mirror of
https://github.com/rust-lang/rust.git
synced 2025-02-24 21:05:12 +00:00
Rollup merge of #91849 - jackh726:gats-outlives-lint-part2, r=nikomatsakis
GATs outlives lint: Try to prove bounds Fixes #91036 Fixes #90888 Fixes #91348 (better error + documentation to be added to linked issue) Instead of checking for bounds directly, try to prove them in the associated type environment. Also, add a bit of extra information to the error, including a link to the relevant discussion issue (#87479). That should be edited to include a brief summary of the current state of the outlives lint, including a brief background. It also might or might not be worth it to bump this to a full error code at some point. r? ``@nikomatsakis``
This commit is contained in:
Matthias Krüger
GitHub
commit
84878336b0
@ -11,7 +11,7 @@ use rustc_middle::ty::{self, Lift, Region, TyCtxt};
|
||||
///
|
||||
/// This stuff is a bit convoluted and should be refactored, but as we
|
||||
/// transition to NLL, it'll all go away anyhow.
|
||||
pub struct RegionRelations<'a, 'tcx> {
|
||||
pub(crate) struct RegionRelations<'a, 'tcx> {
|
||||
pub tcx: TyCtxt<'tcx>,
|
||||
|
||||
/// The context used for debug messages
|
||||
|
||||
@ -28,7 +28,7 @@ use std::fmt;
|
||||
/// assuming such values can be found. It returns the final values of
|
||||
/// all the variables as well as a set of errors that must be reported.
|
||||
#[instrument(level = "debug", skip(region_rels, var_infos, data))]
|
||||
pub fn resolve<'tcx>(
|
||||
pub(crate) fn resolve<'tcx>(
|
||||
region_rels: &RegionRelations<'_, 'tcx>,
|
||||
var_infos: VarInfos,
|
||||
data: RegionConstraintData<'tcx>,
|
||||
|
||||
@ -426,22 +426,48 @@ fn check_gat_where_clauses(
|
||||
}
|
||||
}
|
||||
|
||||
// If there are any missing clauses, emit an error
|
||||
let mut clauses = clauses.unwrap_or_default();
|
||||
// If there are any clauses that aren't provable, emit an error
|
||||
let clauses = clauses.unwrap_or_default();
|
||||
debug!(?clauses);
|
||||
if !clauses.is_empty() {
|
||||
let written_predicates: ty::GenericPredicates<'_> =
|
||||
tcx.explicit_predicates_of(trait_item.def_id);
|
||||
let param_env = tcx.param_env(trait_item.def_id);
|
||||
|
||||
let mut clauses: Vec<_> = clauses
|
||||
.drain_filter(|clause| !written_predicates.predicates.iter().any(|p| &p.0 == clause))
|
||||
.into_iter()
|
||||
.filter(|clause| match clause.kind().skip_binder() {
|
||||
ty::PredicateKind::RegionOutlives(ty::OutlivesPredicate(a, b)) => {
|
||||
!region_known_to_outlive(
|
||||
tcx,
|
||||
trait_item.hir_id(),
|
||||
param_env,
|
||||
&FxHashSet::default(),
|
||||
a,
|
||||
b,
|
||||
)
|
||||
}
|
||||
ty::PredicateKind::TypeOutlives(ty::OutlivesPredicate(a, b)) => {
|
||||
!ty_known_to_outlive(
|
||||
tcx,
|
||||
trait_item.hir_id(),
|
||||
param_env,
|
||||
&FxHashSet::default(),
|
||||
a,
|
||||
b,
|
||||
)
|
||||
}
|
||||
_ => bug!("Unexpected PredicateKind"),
|
||||
})
|
||||
.map(|clause| format!("{}", clause))
|
||||
.collect();
|
||||
|
||||
// We sort so that order is predictable
|
||||
clauses.sort();
|
||||
|
||||
if !clauses.is_empty() {
|
||||
let plural = if clauses.len() > 1 { "s" } else { "" };
|
||||
let mut err = tcx.sess.struct_span_err(
|
||||
trait_item.span,
|
||||
&format!("Missing required bounds on {}", trait_item.ident),
|
||||
&format!("missing required bound{} on `{}`", plural, trait_item.ident),
|
||||
);
|
||||
|
||||
let suggestion = format!(
|
||||
@ -455,11 +481,22 @@ fn check_gat_where_clauses(
|
||||
);
|
||||
err.span_suggestion(
|
||||
trait_item.generics.where_clause.tail_span_for_suggestion(),
|
||||
"add the required where clauses",
|
||||
&format!("add the required where clause{}", plural),
|
||||
suggestion,
|
||||
Applicability::MachineApplicable,
|
||||
);
|
||||
|
||||
let bound = if clauses.len() > 1 { "these bounds are" } else { "this bound is" };
|
||||
err.note(&format!(
|
||||
"{} currently required to ensure that impls have maximum flexibility",
|
||||
bound
|
||||
));
|
||||
err.note(
|
||||
"we are soliciting feedback, see issue #87479 \
|
||||
<https://github.com/rust-lang/rust/issues/87479> \
|
||||
for more information",
|
||||
);
|
||||
|
||||
err.emit()
|
||||
}
|
||||
}
|
||||
@ -541,7 +578,8 @@ fn region_known_to_outlive<'tcx>(
|
||||
});
|
||||
|
||||
use rustc_infer::infer::outlives::obligations::TypeOutlivesDelegate;
|
||||
(&infcx).push_sub_region_constraint(origin, region_a, region_b);
|
||||
// `region_a: region_b` -> `region_b <= region_a`
|
||||
(&infcx).push_sub_region_constraint(origin, region_b, region_a);
|
||||
|
||||
let errors = infcx.resolve_regions(
|
||||
id.expect_owner().to_def_id(),
|
||||
|
||||
@ -9,7 +9,7 @@ enum Either<L, R> {
|
||||
pub trait HasChildrenOf {
|
||||
type T;
|
||||
type TRef<'a>;
|
||||
//~^ Missing required bounds
|
||||
//~^ missing required
|
||||
|
||||
fn ref_children<'a>(&'a self) -> Vec<Self::TRef<'a>>;
|
||||
fn take_children(self) -> Vec<Self::T>;
|
||||
|
||||
@ -1,10 +1,13 @@
|
||||
error: Missing required bounds on TRef
|
||||
error: missing required bound on `TRef`
|
||||
--> $DIR/issue-86787.rs:11:5
|
||||
|
|
||||
LL | type TRef<'a>;
|
||||
| ^^^^^^^^^^^^^-
|
||||
| |
|
||||
| help: add the required where clauses: `where Self: 'a`
|
||||
| help: add the required where clause: `where Self: 'a`
|
||||
|
|
||||
= note: this bound is currently required to ensure that impls have maximum flexibility
|
||||
= note: we are soliciting feedback, see issue #87479 <https://github.com/rust-lang/rust/issues/87479> for more information
|
||||
|
||||
error: aborting due to previous error
|
||||
|
||||
|
||||
@ -7,7 +7,7 @@ use std::fmt::Debug;
|
||||
// We have a `&'a self`, so we need a `Self: 'a`
|
||||
trait Iterable {
|
||||
type Item<'x>;
|
||||
//~^ Missing required bounds
|
||||
//~^ missing required
|
||||
fn iter<'a>(&'a self) -> Self::Item<'a>;
|
||||
}
|
||||
|
||||
@ -23,7 +23,7 @@ impl<T> Iterable for T {
|
||||
// We have a `&'a T`, so we need a `T: 'x`
|
||||
trait Deserializer<T> {
|
||||
type Out<'x>;
|
||||
//~^ Missing required bounds
|
||||
//~^ missing required
|
||||
fn deserialize<'a>(&self, input: &'a T) -> Self::Out<'a>;
|
||||
}
|
||||
|
||||
@ -37,14 +37,14 @@ impl<T> Deserializer<T> for () {
|
||||
// We have a `&'b T` and a `'b: 'a`, so it is implied that `T: 'a`. Therefore, we need a `T: 'x`
|
||||
trait Deserializer2<T> {
|
||||
type Out<'x>;
|
||||
//~^ Missing required bounds
|
||||
//~^ missing required
|
||||
fn deserialize2<'a, 'b: 'a>(&self, input1: &'b T) -> Self::Out<'a>;
|
||||
}
|
||||
|
||||
// We have a `&'a T` and a `&'b U`, so we need a `T: 'x` and a `U: 'y`
|
||||
trait Deserializer3<T, U> {
|
||||
type Out<'x, 'y>;
|
||||
//~^ Missing required bounds
|
||||
//~^ missing required
|
||||
fn deserialize2<'a, 'b>(&self, input: &'a T, input2: &'b U) -> Self::Out<'a, 'b>;
|
||||
}
|
||||
|
||||
@ -59,7 +59,7 @@ struct Wrap<T>(T);
|
||||
// We pass `Wrap<T>` and we see `&'z Wrap<T>`, so we require `D: 'x`
|
||||
trait Des {
|
||||
type Out<'x, D>;
|
||||
//~^ Missing required bounds
|
||||
//~^ missing required
|
||||
fn des<'z, T>(&self, data: &'z Wrap<T>) -> Self::Out<'z, Wrap<T>>;
|
||||
}
|
||||
/*
|
||||
@ -75,7 +75,7 @@ impl Des for () {
|
||||
// implied bound that `T: 'z`, so we require `D: 'x`
|
||||
trait Des2 {
|
||||
type Out<'x, D>;
|
||||
//~^ Missing required bounds
|
||||
//~^ missing required
|
||||
fn des<'z, T>(&self, data: &'z Wrap<T>) -> Self::Out<'z, T>;
|
||||
}
|
||||
/*
|
||||
@ -90,7 +90,7 @@ impl Des2 for () {
|
||||
// We see `&'z T`, so we require `D: 'x`
|
||||
trait Des3 {
|
||||
type Out<'x, D>;
|
||||
//~^ Missing required bounds
|
||||
//~^ missing required
|
||||
fn des<'z, T>(&self, data: &'z T) -> Self::Out<'z, T>;
|
||||
}
|
||||
/*
|
||||
@ -112,7 +112,7 @@ trait NoGat<'a> {
|
||||
// FIXME: we require two bounds (`where Self: 'a, Self: 'b`) when we should only require one
|
||||
trait TraitLifetime<'a> {
|
||||
type Bar<'b>;
|
||||
//~^ Missing required bounds
|
||||
//~^ missing required
|
||||
fn method(&'a self) -> Self::Bar<'a>;
|
||||
}
|
||||
|
||||
@ -120,14 +120,14 @@ trait TraitLifetime<'a> {
|
||||
// FIXME: we require two bounds (`where Self: 'a, Self: 'b`) when we should only require one
|
||||
trait TraitLifetimeWhere<'a> where Self: 'a {
|
||||
type Bar<'b>;
|
||||
//~^ Missing required bounds
|
||||
//~^ missing required
|
||||
fn method(&'a self) -> Self::Bar<'a>;
|
||||
}
|
||||
|
||||
// Explicit bound instead of implicit; we want to still error
|
||||
trait ExplicitBound {
|
||||
type Bar<'b>;
|
||||
//~^ Missing required bounds
|
||||
//~^ missing required
|
||||
fn method<'b>(&self, token: &'b ()) -> Self::Bar<'b> where Self: 'b;
|
||||
}
|
||||
|
||||
@ -141,14 +141,15 @@ trait NotInReturn {
|
||||
trait IterableTwo {
|
||||
type Item<'a>;
|
||||
type Iterator<'a>: Iterator<Item = Self::Item<'a>>;
|
||||
//~^ Missing required bounds
|
||||
//~^ missing required
|
||||
fn iter<'a>(&'a self) -> Self::Iterator<'a>;
|
||||
}
|
||||
|
||||
// We also should report region outlives clauses
|
||||
// We also should report region outlives clauses. Here, we know that `'y: 'x`,
|
||||
// because of `&'x &'y`, so we require that `'b: 'a`.
|
||||
trait RegionOutlives {
|
||||
type Bar<'a, 'b>;
|
||||
//~^ Missing required bounds
|
||||
//~^ missing required
|
||||
fn foo<'x, 'y>(&self, input: &'x &'y ()) -> Self::Bar<'x, 'y>;
|
||||
}
|
||||
|
||||
@ -161,6 +162,17 @@ impl Foo for () {
|
||||
}
|
||||
*/
|
||||
|
||||
// Similar to the above, except with explicit bounds
|
||||
trait ExplicitRegionOutlives<'ctx> {
|
||||
type Fut<'out>;
|
||||
//~^ missing required
|
||||
|
||||
fn test<'out>(ctx: &'ctx i32) -> Self::Fut<'out>
|
||||
where
|
||||
'ctx: 'out;
|
||||
}
|
||||
|
||||
|
||||
// If there are multiple methods that return the GAT, require a set of clauses
|
||||
// that can be satisfied by *all* methods
|
||||
trait MultipleMethods {
|
||||
@ -170,4 +182,11 @@ trait MultipleMethods {
|
||||
fn gimme_default(&self) -> Self::Bar<'static>;
|
||||
}
|
||||
|
||||
// We would normally require `Self: 'a`, but we can prove that `Self: 'static`
|
||||
// because of the the bounds on the trait, so the bound is proven
|
||||
trait Trait: 'static {
|
||||
type Assoc<'a>;
|
||||
fn make_assoc(_: &u32) -> Self::Assoc<'_>;
|
||||
}
|
||||
|
||||
fn main() {}
|
||||
|
||||
@ -1,98 +1,145 @@
|
||||
error: Missing required bounds on Item
|
||||
error: missing required bound on `Item`
|
||||
--> $DIR/self-outlives-lint.rs:9:5
|
||||
|
|
||||
LL | type Item<'x>;
|
||||
| ^^^^^^^^^^^^^-
|
||||
| |
|
||||
| help: add the required where clauses: `where Self: 'x`
|
||||
| help: add the required where clause: `where Self: 'x`
|
||||
|
|
||||
= note: this bound is currently required to ensure that impls have maximum flexibility
|
||||
= note: we are soliciting feedback, see issue #87479 <https://github.com/rust-lang/rust/issues/87479> for more information
|
||||
|
||||
error: Missing required bounds on Out
|
||||
error: missing required bound on `Out`
|
||||
--> $DIR/self-outlives-lint.rs:25:5
|
||||
|
|
||||
LL | type Out<'x>;
|
||||
| ^^^^^^^^^^^^-
|
||||
| |
|
||||
| help: add the required where clauses: `where T: 'x`
|
||||
| help: add the required where clause: `where T: 'x`
|
||||
|
|
||||
= note: this bound is currently required to ensure that impls have maximum flexibility
|
||||
= note: we are soliciting feedback, see issue #87479 <https://github.com/rust-lang/rust/issues/87479> for more information
|
||||
|
||||
error: Missing required bounds on Out
|
||||
error: missing required bound on `Out`
|
||||
--> $DIR/self-outlives-lint.rs:39:5
|
||||
|
|
||||
LL | type Out<'x>;
|
||||
| ^^^^^^^^^^^^-
|
||||
| |
|
||||
| help: add the required where clauses: `where T: 'x`
|
||||
| help: add the required where clause: `where T: 'x`
|
||||
|
|
||||
= note: this bound is currently required to ensure that impls have maximum flexibility
|
||||
= note: we are soliciting feedback, see issue #87479 <https://github.com/rust-lang/rust/issues/87479> for more information
|
||||
|
||||
error: Missing required bounds on Out
|
||||
error: missing required bounds on `Out`
|
||||
--> $DIR/self-outlives-lint.rs:46:5
|
||||
|
|
||||
LL | type Out<'x, 'y>;
|
||||
| ^^^^^^^^^^^^^^^^-
|
||||
| |
|
||||
| help: add the required where clauses: `where T: 'x, U: 'y`
|
||||
|
|
||||
= note: these bounds are currently required to ensure that impls have maximum flexibility
|
||||
= note: we are soliciting feedback, see issue #87479 <https://github.com/rust-lang/rust/issues/87479> for more information
|
||||
|
||||
error: Missing required bounds on Out
|
||||
error: missing required bound on `Out`
|
||||
--> $DIR/self-outlives-lint.rs:61:5
|
||||
|
|
||||
LL | type Out<'x, D>;
|
||||
| ^^^^^^^^^^^^^^^-
|
||||
| |
|
||||
| help: add the required where clauses: `where D: 'x`
|
||||
| help: add the required where clause: `where D: 'x`
|
||||
|
|
||||
= note: this bound is currently required to ensure that impls have maximum flexibility
|
||||
= note: we are soliciting feedback, see issue #87479 <https://github.com/rust-lang/rust/issues/87479> for more information
|
||||
|
||||
error: Missing required bounds on Out
|
||||
error: missing required bound on `Out`
|
||||
--> $DIR/self-outlives-lint.rs:77:5
|
||||
|
|
||||
LL | type Out<'x, D>;
|
||||
| ^^^^^^^^^^^^^^^-
|
||||
| |
|
||||
| help: add the required where clauses: `where D: 'x`
|
||||
| help: add the required where clause: `where D: 'x`
|
||||
|
|
||||
= note: this bound is currently required to ensure that impls have maximum flexibility
|
||||
= note: we are soliciting feedback, see issue #87479 <https://github.com/rust-lang/rust/issues/87479> for more information
|
||||
|
||||
error: Missing required bounds on Out
|
||||
error: missing required bound on `Out`
|
||||
--> $DIR/self-outlives-lint.rs:92:5
|
||||
|
|
||||
LL | type Out<'x, D>;
|
||||
| ^^^^^^^^^^^^^^^-
|
||||
| |
|
||||
| help: add the required where clauses: `where D: 'x`
|
||||
| help: add the required where clause: `where D: 'x`
|
||||
|
|
||||
= note: this bound is currently required to ensure that impls have maximum flexibility
|
||||
= note: we are soliciting feedback, see issue #87479 <https://github.com/rust-lang/rust/issues/87479> for more information
|
||||
|
||||
error: Missing required bounds on Bar
|
||||
error: missing required bounds on `Bar`
|
||||
--> $DIR/self-outlives-lint.rs:114:5
|
||||
|
|
||||
LL | type Bar<'b>;
|
||||
| ^^^^^^^^^^^^-
|
||||
| |
|
||||
| help: add the required where clauses: `where Self: 'a, Self: 'b`
|
||||
|
|
||||
= note: these bounds are currently required to ensure that impls have maximum flexibility
|
||||
= note: we are soliciting feedback, see issue #87479 <https://github.com/rust-lang/rust/issues/87479> for more information
|
||||
|
||||
error: Missing required bounds on Bar
|
||||
error: missing required bound on `Bar`
|
||||
--> $DIR/self-outlives-lint.rs:122:5
|
||||
|
|
||||
LL | type Bar<'b>;
|
||||
| ^^^^^^^^^^^^-
|
||||
| |
|
||||
| help: add the required where clauses: `where Self: 'a, Self: 'b`
|
||||
| help: add the required where clause: `where Self: 'b`
|
||||
|
|
||||
= note: this bound is currently required to ensure that impls have maximum flexibility
|
||||
= note: we are soliciting feedback, see issue #87479 <https://github.com/rust-lang/rust/issues/87479> for more information
|
||||
|
||||
error: Missing required bounds on Bar
|
||||
error: missing required bound on `Bar`
|
||||
--> $DIR/self-outlives-lint.rs:129:5
|
||||
|
|
||||
LL | type Bar<'b>;
|
||||
| ^^^^^^^^^^^^-
|
||||
| |
|
||||
| help: add the required where clauses: `where Self: 'b`
|
||||
| help: add the required where clause: `where Self: 'b`
|
||||
|
|
||||
= note: this bound is currently required to ensure that impls have maximum flexibility
|
||||
= note: we are soliciting feedback, see issue #87479 <https://github.com/rust-lang/rust/issues/87479> for more information
|
||||
|
||||
error: Missing required bounds on Iterator
|
||||
error: missing required bound on `Iterator`
|
||||
--> $DIR/self-outlives-lint.rs:143:5
|
||||
|
|
||||
LL | type Iterator<'a>: Iterator<Item = Self::Item<'a>>;
|
||||
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^-
|
||||
| |
|
||||
| help: add the required where clauses: `where Self: 'a`
|
||||
| help: add the required where clause: `where Self: 'a`
|
||||
|
|
||||
= note: this bound is currently required to ensure that impls have maximum flexibility
|
||||
= note: we are soliciting feedback, see issue #87479 <https://github.com/rust-lang/rust/issues/87479> for more information
|
||||
|
||||
error: Missing required bounds on Bar
|
||||
--> $DIR/self-outlives-lint.rs:150:5
|
||||
error: missing required bound on `Bar`
|
||||
--> $DIR/self-outlives-lint.rs:151:5
|
||||
|
|
||||
LL | type Bar<'a, 'b>;
|
||||
| ^^^^^^^^^^^^^^^^-
|
||||
| |
|
||||
| help: add the required where clauses: `where 'a: 'b`
|
||||
| help: add the required where clause: `where 'b: 'a`
|
||||
|
|
||||
= note: this bound is currently required to ensure that impls have maximum flexibility
|
||||
= note: we are soliciting feedback, see issue #87479 <https://github.com/rust-lang/rust/issues/87479> for more information
|
||||
|
||||
error: aborting due to 12 previous errors
|
||||
error: missing required bound on `Fut`
|
||||
--> $DIR/self-outlives-lint.rs:167:5
|
||||
|
|
||||
LL | type Fut<'out>;
|
||||
| ^^^^^^^^^^^^^^-
|
||||
| |
|
||||
| help: add the required where clause: `where 'ctx: 'out`
|
||||
|
|
||||
= note: this bound is currently required to ensure that impls have maximum flexibility
|
||||
= note: we are soliciting feedback, see issue #87479 <https://github.com/rust-lang/rust/issues/87479> for more information
|
||||
|
||||
error: aborting due to 13 previous errors
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user