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Auto merge of #131186 - compiler-errors:precise-capturing-borrowck, r=estebank

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Try to point out when edition 2024 lifetime capture rules cause borrowck issues

Lifetime capture rules in 2024 are modified to capture more lifetimes, which sometimes lead to some non-local borrowck errors. This PR attempts to link these back together with a useful note pointing out the capture rule changes.

This is not a blocking concern, but I'd appreciate feedback (though, again, I'd like to stress that I don't want to block this PR on this): I'm worried about this note drowning in the sea of other diagnostics that borrowck emits. I was tempted to change the level of the note to `.span_warn` just so it would show up in a different color. Thoughts?

Fixes #130545

Opening as a draft first since it's stacked on #131183.
r? `@ghost`
This commit is contained in:
bors 2024-10-31 03:36:06 +00:00
commit c8b83785dc
27 changed files with 807 additions and 45 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
compiler/rustc_ast_lowering/src/lib.rs
View File

@ -272,7 +272,7 @@ enum ImplTraitContext {
/// Example: `fn foo() -> impl Debug`, where `impl Debug` is conceptually
/// equivalent to a new opaque type like `type T = impl Debug; fn foo() -> T`.
///
OpaqueTy { origin: hir::OpaqueTyOrigin },
OpaqueTy { origin: hir::OpaqueTyOrigin<LocalDefId> },
/// `impl Trait` is unstably accepted in this position.
FeatureGated(ImplTraitPosition, Symbol),
/// `impl Trait` is not accepted in this position.
@ -1416,7 +1416,7 @@ fn lower_ty_direct(&mut self, t: &Ty, itctx: ImplTraitContext) -> hir::Ty<'hir>
fn lower_opaque_impl_trait(
&mut self,
span: Span,
origin: hir::OpaqueTyOrigin,
origin: hir::OpaqueTyOrigin<LocalDefId>,
opaque_ty_node_id: NodeId,
bounds: &GenericBounds,
itctx: ImplTraitContext,
@ -1458,7 +1458,7 @@ fn lower_opaque_impl_trait(
fn lower_opaque_inner(
&mut self,
opaque_ty_node_id: NodeId,
origin: hir::OpaqueTyOrigin,
origin: hir::OpaqueTyOrigin<LocalDefId>,
opaque_ty_span: Span,
lower_item_bounds: impl FnOnce(&mut Self) -> &'hir [hir::GenericBound<'hir>],
) -> hir::TyKind<'hir> {

8
compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
View File

@ -1489,6 +1489,7 @@ pub(crate) fn report_move_out_while_borrowed(
&borrow_msg,
&value_msg,
);
self.note_due_to_edition_2024_opaque_capture_rules(borrow, &mut err);
borrow_spans.var_path_only_subdiag(&mut err, crate::InitializationRequiringAction::Borrow);
@ -1561,6 +1562,8 @@ pub(crate) fn report_use_while_mutably_borrowed(
borrow_span,
&self.describe_any_place(borrow.borrowed_place.as_ref()),
);
self.note_due_to_edition_2024_opaque_capture_rules(borrow, &mut err);
borrow_spans.var_subdiag(&mut err, Some(borrow.kind), |kind, var_span| {
use crate::session_diagnostics::CaptureVarCause::*;
let place = &borrow.borrowed_place;
@ -1820,6 +1823,7 @@ pub(crate) fn report_conflicting_borrow(
unreachable!()
}
};
self.note_due_to_edition_2024_opaque_capture_rules(issued_borrow, &mut err);
if issued_spans == borrow_spans {
borrow_spans.var_subdiag(&mut err, Some(gen_borrow_kind), |kind, var_span| {
@ -2860,7 +2864,7 @@ pub(crate) fn report_borrowed_value_does_not_live_long_enough(
debug!(?place_desc, ?explanation);
let err = match (place_desc, explanation) {
let mut err = match (place_desc, explanation) {
// If the outlives constraint comes from inside the closure,
// for example:
//
@ -2939,6 +2943,7 @@ pub(crate) fn report_borrowed_value_does_not_live_long_enough(
explanation,
),
};
self.note_due_to_edition_2024_opaque_capture_rules(borrow, &mut err);
self.buffer_error(err);
}
@ -3777,6 +3782,7 @@ pub(crate) fn report_illegal_mutation_of_borrowed(
}
let mut err = self.cannot_assign_to_borrowed(span, loan_span, &descr_place);
self.note_due_to_edition_2024_opaque_capture_rules(loan, &mut err);
loan_spans.var_subdiag(&mut err, Some(loan.kind), |kind, var_span| {
use crate::session_diagnostics::CaptureVarCause::*;

1
compiler/rustc_borrowck/src/diagnostics/mod.rs
View File

@ -48,6 +48,7 @@
mod explain_borrow;
mod move_errors;
mod mutability_errors;
mod opaque_suggestions;
mod region_errors;
pub(crate) use bound_region_errors::{ToUniverseInfo, UniverseInfo};

224
compiler/rustc_borrowck/src/diagnostics/opaque_suggestions.rs Normal file
View File

@ -0,0 +1,224 @@
#![allow(rustc::diagnostic_outside_of_impl)]
#![allow(rustc::untranslatable_diagnostic)]
use std::ops::ControlFlow;
use either::Either;
use rustc_data_structures::fx::FxIndexSet;
use rustc_errors::{Applicability, Diag};
use rustc_hir as hir;
use rustc_hir::def_id::DefId;
use rustc_middle::mir::{self, ConstraintCategory, Location};
use rustc_middle::ty::{
self, Ty, TyCtxt, TypeSuperVisitable, TypeVisitable, TypeVisitableExt, TypeVisitor,
};
use rustc_span::Symbol;
use crate::MirBorrowckCtxt;
use crate::borrow_set::BorrowData;
use crate::consumers::RegionInferenceContext;
use crate::type_check::Locations;
impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
/// Try to note when an opaque is involved in a borrowck error and that
/// opaque captures lifetimes due to edition 2024.
// FIXME: This code is otherwise somewhat general, and could easily be adapted
// to explain why other things overcapture... like async fn and RPITITs.
pub(crate) fn note_due_to_edition_2024_opaque_capture_rules(
&self,
borrow: &BorrowData<'tcx>,
diag: &mut Diag<'_>,
) {
// We look at all the locals. Why locals? Because it's the best thing
// I could think of that's correlated with the *instantiated* higer-ranked
// binder for calls, since we don't really store those anywhere else.
for ty in self.body.local_decls.iter().map(|local| local.ty) {
if !ty.has_opaque_types() {
continue;
}
let tcx = self.infcx.tcx;
let ControlFlow::Break((opaque_def_id, offending_region_idx, location)) = ty
.visit_with(&mut FindOpaqueRegion {
regioncx: &self.regioncx,
tcx,
borrow_region: borrow.region,
})
else {
continue;
};
// If an opaque explicitly captures a lifetime, then no need to point it out.
// FIXME: We should be using a better heuristic for `use<>`.
if tcx.rendered_precise_capturing_args(opaque_def_id).is_some() {
continue;
}
// If one of the opaque's bounds mentions the region, then no need to
// point it out, since it would've been captured on edition 2021 as well.
//
// Also, while we're at it, collect all the lifetimes that the opaque
// *does* mention. We'll use that for the `+ use<'a>` suggestion below.
let mut visitor = CheckExplicitRegionMentionAndCollectGenerics {
tcx,
offending_region_idx,
seen_opaques: [opaque_def_id].into_iter().collect(),
seen_lifetimes: Default::default(),
};
if tcx
.explicit_item_bounds(opaque_def_id)
.skip_binder()
.visit_with(&mut visitor)
.is_break()
{
continue;
}
// If we successfully located a terminator, then point it out
// and provide a suggestion if it's local.
match self.body.stmt_at(location) {
Either::Right(mir::Terminator { source_info, .. }) => {
diag.span_note(
source_info.span,
"this call may capture more lifetimes than intended, \
because Rust 2024 has adjusted the `impl Trait` lifetime capture rules",
);
let mut seen_generics: Vec<_> =
visitor.seen_lifetimes.iter().map(ToString::to_string).collect();
// Capture all in-scope ty/const params.
seen_generics.extend(
ty::GenericArgs::identity_for_item(tcx, opaque_def_id)
.iter()
.filter(|arg| {
matches!(
arg.unpack(),
ty::GenericArgKind::Type(_) | ty::GenericArgKind::Const(_)
)
})
.map(|arg| arg.to_string()),
);
if opaque_def_id.is_local() {
diag.span_suggestion_verbose(
tcx.def_span(opaque_def_id).shrink_to_hi(),
"add a precise capturing bound to avoid overcapturing",
format!(" + use<{}>", seen_generics.join(", ")),
Applicability::MaybeIncorrect,
);
} else {
diag.span_help(
tcx.def_span(opaque_def_id),
format!(
"if you can modify this crate, add a precise \
capturing bound to avoid overcapturing: `+ use<{}>`",
seen_generics.join(", ")
),
);
}
return;
}
Either::Left(_) => {}
}
}
}
}
/// This visitor contains the bulk of the logic for this lint.
struct FindOpaqueRegion<'a, 'tcx> {
tcx: TyCtxt<'tcx>,
regioncx: &'a RegionInferenceContext<'tcx>,
borrow_region: ty::RegionVid,
}
impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for FindOpaqueRegion<'_, 'tcx> {
type Result = ControlFlow<(DefId, usize, Location), ()>;
fn visit_ty(&mut self, ty: Ty<'tcx>) -> Self::Result {
// If we find an opaque in a local ty, then for each of its captured regions,
// try to find a path between that captured regions and our borrow region...
if let ty::Alias(ty::Opaque, opaque) = *ty.kind()
&& let hir::OpaqueTyOrigin::FnReturn { parent, in_trait_or_impl: None } =
self.tcx.opaque_ty_origin(opaque.def_id)
{
let variances = self.tcx.variances_of(opaque.def_id);
for (idx, (arg, variance)) in std::iter::zip(opaque.args, variances).enumerate() {
// Skip uncaptured args.
if *variance == ty::Bivariant {
continue;
}
// We only care about regions.
let Some(opaque_region) = arg.as_region() else {
continue;
};
// Don't try to convert a late-bound region, which shouldn't exist anyways (yet).
if opaque_region.is_bound() {
continue;
}
let opaque_region_vid = self.regioncx.to_region_vid(opaque_region);
// Find a path between the borrow region and our opaque capture.
if let Some((path, _)) =
self.regioncx.find_constraint_paths_between_regions(self.borrow_region, |r| {
r == opaque_region_vid
})
{
for constraint in path {
// If we find a call in this path, then check if it defines the opaque.
if let ConstraintCategory::CallArgument(Some(call_ty)) = constraint.category
&& let ty::FnDef(call_def_id, _) = *call_ty.kind()
// This function defines the opaque :D
&& call_def_id == parent
&& let Locations::Single(location) = constraint.locations
{
return ControlFlow::Break((opaque.def_id, idx, location));
}
}
}
}
}
ty.super_visit_with(self)
}
}
struct CheckExplicitRegionMentionAndCollectGenerics<'tcx> {
tcx: TyCtxt<'tcx>,
offending_region_idx: usize,
seen_opaques: FxIndexSet<DefId>,
seen_lifetimes: FxIndexSet<Symbol>,
}
impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for CheckExplicitRegionMentionAndCollectGenerics<'tcx> {
type Result = ControlFlow<(), ()>;
fn visit_ty(&mut self, ty: Ty<'tcx>) -> Self::Result {
match *ty.kind() {
ty::Alias(ty::Opaque, opaque) => {
if self.seen_opaques.insert(opaque.def_id) {
for (bound, _) in self
.tcx
.explicit_item_bounds(opaque.def_id)
.iter_instantiated_copied(self.tcx, opaque.args)
{
bound.visit_with(self)?;
}
}
ControlFlow::Continue(())
}
_ => ty.super_visit_with(self),
}
}
fn visit_region(&mut self, r: ty::Region<'tcx>) -> Self::Result {
match r.kind() {
ty::ReEarlyParam(param) => {
if param.index as usize == self.offending_region_idx {
ControlFlow::Break(())
} else {
self.seen_lifetimes.insert(param.name);
ControlFlow::Continue(())
}
}
_ => ControlFlow::Continue(()),
}
}
}

2
compiler/rustc_borrowck/src/region_infer/opaque_types.rs
View File

@ -502,7 +502,7 @@ fn get_canonical_args(&self) -> ty::GenericArgsRef<'tcx> {
}
let &Self { tcx, def_id, .. } = self;
let origin = tcx.opaque_type_origin(def_id);
let origin = tcx.local_opaque_ty_origin(def_id);
let parent = match origin {
hir::OpaqueTyOrigin::FnReturn { parent, .. }
| hir::OpaqueTyOrigin::AsyncFn { parent, .. }

16
compiler/rustc_hir/src/hir.rs
View File

@ -2746,7 +2746,7 @@ pub struct OpaqueTy<'hir> {
pub hir_id: HirId,
pub def_id: LocalDefId,
pub bounds: GenericBounds<'hir>,
pub origin: OpaqueTyOrigin,
pub origin: OpaqueTyOrigin<LocalDefId>,
pub span: Span,
}
@ -2784,33 +2784,35 @@ pub struct PreciseCapturingNonLifetimeArg {
pub res: Res,
}
#[derive(Copy, Clone, PartialEq, Eq, Debug, HashStable_Generic)]
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
#[derive(HashStable_Generic, Encodable, Decodable)]
pub enum RpitContext {
Trait,
TraitImpl,
}
/// From whence the opaque type came.
#[derive(Copy, Clone, PartialEq, Eq, Debug, HashStable_Generic)]
pub enum OpaqueTyOrigin {
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
#[derive(HashStable_Generic, Encodable, Decodable)]
pub enum OpaqueTyOrigin<D> {
/// `-> impl Trait`
FnReturn {
/// The defining function.
parent: LocalDefId,
parent: D,
// Whether this is an RPITIT (return position impl trait in trait)
in_trait_or_impl: Option<RpitContext>,
},
/// `async fn`
AsyncFn {
/// The defining function.
parent: LocalDefId,
parent: D,
// Whether this is an AFIT (async fn in trait)
in_trait_or_impl: Option<RpitContext>,
},
/// type aliases: `type Foo = impl Trait;`
TyAlias {
/// The type alias or associated type parent of the TAIT/ATPIT
parent: LocalDefId,
parent: D,
/// associated types in impl blocks for traits.
in_assoc_ty: bool,
},

4
compiler/rustc_hir_analysis/src/check/check.rs
View File

@ -268,7 +268,7 @@ fn check_opaque_meets_bounds<'tcx>(
tcx: TyCtxt<'tcx>,
def_id: LocalDefId,
span: Span,
origin: &hir::OpaqueTyOrigin,
origin: &hir::OpaqueTyOrigin<LocalDefId>,
) -> Result<(), ErrorGuaranteed> {
let defining_use_anchor = match *origin {
hir::OpaqueTyOrigin::FnReturn { parent, .. }
@ -677,7 +677,7 @@ pub(crate) fn check_item_type(tcx: TyCtxt<'_>, def_id: LocalDefId) {
DefKind::OpaqueTy => {
check_opaque_precise_captures(tcx, def_id);
let origin = tcx.opaque_type_origin(def_id);
let origin = tcx.local_opaque_ty_origin(def_id);
if let hir::OpaqueTyOrigin::FnReturn { parent: fn_def_id, .. }
| hir::OpaqueTyOrigin::AsyncFn { parent: fn_def_id, .. } = origin
&& let hir::Node::TraitItem(trait_item) = tcx.hir_node_by_def_id(fn_def_id)

17
compiler/rustc_hir_analysis/src/collect.rs
View File

@ -86,7 +86,7 @@ pub fn provide(providers: &mut Providers) {
impl_trait_header,
coroutine_kind,
coroutine_for_closure,
is_type_alias_impl_trait,
opaque_ty_origin,
rendered_precise_capturing_args,
..*providers
};
@ -1759,9 +1759,18 @@ fn coroutine_for_closure(tcx: TyCtxt<'_>, def_id: LocalDefId) -> DefId {
def_id.to_def_id()
}
fn is_type_alias_impl_trait<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> bool {
let opaque = tcx.hir().expect_opaque_ty(def_id);
matches!(opaque.origin, hir::OpaqueTyOrigin::TyAlias { .. })
fn opaque_ty_origin<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> hir::OpaqueTyOrigin<DefId> {
match tcx.hir_node_by_def_id(def_id).expect_opaque_ty().origin {
hir::OpaqueTyOrigin::FnReturn { parent, in_trait_or_impl } => {
hir::OpaqueTyOrigin::FnReturn { parent: parent.to_def_id(), in_trait_or_impl }
}
hir::OpaqueTyOrigin::AsyncFn { parent, in_trait_or_impl } => {
hir::OpaqueTyOrigin::AsyncFn { parent: parent.to_def_id(), in_trait_or_impl }
}
hir::OpaqueTyOrigin::TyAlias { parent, in_assoc_ty } => {
hir::OpaqueTyOrigin::TyAlias { parent: parent.to_def_id(), in_assoc_ty }
}
}
}
fn rendered_precise_capturing_args<'tcx>(

3
compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs
View File

@ -20,6 +20,7 @@
pub mod generics;
mod lint;
use std::assert_matches::assert_matches;
use std::slice;
use rustc_ast::TraitObjectSyntax;
@ -1811,7 +1812,7 @@ pub fn lower_path(
match path.res {
Res::Def(DefKind::OpaqueTy, did) => {
// Check for desugared `impl Trait`.
assert!(tcx.is_type_alias_impl_trait(did));
assert_matches!(tcx.opaque_ty_origin(did), hir::OpaqueTyOrigin::TyAlias { .. });
let item_segment = path.segments.split_last().unwrap();
let _ = self
.prohibit_generic_args(item_segment.1.iter(), GenericsArgsErrExtend::OpaqueTy);

2
compiler/rustc_hir_typeck/src/_match.rs
View File

@ -601,7 +601,7 @@ pub(crate) fn return_position_impl_trait_from_match_expectation(
_ => return None,
};
let hir::OpaqueTyOrigin::FnReturn { parent: parent_def_id, .. } =
self.tcx.opaque_type_origin(def_id)
self.tcx.local_opaque_ty_origin(def_id)
else {
return None;
};

5
compiler/rustc_infer/src/infer/opaque_types/mod.rs
View File

@ -155,7 +155,10 @@ pub fn handle_opaque_type(
// however in `fn fut() -> impl Future<Output = i32> { async { 42 } }`, where
// it is of no concern, so we only check for TAITs.
if self.can_define_opaque_ty(b_def_id)
&& self.tcx.is_type_alias_impl_trait(b_def_id)
&& matches!(
self.tcx.opaque_ty_origin(b_def_id),
hir::OpaqueTyOrigin::TyAlias { .. }
)
{
self.dcx().emit_err(OpaqueHiddenTypeDiag {
span,

5
compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
View File

@ -316,10 +316,7 @@ fn into_args(self) -> (DefId, SimplifiedType) {
})
.unwrap_or_default()
}
is_type_alias_impl_trait => {
debug_assert_eq!(tcx.def_kind(def_id), DefKind::OpaqueTy);
cdata.root.tables.is_type_alias_impl_trait.get(cdata, def_id.index)
}
opaque_ty_origin => { table }
assumed_wf_types_for_rpitit => { table }
collect_return_position_impl_trait_in_trait_tys => {
Ok(cdata

6
compiler/rustc_metadata/src/rmeta/encoder.rs
View File

@ -1188,7 +1188,7 @@ fn should_encode_type(tcx: TyCtxt<'_>, def_id: LocalDefId, def_kind: DefKind) ->
| DefKind::SyntheticCoroutineBody => true,
DefKind::OpaqueTy => {
let origin = tcx.opaque_type_origin(def_id);
let origin = tcx.local_opaque_ty_origin(def_id);
if let hir::OpaqueTyOrigin::FnReturn { parent, .. }
| hir::OpaqueTyOrigin::AsyncFn { parent, .. } = origin
&& let hir::Node::TraitItem(trait_item) = tcx.hir_node_by_def_id(parent)
@ -1530,9 +1530,7 @@ fn encode_def_ids(&mut self) {
if let DefKind::OpaqueTy = def_kind {
self.encode_explicit_item_bounds(def_id);
self.encode_explicit_item_super_predicates(def_id);
self.tables
.is_type_alias_impl_trait
.set(def_id.index, self.tcx.is_type_alias_impl_trait(def_id));
record!(self.tables.opaque_ty_origin[def_id] <- self.tcx.opaque_ty_origin(def_id));
self.encode_precise_capturing_args(def_id);
}
if tcx.impl_method_has_trait_impl_trait_tys(def_id)

2
compiler/rustc_metadata/src/rmeta/mod.rs
View File

@ -378,7 +378,6 @@ fn encode(&self, buf: &mut FileEncoder) -> LazyTables {
- defaulted:
intrinsic: Table<DefIndex, Option<LazyValue<ty::IntrinsicDef>>>,
is_macro_rules: Table<DefIndex, bool>,
is_type_alias_impl_trait: Table<DefIndex, bool>,
type_alias_is_lazy: Table<DefIndex, bool>,
attr_flags: Table<DefIndex, AttrFlags>,
// The u64 is the crate-local part of the DefPathHash. All hashes in this crate have the same
@ -468,6 +467,7 @@ fn encode(&self, buf: &mut FileEncoder) -> LazyTables {
doc_link_resolutions: Table<DefIndex, LazyValue<DocLinkResMap>>,
doc_link_traits_in_scope: Table<DefIndex, LazyArray<DefId>>,
assumed_wf_types_for_rpitit: Table<DefIndex, LazyArray<(Ty<'static>, Span)>>,
opaque_ty_origin: Table<DefIndex, LazyValue<hir::OpaqueTyOrigin<DefId>>>,
}
#[derive(TyEncodable, TyDecodable)]

1
compiler/rustc_middle/src/query/erase.rs
View File

@ -280,6 +280,7 @@ impl EraseType for $ty {
rustc_hir::IsAsync,
rustc_hir::ItemLocalId,
rustc_hir::LangItem,
rustc_hir::OpaqueTyOrigin<rustc_hir::def_id::DefId>,
rustc_hir::OwnerId,
rustc_hir::Upvar,
rustc_index::bit_set::FiniteBitSet<u32>,

5
compiler/rustc_middle/src/query/mod.rs
View File

@ -260,11 +260,10 @@
separate_provide_extern
}
query is_type_alias_impl_trait(key: DefId) -> bool
query opaque_ty_origin(key: DefId) -> hir::OpaqueTyOrigin<DefId>
{
desc { "determine whether the opaque is a type-alias impl trait" }
desc { "determine where the opaque originates from" }
separate_provide_extern
feedable
}
query unsizing_params_for_adt(key: DefId) -> &'tcx rustc_index::bit_set::BitSet<u32>

10
compiler/rustc_middle/src/ty/context.rs
View File

@ -55,7 +55,7 @@
use rustc_type_ir::lang_items::TraitSolverLangItem;
pub use rustc_type_ir::lift::Lift;
use rustc_type_ir::{CollectAndApply, Interner, TypeFlags, WithCachedTypeInfo, search_graph};
use tracing::{debug, trace};
use tracing::{debug, instrument};
use crate::arena::Arena;
use crate::dep_graph::{DepGraph, DepKindStruct};
@ -2103,11 +2103,9 @@ pub fn local_visibility(self, def_id: LocalDefId) -> Visibility {
}
/// Returns the origin of the opaque type `def_id`.
#[track_caller]
pub fn opaque_type_origin(self, def_id: LocalDefId) -> hir::OpaqueTyOrigin {
let origin = self.hir().expect_opaque_ty(def_id).origin;
trace!("opaque_type_origin({def_id:?}) => {origin:?}");
origin
#[instrument(skip(self), level = "trace", ret)]
pub fn local_opaque_ty_origin(self, def_id: LocalDefId) -> hir::OpaqueTyOrigin<LocalDefId> {
self.hir().expect_opaque_ty(def_id).origin
}
}

1
compiler/rustc_middle/src/ty/parameterized.rs
View File

@ -94,6 +94,7 @@ impl $crate::ty::ParameterizedOverTcx for $ty {
rustc_hir::def_id::DefId,
rustc_hir::def_id::DefIndex,
rustc_hir::definitions::DefKey,
rustc_hir::OpaqueTyOrigin<rustc_hir::def_id::DefId>,
rustc_index::bit_set::BitSet<u32>,
rustc_index::bit_set::FiniteBitSet<u32>,
rustc_session::cstore::ForeignModule,

5
compiler/rustc_trait_selection/src/error_reporting/infer/note_and_explain.rs
View File

@ -384,7 +384,10 @@ fn foo(&self, x: T) -> T { x }
| DefKind::AssocFn
| DefKind::AssocConst
)
&& tcx.is_type_alias_impl_trait(opaque_ty.def_id)
&& matches!(
tcx.opaque_ty_origin(opaque_ty.def_id),
hir::OpaqueTyOrigin::TyAlias { .. }
)
&& !tcx
.opaque_types_defined_by(body_owner_def_id.expect_local())
.contains(&opaque_ty.def_id.expect_local())

2
compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs
View File

@ -2648,7 +2648,7 @@ fn report_opaque_type_auto_trait_leakage(
obligation: &PredicateObligation<'tcx>,
def_id: DefId,
) -> ErrorGuaranteed {
let name = match self.tcx.opaque_type_origin(def_id.expect_local()) {
let name = match self.tcx.local_opaque_ty_origin(def_id.expect_local()) {
hir::OpaqueTyOrigin::FnReturn { .. } | hir::OpaqueTyOrigin::AsyncFn { .. } => {
"opaque type".to_string()
}

4
compiler/rustc_ty_utils/src/assoc.rs
View File

@ -244,7 +244,7 @@ fn associated_type_for_impl_trait_in_trait(
) -> LocalDefId {
let (hir::OpaqueTyOrigin::FnReturn { parent: fn_def_id, .. }
| hir::OpaqueTyOrigin::AsyncFn { parent: fn_def_id, .. }) =
tcx.opaque_type_origin(opaque_ty_def_id)
tcx.local_opaque_ty_origin(opaque_ty_def_id)
else {
bug!("expected opaque for {opaque_ty_def_id:?}");
};
@ -281,8 +281,6 @@ fn associated_type_for_impl_trait_in_trait(
// Copy defaultness of the containing function.
trait_assoc_ty.defaultness(tcx.defaultness(fn_def_id));
trait_assoc_ty.is_type_alias_impl_trait(false);
// There are no inferred outlives for the synthesized associated type.
trait_assoc_ty.inferred_outlives_of(&[]);

2
compiler/rustc_ty_utils/src/opaque_types.rs
View File

@ -139,7 +139,7 @@ fn visit_opaque_ty(&mut self, alias_ty: ty::AliasTy<'tcx>) {
}
// TAITs outside their defining scopes are ignored.
let origin = self.tcx.opaque_type_origin(alias_ty.def_id.expect_local());
let origin = self.tcx.local_opaque_ty_origin(alias_ty.def_id.expect_local());
trace!(?origin);
match origin {
rustc_hir::OpaqueTyOrigin::FnReturn { .. }

6
tests/ui/impl-trait/precise-capturing/auxiliary/foreign.rs Normal file
View File

@ -0,0 +1,6 @@
//@ edition: 2024
//@ compile-flags: -Zunstable-options
use std::fmt::Display;
pub fn hello(x: &Vec<i32>) -> impl Display { 0 }

15
tests/ui/impl-trait/precise-capturing/foreign-2021.rs Normal file
View File

@ -0,0 +1,15 @@
//@ aux-build: foreign.rs
extern crate foreign;
fn main() {
let mut x = vec![];
let h = foreign::hello(&x);
//~^ NOTE this call may capture more lifetimes than intended
//~| NOTE immutable borrow occurs here
x.push(0);
//~^ ERROR cannot borrow `x` as mutable
//~| NOTE mutable borrow occurs here
println!("{h}");
//~^ NOTE immutable borrow later used here
}

26
tests/ui/impl-trait/precise-capturing/foreign-2021.stderr Normal file
View File

@ -0,0 +1,26 @@
error[E0502]: cannot borrow `x` as mutable because it is also borrowed as immutable
--> $DIR/foreign-2021.rs:10:5
|
LL | let h = foreign::hello(&x);
| -- immutable borrow occurs here
...
LL | x.push(0);
| ^^^^^^^^^ mutable borrow occurs here
...
LL | println!("{h}");
| --- immutable borrow later used here
|
note: this call may capture more lifetimes than intended, because Rust 2024 has adjusted the `impl Trait` lifetime capture rules
--> $DIR/foreign-2021.rs:7:13
|
LL | let h = foreign::hello(&x);
| ^^^^^^^^^^^^^^^^^^
help: if you can modify this crate, add a precise capturing bound to avoid overcapturing: `+ use<>`
--> $DIR/auxiliary/foreign.rs:6:31
|
LL | pub fn hello(x: &Vec<i32>) -> impl Display { 0 }
| ^^^^^^^^^^^^
error: aborting due to 1 previous error
For more information about this error, try `rustc --explain E0502`.

190
tests/ui/impl-trait/precise-capturing/migration-note.rs Normal file
View File

@ -0,0 +1,190 @@
//@ edition: 2024
//@ compile-flags: -Zunstable-options
use std::fmt::Display;
fn display_len<T>(x: &Vec<T>) -> impl Display {
//~^ NOTE in this expansion of desugaring of `impl Trait`
//~| NOTE in this expansion of desugaring of `impl Trait`
//~| NOTE in this expansion of desugaring of `impl Trait`
//~| NOTE in this expansion of desugaring of `impl Trait`
//~| NOTE in this expansion of desugaring of `impl Trait`
x.len()
}
fn conflicting_borrow() {
let mut x = vec![];
let a = display_len(&x);
//~^ NOTE this call may capture more lifetimes than intended
//~| NOTE immutable borrow occurs here
x.push(1);
//~^ ERROR cannot borrow `x` as mutable because it is also borrowed as immutable
//~| NOTE mutable borrow occurs here
println!("{a}");
//~^ NOTE immutable borrow later used here
}
fn needs_static() {
let x = vec![1];
//~^ NOTE binding `x` declared here
let a = display_len(&x);
//~^ ERROR `x` does not live long enough
//~| NOTE this call may capture more lifetimes than intended
//~| NOTE argument requires that `x` is borrowed for `'static`
//~| NOTE borrowed value does not live long enoug
fn needs_static(_: impl Sized + 'static) {}
needs_static(a);
}
//~^ NOTE `x` dropped here while still borrowed
fn is_moved() {
let x = vec![1];
//~^ NOTE binding `x` declared here
let a = display_len(&x);
//~^ NOTE this call may capture more lifetimes than intended
//~| NOTE borrow of `x` occurs here
fn mv(_: impl Sized) {}
mv(x);
//~^ ERROR cannot move out of `x` because it is borrowed
//~| NOTE move out of `x` occurs here
}
//~^ NOTE borrow might be used here, when `a` is dropped
fn display_len_mut<T>(x: &mut Vec<T>) -> impl Display {
//~^ NOTE in this expansion of desugaring of `impl Trait`
//~| NOTE in this expansion of desugaring of `impl Trait`
//~| NOTE in this expansion of desugaring of `impl Trait`
x.len()
}
fn conflicting_borrow_mut() {
let mut x = vec![];
let a = display_len_mut(&mut x);
//~^ NOTE this call may capture more lifetimes than intended
//~| NOTE first mutable borrow occurs here
x.push(1);
//~^ ERROR cannot borrow `x` as mutable more than once
//~| NOTE second mutable borrow occurs here
println!("{a}");
//~^ NOTE first borrow later used here
}
fn needs_static_mut() {
let mut x = vec![1];
//~^ NOTE binding `x` declared here
let a = display_len_mut(&mut x);
//~^ ERROR `x` does not live long enough
//~| NOTE this call may capture more lifetimes than intended
//~| NOTE argument requires that `x` is borrowed for `'static`
//~| NOTE borrowed value does not live long enough
fn needs_static(_: impl Sized + 'static) {}
needs_static(a);
}
//~^ NOTE `x` dropped here while still borrowed
fn is_move_mut() {
let mut x = vec![1];
//~^ NOTE binding `x` declared here
let a = display_len_mut(&mut x);
//~^ NOTE this call may capture more lifetimes than intended
//~| NOTE borrow of `x` occurs here
fn mv(_: impl Sized) {}
mv(x);
//~^ ERROR cannot move out of `x` because it is borrowed
//~| NOTE move out of `x` occurs here
}
//~^ NOTE borrow might be used here, when `a` is dropped
struct S { f: i32 }
fn display_field<T: Copy + Display>(t: &T) -> impl Display {
//~^ NOTE in this expansion of desugaring of `impl Trait`
//~| NOTE in this expansion of desugaring of `impl Trait`
//~| NOTE in this expansion of desugaring of `impl Trait`
*t
}
fn conflicting_borrow_field() {
let mut s = S { f: 0 };
let a = display_field(&s.f);
//~^ NOTE this call may capture more lifetimes than intended
//~| NOTE `s.f` is borrowed here
s.f = 1;
//~^ ERROR cannot assign to `s.f` because it is borrowed
//~| NOTE `s.f` is assigned to here but it was already borrowed
println!("{a}");
//~^ NOTE borrow later used here
}
fn display_field_mut<T: Copy + Display>(t: &mut T) -> impl Display {
*t
}
fn conflicting_borrow_field_mut() {
let mut s = S { f: 0 };
let a = display_field(&mut s.f);
//~^ NOTE this call may capture more lifetimes than intended
//~| NOTE `s.f` is borrowed here
s.f = 1;
//~^ ERROR cannot assign to `s.f` because it is borrowed
//~| NOTE `s.f` is assigned to here but it was already borrowed
println!("{a}");
//~^ NOTE borrow later used here
}
fn field_move() {
let mut s = S { f: 0 };
let a = display_field(&mut s.f);
//~^ NOTE this call may capture more lifetimes than intended
//~| NOTE `s.f` is borrowed here
s.f;
//~^ ERROR cannot use `s.f` because it was mutably borrowed
//~| NOTE use of borrowed `s.f`
println!("{a}");
//~^ NOTE borrow later used here
}
struct Z {
f: Vec<i32>,
}
fn live_long() {
let x;
{
let z = Z { f: vec![1] };
//~^ NOTE binding `z` declared here
x = display_len(&z.f);
//~^ ERROR `z.f` does not live long enough
//~| NOTE this call may capture more lifetimes than intended
//~| NOTE values in a scope are dropped in the opposite order they are defined
//~| NOTE borrowed value does not live long enough
}
//~^ NOTE `z.f` dropped here while still borrowed
}
//~^ NOTE borrow might be used here, when `x` is dropped
fn temp() {
let x = { let x = display_len(&mut vec![0]); x };
//~^ ERROR temporary value dropped while borrowed
//~| NOTE this call may capture more lifetimes than intended
//~| NOTE consider using a `let` binding to create a longer lived value
//~| NOTE borrow later used here
//~| NOTE temporary value is freed at the end of this statement
}
// FIXME: This doesn't display a useful Rust 2024 suggestion :(
fn returned() -> impl Sized {
let x = vec![0];
//~^ NOTE binding `x` declared here
display_len(&x)
//~^ ERROR `x` does not live long enough
//~| NOTE borrowed value does not live long enough
//~| NOTE argument requires that `x` is borrowed for `'static`
}
//~^ NOTE `x` dropped here while still borrowed
fn main() {}

284
tests/ui/impl-trait/precise-capturing/migration-note.stderr Normal file
View File

@ -0,0 +1,284 @@
error[E0597]: `x` does not live long enough
--> $DIR/migration-note.rs:183:17
|
LL | let x = vec![0];
| - binding `x` declared here
LL |
LL | display_len(&x)
| ------------^^-
| | |
| | borrowed value does not live long enough
| argument requires that `x` is borrowed for `'static`
...
LL | }
| - `x` dropped here while still borrowed
error[E0502]: cannot borrow `x` as mutable because it is also borrowed as immutable
--> $DIR/migration-note.rs:20:5
|
LL | let a = display_len(&x);
| -- immutable borrow occurs here
...
LL | x.push(1);
| ^^^^^^^^^ mutable borrow occurs here
...
LL | println!("{a}");
| --- immutable borrow later used here
|
note: this call may capture more lifetimes than intended, because Rust 2024 has adjusted the `impl Trait` lifetime capture rules
--> $DIR/migration-note.rs:17:13
|
LL | let a = display_len(&x);
| ^^^^^^^^^^^^^^^
help: add a precise capturing bound to avoid overcapturing
|
LL | fn display_len<T>(x: &Vec<T>) -> impl Display + use<T> {
| ++++++++
error[E0597]: `x` does not live long enough
--> $DIR/migration-note.rs:30:25
|
LL | let x = vec![1];
| - binding `x` declared here
LL |
LL | let a = display_len(&x);
| ------------^^-
| | |
| | borrowed value does not live long enough
| argument requires that `x` is borrowed for `'static`
...
LL | }
| - `x` dropped here while still borrowed
|
note: this call may capture more lifetimes than intended, because Rust 2024 has adjusted the `impl Trait` lifetime capture rules
--> $DIR/migration-note.rs:30:13
|
LL | let a = display_len(&x);
| ^^^^^^^^^^^^^^^
help: add a precise capturing bound to avoid overcapturing
|
LL | fn display_len<T>(x: &Vec<T>) -> impl Display + use<T> {
| ++++++++
error[E0505]: cannot move out of `x` because it is borrowed
--> $DIR/migration-note.rs:49:8
|
LL | let x = vec![1];
| - binding `x` declared here
LL |
LL | let a = display_len(&x);
| -- borrow of `x` occurs here
...
LL | mv(x);
| ^ move out of `x` occurs here
...
LL | }
| - borrow might be used here, when `a` is dropped and runs the destructor for type `impl std::fmt::Display`
|
note: this call may capture more lifetimes than intended, because Rust 2024 has adjusted the `impl Trait` lifetime capture rules
--> $DIR/migration-note.rs:44:13
|
LL | let a = display_len(&x);
| ^^^^^^^^^^^^^^^
help: add a precise capturing bound to avoid overcapturing
|
LL | fn display_len<T>(x: &Vec<T>) -> impl Display + use<T> {
| ++++++++
help: consider cloning the value if the performance cost is acceptable
|
LL | let a = display_len(&x.clone());
| ++++++++
error[E0499]: cannot borrow `x` as mutable more than once at a time
--> $DIR/migration-note.rs:67:5
|
LL | let a = display_len_mut(&mut x);
| ------ first mutable borrow occurs here
...
LL | x.push(1);
| ^ second mutable borrow occurs here
...
LL | println!("{a}");
| --- first borrow later used here
|
note: this call may capture more lifetimes than intended, because Rust 2024 has adjusted the `impl Trait` lifetime capture rules
--> $DIR/migration-note.rs:64:13
|
LL | let a = display_len_mut(&mut x);
| ^^^^^^^^^^^^^^^^^^^^^^^
help: add a precise capturing bound to avoid overcapturing
|
LL | fn display_len_mut<T>(x: &mut Vec<T>) -> impl Display + use<T> {
| ++++++++
error[E0597]: `x` does not live long enough
--> $DIR/migration-note.rs:77:29
|
LL | let mut x = vec![1];
| ----- binding `x` declared here
LL |
LL | let a = display_len_mut(&mut x);
| ----------------^^^^^^-
| | |
| | borrowed value does not live long enough
| argument requires that `x` is borrowed for `'static`
...
LL | }
| - `x` dropped here while still borrowed
|
note: this call may capture more lifetimes than intended, because Rust 2024 has adjusted the `impl Trait` lifetime capture rules
--> $DIR/migration-note.rs:77:13
|
LL | let a = display_len_mut(&mut x);
| ^^^^^^^^^^^^^^^^^^^^^^^
help: add a precise capturing bound to avoid overcapturing
|
LL | fn display_len_mut<T>(x: &mut Vec<T>) -> impl Display + use<T> {
| ++++++++
error[E0505]: cannot move out of `x` because it is borrowed
--> $DIR/migration-note.rs:96:8
|
LL | let mut x = vec![1];
| ----- binding `x` declared here
LL |
LL | let a = display_len_mut(&mut x);
| ------ borrow of `x` occurs here
...
LL | mv(x);
| ^ move out of `x` occurs here
...
LL | }
| - borrow might be used here, when `a` is dropped and runs the destructor for type `impl std::fmt::Display`
|
note: this call may capture more lifetimes than intended, because Rust 2024 has adjusted the `impl Trait` lifetime capture rules
--> $DIR/migration-note.rs:91:13
|
LL | let a = display_len_mut(&mut x);
| ^^^^^^^^^^^^^^^^^^^^^^^
help: add a precise capturing bound to avoid overcapturing
|
LL | fn display_len_mut<T>(x: &mut Vec<T>) -> impl Display + use<T> {
| ++++++++
help: consider cloning the value if the performance cost is acceptable
|
LL | let a = display_len_mut(&mut x.clone());
| ++++++++
error[E0506]: cannot assign to `s.f` because it is borrowed
--> $DIR/migration-note.rs:116:5
|
LL | let a = display_field(&s.f);
| ---- `s.f` is borrowed here
...
LL | s.f = 1;
| ^^^^^^^ `s.f` is assigned to here but it was already borrowed
...
LL | println!("{a}");
| --- borrow later used here
|
note: this call may capture more lifetimes than intended, because Rust 2024 has adjusted the `impl Trait` lifetime capture rules
--> $DIR/migration-note.rs:113:13
|
LL | let a = display_field(&s.f);
| ^^^^^^^^^^^^^^^^^^^
help: add a precise capturing bound to avoid overcapturing
|
LL | fn display_field<T: Copy + Display>(t: &T) -> impl Display + use<T> {
| ++++++++
error[E0506]: cannot assign to `s.f` because it is borrowed
--> $DIR/migration-note.rs:132:5
|
LL | let a = display_field(&mut s.f);
| -------- `s.f` is borrowed here
...
LL | s.f = 1;
| ^^^^^^^ `s.f` is assigned to here but it was already borrowed
...
LL | println!("{a}");
| --- borrow later used here
|
note: this call may capture more lifetimes than intended, because Rust 2024 has adjusted the `impl Trait` lifetime capture rules
--> $DIR/migration-note.rs:129:13
|
LL | let a = display_field(&mut s.f);
| ^^^^^^^^^^^^^^^^^^^^^^^
help: add a precise capturing bound to avoid overcapturing
|
LL | fn display_field<T: Copy + Display>(t: &T) -> impl Display + use<T> {
| ++++++++
error[E0503]: cannot use `s.f` because it was mutably borrowed
--> $DIR/migration-note.rs:144:5
|
LL | let a = display_field(&mut s.f);
| -------- `s.f` is borrowed here
...
LL | s.f;
| ^^^ use of borrowed `s.f`
...
LL | println!("{a}");
| --- borrow later used here
|
note: this call may capture more lifetimes than intended, because Rust 2024 has adjusted the `impl Trait` lifetime capture rules
--> $DIR/migration-note.rs:141:13
|
LL | let a = display_field(&mut s.f);
| ^^^^^^^^^^^^^^^^^^^^^^^
help: add a precise capturing bound to avoid overcapturing
|
LL | fn display_field<T: Copy + Display>(t: &T) -> impl Display + use<T> {
| ++++++++
error[E0597]: `z.f` does not live long enough
--> $DIR/migration-note.rs:160:25
|
LL | let z = Z { f: vec![1] };
| - binding `z` declared here
LL |
LL | x = display_len(&z.f);
| ^^^^ borrowed value does not live long enough
...
LL | }
| - `z.f` dropped here while still borrowed
LL |
LL | }
| - borrow might be used here, when `x` is dropped and runs the destructor for type `impl std::fmt::Display`
|
= note: values in a scope are dropped in the opposite order they are defined
note: this call may capture more lifetimes than intended, because Rust 2024 has adjusted the `impl Trait` lifetime capture rules
--> $DIR/migration-note.rs:160:13
|
LL | x = display_len(&z.f);
| ^^^^^^^^^^^^^^^^^
help: add a precise capturing bound to avoid overcapturing
|
LL | fn display_len<T>(x: &Vec<T>) -> impl Display + use<T> {
| ++++++++
error[E0716]: temporary value dropped while borrowed
--> $DIR/migration-note.rs:171:40
|
LL | let x = { let x = display_len(&mut vec![0]); x };
| ^^^^^^^ - - borrow later used here
| | |
| | temporary value is freed at the end of this statement
| creates a temporary value which is freed while still in use
|
= note: consider using a `let` binding to create a longer lived value
note: this call may capture more lifetimes than intended, because Rust 2024 has adjusted the `impl Trait` lifetime capture rules
--> $DIR/migration-note.rs:171:23
|
LL | let x = { let x = display_len(&mut vec![0]); x };
| ^^^^^^^^^^^^^^^^^^^^^^^^^
= note: this error originates in the macro `vec` (in Nightly builds, run with -Z macro-backtrace for more info)
help: add a precise capturing bound to avoid overcapturing
|
LL | fn display_len<T>(x: &Vec<T>) -> impl Display + use<T> {
| ++++++++
error: aborting due to 12 previous errors
Some errors have detailed explanations: E0499, E0502, E0503, E0505, E0506, E0597, E0716.
For more information about an error, try `rustc --explain E0499`.