the trait `Bound` is implemented for `u32` +note: required by a bound in `impls_bound` + --> $DIR/normalizes-to-is-not-productive.rs:28:19 + | +LL | fn impls_bound<T: Bound>() { + | ^^^^^ required by this bound in `impls_bound` + +error: aborting due to 2 previous errors + +For more information about this error, try `rustc --explain E0277`. diff --git a/tests/ui/traits/next-solver/cycles/normalizes-to-is-not-productive.rs b/tests/ui/traits/next-solver/cycles/normalizes-to-is-not-productive.rs new file mode 100644 index 00000000000..ffbbecaf895 --- /dev/null +++ b/tests/ui/traits/next-solver/cycles/normalizes-to-is-not-productive.rs @@ -0,0 +1,54 @@ +//@ ignore-compare-mode-next-solver (explicit) +//@ compile-flags: -Znext-solver + +// Make sure that stepping into impl where-clauses of `NormalizesTo` +// goals is unproductive. This must not compile, see the inline +// comments. + +trait Bound { + fn method(); +} +impl Bound for u32 { + fn method() {} +} +trait Trait<T> { + type Assoc: Bound; +} + +struct Foo; + +impl Trait<u32> for Foo { + type Assoc = u32; +} +impl<T: Bound, U> Trait<U> for T { + type Assoc = T; +} + +fn impls_bound<T: Bound>() { + T::method(); +} + +// The where-clause requires `Foo: Trait<T>` to hold to be wf. +// If stepping into where-clauses during normalization is considered +// to be productive, this would be the case: +// +// - `Foo: Trait<T>` +// - via blanket impls, requires `Foo: Bound` +// - via where-bound, requires `Foo eq <Foo as Trait<T>>::Assoc` +// - normalize `<Foo as Trait<T>>::Assoc` +// - via blanket impl, requires where-clause `Foo: Bound` -> cycle +fn generic<T>() +where + <Foo as Trait<T>>::Assoc: Bound, + //~^ ERROR the trait bound `Foo: Bound` is not satisfied +{ + // Requires proving `Foo: Bound` by normalizing + // `<Foo as Trait<T>>::Assoc` to `Foo`. + impls_bound::<Foo>(); + //~^ ERROR the trait bound `Foo: Bound` is not satisfied +} +fn main() { + // Requires proving `<Foo as Trait<u32>>::Assoc: Bound`. + // This is trivially true. + generic::<u32>(); +} diff --git a/tests/ui/traits/next-solver/cycles/normalizes-to-is-not-productive.stderr b/tests/ui/traits/next-solver/cycles/normalizes-to-is-not-productive.stderr new file mode 100644 index 00000000000..8901805a20f --- /dev/null +++ b/tests/ui/traits/next-solver/cycles/normalizes-to-is-not-productive.stderr @@ -0,0 +1,31 @@ +error[E0277]: the trait bound `Foo: Bound` is not satisfied + --> $DIR/normalizes-to-is-not-productive.rs:42:31 + | +LL | <Foo as Trait<T>>::Assoc: Bound, + | ^^^^^ the trait `Bound` is not implemented for `Foo` + | + = help: the trait `Bound` is implemented for `u32` +note: required for `Foo` to implement `Trait<T>` + --> $DIR/normalizes-to-is-not-productive.rs:23:19 + | +LL | impl<T: Bound, U> Trait<U> for T { + | ----- ^^^^^^^^ ^ + | | + | unsatisfied trait bound introduced here + +error[E0277]: the trait bound `Foo: Bound` is not satisfied + --> $DIR/normalizes-to-is-not-productive.rs:47:19 + | +LL | impls_bound::<Foo>(); + | ^^^ the trait `Bound` is not implemented for `Foo` + | + = help: the trait `Bound` is implemented for `u32` +note: required by a bound in `impls_bound` + --> $DIR/normalizes-to-is-not-productive.rs:27:19 + | +LL | fn impls_bound<T: Bound>() { + | ^^^^^ required by this bound in `impls_bound` + +error: aborting due to 2 previous errors + +For more information about this error, try `rustc --explain E0277`. |