diff options
18 files changed, 204 insertions, 48 deletions
diff --git a/compiler/rustc_typeck/src/coherence/orphan.rs b/compiler/rustc_typeck/src/coherence/orphan.rs index 4b23cc4db85..77a53744829 100644 --- a/compiler/rustc_typeck/src/coherence/orphan.rs +++ b/compiler/rustc_typeck/src/coherence/orphan.rs @@ -7,6 +7,7 @@ use rustc_errors::ErrorGuaranteed; use rustc_hir as hir; use rustc_index::bit_set::GrowableBitSet; use rustc_infer::infer::TyCtxtInferExt; +use rustc_middle::ty::subst::GenericArgKind; use rustc_middle::ty::subst::{GenericArg, InternalSubsts}; use rustc_middle::ty::{self, ImplPolarity, Ty, TyCtxt, TypeFoldable, TypeVisitor}; use rustc_session::lint; @@ -141,13 +142,56 @@ fn orphan_check_impl(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Result<(), ErrorGua } } - if let ty::Opaque(def_id, _) = *trait_ref.self_ty().kind() { - let reported = tcx - .sess - .struct_span_err(sp, "cannot implement trait on type alias impl trait") - .span_note(tcx.def_span(def_id), "type alias impl trait defined here") - .emit(); - return Err(reported); + // Ensure no opaque types are present in this impl header. See issues #76202 and #86411 for examples, + // and #84660 where it would otherwise allow unsoundness. + if trait_ref.has_opaque_types() { + trace!("{:#?}", item); + // First we find the opaque type in question. + for ty in trait_ref.substs { + for ty in ty.walk() { + let ty::subst::GenericArgKind::Type(ty) = ty.unpack() else { continue }; + let ty::Opaque(def_id, _) = *ty.kind() else { continue }; + trace!(?def_id); + + // Then we search for mentions of the opaque type's type alias in the HIR + struct SpanFinder<'tcx> { + sp: Span, + def_id: DefId, + tcx: TyCtxt<'tcx>, + } + impl<'v, 'tcx> hir::intravisit::Visitor<'v> for SpanFinder<'tcx> { + #[instrument(level = "trace", skip(self, _id))] + fn visit_path(&mut self, path: &'v hir::Path<'v>, _id: hir::HirId) { + // You can't mention an opaque type directly, so we look for type aliases + if let hir::def::Res::Def(hir::def::DefKind::TyAlias, def_id) = path.res { + // And check if that type alias's type contains the opaque type we're looking for + for arg in self.tcx.type_of(def_id).walk() { + if let GenericArgKind::Type(ty) = arg.unpack() { + if let ty::Opaque(def_id, _) = *ty.kind() { + if def_id == self.def_id { + // Finally we update the span to the mention of the type alias + self.sp = path.span; + return; + } + } + } + } + } + hir::intravisit::walk_path(self, path) + } + } + + let mut visitor = SpanFinder { sp, def_id, tcx }; + hir::intravisit::walk_item(&mut visitor, item); + let reported = tcx + .sess + .struct_span_err(visitor.sp, "cannot implement trait on type alias impl trait") + .span_note(tcx.def_span(def_id), "type alias impl trait defined here") + .emit(); + return Err(reported); + } + } + span_bug!(sp, "opaque type not found, but `has_opaque_types` is set") } Ok(()) diff --git a/src/test/ui/impl-trait/auto-trait.rs b/src/test/ui/impl-trait/auto-trait.rs index 35994e4a5ba..afa95645a27 100644 --- a/src/test/ui/impl-trait/auto-trait.rs +++ b/src/test/ui/impl-trait/auto-trait.rs @@ -20,6 +20,7 @@ impl<T: Send> AnotherTrait for T {} // in the future.) impl AnotherTrait for D<OpaqueType> { //~^ ERROR conflicting implementations of trait `AnotherTrait` for type `D<OpaqueType>` + //~| ERROR cannot implement trait on type alias impl trait } fn main() {} diff --git a/src/test/ui/impl-trait/auto-trait.stderr b/src/test/ui/impl-trait/auto-trait.stderr index 81009413c9a..3b360f492b7 100644 --- a/src/test/ui/impl-trait/auto-trait.stderr +++ b/src/test/ui/impl-trait/auto-trait.stderr @@ -1,3 +1,15 @@ +error: cannot implement trait on type alias impl trait + --> $DIR/auto-trait.rs:21:25 + | +LL | impl AnotherTrait for D<OpaqueType> { + | ^^^^^^^^^^ + | +note: type alias impl trait defined here + --> $DIR/auto-trait.rs:7:19 + | +LL | type OpaqueType = impl OpaqueTrait; + | ^^^^^^^^^^^^^^^^ + error[E0119]: conflicting implementations of trait `AnotherTrait` for type `D<OpaqueType>` --> $DIR/auto-trait.rs:21:1 | @@ -7,6 +19,6 @@ LL | impl<T: Send> AnotherTrait for T {} LL | impl AnotherTrait for D<OpaqueType> { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `D<OpaqueType>` -error: aborting due to previous error +error: aborting due to 2 previous errors For more information about this error, try `rustc --explain E0119`. diff --git a/src/test/ui/impl-trait/negative-reasoning.rs b/src/test/ui/impl-trait/negative-reasoning.rs index 70e24a3a9d0..da69bb349ae 100644 --- a/src/test/ui/impl-trait/negative-reasoning.rs +++ b/src/test/ui/impl-trait/negative-reasoning.rs @@ -18,6 +18,7 @@ impl<T: std::fmt::Debug> AnotherTrait for T {} // This is in error, because we cannot assume that `OpaqueType: !Debug` impl AnotherTrait for D<OpaqueType> { //~^ ERROR conflicting implementations of trait `AnotherTrait` for type `D<OpaqueType>` + //~| ERROR cannot implement trait on type alias impl trait } fn main() {} diff --git a/src/test/ui/impl-trait/negative-reasoning.stderr b/src/test/ui/impl-trait/negative-reasoning.stderr index 6b8cc9e7374..98f9fbd8fef 100644 --- a/src/test/ui/impl-trait/negative-reasoning.stderr +++ b/src/test/ui/impl-trait/negative-reasoning.stderr @@ -1,3 +1,15 @@ +error: cannot implement trait on type alias impl trait + --> $DIR/negative-reasoning.rs:19:25 + | +LL | impl AnotherTrait for D<OpaqueType> { + | ^^^^^^^^^^ + | +note: type alias impl trait defined here + --> $DIR/negative-reasoning.rs:7:19 + | +LL | type OpaqueType = impl OpaqueTrait; + | ^^^^^^^^^^^^^^^^ + error[E0119]: conflicting implementations of trait `AnotherTrait` for type `D<OpaqueType>` --> $DIR/negative-reasoning.rs:19:1 | @@ -9,6 +21,6 @@ LL | impl AnotherTrait for D<OpaqueType> { | = note: upstream crates may add a new impl of trait `std::fmt::Debug` for type `OpaqueType` in future versions -error: aborting due to previous error +error: aborting due to 2 previous errors For more information about this error, try `rustc --explain E0119`. diff --git a/src/test/ui/impl-trait/recursive-type-alias-impl-trait-declaration-too-subtle-2.rs b/src/test/ui/impl-trait/recursive-type-alias-impl-trait-declaration-too-subtle-2.rs index 6b200d7e3a8..621c4ea6e0d 100644 --- a/src/test/ui/impl-trait/recursive-type-alias-impl-trait-declaration-too-subtle-2.rs +++ b/src/test/ui/impl-trait/recursive-type-alias-impl-trait-declaration-too-subtle-2.rs @@ -5,13 +5,14 @@ type Foo = impl PartialEq<(Foo, i32)>; struct Bar; impl PartialEq<(Foo, i32)> for Bar { +//~^ ERROR cannot implement trait on type alias impl trait fn eq(&self, _other: &(Foo, i32)) -> bool { true } } fn foo() -> Foo { - Bar //~ ERROR can't compare `Bar` with `(Bar, i32)` + Bar } fn main() {} diff --git a/src/test/ui/impl-trait/recursive-type-alias-impl-trait-declaration-too-subtle-2.stderr b/src/test/ui/impl-trait/recursive-type-alias-impl-trait-declaration-too-subtle-2.stderr index 6cd63db44fa..2ef1697ba34 100644 --- a/src/test/ui/impl-trait/recursive-type-alias-impl-trait-declaration-too-subtle-2.stderr +++ b/src/test/ui/impl-trait/recursive-type-alias-impl-trait-declaration-too-subtle-2.stderr @@ -1,12 +1,14 @@ -error[E0277]: can't compare `Bar` with `(Bar, i32)` - --> $DIR/recursive-type-alias-impl-trait-declaration-too-subtle-2.rs:14:5 +error: cannot implement trait on type alias impl trait + --> $DIR/recursive-type-alias-impl-trait-declaration-too-subtle-2.rs:7:17 | -LL | Bar - | ^^^ no implementation for `Bar == (Bar, i32)` +LL | impl PartialEq<(Foo, i32)> for Bar { + | ^^^ | - = help: the trait `PartialEq<(Bar, i32)>` is not implemented for `Bar` - = help: the trait `PartialEq<(Foo, i32)>` is implemented for `Bar` +note: type alias impl trait defined here + --> $DIR/recursive-type-alias-impl-trait-declaration-too-subtle-2.rs:3:12 + | +LL | type Foo = impl PartialEq<(Foo, i32)>; + | ^^^^^^^^^^^^^^^^^^^^^^^^^^ error: aborting due to previous error -For more information about this error, try `rustc --explain E0277`. diff --git a/src/test/ui/impl-trait/recursive-type-alias-impl-trait-declaration-too-subtle.rs b/src/test/ui/impl-trait/recursive-type-alias-impl-trait-declaration-too-subtle.rs index 6aa832cde71..df7966f00e1 100644 --- a/src/test/ui/impl-trait/recursive-type-alias-impl-trait-declaration-too-subtle.rs +++ b/src/test/ui/impl-trait/recursive-type-alias-impl-trait-declaration-too-subtle.rs @@ -2,7 +2,6 @@ mod a { type Foo = impl PartialEq<(Foo, i32)>; - //~^ ERROR unconstrained opaque type struct Bar; @@ -15,13 +14,12 @@ mod a { mod b { type Foo = impl PartialEq<(Foo, i32)>; - //~^ ERROR unconstrained opaque type struct Bar; impl PartialEq<(Foo, i32)> for Bar { + //~^ ERROR cannot implement trait on type alias impl trait fn eq(&self, _other: &(Bar, i32)) -> bool { - //~^ ERROR impl has stricter requirements than trait true } } diff --git a/src/test/ui/impl-trait/recursive-type-alias-impl-trait-declaration-too-subtle.stderr b/src/test/ui/impl-trait/recursive-type-alias-impl-trait-declaration-too-subtle.stderr index 19d5cdb9d0a..6cd63dcf81c 100644 --- a/src/test/ui/impl-trait/recursive-type-alias-impl-trait-declaration-too-subtle.stderr +++ b/src/test/ui/impl-trait/recursive-type-alias-impl-trait-declaration-too-subtle.stderr @@ -1,25 +1,14 @@ -error: unconstrained opaque type - --> $DIR/recursive-type-alias-impl-trait-declaration-too-subtle.rs:4:16 +error: cannot implement trait on type alias impl trait + --> $DIR/recursive-type-alias-impl-trait-declaration-too-subtle.rs:20:21 | -LL | type Foo = impl PartialEq<(Foo, i32)>; - | ^^^^^^^^^^^^^^^^^^^^^^^^^^ +LL | impl PartialEq<(Foo, i32)> for Bar { + | ^^^ | - = note: `Foo` must be used in combination with a concrete type within the same module - -error: unconstrained opaque type - --> $DIR/recursive-type-alias-impl-trait-declaration-too-subtle.rs:17:16 +note: type alias impl trait defined here + --> $DIR/recursive-type-alias-impl-trait-declaration-too-subtle.rs:16:16 | LL | type Foo = impl PartialEq<(Foo, i32)>; | ^^^^^^^^^^^^^^^^^^^^^^^^^^ - | - = note: `Foo` must be used in combination with a concrete type within the same module - -error[E0276]: impl has stricter requirements than trait - --> $DIR/recursive-type-alias-impl-trait-declaration-too-subtle.rs:23:9 - | -LL | fn eq(&self, _other: &(Bar, i32)) -> bool { - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ impl has extra requirement `b::Bar: PartialEq<(b::Bar, i32)>` -error: aborting due to 3 previous errors +error: aborting due to previous error -For more information about this error, try `rustc --explain E0276`. diff --git a/src/test/ui/traits/alias/issue-83613.stderr b/src/test/ui/traits/alias/issue-83613.stderr index 4f19e6607c8..bbc240b6aec 100644 --- a/src/test/ui/traits/alias/issue-83613.stderr +++ b/src/test/ui/traits/alias/issue-83613.stderr @@ -1,8 +1,8 @@ error: cannot implement trait on type alias impl trait - --> $DIR/issue-83613.rs:10:1 + --> $DIR/issue-83613.rs:10:23 | LL | impl AnotherTrait for OpaqueType {} - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | ^^^^^^^^^^ | note: type alias impl trait defined here --> $DIR/issue-83613.rs:4:19 diff --git a/src/test/ui/type-alias-impl-trait/issue-65384.stderr b/src/test/ui/type-alias-impl-trait/issue-65384.stderr index 27680f0ad75..41bcea27e1f 100644 --- a/src/test/ui/type-alias-impl-trait/issue-65384.stderr +++ b/src/test/ui/type-alias-impl-trait/issue-65384.stderr @@ -1,8 +1,8 @@ error: cannot implement trait on type alias impl trait - --> $DIR/issue-65384.rs:10:1 + --> $DIR/issue-65384.rs:10:18 | LL | impl MyTrait for Bar {} - | ^^^^^^^^^^^^^^^^^^^^ + | ^^^ | note: type alias impl trait defined here --> $DIR/issue-65384.rs:8:12 diff --git a/src/test/ui/type-alias-impl-trait/issue-76202-trait-impl-for-tait.stderr b/src/test/ui/type-alias-impl-trait/issue-76202-trait-impl-for-tait.stderr index 8689ee53660..2d4a6854a92 100644 --- a/src/test/ui/type-alias-impl-trait/issue-76202-trait-impl-for-tait.stderr +++ b/src/test/ui/type-alias-impl-trait/issue-76202-trait-impl-for-tait.stderr @@ -1,8 +1,8 @@ error: cannot implement trait on type alias impl trait - --> $DIR/issue-76202-trait-impl-for-tait.rs:16:1 + --> $DIR/issue-76202-trait-impl-for-tait.rs:16:15 | LL | impl Test for F { - | ^^^^^^^^^^^^^^^ + | ^ | note: type alias impl trait defined here --> $DIR/issue-76202-trait-impl-for-tait.rs:9:10 diff --git a/src/test/ui/type-alias-impl-trait/issue-84660-trait-impl-for-tait.rs b/src/test/ui/type-alias-impl-trait/issue-84660-trait-impl-for-tait.rs new file mode 100644 index 00000000000..fa25d8f762e --- /dev/null +++ b/src/test/ui/type-alias-impl-trait/issue-84660-trait-impl-for-tait.rs @@ -0,0 +1,23 @@ +// Regression test for issues #84660 and #86411: both are variations on #76202. +// Tests that we don't ICE when we have an opaque type appearing anywhere in an impl header. + +#![feature(type_alias_impl_trait)] + +trait Foo {} +impl Foo for () {} +type Bar = impl Foo; +fn _defining_use() -> Bar {} + +trait TraitArg<T> { + fn f(); +} + +impl TraitArg<Bar> for () { //~ ERROR cannot implement trait + fn f() { + println!("ho"); + } +} + +fn main() { + <() as TraitArg<Bar>>::f(); +} diff --git a/src/test/ui/type-alias-impl-trait/issue-84660-trait-impl-for-tait.stderr b/src/test/ui/type-alias-impl-trait/issue-84660-trait-impl-for-tait.stderr new file mode 100644 index 00000000000..bb70d07be59 --- /dev/null +++ b/src/test/ui/type-alias-impl-trait/issue-84660-trait-impl-for-tait.stderr @@ -0,0 +1,14 @@ +error: cannot implement trait on type alias impl trait + --> $DIR/issue-84660-trait-impl-for-tait.rs:15:15 + | +LL | impl TraitArg<Bar> for () { + | ^^^ + | +note: type alias impl trait defined here + --> $DIR/issue-84660-trait-impl-for-tait.rs:8:12 + | +LL | type Bar = impl Foo; + | ^^^^^^^^ + +error: aborting due to previous error + diff --git a/src/test/ui/type-alias-impl-trait/issue-84660-unsoundness.rs b/src/test/ui/type-alias-impl-trait/issue-84660-unsoundness.rs new file mode 100644 index 00000000000..f12d1b6d953 --- /dev/null +++ b/src/test/ui/type-alias-impl-trait/issue-84660-unsoundness.rs @@ -0,0 +1,41 @@ +// Another example from issue #84660, this time weaponized as a safe transmute: an opaque type in an +// impl header being accepted was used to create unsoundness. + +#![feature(type_alias_impl_trait)] + +trait Foo {} +impl Foo for () {} +type Bar = impl Foo; +fn _defining_use() -> Bar {} + +trait Trait<T, In> { + type Out; + fn convert(i: In) -> Self::Out; +} + +impl<In, Out> Trait<Bar, In> for Out { //~ ERROR cannot implement trait + type Out = Out; + fn convert(_i: In) -> Self::Out { + unreachable!(); + } +} + +impl<In, Out> Trait<(), In> for Out { + type Out = In; + fn convert(i: In) -> Self::Out { + i + } +} + +fn transmute<In, Out>(i: In) -> Out { + <Out as Trait<Bar, In>>::convert(i) +} + +fn main() { + let d; + { + let x = "Hello World".to_string(); + d = transmute::<&String, &String>(&x); + } + println!("{}", d); +} diff --git a/src/test/ui/type-alias-impl-trait/issue-84660-unsoundness.stderr b/src/test/ui/type-alias-impl-trait/issue-84660-unsoundness.stderr new file mode 100644 index 00000000000..f2d600fb46c --- /dev/null +++ b/src/test/ui/type-alias-impl-trait/issue-84660-unsoundness.stderr @@ -0,0 +1,14 @@ +error: cannot implement trait on type alias impl trait + --> $DIR/issue-84660-unsoundness.rs:16:21 + | +LL | impl<In, Out> Trait<Bar, In> for Out { + | ^^^ + | +note: type alias impl trait defined here + --> $DIR/issue-84660-unsoundness.rs:8:12 + | +LL | type Bar = impl Foo; + | ^^^^^^^^ + +error: aborting due to previous error + diff --git a/src/test/ui/type-alias-impl-trait/nested-tait-inference3.rs b/src/test/ui/type-alias-impl-trait/nested-tait-inference3.rs index fbab5470b4f..ebf3a99bbf9 100644 --- a/src/test/ui/type-alias-impl-trait/nested-tait-inference3.rs +++ b/src/test/ui/type-alias-impl-trait/nested-tait-inference3.rs @@ -4,11 +4,11 @@ use std::fmt::Debug; type FooX = impl Debug; -//~^ unconstrained opaque type trait Foo<A> { } impl Foo<FooX> for () { } +//~^ cannot implement trait on type alias impl trait fn foo() -> impl Foo<FooX> { () diff --git a/src/test/ui/type-alias-impl-trait/nested-tait-inference3.stderr b/src/test/ui/type-alias-impl-trait/nested-tait-inference3.stderr index b1d947a9ccf..4a3fb16733e 100644 --- a/src/test/ui/type-alias-impl-trait/nested-tait-inference3.stderr +++ b/src/test/ui/type-alias-impl-trait/nested-tait-inference3.stderr @@ -1,10 +1,14 @@ -error: unconstrained opaque type +error: cannot implement trait on type alias impl trait + --> $DIR/nested-tait-inference3.rs:10:10 + | +LL | impl Foo<FooX> for () { } + | ^^^^ + | +note: type alias impl trait defined here --> $DIR/nested-tait-inference3.rs:6:13 | LL | type FooX = impl Debug; | ^^^^^^^^^^ - | - = note: `FooX` must be used in combination with a concrete type within the same module error: aborting due to previous error |