From ba4510ece85018408627b2d3ceef1a3b7889cb71 Mon Sep 17 00:00:00 2001 From: Oli Scherer Date: Mon, 27 May 2024 11:49:05 +0000 Subject: [PATCH] Allow constraining opaque types during subtyping in the trait system --- compiler/rustc_infer/src/infer/mod.rs | 4 +- .../impl-trait/lazy_subtyping_of_opaques.rs | 67 +++++-------------- .../lazy_subtyping_of_opaques.stderr | 21 ------ .../lazy_subtyping_of_opaques.rs | 3 +- .../lazy_subtyping_of_opaques.stderr | 31 +++++---- 5 files changed, 38 insertions(+), 88 deletions(-) delete mode 100644 tests/ui/impl-trait/lazy_subtyping_of_opaques.stderr diff --git a/compiler/rustc_infer/src/infer/mod.rs b/compiler/rustc_infer/src/infer/mod.rs index 510e9a06dfb06..4d6ddd7ba66ab 100644 --- a/compiler/rustc_infer/src/infer/mod.rs +++ b/compiler/rustc_infer/src/infer/mod.rs @@ -878,9 +878,9 @@ impl<'tcx> InferCtxt<'tcx> { self.enter_forall(predicate, |ty::SubtypePredicate { a_is_expected, a, b }| { if a_is_expected { - Ok(self.at(cause, param_env).sub(DefineOpaqueTypes::No, a, b)) + Ok(self.at(cause, param_env).sub(DefineOpaqueTypes::Yes, a, b)) } else { - Ok(self.at(cause, param_env).sup(DefineOpaqueTypes::No, b, a)) + Ok(self.at(cause, param_env).sup(DefineOpaqueTypes::Yes, b, a)) } }) } diff --git a/tests/ui/impl-trait/lazy_subtyping_of_opaques.rs b/tests/ui/impl-trait/lazy_subtyping_of_opaques.rs index 65331894725a8..8fd1f35645a8a 100644 --- a/tests/ui/impl-trait/lazy_subtyping_of_opaques.rs +++ b/tests/ui/impl-trait/lazy_subtyping_of_opaques.rs @@ -2,58 +2,23 @@ //! No hidden types are being constrained in the subtyping predicate, but type and //! lifetime variables get subtyped in the generic parameter list of the opaque. -use std::iter; - -mod either { - pub enum Either { - Left(L), - Right(R), - } - - impl> Iterator for Either { - type Item = L::Item; - fn next(&mut self) -> Option { - todo!() - } - } - pub use self::Either::{Left, Right}; -} - -pub enum BabeConsensusLogRef<'a> { - NextEpochData(BabeNextEpochRef<'a>), - NextConfigData, -} - -impl<'a> BabeConsensusLogRef<'a> { - pub fn scale_encoding( - &self, - ) -> impl Iterator + Clone + 'a> + Clone + 'a { - //~^ ERROR is not satisfied - //~| ERROR is not satisfied - //~| ERROR is not satisfied - match self { - BabeConsensusLogRef::NextEpochData(digest) => either::Left(either::Left( - digest.scale_encoding().map(either::Left).map(either::Left), - )), - BabeConsensusLogRef::NextConfigData => either::Right( - // The Opaque type from ``scale_encoding` gets used opaquely here, while the `R` - // generic parameter of `Either` contains type variables that get subtyped and the - // opaque type contains lifetime variables that get subtyped. - iter::once(either::Right(either::Left([1]))) - .chain(std::iter::once([1]).map(either::Right).map(either::Right)), - ), - } - } -} - -pub struct BabeNextEpochRef<'a>(&'a ()); - -impl<'a> BabeNextEpochRef<'a> { - pub fn scale_encoding( - &self, - ) -> impl Iterator + Clone + 'a> + Clone + 'a { - std::iter::once([1]) +//@ check-pass + +fn foo() -> impl Default + Copy { + if false { + let x = Default::default(); + // add `Subtype(?x, ?y)` obligation + let y = x; + + // Make a tuple `(?x, ?y)` and equate it with `(impl Default, u32)`. + // For us to try and prove a `Subtype(impl Default, u32)` obligation, + // we have to instantiate both `?x` and `?y` without any + // `select_where_possible` calls inbetween. + let mut tup = &mut (x, y); + let assign_tup = &mut (foo(), 1u32); + tup = assign_tup; } + 1u32 } fn main() {} diff --git a/tests/ui/impl-trait/lazy_subtyping_of_opaques.stderr b/tests/ui/impl-trait/lazy_subtyping_of_opaques.stderr deleted file mode 100644 index 2f8c957c2c7dc..0000000000000 --- a/tests/ui/impl-trait/lazy_subtyping_of_opaques.stderr +++ /dev/null @@ -1,21 +0,0 @@ -error[E0277]: the trait bound `Either + Clone + '_> + Clone + '_, fn(impl AsRef<[u8]> + Clone + '_) -> Either + Clone + '_, _> {Either:: + Clone + '_, _>::Left}>, fn(Either + Clone + '_, _>) -> Either + Clone + '_, _>, Either<[{integer}; 1], [{integer}; 1]>> {Either:: + Clone + '_, _>, Either<[{integer}; 1], [{integer}; 1]>>::Left}>, _>, std::iter::Chain + Clone + '_, _>, Either<[{integer}; 1], [{integer}; 1]>>>, Map, fn([{integer}; 1]) -> Either<[{integer}; 1], [{integer}; 1]> {Either::<[{integer}; 1], [{integer}; 1]>::Right}>, fn(Either<[{integer}; 1], [{integer}; 1]>) -> Either + Clone + '_, _>, Either<[{integer}; 1], [{integer}; 1]>> {Either:: + Clone + '_, _>, Either<[{integer}; 1], [{integer}; 1]>>::Right}>>>: Clone` is not satisfied - --> $DIR/lazy_subtyping_of_opaques.rs:30:10 - | -LL | ) -> impl Iterator + Clone + 'a> + Clone + 'a { - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Clone` is not implemented for `Either + Clone + '_> + Clone + '_, fn(impl AsRef<[u8]> + Clone + '_) -> Either + Clone + '_, _> {Either:: + Clone + '_, _>::Left}>, fn(Either + Clone + '_, _>) -> Either + Clone + '_, _>, Either<[{integer}; 1], [{integer}; 1]>> {Either:: + Clone + '_, _>, Either<[{integer}; 1], [{integer}; 1]>>::Left}>, _>, std::iter::Chain + Clone + '_, _>, Either<[{integer}; 1], [{integer}; 1]>>>, Map, fn([{integer}; 1]) -> Either<[{integer}; 1], [{integer}; 1]> {Either::<[{integer}; 1], [{integer}; 1]>::Right}>, fn(Either<[{integer}; 1], [{integer}; 1]>) -> Either + Clone + '_, _>, Either<[{integer}; 1], [{integer}; 1]>> {Either:: + Clone + '_, _>, Either<[{integer}; 1], [{integer}; 1]>>::Right}>>>` - -error[E0277]: the trait bound `Either + Clone + '_, _>, Either<[{integer}; 1], [{integer}; 1]>>: AsRef<[u8]>` is not satisfied - --> $DIR/lazy_subtyping_of_opaques.rs:30:31 - | -LL | ) -> impl Iterator + Clone + 'a> + Clone + 'a { - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `AsRef<[u8]>` is not implemented for `Either + Clone + '_, _>, Either<[{integer}; 1], [{integer}; 1]>>` - -error[E0277]: the trait bound `Either + Clone + '_, _>, Either<[{integer}; 1], [{integer}; 1]>>: Clone` is not satisfied - --> $DIR/lazy_subtyping_of_opaques.rs:30:31 - | -LL | ) -> impl Iterator + Clone + 'a> + Clone + 'a { - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Clone` is not implemented for `Either + Clone + '_, _>, Either<[{integer}; 1], [{integer}; 1]>>` - -error: aborting due to 3 previous errors - -For more information about this error, try `rustc --explain E0277`. diff --git a/tests/ui/type-alias-impl-trait/lazy_subtyping_of_opaques.rs b/tests/ui/type-alias-impl-trait/lazy_subtyping_of_opaques.rs index 72a90287e374f..1bc352041a57d 100644 --- a/tests/ui/type-alias-impl-trait/lazy_subtyping_of_opaques.rs +++ b/tests/ui/type-alias-impl-trait/lazy_subtyping_of_opaques.rs @@ -7,9 +7,10 @@ type Tait = impl FnOnce() -> (); fn reify_as_tait() -> Thunk { + //~^ ERROR: expected a `FnOnce()` closure, found `()` Thunk::new(|cont| cont) //~^ ERROR: mismatched types - //~| ERROR: mismatched types + //~| ERROR: expected a `FnOnce()` closure, found `()` } struct Thunk(F); diff --git a/tests/ui/type-alias-impl-trait/lazy_subtyping_of_opaques.stderr b/tests/ui/type-alias-impl-trait/lazy_subtyping_of_opaques.stderr index 5a35dc27446cb..7bc2fa1b09ea6 100644 --- a/tests/ui/type-alias-impl-trait/lazy_subtyping_of_opaques.stderr +++ b/tests/ui/type-alias-impl-trait/lazy_subtyping_of_opaques.stderr @@ -1,26 +1,31 @@ -error[E0308]: mismatched types - --> $DIR/lazy_subtyping_of_opaques.rs:10:23 +error[E0277]: expected a `FnOnce()` closure, found `()` + --> $DIR/lazy_subtyping_of_opaques.rs:11:23 | -LL | type Tait = impl FnOnce() -> (); - | ------------------- the found opaque type -... LL | Thunk::new(|cont| cont) - | ^^^^ expected `()`, found opaque type + | ^^^^ expected an `FnOnce()` closure, found `()` | - = note: expected unit type `()` - found opaque type `Tait` + = help: the trait `FnOnce()` is not implemented for `()` + = note: wrap the `()` in a closure with no arguments: `|| { /* code */ }` -error[E0308]: mismatched types - --> $DIR/lazy_subtyping_of_opaques.rs:10:5 +error[E0277]: expected a `FnOnce()` closure, found `()` + --> $DIR/lazy_subtyping_of_opaques.rs:9:23 | LL | fn reify_as_tait() -> Thunk { - | ----------- expected `Thunk<_>` because of return type + | ^^^^^^^^^^^ expected an `FnOnce()` closure, found `()` + | + = help: the trait `FnOnce()` is not implemented for `()` + = note: wrap the `()` in a closure with no arguments: `|| { /* code */ }` + +error[E0308]: mismatched types + --> $DIR/lazy_subtyping_of_opaques.rs:11:5 + | LL | Thunk::new(|cont| cont) | ^^^^^^^^^^^^^^^^^^^^^^^ expected `Thunk<_>`, found `()` | = note: expected struct `Thunk<_>` found unit type `()` -error: aborting due to 2 previous errors +error: aborting due to 3 previous errors -For more information about this error, try `rustc --explain E0308`. +Some errors have detailed explanations: E0277, E0308. +For more information about an error, try `rustc --explain E0277`.