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Point at Sized bound

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This commit is contained in:
Esteban Küber 2020-01-19 14:53:37 -08:00
parent fca5c64abd
commit 1c9242f83f
9 changed files with 76 additions and 9 deletions
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40
src/librustc/traits/object_safety.rs
View File

@ -26,7 +26,7 @@ use std::iter::{self};
#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
pub enum ObjectSafetyViolation {
/// `Self: Sized` declared on the trait.
SizedSelf,
SizedSelf(Span),
/// Supertrait reference references `Self` an in illegal location
/// (e.g., `trait Foo : Bar<Self>`).
@ -42,7 +42,7 @@ pub enum ObjectSafetyViolation {
impl ObjectSafetyViolation {
pub fn error_msg(&self) -> Cow<'static, str> {
match *self {
ObjectSafetyViolation::SizedSelf => {
ObjectSafetyViolation::SizedSelf(_) => {
"the trait cannot require that `Self : Sized`".into()
}
ObjectSafetyViolation::SupertraitSelf => {
@ -80,6 +80,7 @@ impl ObjectSafetyViolation {
// diagnostics use a `note` instead of a `span_label`.
match *self {
ObjectSafetyViolation::AssocConst(_, span)
| ObjectSafetyViolation::SizedSelf(span)
| ObjectSafetyViolation::Method(_, _, span)
if span != DUMMY_SP =>
{
@ -179,7 +180,7 @@ fn object_safety_violations_for_trait(
{
// Using `CRATE_NODE_ID` is wrong, but it's hard to get a more precise id.
// It's also hard to get a use site span, so we use the method definition span.
tcx.struct_span_lint_hir(
let mut err = tcx.struct_span_lint_hir(
WHERE_CLAUSES_OBJECT_SAFETY,
hir::CRATE_HIR_ID,
*span,
@ -187,9 +188,12 @@ fn object_safety_violations_for_trait(
"the trait `{}` cannot be made into an object",
tcx.def_path_str(trait_def_id)
),
)
.note(&violation.error_msg())
.emit();
);
match violation.span() {
Some(span) => err.span_label(span, violation.error_msg()),
None => err.note(&violation.error_msg()),
};
err.emit();
false
} else {
true
@ -199,7 +203,8 @@ fn object_safety_violations_for_trait(
// Check the trait itself.
if trait_has_sized_self(tcx, trait_def_id) {
violations.push(ObjectSafetyViolation::SizedSelf);
let span = get_sized_bound(tcx, trait_def_id);
violations.push(ObjectSafetyViolation::SizedSelf(span));
}
if predicates_reference_self(tcx, trait_def_id, false) {
violations.push(ObjectSafetyViolation::SupertraitSelf);
@ -219,6 +224,27 @@ fn object_safety_violations_for_trait(
violations
}
fn get_sized_bound(tcx: TyCtxt<'_>, trait_def_id: DefId) -> Span {
tcx.hir()
.get_if_local(trait_def_id)
.and_then(|node| match node {
hir::Node::Item(hir::Item { kind: hir::ItemKind::Trait(.., bounds, _), .. }) => bounds
.iter()
.filter_map(|b| match b {
hir::GenericBound::Trait(trait_ref, hir::TraitBoundModifier::None)
if Some(trait_ref.trait_ref.trait_def_id())
== tcx.lang_items().sized_trait() =>
{
Some(trait_ref.span)
}
_ => None,
})
.next(),
_ => None,
})
.unwrap_or(DUMMY_SP)
}
fn predicates_reference_self(tcx: TyCtxt<'_>, trait_def_id: DefId, supertraits_only: bool) -> bool {
let trait_ref = ty::Binder::dummy(ty::TraitRef::identity(tcx, trait_def_id));
let predicates = if supertraits_only {

6
src/test/ui/feature-gates/feature-gate-object_safe_for_dispatch.stderr
View File

@ -1,6 +1,9 @@
error[E0038]: the trait `NonObjectSafe1` cannot be made into an object
--> $DIR/feature-gate-object_safe_for_dispatch.rs:18:38
|
LL | trait NonObjectSafe1: Sized {}
| ----- the trait cannot require that `Self : Sized`
...
LL | fn takes_non_object_safe_ref<T>(obj: &dyn NonObjectSafe1) {
| ^^^^^^^^^^^^^^^^^^^ the trait `NonObjectSafe1` cannot be made into an object
|
@ -36,6 +39,9 @@ LL | fn return_non_object_safe_rc() -> std::rc::Rc<dyn NonObjectSafe4> {
error[E0038]: the trait `NonObjectSafe1` cannot be made into an object
--> $DIR/feature-gate-object_safe_for_dispatch.rs:38:6
|
LL | trait NonObjectSafe1: Sized {}
| ----- the trait cannot require that `Self : Sized`
...
LL | impl Trait for dyn NonObjectSafe1 {}
| ^^^^^ the trait `NonObjectSafe1` cannot be made into an object
|

6
src/test/ui/issues/issue-20692.stderr
View File

@ -1,6 +1,9 @@
error[E0038]: the trait `Array` cannot be made into an object
--> $DIR/issue-20692.rs:7:5
|
LL | trait Array: Sized {}
| ----- the trait cannot require that `Self : Sized`
...
LL | &dyn Array;
| ^^^^^^^^^^ the trait `Array` cannot be made into an object
|
@ -9,6 +12,9 @@ LL | &dyn Array;
error[E0038]: the trait `Array` cannot be made into an object
--> $DIR/issue-20692.rs:4:13
|
LL | trait Array: Sized {}
| ----- the trait cannot require that `Self : Sized`
...
LL | let _ = x
| ^ the trait `Array` cannot be made into an object
|

3
src/test/ui/issues/issue-50781.stderr
View File

@ -2,7 +2,7 @@ error: the trait `X` cannot be made into an object
--> $DIR/issue-50781.rs:6:8
|
LL | fn foo(&self) where Self: Trait;
| ^^^
| ^^^ method `foo` references the `Self` type in where clauses
|
note: the lint level is defined here
--> $DIR/issue-50781.rs:1:9
@ -11,7 +11,6 @@ LL | #![deny(where_clauses_object_safety)]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^
= warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
= note: for more information, see issue #51443 <https://github.com/rust-lang/rust/issues/51443>
= note: method `foo` references the `Self` type in where clauses
error: aborting due to previous error

3
src/test/ui/object-safety/object-safety-sized.curr.stderr
View File

@ -1,6 +1,9 @@
error[E0038]: the trait `Bar` cannot be made into an object
--> $DIR/object-safety-sized.rs:12:30
|
LL | trait Bar : Sized {
| ----- the trait cannot require that `Self : Sized`
...
LL | fn make_bar<T:Bar>(t: &T) -> &dyn Bar {
| ^^^^^^^^ the trait `Bar` cannot be made into an object
|

3
src/test/ui/object-safety/object-safety-sized.object_safe_for_dispatch.stderr
View File

@ -1,6 +1,9 @@
error[E0038]: the trait `Bar` cannot be made into an object
--> $DIR/object-safety-sized.rs:14:5
|
LL | trait Bar : Sized {
| ----- the trait cannot require that `Self : Sized`
...
LL | t
| ^ the trait `Bar` cannot be made into an object
|

9
src/test/ui/wf/wf-convert-unsafe-trait-obj-box.stderr
View File

@ -1,6 +1,9 @@
error[E0038]: the trait `Trait` cannot be made into an object
--> $DIR/wf-convert-unsafe-trait-obj-box.rs:16:33
|
LL | trait Trait: Sized {}
| ----- the trait cannot require that `Self : Sized`
...
LL | let t_box: Box<dyn Trait> = Box::new(S);
| ^^^^^^^^^^^ the trait `Trait` cannot be made into an object
|
@ -11,6 +14,9 @@ LL | let t_box: Box<dyn Trait> = Box::new(S);
error[E0038]: the trait `Trait` cannot be made into an object
--> $DIR/wf-convert-unsafe-trait-obj-box.rs:17:15
|
LL | trait Trait: Sized {}
| ----- the trait cannot require that `Self : Sized`
...
LL | takes_box(Box::new(S));
| ^^^^^^^^^^^ the trait `Trait` cannot be made into an object
|
@ -21,6 +27,9 @@ LL | takes_box(Box::new(S));
error[E0038]: the trait `Trait` cannot be made into an object
--> $DIR/wf-convert-unsafe-trait-obj-box.rs:15:5
|
LL | trait Trait: Sized {}
| ----- the trait cannot require that `Self : Sized`
...
LL | Box::new(S) as Box<dyn Trait>;
| ^^^^^^^^^^^ the trait `Trait` cannot be made into an object
|

9
src/test/ui/wf/wf-convert-unsafe-trait-obj.stderr
View File

@ -1,6 +1,9 @@
error[E0038]: the trait `Trait` cannot be made into an object
--> $DIR/wf-convert-unsafe-trait-obj.rs:16:25
|
LL | trait Trait: Sized {}
| ----- the trait cannot require that `Self : Sized`
...
LL | let t: &dyn Trait = &S;
| ^^ the trait `Trait` cannot be made into an object
|
@ -11,6 +14,9 @@ LL | let t: &dyn Trait = &S;
error[E0038]: the trait `Trait` cannot be made into an object
--> $DIR/wf-convert-unsafe-trait-obj.rs:17:17
|
LL | trait Trait: Sized {}
| ----- the trait cannot require that `Self : Sized`
...
LL | takes_trait(&S);
| ^^ the trait `Trait` cannot be made into an object
|
@ -21,6 +27,9 @@ LL | takes_trait(&S);
error[E0038]: the trait `Trait` cannot be made into an object
--> $DIR/wf-convert-unsafe-trait-obj.rs:15:5
|
LL | trait Trait: Sized {}
| ----- the trait cannot require that `Self : Sized`
...
LL | &S as &dyn Trait;
| ^^ the trait `Trait` cannot be made into an object
|

6
src/test/ui/wf/wf-unsafe-trait-obj-match.stderr
View File

@ -15,6 +15,9 @@ LL | | }
error[E0038]: the trait `Trait` cannot be made into an object
--> $DIR/wf-unsafe-trait-obj-match.rs:26:21
|
LL | trait Trait: Sized {}
| ----- the trait cannot require that `Self : Sized`
...
LL | Some(()) => &S,
| ^^ the trait `Trait` cannot be made into an object
|
@ -25,6 +28,9 @@ LL | Some(()) => &S,
error[E0038]: the trait `Trait` cannot be made into an object
--> $DIR/wf-unsafe-trait-obj-match.rs:25:25
|
LL | trait Trait: Sized {}
| ----- the trait cannot require that `Self : Sized`
...
LL | let t: &dyn Trait = match opt() {
| ^^^^^^^^^^^ the trait `Trait` cannot be made into an object
|