prevent opaque types from appearing in impl headers
This commit is contained in:
Rémy Rakic
Oli Scherer
parent
d00e77078c
commit
7d5bbf55f2
@ -141,13 +141,22 @@ fn orphan_check_impl(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Result<(), ErrorGua
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}
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}
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if let ty::Opaque(def_id, _) = *trait_ref.self_ty().kind() {
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let reported = tcx
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.sess
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.struct_span_err(sp, "cannot implement trait on type alias impl trait")
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.span_note(tcx.def_span(def_id), "type alias impl trait defined here")
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.emit();
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return Err(reported);
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// Ensure no opaque types are present in this impl header. See issues #76202 and #86411 for examples,
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// and #84660 where it would otherwise allow unsoundness.
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if trait_ref.has_opaque_types() {
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for ty in trait_ref.substs {
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for ty in ty.walk() {
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let ty::subst::GenericArgKind::Type(ty) = ty.unpack() else { continue };
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let ty::Opaque(def_id, _) = ty.kind() else { continue };
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let reported = tcx
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.sess
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.struct_span_err(sp, "cannot implement trait on type alias impl trait")
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.span_note(tcx.def_span(def_id), "type alias impl trait defined here")
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.emit();
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return Err(reported);
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}
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}
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span_bug!(sp, "opque type not found, but `has_opaque_types` is set")
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}
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Ok(())
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@ -20,6 +20,7 @@ impl<T: Send> AnotherTrait for T {}
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// in the future.)
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impl AnotherTrait for D<OpaqueType> {
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//~^ ERROR conflicting implementations of trait `AnotherTrait` for type `D<OpaqueType>`
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//~| ERROR cannot implement trait on type alias impl trait
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}
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fn main() {}
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@ -1,3 +1,15 @@
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error: cannot implement trait on type alias impl trait
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--> $DIR/auto-trait.rs:21:1
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LL | impl AnotherTrait for D<OpaqueType> {
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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note: type alias impl trait defined here
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--> $DIR/auto-trait.rs:7:19
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LL | type OpaqueType = impl OpaqueTrait;
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| ^^^^^^^^^^^^^^^^
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error[E0119]: conflicting implementations of trait `AnotherTrait` for type `D<OpaqueType>`
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--> $DIR/auto-trait.rs:21:1
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@ -7,6 +19,6 @@ LL | impl<T: Send> AnotherTrait for T {}
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LL | impl AnotherTrait for D<OpaqueType> {
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `D<OpaqueType>`
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error: aborting due to previous error
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error: aborting due to 2 previous errors
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For more information about this error, try `rustc --explain E0119`.
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@ -18,6 +18,7 @@ impl<T: std::fmt::Debug> AnotherTrait for T {}
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// This is in error, because we cannot assume that `OpaqueType: !Debug`
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impl AnotherTrait for D<OpaqueType> {
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//~^ ERROR conflicting implementations of trait `AnotherTrait` for type `D<OpaqueType>`
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//~| ERROR cannot implement trait on type alias impl trait
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}
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fn main() {}
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@ -1,3 +1,15 @@
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error: cannot implement trait on type alias impl trait
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--> $DIR/negative-reasoning.rs:19:1
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LL | impl AnotherTrait for D<OpaqueType> {
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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note: type alias impl trait defined here
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--> $DIR/negative-reasoning.rs:7:19
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LL | type OpaqueType = impl OpaqueTrait;
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| ^^^^^^^^^^^^^^^^
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error[E0119]: conflicting implementations of trait `AnotherTrait` for type `D<OpaqueType>`
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--> $DIR/negative-reasoning.rs:19:1
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@ -9,6 +21,6 @@ LL | impl AnotherTrait for D<OpaqueType> {
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= note: upstream crates may add a new impl of trait `std::fmt::Debug` for type `OpaqueType` in future versions
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error: aborting due to previous error
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error: aborting due to 2 previous errors
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For more information about this error, try `rustc --explain E0119`.
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@ -5,13 +5,14 @@
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struct Bar;
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impl PartialEq<(Foo, i32)> for Bar {
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//~^ ERROR cannot implement trait on type alias impl trait
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fn eq(&self, _other: &(Foo, i32)) -> bool {
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true
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}
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}
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fn foo() -> Foo {
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Bar //~ ERROR can't compare `Bar` with `(Bar, i32)`
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Bar
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}
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fn main() {}
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@ -1,12 +1,14 @@
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error[E0277]: can't compare `Bar` with `(Bar, i32)`
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--> $DIR/recursive-type-alias-impl-trait-declaration-too-subtle-2.rs:14:5
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error: cannot implement trait on type alias impl trait
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--> $DIR/recursive-type-alias-impl-trait-declaration-too-subtle-2.rs:7:1
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LL | Bar
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| ^^^ no implementation for `Bar == (Bar, i32)`
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LL | impl PartialEq<(Foo, i32)> for Bar {
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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= help: the trait `PartialEq<(Bar, i32)>` is not implemented for `Bar`
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= help: the trait `PartialEq<(Foo, i32)>` is implemented for `Bar`
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note: type alias impl trait defined here
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--> $DIR/recursive-type-alias-impl-trait-declaration-too-subtle-2.rs:3:12
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LL | type Foo = impl PartialEq<(Foo, i32)>;
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^
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error: aborting due to previous error
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For more information about this error, try `rustc --explain E0277`.
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@ -2,7 +2,6 @@
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mod a {
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type Foo = impl PartialEq<(Foo, i32)>;
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//~^ ERROR unconstrained opaque type
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struct Bar;
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@ -15,13 +14,12 @@ fn eq(&self, _other: &(Foo, i32)) -> bool {
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mod b {
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type Foo = impl PartialEq<(Foo, i32)>;
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//~^ ERROR unconstrained opaque type
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struct Bar;
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impl PartialEq<(Foo, i32)> for Bar {
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//~^ ERROR cannot implement trait on type alias impl trait
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fn eq(&self, _other: &(Bar, i32)) -> bool {
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//~^ ERROR impl has stricter requirements than trait
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true
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}
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}
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@ -1,25 +1,14 @@
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error: unconstrained opaque type
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--> $DIR/recursive-type-alias-impl-trait-declaration-too-subtle.rs:4:16
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error: cannot implement trait on type alias impl trait
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--> $DIR/recursive-type-alias-impl-trait-declaration-too-subtle.rs:20:5
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LL | impl PartialEq<(Foo, i32)> for Bar {
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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note: type alias impl trait defined here
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--> $DIR/recursive-type-alias-impl-trait-declaration-too-subtle.rs:16:16
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LL | type Foo = impl PartialEq<(Foo, i32)>;
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^
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= note: `Foo` must be used in combination with a concrete type within the same module
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error: unconstrained opaque type
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--> $DIR/recursive-type-alias-impl-trait-declaration-too-subtle.rs:17:16
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LL | type Foo = impl PartialEq<(Foo, i32)>;
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^
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= note: `Foo` must be used in combination with a concrete type within the same module
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error: aborting due to previous error
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error[E0276]: impl has stricter requirements than trait
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--> $DIR/recursive-type-alias-impl-trait-declaration-too-subtle.rs:23:9
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LL | fn eq(&self, _other: &(Bar, i32)) -> bool {
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ impl has extra requirement `b::Bar: PartialEq<(b::Bar, i32)>`
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error: aborting due to 3 previous errors
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For more information about this error, try `rustc --explain E0276`.
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@ -4,11 +4,11 @@
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use std::fmt::Debug;
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type FooX = impl Debug;
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//~^ unconstrained opaque type
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trait Foo<A> { }
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impl Foo<FooX> for () { }
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//~^ cannot implement trait on type alias impl trait
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fn foo() -> impl Foo<FooX> {
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()
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@ -1,10 +1,14 @@
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error: unconstrained opaque type
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error: cannot implement trait on type alias impl trait
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--> $DIR/nested-tait-inference3.rs:10:1
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LL | impl Foo<FooX> for () { }
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| ^^^^^^^^^^^^^^^^^^^^^
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note: type alias impl trait defined here
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--> $DIR/nested-tait-inference3.rs:6:13
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LL | type FooX = impl Debug;
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| ^^^^^^^^^^
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= note: `FooX` must be used in combination with a concrete type within the same module
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error: aborting due to previous error
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