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Remap impl-trait lifetimes on HIR instead of AST lowering.

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This commit is contained in:
Camille GILLOT 2024-08-20 00:48:43 +00:00
parent 298c7462c3
commit b6e1214ac0
35 changed files with 508 additions and 597 deletions
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255
compiler/rustc_ast_lowering/src/lib.rs
View file

@ -45,16 +45,14 @@ use rustc_ast::ptr::P;
use rustc_ast::{self as ast, *}; use rustc_ast::{self as ast, *};
use rustc_data_structures::captures::Captures; use rustc_data_structures::captures::Captures;
use rustc_data_structures::fingerprint::Fingerprint; use rustc_data_structures::fingerprint::Fingerprint;
use rustc_data_structures::fx::FxIndexSet;
use rustc_data_structures::sorted_map::SortedMap; use rustc_data_structures::sorted_map::SortedMap;
use rustc_data_structures::stable_hasher::{HashStable, StableHasher}; use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
use rustc_data_structures::sync::Lrc; use rustc_data_structures::sync::Lrc;
use rustc_errors::{DiagArgFromDisplay, DiagCtxtHandle, StashKey}; use rustc_errors::{DiagArgFromDisplay, DiagCtxtHandle, StashKey};
use rustc_hir::def::{DefKind, LifetimeRes, Namespace, PartialRes, PerNS, Res}; use rustc_hir::def::{DefKind, LifetimeRes, Namespace, PartialRes, PerNS, Res};
use rustc_hir::def_id::{CRATE_DEF_ID, LOCAL_CRATE, LocalDefId, LocalDefIdMap}; use rustc_hir::def_id::{CRATE_DEF_ID, LOCAL_CRATE, LocalDefId};
use rustc_hir::{ use rustc_hir::{
self as hir, ConstArg, GenericArg, HirId, ItemLocalMap, LangItem, MissingLifetimeKind, self as hir, ConstArg, GenericArg, HirId, ItemLocalMap, LangItem, ParamName, TraitCandidate,
ParamName, TraitCandidate,
}; };
use rustc_index::{Idx, IndexSlice, IndexVec}; use rustc_index::{Idx, IndexSlice, IndexVec};
use rustc_macros::extension; use rustc_macros::extension;
@ -83,7 +81,6 @@ mod expr;
mod format; mod format;
mod index; mod index;
mod item; mod item;
mod lifetime_collector;
mod pat; mod pat;
mod path; mod path;
@ -149,12 +146,6 @@ struct LoweringContext<'a, 'hir> {
allow_async_iterator: Lrc<[Symbol]>, allow_async_iterator: Lrc<[Symbol]>,
allow_for_await: Lrc<[Symbol]>, allow_for_await: Lrc<[Symbol]>,
allow_async_fn_traits: Lrc<[Symbol]>, allow_async_fn_traits: Lrc<[Symbol]>,
/// Mapping from generics `def_id`s to TAIT generics `def_id`s.
/// For each captured lifetime (e.g., 'a), we create a new lifetime parameter that is a generic
/// defined on the TAIT, so we have type Foo<'a1> = ... and we establish a mapping in this
/// field from the original parameter 'a to the new parameter 'a1.
generics_def_id_map: Vec<LocalDefIdMap<LocalDefId>>,
} }
impl<'a, 'hir> LoweringContext<'a, 'hir> { impl<'a, 'hir> LoweringContext<'a, 'hir> {
@ -199,7 +190,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
// FIXME(gen_blocks): how does `closure_track_caller`/`async_fn_track_caller` // FIXME(gen_blocks): how does `closure_track_caller`/`async_fn_track_caller`
// interact with `gen`/`async gen` blocks // interact with `gen`/`async gen` blocks
allow_async_iterator: [sym::gen_future, sym::async_iterator].into(), allow_async_iterator: [sym::gen_future, sym::async_iterator].into(),
generics_def_id_map: Default::default(),
} }
} }
@ -528,54 +518,14 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
/// Given the id of some node in the AST, finds the `LocalDefId` associated with it by the name /// Given the id of some node in the AST, finds the `LocalDefId` associated with it by the name
/// resolver (if any). /// resolver (if any).
fn orig_opt_local_def_id(&self, node: NodeId) -> Option<LocalDefId> {
self.resolver.node_id_to_def_id.get(&node).copied()
}
/// Given the id of some node in the AST, finds the `LocalDefId` associated with it by the name
/// resolver (if any), after applying any remapping from `get_remapped_def_id`.
///
/// For example, in a function like `fn foo<'a>(x: &'a u32)`,
/// invoking with the id from the `ast::Lifetime` node found inside
/// the `&'a u32` type would return the `LocalDefId` of the
/// `'a` parameter declared on `foo`.
///
/// This function also applies remapping from `get_remapped_def_id`.
/// These are used when synthesizing opaque types from `-> impl Trait` return types and so forth.
/// For example, in a function like `fn foo<'a>() -> impl Debug + 'a`,
/// we would create an opaque type `type FooReturn<'a1> = impl Debug + 'a1`.
/// When lowering the `Debug + 'a` bounds, we add a remapping to map `'a` to `'a1`.
fn opt_local_def_id(&self, node: NodeId) -> Option<LocalDefId> { fn opt_local_def_id(&self, node: NodeId) -> Option<LocalDefId> {
self.orig_opt_local_def_id(node).map(|local_def_id| self.get_remapped_def_id(local_def_id)) self.resolver.node_id_to_def_id.get(&node).copied()
} }
fn local_def_id(&self, node: NodeId) -> LocalDefId { fn local_def_id(&self, node: NodeId) -> LocalDefId {
self.opt_local_def_id(node).unwrap_or_else(|| panic!("no entry for node id: `{node:?}`")) self.opt_local_def_id(node).unwrap_or_else(|| panic!("no entry for node id: `{node:?}`"))
} }
/// Get the previously recorded `to` local def id given the `from` local def id, obtained using
/// `generics_def_id_map` field.
fn get_remapped_def_id(&self, local_def_id: LocalDefId) -> LocalDefId {
// `generics_def_id_map` is a stack of mappings. As we go deeper in impl traits nesting we
// push new mappings, so we first need to get the latest (innermost) mappings, hence `iter().rev()`.
//
// Consider:
//
// `fn test<'a, 'b>() -> impl Trait<&'a u8, Ty = impl Sized + 'b> {}`
//
// We would end with a generics_def_id_map like:
//
// `[[fn#'b -> impl_trait#'b], [fn#'b -> impl_sized#'b]]`
//
// for the opaque type generated on `impl Sized + 'b`, we want the result to be: impl_sized#'b.
// So, if we were trying to find first from the start (outermost) would give the wrong result, impl_trait#'b.
self.generics_def_id_map
.iter()
.rev()
.find_map(|map| map.get(&local_def_id).copied())
.unwrap_or(local_def_id)
}
/// Freshen the `LoweringContext` and ready it to lower a nested item. /// Freshen the `LoweringContext` and ready it to lower a nested item.
/// The lowered item is registered into `self.children`. /// The lowered item is registered into `self.children`.
/// ///
@ -647,27 +597,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
result result
} }
/// Installs the remapping `remap` in scope while `f` is being executed.
/// This causes references to the `LocalDefId` keys to be changed to
/// refer to the values instead.
///
/// The remapping is used when one piece of AST expands to multiple
/// pieces of HIR. For example, the function `fn foo<'a>(...) -> impl Debug + 'a`,
/// expands to both a function definition (`foo`) and a TAIT for the return value,
/// both of which have a lifetime parameter `'a`. The remapping allows us to
/// rewrite the `'a` in the return value to refer to the
/// `'a` declared on the TAIT, instead of the function.
fn with_remapping<R>(
&mut self,
remap: LocalDefIdMap<LocalDefId>,
f: impl FnOnce(&mut Self) -> R,
) -> R {
self.generics_def_id_map.push(remap);
let res = f(self);
self.generics_def_id_map.pop();
res
}
fn make_owner_info(&mut self, node: hir::OwnerNode<'hir>) -> &'hir hir::OwnerInfo<'hir> { fn make_owner_info(&mut self, node: hir::OwnerNode<'hir>) -> &'hir hir::OwnerInfo<'hir> {
let attrs = std::mem::take(&mut self.attrs); let attrs = std::mem::take(&mut self.attrs);
let mut bodies = std::mem::take(&mut self.bodies); let mut bodies = std::mem::take(&mut self.bodies);
@ -1499,27 +1428,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
// frequently opened issues show. // frequently opened issues show.
let opaque_ty_span = self.mark_span_with_reason(DesugaringKind::OpaqueTy, span, None); let opaque_ty_span = self.mark_span_with_reason(DesugaringKind::OpaqueTy, span, None);
// Whether this opaque always captures lifetimes in scope.
// Right now, this is all RPITIT and TAITs, and when `lifetime_capture_rules_2024`
// is enabled. We don't check the span of the edition, since this is done
// on a per-opaque basis to account for nested opaques.
let always_capture_in_scope = match origin {
_ if self.tcx.features().lifetime_capture_rules_2024() => true,
hir::OpaqueTyOrigin::TyAlias { .. } => true,
hir::OpaqueTyOrigin::FnReturn { in_trait_or_impl, .. } => in_trait_or_impl.is_some(),
hir::OpaqueTyOrigin::AsyncFn { .. } => {
unreachable!("should be using `lower_coroutine_fn_ret_ty`")
}
};
let captured_lifetimes_to_duplicate = lifetime_collector::lifetimes_for_opaque(
self.resolver,
always_capture_in_scope,
opaque_ty_node_id,
bounds,
span,
);
debug!(?captured_lifetimes_to_duplicate);
// Feature gate for RPITIT + use<..> // Feature gate for RPITIT + use<..>
match origin { match origin {
rustc_hir::OpaqueTyOrigin::FnReturn { in_trait_or_impl: Some(_), .. } => { rustc_hir::OpaqueTyOrigin::FnReturn { in_trait_or_impl: Some(_), .. } => {
@ -1542,22 +1450,15 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
_ => {} _ => {}
} }
self.lower_opaque_inner( self.lower_opaque_inner(opaque_ty_node_id, origin, opaque_ty_span, |this| {
opaque_ty_node_id, this.lower_param_bounds(bounds, itctx)
origin, })
captured_lifetimes_to_duplicate,
span,
opaque_ty_span,
|this| this.lower_param_bounds(bounds, itctx),
)
} }
fn lower_opaque_inner( fn lower_opaque_inner(
&mut self, &mut self,
opaque_ty_node_id: NodeId, opaque_ty_node_id: NodeId,
origin: hir::OpaqueTyOrigin, origin: hir::OpaqueTyOrigin,
captured_lifetimes_to_duplicate: FxIndexSet<Lifetime>,
span: Span,
opaque_ty_span: Span, opaque_ty_span: Span,
lower_item_bounds: impl FnOnce(&mut Self) -> &'hir [hir::GenericBound<'hir>], lower_item_bounds: impl FnOnce(&mut Self) -> &'hir [hir::GenericBound<'hir>],
) -> hir::TyKind<'hir> { ) -> hir::TyKind<'hir> {
@ -1565,145 +1466,19 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
let opaque_ty_hir_id = self.lower_node_id(opaque_ty_node_id); let opaque_ty_hir_id = self.lower_node_id(opaque_ty_node_id);
debug!(?opaque_ty_def_id, ?opaque_ty_hir_id); debug!(?opaque_ty_def_id, ?opaque_ty_hir_id);
// Map from captured (old) lifetime to synthetic (new) lifetime.
// Used to resolve lifetimes in the bounds of the opaque.
let mut captured_to_synthesized_mapping = LocalDefIdMap::default();
// List of (early-bound) synthetic lifetimes that are owned by the opaque.
// This is used to create the `hir::Generics` owned by the opaque.
let mut synthesized_lifetime_definitions = vec![];
// Pairs of lifetime arg (that resolves to the captured lifetime)
// and the def-id of the (early-bound) synthetic lifetime definition.
// This is used both to create generics for the `TyKind::OpaqueDef` that
// we return, and also as a captured lifetime mapping for RPITITs.
let mut synthesized_lifetime_args = vec![];
for lifetime in captured_lifetimes_to_duplicate {
let res = self.resolver.get_lifetime_res(lifetime.id).unwrap_or(LifetimeRes::Error);
let (old_def_id, missing_kind) = match res {
LifetimeRes::Param { param: old_def_id, binder: _ } => (old_def_id, None),
LifetimeRes::Fresh { param, kind, .. } => {
debug_assert_eq!(lifetime.ident.name, kw::UnderscoreLifetime);
if let Some(old_def_id) = self.orig_opt_local_def_id(param) {
(old_def_id, Some(kind))
} else {
self.dcx()
.span_delayed_bug(lifetime.ident.span, "no def-id for fresh lifetime");
continue;
}
}
// Opaques do not capture `'static`
LifetimeRes::Static { .. } | LifetimeRes::Error => {
continue;
}
res => {
let bug_msg = format!(
"Unexpected lifetime resolution {:?} for {:?} at {:?}",
res, lifetime.ident, lifetime.ident.span
);
span_bug!(lifetime.ident.span, "{}", bug_msg);
}
};
if captured_to_synthesized_mapping.get(&old_def_id).is_none() {
// Create a new lifetime parameter local to the opaque.
let duplicated_lifetime_node_id = self.next_node_id();
let duplicated_lifetime_def_id = self.create_def(
opaque_ty_def_id,
duplicated_lifetime_node_id,
lifetime.ident.name,
DefKind::LifetimeParam,
self.lower_span(lifetime.ident.span),
);
captured_to_synthesized_mapping.insert(old_def_id, duplicated_lifetime_def_id);
// FIXME: Instead of doing this, we could move this whole loop
// into the `with_hir_id_owner`, then just directly construct
// the `hir::GenericParam` here.
synthesized_lifetime_definitions.push((
duplicated_lifetime_node_id,
duplicated_lifetime_def_id,
self.lower_ident(lifetime.ident),
missing_kind,
));
// Now make an arg that we can use for the generic params of the opaque tykind.
let id = self.next_node_id();
let lifetime_arg = self.new_named_lifetime_with_res(id, lifetime.ident, res);
let duplicated_lifetime_def_id = self.local_def_id(duplicated_lifetime_node_id);
synthesized_lifetime_args.push((lifetime_arg, duplicated_lifetime_def_id))
}
}
let opaque_ty_def = self.with_def_id_parent(opaque_ty_def_id, |this| { let opaque_ty_def = self.with_def_id_parent(opaque_ty_def_id, |this| {
// Install the remapping from old to new (if any). This makes sure that let bounds = lower_item_bounds(this);
// any lifetimes that would have resolved to the def-id of captured
// lifetimes are remapped to the new *synthetic* lifetimes of the opaque.
let bounds = this
.with_remapping(captured_to_synthesized_mapping, |this| lower_item_bounds(this));
let generic_params =
this.arena.alloc_from_iter(synthesized_lifetime_definitions.iter().map(
|&(new_node_id, new_def_id, ident, missing_kind)| {
let hir_id = this.lower_node_id(new_node_id);
let (name, kind) = if ident.name == kw::UnderscoreLifetime {
(
hir::ParamName::Fresh,
hir::LifetimeParamKind::Elided(
missing_kind.unwrap_or(MissingLifetimeKind::Underscore),
),
)
} else {
(hir::ParamName::Plain(ident), hir::LifetimeParamKind::Explicit)
};
hir::GenericParam {
hir_id,
def_id: new_def_id,
name,
span: ident.span,
pure_wrt_drop: false,
kind: hir::GenericParamKind::Lifetime { kind },
colon_span: None,
source: hir::GenericParamSource::Generics,
}
},
));
debug!("lower_async_fn_ret_ty: generic_params={:#?}", generic_params);
let lifetime_mapping = self.arena.alloc_slice(&synthesized_lifetime_args);
trace!("registering opaque type with id {:#?}", opaque_ty_def_id);
let opaque_ty_def = hir::OpaqueTy { let opaque_ty_def = hir::OpaqueTy {
hir_id: opaque_ty_hir_id, hir_id: opaque_ty_hir_id,
def_id: opaque_ty_def_id, def_id: opaque_ty_def_id,
generics: this.arena.alloc(hir::Generics {
params: generic_params,
predicates: &[],
has_where_clause_predicates: false,
where_clause_span: this.lower_span(span),
span: this.lower_span(span),
}),
bounds, bounds,
origin, origin,
lifetime_mapping,
span: this.lower_span(opaque_ty_span), span: this.lower_span(opaque_ty_span),
}; };
this.arena.alloc(opaque_ty_def) this.arena.alloc(opaque_ty_def)
}); });
let generic_args = self.arena.alloc_from_iter( hir::TyKind::OpaqueDef(opaque_ty_def)
synthesized_lifetime_args
.iter()
.map(|(lifetime, _)| hir::GenericArg::Lifetime(*lifetime)),
);
// Create the `Foo<...>` reference itself. Note that the `type
// Foo = impl Trait` is, internally, created as a child of the
// async fn, so the *type parameters* are inherited. It's
// only the lifetime parameters that we must supply.
hir::TyKind::OpaqueDef(opaque_ty_def, generic_args)
} }
fn lower_precise_capturing_args( fn lower_precise_capturing_args(
@ -1885,13 +1660,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
let opaque_ty_span = let opaque_ty_span =
self.mark_span_with_reason(DesugaringKind::Async, span, allowed_features); self.mark_span_with_reason(DesugaringKind::Async, span, allowed_features);
let captured_lifetimes = self
.resolver
.extra_lifetime_params(opaque_ty_node_id)
.into_iter()
.map(|(ident, id, _)| Lifetime { id, ident })
.collect();
let in_trait_or_impl = match fn_kind { let in_trait_or_impl = match fn_kind {
FnDeclKind::Trait => Some(hir::RpitContext::Trait), FnDeclKind::Trait => Some(hir::RpitContext::Trait),
FnDeclKind::Impl => Some(hir::RpitContext::TraitImpl), FnDeclKind::Impl => Some(hir::RpitContext::TraitImpl),
@ -1902,8 +1670,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
let opaque_ty_ref = self.lower_opaque_inner( let opaque_ty_ref = self.lower_opaque_inner(
opaque_ty_node_id, opaque_ty_node_id,
hir::OpaqueTyOrigin::AsyncFn { parent: fn_def_id, in_trait_or_impl }, hir::OpaqueTyOrigin::AsyncFn { parent: fn_def_id, in_trait_or_impl },
captured_lifetimes,
span,
opaque_ty_span, opaque_ty_span,
|this| { |this| {
let bound = this.lower_coroutine_fn_output_type_to_bound( let bound = this.lower_coroutine_fn_output_type_to_bound(
@ -2000,10 +1766,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
res: LifetimeRes, res: LifetimeRes,
) -> &'hir hir::Lifetime { ) -> &'hir hir::Lifetime {
let res = match res { let res = match res {
LifetimeRes::Param { param, .. } => { LifetimeRes::Param { param, .. } => hir::LifetimeName::Param(param),
let param = self.get_remapped_def_id(param);
hir::LifetimeName::Param(param)
}
LifetimeRes::Fresh { param, .. } => { LifetimeRes::Fresh { param, .. } => {
let param = self.local_def_id(param); let param = self.local_def_id(param);
hir::LifetimeName::Param(param) hir::LifetimeName::Param(param)

2
compiler/rustc_borrowck/src/diagnostics/region_name.rs
View file

@ -830,7 +830,7 @@ impl<'tcx> MirBorrowckCtxt<'_, '_, 'tcx> {
/// ///
/// [`OpaqueDef`]: hir::TyKind::OpaqueDef /// [`OpaqueDef`]: hir::TyKind::OpaqueDef
fn get_future_inner_return_ty(&self, hir_ty: &'tcx hir::Ty<'tcx>) -> &'tcx hir::Ty<'tcx> { fn get_future_inner_return_ty(&self, hir_ty: &'tcx hir::Ty<'tcx>) -> &'tcx hir::Ty<'tcx> {
let hir::TyKind::OpaqueDef(opaque_ty, _) = hir_ty.kind else { let hir::TyKind::OpaqueDef(opaque_ty) = hir_ty.kind else {
span_bug!( span_bug!(
hir_ty.span, hir_ty.span,
"lowered return type of async fn is not OpaqueDef: {:?}", "lowered return type of async fn is not OpaqueDef: {:?}",

15
compiler/rustc_hir/src/hir.rs
View file

@ -2627,7 +2627,6 @@ impl<'hir> Ty<'hir> {
} }
TyKind::Tup(tys) => tys.iter().any(Self::is_suggestable_infer_ty), TyKind::Tup(tys) => tys.iter().any(Self::is_suggestable_infer_ty),
TyKind::Ptr(mut_ty) | TyKind::Ref(_, mut_ty) => mut_ty.ty.is_suggestable_infer_ty(), TyKind::Ptr(mut_ty) | TyKind::Ref(_, mut_ty) => mut_ty.ty.is_suggestable_infer_ty(),
TyKind::OpaqueDef(_, generic_args) => are_suggestable_generic_args(generic_args),
TyKind::Path(QPath::TypeRelative(ty, segment)) => { TyKind::Path(QPath::TypeRelative(ty, segment)) => {
ty.is_suggestable_infer_ty() || are_suggestable_generic_args(segment.args().args) ty.is_suggestable_infer_ty() || are_suggestable_generic_args(segment.args().args)
} }
@ -2746,19 +2745,8 @@ pub struct BareFnTy<'hir> {
pub struct OpaqueTy<'hir> { pub struct OpaqueTy<'hir> {
pub hir_id: HirId, pub hir_id: HirId,
pub def_id: LocalDefId, pub def_id: LocalDefId,
pub generics: &'hir Generics<'hir>,
pub bounds: GenericBounds<'hir>, pub bounds: GenericBounds<'hir>,
pub origin: OpaqueTyOrigin, pub origin: OpaqueTyOrigin,
/// Return-position impl traits (and async futures) must "reify" any late-bound
/// lifetimes that are captured from the function signature they originate from.
///
/// This is done by generating a new early-bound lifetime parameter local to the
/// opaque which is instantiated in the function signature with the late-bound
/// lifetime.
///
/// This mapping associated a captured lifetime (first parameter) with the new
/// early-bound lifetime that was generated for the opaque.
pub lifetime_mapping: &'hir [(&'hir Lifetime, LocalDefId)],
pub span: Span, pub span: Span,
} }
@ -2866,7 +2854,7 @@ pub enum TyKind<'hir> {
/// possibly parameters) that are actually bound on the `impl Trait`. /// possibly parameters) that are actually bound on the `impl Trait`.
/// ///
/// The last parameter specifies whether this opaque appears in a trait definition. /// The last parameter specifies whether this opaque appears in a trait definition.
OpaqueDef(&'hir OpaqueTy<'hir>, &'hir [GenericArg<'hir>]), OpaqueDef(&'hir OpaqueTy<'hir>),
/// A trait object type `Bound1 + Bound2 + Bound3` /// A trait object type `Bound1 + Bound2 + Bound3`
/// where `Bound` is a trait or a lifetime. /// where `Bound` is a trait or a lifetime.
TraitObject(&'hir [PolyTraitRef<'hir>], &'hir Lifetime, TraitObjectSyntax), TraitObject(&'hir [PolyTraitRef<'hir>], &'hir Lifetime, TraitObjectSyntax),
@ -3991,7 +3979,6 @@ impl<'hir> Node<'hir> {
| Node::TraitItem(TraitItem { generics, .. }) | Node::TraitItem(TraitItem { generics, .. })
| Node::ImplItem(ImplItem { generics, .. }) => Some(generics), | Node::ImplItem(ImplItem { generics, .. }) => Some(generics),
Node::Item(item) => item.kind.generics(), Node::Item(item) => item.kind.generics(),
Node::OpaqueTy(opaque) => Some(opaque.generics),
_ => None, _ => None,
} }
} }

7
compiler/rustc_hir/src/intravisit.rs
View file

@ -896,9 +896,8 @@ pub fn walk_ty<'v, V: Visitor<'v>>(visitor: &mut V, typ: &'v Ty<'v>) -> V::Resul
TyKind::Path(ref qpath) => { TyKind::Path(ref qpath) => {
try_visit!(visitor.visit_qpath(qpath, typ.hir_id, typ.span)); try_visit!(visitor.visit_qpath(qpath, typ.hir_id, typ.span));
} }
TyKind::OpaqueDef(opaque, lifetimes) => { TyKind::OpaqueDef(opaque) => {
try_visit!(visitor.visit_opaque_ty(opaque)); try_visit!(visitor.visit_opaque_ty(opaque));
walk_list!(visitor, visit_generic_arg, lifetimes);
} }
TyKind::Array(ref ty, ref length) => { TyKind::Array(ref ty, ref length) => {
try_visit!(visitor.visit_ty(ty)); try_visit!(visitor.visit_ty(ty));
@ -1188,10 +1187,8 @@ pub fn walk_poly_trait_ref<'v, V: Visitor<'v>>(
} }
pub fn walk_opaque_ty<'v, V: Visitor<'v>>(visitor: &mut V, opaque: &'v OpaqueTy<'v>) -> V::Result { pub fn walk_opaque_ty<'v, V: Visitor<'v>>(visitor: &mut V, opaque: &'v OpaqueTy<'v>) -> V::Result {
let &OpaqueTy { hir_id, def_id: _, generics, bounds, origin: _, lifetime_mapping: _, span: _ } = let &OpaqueTy { hir_id, def_id: _, bounds, origin: _, span: _ } = opaque;
opaque;
try_visit!(visitor.visit_id(hir_id)); try_visit!(visitor.visit_id(hir_id));
try_visit!(walk_generics(visitor, generics));
walk_list!(visitor, visit_param_bound, bounds); walk_list!(visitor, visit_param_bound, bounds);
V::Result::output() V::Result::output()
} }

2
compiler/rustc_hir_analysis/src/collect.rs
View file

@ -1302,7 +1302,7 @@ fn trait_def(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::TraitDef {
} }
} }
#[instrument(level = "debug", skip(tcx))] #[instrument(level = "debug", skip(tcx), ret)]
fn fn_sig(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::EarlyBinder<'_, ty::PolyFnSig<'_>> { fn fn_sig(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::EarlyBinder<'_, ty::PolyFnSig<'_>> {
use rustc_hir::Node::*; use rustc_hir::Node::*;
use rustc_hir::*; use rustc_hir::*;

15
compiler/rustc_hir_analysis/src/collect/generics_of.rs
View file

@ -426,6 +426,21 @@ pub(super) fn generics_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Generics {
}); });
} }
if let Node::OpaqueTy(&hir::OpaqueTy { .. }) = node {
assert!(own_params.is_empty());
let lifetimes = tcx.opaque_captured_lifetimes(def_id);
debug!(?lifetimes);
own_params.extend(lifetimes.iter().map(|&(_, param)| ty::GenericParamDef {
name: tcx.item_name(param.to_def_id()),
index: next_index(),
def_id: param.to_def_id(),
pure_wrt_drop: false,
kind: ty::GenericParamDefKind::Lifetime,
}))
}
let param_def_id_to_index = let param_def_id_to_index =
own_params.iter().map(|param| (param.def_id, param.index)).collect(); own_params.iter().map(|param| (param.def_id, param.index)).collect();

7
compiler/rustc_hir_analysis/src/collect/predicates_of.rs
View file

@ -329,13 +329,6 @@ fn gather_explicit_predicates_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Gen
// We create bi-directional Outlives predicates between the original // We create bi-directional Outlives predicates between the original
// and the duplicated parameter, to ensure that they do not get out of sync. // and the duplicated parameter, to ensure that they do not get out of sync.
if let Node::OpaqueTy(..) = node { if let Node::OpaqueTy(..) = node {
let opaque_ty_node = tcx.parent_hir_node(hir_id);
let Node::Ty(&hir::Ty { kind: TyKind::OpaqueDef(_, lifetimes), .. }) = opaque_ty_node
else {
bug!("unexpected {opaque_ty_node:?}")
};
debug!(?lifetimes);
compute_bidirectional_outlives_predicates(tcx, &generics.own_params, &mut predicates); compute_bidirectional_outlives_predicates(tcx, &generics.own_params, &mut predicates);
debug!(?predicates); debug!(?predicates);
} }

377
compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs
View file

@ -6,12 +6,14 @@
//! the types in HIR to identify late-bound lifetimes and assign their Debruijn indices. This file //! the types in HIR to identify late-bound lifetimes and assign their Debruijn indices. This file
//! is also responsible for assigning their semantics to implicit lifetimes in trait objects. //! is also responsible for assigning their semantics to implicit lifetimes in trait objects.
use core::ops::ControlFlow; use std::cell::RefCell;
use std::fmt; use std::fmt;
use std::ops::ControlFlow;
use rustc_ast::visit::walk_list; use rustc_ast::visit::walk_list;
use rustc_data_structures::fx::{FxHashSet, FxIndexMap, FxIndexSet}; use rustc_data_structures::fx::{FxHashSet, FxIndexMap, FxIndexSet};
use rustc_data_structures::sorted_map::SortedMap; use rustc_data_structures::sorted_map::SortedMap;
use rustc_errors::ErrorGuaranteed;
use rustc_hir as hir; use rustc_hir as hir;
use rustc_hir::def::{DefKind, Res}; use rustc_hir::def::{DefKind, Res};
use rustc_hir::intravisit::{self, Visitor}; use rustc_hir::intravisit::{self, Visitor};
@ -25,7 +27,7 @@ use rustc_middle::query::Providers;
use rustc_middle::ty::{self, TyCtxt, TypeSuperVisitable, TypeVisitor}; use rustc_middle::ty::{self, TyCtxt, TypeSuperVisitable, TypeVisitor};
use rustc_middle::{bug, span_bug}; use rustc_middle::{bug, span_bug};
use rustc_span::Span; use rustc_span::Span;
use rustc_span::def_id::{DefId, LocalDefId}; use rustc_span::def_id::{DefId, LocalDefId, LocalDefIdMap};
use rustc_span::symbol::{Ident, sym}; use rustc_span::symbol::{Ident, sym};
use tracing::{debug, debug_span, instrument}; use tracing::{debug, debug_span, instrument};
@ -80,6 +82,9 @@ struct NamedVarMap {
// - trait refs // - trait refs
// - bound types (like `T` in `for<'a> T<'a>: Foo`) // - bound types (like `T` in `for<'a> T<'a>: Foo`)
late_bound_vars: ItemLocalMap<Vec<ty::BoundVariableKind>>, late_bound_vars: ItemLocalMap<Vec<ty::BoundVariableKind>>,
// List captured variables for each opaque type.
opaque_captured_lifetimes: LocalDefIdMap<Vec<(ResolvedArg, LocalDefId)>>,
} }
struct BoundVarContext<'a, 'tcx> { struct BoundVarContext<'a, 'tcx> {
@ -147,6 +152,20 @@ enum Scope<'a> {
s: ScopeRef<'a>, s: ScopeRef<'a>,
}, },
/// Resolve the lifetimes in the bounds to the lifetime defs in the generics.
/// `fn foo<'a>() -> impl MyTrait<'a> { ... }` desugars to
/// `type MyAnonTy<'b> = impl MyTrait<'b>;`
/// ^ ^ this gets resolved in the scope of
/// the opaque_ty generics
Opaque {
/// The opaque type we are traversing.
def_id: LocalDefId,
/// Mapping from each captured lifetime `'a` to the duplicate generic parameter `'b`.
captures: &'a RefCell<FxIndexMap<ResolvedArg, LocalDefId>>,
s: ScopeRef<'a>,
},
/// Disallows capturing late-bound vars from parent scopes. /// Disallows capturing late-bound vars from parent scopes.
/// ///
/// This is necessary for something like `for<T> [(); { /* references T */ }]:`, /// This is necessary for something like `for<T> [(); { /* references T */ }]:`,
@ -192,6 +211,12 @@ impl<'a> fmt::Debug for TruncatedScopeDebug<'a> {
.field("where_bound_origin", where_bound_origin) .field("where_bound_origin", where_bound_origin)
.field("s", &"..") .field("s", &"..")
.finish(), .finish(),
Scope::Opaque { captures, def_id, s: _ } => f
.debug_struct("Opaque")
.field("def_id", def_id)
.field("captures", &captures.borrow())
.field("s", &"..")
.finish(),
Scope::Body { id, s: _ } => { Scope::Body { id, s: _ } => {
f.debug_struct("Body").field("id", id).field("s", &"..").finish() f.debug_struct("Body").field("id", id).field("s", &"..").finish()
} }
@ -226,6 +251,12 @@ pub(crate) fn provide(providers: &mut Providers) {
is_late_bound_map, is_late_bound_map,
object_lifetime_default, object_lifetime_default,
late_bound_vars_map: |tcx, id| &tcx.resolve_bound_vars(id).late_bound_vars, late_bound_vars_map: |tcx, id| &tcx.resolve_bound_vars(id).late_bound_vars,
opaque_captured_lifetimes: |tcx, id| {
&tcx.resolve_bound_vars(tcx.local_def_id_to_hir_id(id).owner)
.opaque_captured_lifetimes
.get(&id)
.map_or(&[][..], |x| &x[..])
},
..*providers ..*providers
}; };
@ -236,8 +267,11 @@ pub(crate) fn provide(providers: &mut Providers) {
/// `named_variable_map`, `is_late_bound_map`, etc. /// `named_variable_map`, `is_late_bound_map`, etc.
#[instrument(level = "debug", skip(tcx))] #[instrument(level = "debug", skip(tcx))]
fn resolve_bound_vars(tcx: TyCtxt<'_>, local_def_id: hir::OwnerId) -> ResolveBoundVars { fn resolve_bound_vars(tcx: TyCtxt<'_>, local_def_id: hir::OwnerId) -> ResolveBoundVars {
let mut named_variable_map = let mut named_variable_map = NamedVarMap {
NamedVarMap { defs: Default::default(), late_bound_vars: Default::default() }; defs: Default::default(),
late_bound_vars: Default::default(),
opaque_captured_lifetimes: Default::default(),
};
let mut visitor = BoundVarContext { let mut visitor = BoundVarContext {
tcx, tcx,
map: &mut named_variable_map, map: &mut named_variable_map,
@ -264,13 +298,16 @@ fn resolve_bound_vars(tcx: TyCtxt<'_>, local_def_id: hir::OwnerId) -> ResolveBou
let defs = named_variable_map.defs.into_sorted_stable_ord(); let defs = named_variable_map.defs.into_sorted_stable_ord();
let late_bound_vars = named_variable_map.late_bound_vars.into_sorted_stable_ord(); let late_bound_vars = named_variable_map.late_bound_vars.into_sorted_stable_ord();
let opaque_captured_lifetimes = named_variable_map.opaque_captured_lifetimes;
let rl = ResolveBoundVars { let rl = ResolveBoundVars {
defs: SortedMap::from_presorted_elements(defs), defs: SortedMap::from_presorted_elements(defs),
late_bound_vars: SortedMap::from_presorted_elements(late_bound_vars), late_bound_vars: SortedMap::from_presorted_elements(late_bound_vars),
opaque_captured_lifetimes,
}; };
debug!(?rl.defs); debug!(?rl.defs);
debug!(?rl.late_bound_vars); debug!(?rl.late_bound_vars);
debug!(?rl.opaque_captured_lifetimes);
rl rl
} }
@ -306,6 +343,26 @@ fn generic_param_def_as_bound_arg(param: &ty::GenericParamDef) -> ty::BoundVaria
} }
} }
/// Whether this opaque always captures lifetimes in scope.
/// Right now, this is all RPITIT and TAITs, and when `lifetime_capture_rules_2024`
/// is enabled. We don't check the span of the edition, since this is done
/// on a per-opaque basis to account for nested opaques.
fn opaque_captures_all_in_scope_lifetimes<'tcx>(
tcx: TyCtxt<'tcx>,
opaque: &'tcx hir::OpaqueTy<'tcx>,
) -> bool {
match opaque.origin {
// if the opaque has the `use<...>` syntax, the user is telling us that they only want
// to account for those lifetimes, so do not try to be clever.
_ if opaque.bounds.iter().any(|bound| matches!(bound, hir::GenericBound::Use(..))) => false,
hir::OpaqueTyOrigin::AsyncFn { .. } | hir::OpaqueTyOrigin::TyAlias { .. } => true,
_ if tcx.features().lifetime_capture_rules_2024() || opaque.span.at_least_rust_2024() => {
true
}
hir::OpaqueTyOrigin::FnReturn { in_trait_or_impl, .. } => in_trait_or_impl.is_some(),
}
}
impl<'a, 'tcx> BoundVarContext<'a, 'tcx> { impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
/// Returns the binders in scope and the type of `Binder` that should be created for a poly trait ref. /// Returns the binders in scope and the type of `Binder` that should be created for a poly trait ref.
fn poly_trait_ref_binder_info(&mut self) -> (Vec<ty::BoundVariableKind>, BinderScopeType) { fn poly_trait_ref_binder_info(&mut self) -> (Vec<ty::BoundVariableKind>, BinderScopeType) {
@ -317,7 +374,9 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
break (vec![], BinderScopeType::Normal); break (vec![], BinderScopeType::Normal);
} }
Scope::ObjectLifetimeDefault { s, .. } | Scope::LateBoundary { s, .. } => { Scope::Opaque { s, .. }
| Scope::ObjectLifetimeDefault { s, .. }
| Scope::LateBoundary { s, .. } => {
scope = s; scope = s;
} }
@ -488,29 +547,100 @@ impl<'a, 'tcx> Visitor<'tcx> for BoundVarContext<'a, 'tcx> {
} }
} }
/// Resolve the lifetimes that are applied to the opaque type.
/// These are resolved in the current scope.
/// `fn foo<'a>() -> impl MyTrait<'a> { ... }` desugars to
/// `fn foo<'a>() -> MyAnonTy<'a> { ... }`
/// ^ ^this gets resolved in the current scope
#[instrument(level = "debug", skip(self))] #[instrument(level = "debug", skip(self))]
fn visit_opaque_ty(&mut self, opaque: &'tcx rustc_hir::OpaqueTy<'tcx>) { fn visit_opaque_ty(&mut self, opaque: &'tcx rustc_hir::OpaqueTy<'tcx>) {
// We want to start our early-bound indices at the end of the parent scope, let mut captures = FxIndexMap::default();
// not including any parent `impl Trait`s.
let mut bound_vars = FxIndexMap::default(); let capture_all_in_scope_lifetimes =
debug!(?opaque.generics.params); opaque_captures_all_in_scope_lifetimes(self.tcx, opaque);
for param in opaque.generics.params { if capture_all_in_scope_lifetimes {
let arg = ResolvedArg::early(param); let mut create_def_for_duplicated_param = |original_lifetime: LocalDefId, def| {
bound_vars.insert(param.def_id, arg); captures.entry(def).or_insert_with(|| {
let name = self.tcx.item_name(original_lifetime.to_def_id());
let span = self.tcx.def_span(original_lifetime);
let feed = self.tcx.create_def(opaque.def_id, name, DefKind::LifetimeParam);
feed.def_span(span);
feed.def_ident_span(Some(span));
feed.def_id()
});
};
// We list scopes outwards, this causes us to see lifetime parameters in reverse
// declaration order. In order to make it consistent with what `generics_of` might
// give, we will reverse the IndexMap after early captures.
let mut scope = self.scope;
loop {
match *scope {
Scope::Binder { ref bound_vars, s, .. } => {
for (&original_lifetime, &(mut def)) in bound_vars.iter().rev() {
if let DefKind::LifetimeParam = self.tcx.def_kind(original_lifetime) {
if let Err(guar) =
self.check_lifetime_is_capturable(opaque.def_id, def, None)
{
def = ResolvedArg::Error(guar);
}
create_def_for_duplicated_param(original_lifetime, def);
}
}
scope = s;
} }
let hir_id = self.tcx.local_def_id_to_hir_id(opaque.def_id); Scope::Root { mut opt_parent_item } => {
let scope = Scope::Binder { while let Some(parent_item) = opt_parent_item {
hir_id, let parent_generics = self.tcx.generics_of(parent_item);
bound_vars, for param in parent_generics.own_params.iter().rev() {
s: self.scope, if let ty::GenericParamDefKind::Lifetime = param.kind {
scope_type: BinderScopeType::Normal, create_def_for_duplicated_param(
where_bound_origin: None, param.def_id.expect_local(),
}; ResolvedArg::EarlyBound(param.def_id.expect_local()),
);
}
}
opt_parent_item = parent_generics.parent.and_then(DefId::as_local);
}
break;
}
Scope::Opaque { captures: outer_captures, .. } => {
for (_, &duplicated_param) in outer_captures.borrow().iter().rev() {
create_def_for_duplicated_param(
duplicated_param,
ResolvedArg::EarlyBound(duplicated_param),
);
}
break;
}
Scope::Body { .. } => {
bug!("{:?}", scope)
}
Scope::ObjectLifetimeDefault { s, .. }
| Scope::Supertrait { s, .. }
| Scope::TraitRefBoundary { s, .. }
| Scope::LateBoundary { s, .. } => {
scope = s;
}
}
}
captures.reverse();
}
let captures = RefCell::new(captures);
let scope = Scope::Opaque { captures: &captures, def_id: opaque.def_id, s: self.scope };
self.with(scope, |this| { self.with(scope, |this| {
let scope = Scope::TraitRefBoundary { s: this.scope }; let scope = Scope::TraitRefBoundary { s: this.scope };
this.with(scope, |this| intravisit::walk_opaque_ty(this, opaque)) this.with(scope, |this| intravisit::walk_opaque_ty(this, opaque))
}) });
let captures = captures.into_inner().into_iter().collect();
self.map.opaque_captured_lifetimes.insert(opaque.def_id, captures);
} }
#[instrument(level = "debug", skip(self))] #[instrument(level = "debug", skip(self))]
@ -685,66 +815,8 @@ impl<'a, 'tcx> Visitor<'tcx> for BoundVarContext<'a, 'tcx> {
}; };
self.with(scope, |this| this.visit_ty(mt.ty)); self.with(scope, |this| this.visit_ty(mt.ty));
} }
hir::TyKind::OpaqueDef(opaque_ty, lifetimes) => { hir::TyKind::OpaqueDef(opaque_ty) => {
self.visit_opaque_ty(opaque_ty); self.visit_opaque_ty(opaque_ty);
// Resolve the lifetimes in the bounds to the lifetime defs in the generics.
// `fn foo<'a>() -> impl MyTrait<'a> { ... }` desugars to
// `type MyAnonTy<'b> = impl MyTrait<'b>;`
// ^ ^ this gets resolved in the scope of
// the opaque_ty generics
// Resolve the lifetimes that are applied to the opaque type.
// These are resolved in the current scope.
// `fn foo<'a>() -> impl MyTrait<'a> { ... }` desugars to
// `fn foo<'a>() -> MyAnonTy<'a> { ... }`
// ^ ^this gets resolved in the current scope
for lifetime in lifetimes {
let hir::GenericArg::Lifetime(lifetime) = lifetime else { continue };
self.visit_lifetime(lifetime);
// Check for predicates like `impl for<'a> Trait<impl OtherTrait<'a>>`
// and ban them. Type variables instantiated inside binders aren't
// well-supported at the moment, so this doesn't work.
// In the future, this should be fixed and this error should be removed.
let def = self.map.defs.get(&lifetime.hir_id.local_id).copied();
let Some(ResolvedArg::LateBound(_, _, lifetime_def_id)) = def else { continue };
let lifetime_hir_id = self.tcx.local_def_id_to_hir_id(lifetime_def_id);
let bad_place = match self.tcx.hir_node(self.tcx.parent_hir_id(lifetime_hir_id))
{
// Opaques do not declare their own lifetimes, so if a lifetime comes from an opaque
// it must be a reified late-bound lifetime from a trait goal.
hir::Node::OpaqueTy(_) => "higher-ranked lifetime from outer `impl Trait`",
// Other items are fine.
hir::Node::Item(_) | hir::Node::TraitItem(_) | hir::Node::ImplItem(_) => {
continue;
}
hir::Node::Ty(hir::Ty { kind: hir::TyKind::BareFn(_), .. }) => {
"higher-ranked lifetime from function pointer"
}
hir::Node::Ty(hir::Ty { kind: hir::TyKind::TraitObject(..), .. }) => {
"higher-ranked lifetime from `dyn` type"
}
_ => "higher-ranked lifetime",
};
let (span, label) = if lifetime.ident.span == self.tcx.def_span(lifetime_def_id)
{
(opaque_ty.span, Some(opaque_ty.span))
} else {
(lifetime.ident.span, None)
};
// Ensure that the parent of the def is an item, not HRTB
self.tcx.dcx().emit_err(errors::OpaqueCapturesHigherRankedLifetime {
span,
label,
decl_span: self.tcx.def_span(lifetime_def_id),
bad_place,
});
self.uninsert_lifetime_on_error(lifetime, def.unwrap());
}
} }
_ => intravisit::walk_ty(self, ty), _ => intravisit::walk_ty(self, ty),
} }
@ -1129,6 +1201,7 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
let mut scope = self.scope; let mut scope = self.scope;
let mut outermost_body = None; let mut outermost_body = None;
let mut crossed_late_boundary = None; let mut crossed_late_boundary = None;
let mut opaque_capture_scopes = vec![];
let result = loop { let result = loop {
match *scope { match *scope {
Scope::Body { id, s } => { Scope::Body { id, s } => {
@ -1204,6 +1277,12 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
scope = s; scope = s;
} }
Scope::Opaque { captures, def_id, s } => {
opaque_capture_scopes.push((def_id, captures));
late_depth = 0;
scope = s;
}
Scope::ObjectLifetimeDefault { s, .. } Scope::ObjectLifetimeDefault { s, .. }
| Scope::Supertrait { s, .. } | Scope::Supertrait { s, .. }
| Scope::TraitRefBoundary { s, .. } => { | Scope::TraitRefBoundary { s, .. } => {
@ -1218,6 +1297,8 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
}; };
if let Some(mut def) = result { if let Some(mut def) = result {
def = self.remap_opaque_captures(opaque_capture_scopes, def, lifetime_ref.ident);
if let ResolvedArg::EarlyBound(..) = def { if let ResolvedArg::EarlyBound(..) = def {
// Do not free early-bound regions, only late-bound ones. // Do not free early-bound regions, only late-bound ones.
} else if let ResolvedArg::LateBound(_, _, param_def_id) = def } else if let ResolvedArg::LateBound(_, _, param_def_id) = def
@ -1291,6 +1372,7 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
Scope::Root { .. } => break, Scope::Root { .. } => break,
Scope::Binder { s, .. } Scope::Binder { s, .. }
| Scope::Body { s, .. } | Scope::Body { s, .. }
| Scope::Opaque { s, .. }
| Scope::ObjectLifetimeDefault { s, .. } | Scope::ObjectLifetimeDefault { s, .. }
| Scope::Supertrait { s, .. } | Scope::Supertrait { s, .. }
| Scope::TraitRefBoundary { s, .. } | Scope::TraitRefBoundary { s, .. }
@ -1306,6 +1388,78 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
); );
} }
/// Check for predicates like `impl for<'a> Trait<impl OtherTrait<'a>>`
/// and ban them. Type variables instantiated inside binders aren't
/// well-supported at the moment, so this doesn't work.
/// In the future, this should be fixed and this error should be removed.
fn check_lifetime_is_capturable(
&self,
opaque_def_id: LocalDefId,
lifetime: ResolvedArg,
span: Option<Span>,
) -> Result<(), ErrorGuaranteed> {
let ResolvedArg::LateBound(_, _, lifetime_def_id) = lifetime else { return Ok(()) };
let lifetime_hir_id = self.tcx.local_def_id_to_hir_id(lifetime_def_id);
let bad_place = match self.tcx.hir_node(self.tcx.parent_hir_id(lifetime_hir_id)) {
// Opaques do not declare their own lifetimes, so if a lifetime comes from an opaque
// it must be a reified late-bound lifetime from a trait goal.
hir::Node::OpaqueTy(_) => "higher-ranked lifetime from outer `impl Trait`",
// Other items are fine.
hir::Node::Item(_) | hir::Node::TraitItem(_) | hir::Node::ImplItem(_) => return Ok(()),
hir::Node::Ty(hir::Ty { kind: hir::TyKind::BareFn(_), .. }) => {
"higher-ranked lifetime from function pointer"
}
hir::Node::Ty(hir::Ty { kind: hir::TyKind::TraitObject(..), .. }) => {
"higher-ranked lifetime from `dyn` type"
}
_ => "higher-ranked lifetime",
};
let decl_span = self.tcx.def_span(lifetime_def_id);
let (span, label) = if let Some(span) = span
&& span != decl_span
{
(span, None)
} else {
let opaque_span = self.tcx.def_span(opaque_def_id);
(opaque_span, Some(opaque_span))
};
// Ensure that the parent of the def is an item, not HRTB
let guar = self.tcx.dcx().emit_err(errors::OpaqueCapturesHigherRankedLifetime {
span,
label,
decl_span,
bad_place,
});
Err(guar)
}
fn remap_opaque_captures(
&self,
opaque_capture_scopes: Vec<(LocalDefId, &RefCell<FxIndexMap<ResolvedArg, LocalDefId>>)>,
mut lifetime: ResolvedArg,
ident: Ident,
) -> ResolvedArg {
for (opaque_def_id, captures) in opaque_capture_scopes.into_iter().rev() {
if let Err(guar) =
self.check_lifetime_is_capturable(opaque_def_id, lifetime, Some(ident.span))
{
return ResolvedArg::Error(guar);
}
let mut captures = captures.borrow_mut();
let remapped = *captures.entry(lifetime).or_insert_with(|| {
let feed = self.tcx.create_def(opaque_def_id, ident.name, DefKind::LifetimeParam);
feed.def_span(ident.span);
feed.def_ident_span(Some(ident.span));
feed.def_id()
});
lifetime = ResolvedArg::EarlyBound(remapped);
}
lifetime
}
fn resolve_type_ref(&mut self, param_def_id: LocalDefId, hir_id: HirId) { fn resolve_type_ref(&mut self, param_def_id: LocalDefId, hir_id: HirId) {
// Walk up the scope chain, tracking the number of fn scopes // Walk up the scope chain, tracking the number of fn scopes
// that we pass through, until we find a lifetime with the // that we pass through, until we find a lifetime with the
@ -1345,6 +1499,7 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
} }
Scope::ObjectLifetimeDefault { s, .. } Scope::ObjectLifetimeDefault { s, .. }
| Scope::Opaque { s, .. }
| Scope::Supertrait { s, .. } | Scope::Supertrait { s, .. }
| Scope::TraitRefBoundary { s, .. } => { | Scope::TraitRefBoundary { s, .. } => {
scope = s; scope = s;
@ -1425,6 +1580,7 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
Scope::Root { .. } => break, Scope::Root { .. } => break,
Scope::Binder { s, .. } Scope::Binder { s, .. }
| Scope::Body { s, .. } | Scope::Body { s, .. }
| Scope::Opaque { s, .. }
| Scope::ObjectLifetimeDefault { s, .. } | Scope::ObjectLifetimeDefault { s, .. }
| Scope::Supertrait { s, .. } | Scope::Supertrait { s, .. }
| Scope::TraitRefBoundary { s, .. } | Scope::TraitRefBoundary { s, .. }
@ -1501,6 +1657,7 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
Scope::Binder { s, .. } Scope::Binder { s, .. }
| Scope::ObjectLifetimeDefault { s, .. } | Scope::ObjectLifetimeDefault { s, .. }
| Scope::Opaque { s, .. }
| Scope::Supertrait { s, .. } | Scope::Supertrait { s, .. }
| Scope::TraitRefBoundary { s, .. } | Scope::TraitRefBoundary { s, .. }
| Scope::LateBoundary { s, .. } => { | Scope::LateBoundary { s, .. } => {
@ -1786,7 +1943,8 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
fn resolve_object_lifetime_default(&mut self, lifetime_ref: &'tcx hir::Lifetime) { fn resolve_object_lifetime_default(&mut self, lifetime_ref: &'tcx hir::Lifetime) {
let mut late_depth = 0; let mut late_depth = 0;
let mut scope = self.scope; let mut scope = self.scope;
let lifetime = loop { let mut opaque_capture_scopes = vec![];
let mut lifetime = loop {
match *scope { match *scope {
Scope::Binder { s, scope_type, .. } => { Scope::Binder { s, scope_type, .. } => {
match scope_type { match scope_type {
@ -1800,7 +1958,15 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
Scope::Body { .. } | Scope::ObjectLifetimeDefault { lifetime: None, .. } => return, Scope::Body { .. } | Scope::ObjectLifetimeDefault { lifetime: None, .. } => return,
Scope::ObjectLifetimeDefault { lifetime: Some(l), .. } => break l, Scope::ObjectLifetimeDefault { lifetime: Some(l), .. } => {
break l.shifted(late_depth);
}
Scope::Opaque { captures, def_id, s } => {
opaque_capture_scopes.push((def_id, captures));
late_depth = 0;
scope = s;
}
Scope::Supertrait { s, .. } Scope::Supertrait { s, .. }
| Scope::TraitRefBoundary { s, .. } | Scope::TraitRefBoundary { s, .. }
@ -1809,7 +1975,10 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
} }
} }
}; };
self.insert_lifetime(lifetime_ref, lifetime.shifted(late_depth));
lifetime = self.remap_opaque_captures(opaque_capture_scopes, lifetime, lifetime_ref.ident);
self.insert_lifetime(lifetime_ref, lifetime);
} }
#[instrument(level = "debug", skip(self))] #[instrument(level = "debug", skip(self))]
@ -1818,18 +1987,6 @@ impl<'a, 'tcx> BoundVarContext<'a, 'tcx> {
self.map.defs.insert(lifetime_ref.hir_id.local_id, def); self.map.defs.insert(lifetime_ref.hir_id.local_id, def);
} }
/// Sometimes we resolve a lifetime, but later find that it is an
/// error (esp. around impl trait). In that case, we remove the
/// entry into `map.defs` so as not to confuse later code.
fn uninsert_lifetime_on_error(
&mut self,
lifetime_ref: &'tcx hir::Lifetime,
bad_def: ResolvedArg,
) {
let old_value = self.map.defs.remove(&lifetime_ref.hir_id.local_id);
assert_eq!(old_value, Some(bad_def));
}
// When we have a return type notation type in a where clause, like // When we have a return type notation type in a where clause, like
// `where <T as Trait>::method(..): Send`, we need to introduce new bound // `where <T as Trait>::method(..): Send`, we need to introduce new bound
// vars to the existing where clause's binder, to represent the lifetimes // vars to the existing where clause's binder, to represent the lifetimes
@ -2013,18 +2170,22 @@ fn is_late_bound_map(
tcx: TyCtxt<'_>, tcx: TyCtxt<'_>,
owner_id: hir::OwnerId, owner_id: hir::OwnerId,
) -> Option<&FxIndexSet<hir::ItemLocalId>> { ) -> Option<&FxIndexSet<hir::ItemLocalId>> {
let decl = tcx.hir().fn_decl_by_hir_id(owner_id.into())?; let sig = tcx.hir().fn_sig_by_hir_id(owner_id.into())?;
let generics = tcx.hir().get_generics(owner_id.def_id)?; let generics = tcx.hir().get_generics(owner_id.def_id)?;
let mut late_bound = FxIndexSet::default(); let mut late_bound = FxIndexSet::default();
let mut constrained_by_input = ConstrainedCollector { regions: Default::default(), tcx }; let mut constrained_by_input = ConstrainedCollector { regions: Default::default(), tcx };
for arg_ty in decl.inputs { for arg_ty in sig.decl.inputs {
constrained_by_input.visit_ty(arg_ty); constrained_by_input.visit_ty(arg_ty);
} }
let mut appears_in_output = AllCollector::default(); let mut appears_in_output =
intravisit::walk_fn_ret_ty(&mut appears_in_output, &decl.output); AllCollector { tcx, has_fully_capturing_opaque: false, regions: Default::default() };
intravisit::walk_fn_ret_ty(&mut appears_in_output, &sig.decl.output);
if appears_in_output.has_fully_capturing_opaque {
appears_in_output.regions.extend(generics.params.iter().map(|param| param.def_id));
}
debug!(?constrained_by_input.regions); debug!(?constrained_by_input.regions);
@ -2032,7 +2193,8 @@ fn is_late_bound_map(
// //
// Subtle point: because we disallow nested bindings, we can just // Subtle point: because we disallow nested bindings, we can just
// ignore binders here and scrape up all names we see. // ignore binders here and scrape up all names we see.
let mut appears_in_where_clause = AllCollector::default(); let mut appears_in_where_clause =
AllCollector { tcx, has_fully_capturing_opaque: true, regions: Default::default() };
appears_in_where_clause.visit_generics(generics); appears_in_where_clause.visit_generics(generics);
debug!(?appears_in_where_clause.regions); debug!(?appears_in_where_clause.regions);
@ -2198,17 +2360,26 @@ fn is_late_bound_map(
} }
} }
#[derive(Default)] struct AllCollector<'tcx> {
struct AllCollector { tcx: TyCtxt<'tcx>,
has_fully_capturing_opaque: bool,
regions: FxHashSet<LocalDefId>, regions: FxHashSet<LocalDefId>,
} }
impl<'v> Visitor<'v> for AllCollector { impl<'v> Visitor<'v> for AllCollector<'v> {
fn visit_lifetime(&mut self, lifetime_ref: &'v hir::Lifetime) { fn visit_lifetime(&mut self, lifetime_ref: &'v hir::Lifetime) {
if let hir::LifetimeName::Param(def_id) = lifetime_ref.res { if let hir::LifetimeName::Param(def_id) = lifetime_ref.res {
self.regions.insert(def_id); self.regions.insert(def_id);
} }
} }
fn visit_opaque_ty(&mut self, opaque: &'v hir::OpaqueTy<'v>) {
if !self.has_fully_capturing_opaque {
self.has_fully_capturing_opaque =
opaque_captures_all_in_scope_lifetimes(self.tcx, opaque);
}
intravisit::walk_opaque_ty(self, opaque);
}
} }
} }

90
compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs
View file

@ -294,13 +294,23 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
lifetime: &hir::Lifetime, lifetime: &hir::Lifetime,
reason: RegionInferReason<'_>, reason: RegionInferReason<'_>,
) -> ty::Region<'tcx> { ) -> ty::Region<'tcx> {
if let Some(resolved) = self.tcx().named_bound_var(lifetime.hir_id) {
self.lower_resolved_lifetime(resolved)
} else {
self.re_infer(lifetime.ident.span, reason)
}
}
/// Lower a lifetime from the HIR to our internal notion of a lifetime called a *region*.
#[instrument(level = "debug", skip(self), ret)]
pub fn lower_resolved_lifetime(&self, resolved: rbv::ResolvedArg) -> ty::Region<'tcx> {
let tcx = self.tcx(); let tcx = self.tcx();
let lifetime_name = |def_id| tcx.hir().name(tcx.local_def_id_to_hir_id(def_id)); let lifetime_name = |def_id| tcx.hir().name(tcx.local_def_id_to_hir_id(def_id));
match tcx.named_bound_var(lifetime.hir_id) { match resolved {
Some(rbv::ResolvedArg::StaticLifetime) => tcx.lifetimes.re_static, rbv::ResolvedArg::StaticLifetime => tcx.lifetimes.re_static,
Some(rbv::ResolvedArg::LateBound(debruijn, index, def_id)) => { rbv::ResolvedArg::LateBound(debruijn, index, def_id) => {
let name = lifetime_name(def_id); let name = lifetime_name(def_id);
let br = ty::BoundRegion { let br = ty::BoundRegion {
var: ty::BoundVar::from_u32(index), var: ty::BoundVar::from_u32(index),
@ -309,7 +319,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
ty::Region::new_bound(tcx, debruijn, br) ty::Region::new_bound(tcx, debruijn, br)
} }
Some(rbv::ResolvedArg::EarlyBound(def_id)) => { rbv::ResolvedArg::EarlyBound(def_id) => {
let name = tcx.hir().ty_param_name(def_id); let name = tcx.hir().ty_param_name(def_id);
let item_def_id = tcx.hir().ty_param_owner(def_id); let item_def_id = tcx.hir().ty_param_owner(def_id);
let generics = tcx.generics_of(item_def_id); let generics = tcx.generics_of(item_def_id);
@ -317,7 +327,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
ty::Region::new_early_param(tcx, ty::EarlyParamRegion { index, name }) ty::Region::new_early_param(tcx, ty::EarlyParamRegion { index, name })
} }
Some(rbv::ResolvedArg::Free(scope, id)) => { rbv::ResolvedArg::Free(scope, id) => {
let name = lifetime_name(id); let name = lifetime_name(id);
ty::Region::new_late_param( ty::Region::new_late_param(
tcx, tcx,
@ -328,9 +338,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
// (*) -- not late-bound, won't change // (*) -- not late-bound, won't change
} }
Some(rbv::ResolvedArg::Error(guar)) => ty::Region::new_error(tcx, guar), rbv::ResolvedArg::Error(guar) => ty::Region::new_error(tcx, guar),
None => self.re_infer(lifetime.ident.span, reason),
} }
} }
@ -2094,13 +2102,11 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
let opt_self_ty = maybe_qself.as_ref().map(|qself| self.lower_ty(qself)); let opt_self_ty = maybe_qself.as_ref().map(|qself| self.lower_ty(qself));
self.lower_path(opt_self_ty, path, hir_ty.hir_id, false) self.lower_path(opt_self_ty, path, hir_ty.hir_id, false)
} }
&hir::TyKind::OpaqueDef(opaque_ty, lifetimes) => { &hir::TyKind::OpaqueDef(opaque_ty) => {
let local_def_id = opaque_ty.def_id;
// If this is an RPITIT and we are using the new RPITIT lowering scheme, we // If this is an RPITIT and we are using the new RPITIT lowering scheme, we
// generate the def_id of an associated type for the trait and return as // generate the def_id of an associated type for the trait and return as
// type a projection. // type a projection.
match opaque_ty.origin { let in_trait = match opaque_ty.origin {
hir::OpaqueTyOrigin::FnReturn { hir::OpaqueTyOrigin::FnReturn {
in_trait_or_impl: Some(hir::RpitContext::Trait), in_trait_or_impl: Some(hir::RpitContext::Trait),
.. ..
@ -2108,11 +2114,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
| hir::OpaqueTyOrigin::AsyncFn { | hir::OpaqueTyOrigin::AsyncFn {
in_trait_or_impl: Some(hir::RpitContext::Trait), in_trait_or_impl: Some(hir::RpitContext::Trait),
.. ..
} => self.lower_opaque_ty( } => true,
tcx.associated_type_for_impl_trait_in_trait(local_def_id).to_def_id(),
lifetimes,
true,
),
hir::OpaqueTyOrigin::FnReturn { hir::OpaqueTyOrigin::FnReturn {
in_trait_or_impl: None | Some(hir::RpitContext::TraitImpl), in_trait_or_impl: None | Some(hir::RpitContext::TraitImpl),
.. ..
@ -2121,10 +2123,10 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
in_trait_or_impl: None | Some(hir::RpitContext::TraitImpl), in_trait_or_impl: None | Some(hir::RpitContext::TraitImpl),
.. ..
} }
| hir::OpaqueTyOrigin::TyAlias { .. } => { | hir::OpaqueTyOrigin::TyAlias { .. } => false,
self.lower_opaque_ty(local_def_id.to_def_id(), lifetimes, false) };
}
} self.lower_opaque_ty(opaque_ty.def_id, in_trait)
} }
// If we encounter a type relative path with RTN generics, then it must have // If we encounter a type relative path with RTN generics, then it must have
// *not* gone through `lower_ty_maybe_return_type_notation`, and therefore // *not* gone through `lower_ty_maybe_return_type_notation`, and therefore
@ -2264,40 +2266,34 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
} }
/// Lower an opaque type (i.e., an existential impl-Trait type) from the HIR. /// Lower an opaque type (i.e., an existential impl-Trait type) from the HIR.
#[instrument(level = "debug", skip_all, ret)] #[instrument(level = "debug", skip(self), ret)]
fn lower_opaque_ty( fn lower_opaque_ty(&self, def_id: LocalDefId, in_trait: bool) -> Ty<'tcx> {
&self,
def_id: DefId,
lifetimes: &[hir::GenericArg<'_>],
in_trait: bool,
) -> Ty<'tcx> {
debug!(?def_id, ?lifetimes);
let tcx = self.tcx(); let tcx = self.tcx();
let lifetimes = tcx.opaque_captured_lifetimes(def_id);
debug!(?lifetimes);
// If this is an RPITIT and we are using the new RPITIT lowering scheme, we
// generate the def_id of an associated type for the trait and return as
// type a projection.
let def_id = if in_trait {
tcx.associated_type_for_impl_trait_in_trait(def_id).to_def_id()
} else {
def_id.to_def_id()
};
let generics = tcx.generics_of(def_id); let generics = tcx.generics_of(def_id);
debug!(?generics); debug!(?generics);
let args = ty::GenericArgs::for_item(tcx, def_id, |param, _| {
// We use `generics.count() - lifetimes.len()` here instead of `generics.parent_count` // We use `generics.count() - lifetimes.len()` here instead of `generics.parent_count`
// since return-position impl trait in trait squashes all of the generics from its source fn // since return-position impl trait in trait squashes all of the generics from its source fn
// into its own generics, so the opaque's "own" params isn't always just lifetimes. // into its own generics, so the opaque's "own" params isn't always just lifetimes.
if let Some(i) = (param.index as usize).checked_sub(generics.count() - lifetimes.len()) let offset = generics.count() - lifetimes.len();
{
// Resolve our own lifetime parameters. let args = ty::GenericArgs::for_item(tcx, def_id, |param, _| {
let GenericParamDefKind::Lifetime { .. } = param.kind else { if let Some(i) = (param.index as usize).checked_sub(offset) {
span_bug!( let (lifetime, _) = lifetimes[i];
tcx.def_span(param.def_id), self.lower_resolved_lifetime(lifetime).into()
"only expected lifetime for opaque's own generics, got {:?}",
param
);
};
let hir::GenericArg::Lifetime(lifetime) = &lifetimes[i] else {
bug!(
"expected lifetime argument for param {param:?}, found {:?}",
&lifetimes[i]
)
};
self.lower_lifetime(lifetime, RegionInferReason::Param(&param)).into()
} else { } else {
tcx.mk_param_from_def(param) tcx.mk_param_from_def(param)
} }

2
compiler/rustc_hir_pretty/src/lib.rs
View file

@ -659,8 +659,6 @@ impl<'a> State<'a> {
fn print_opaque_ty(&mut self, o: &hir::OpaqueTy<'_>) { fn print_opaque_ty(&mut self, o: &hir::OpaqueTy<'_>) {
self.head("opaque"); self.head("opaque");
self.print_generic_params(o.generics.params);
self.print_where_clause(o.generics);
self.word("{"); self.word("{");
self.print_bounds("impl", o.bounds); self.print_bounds("impl", o.bounds);
self.word("}"); self.word("}");

2
compiler/rustc_lint/src/opaque_hidden_inferred_bound.rs
View file

@ -69,7 +69,7 @@ declare_lint_pass!(OpaqueHiddenInferredBound => [OPAQUE_HIDDEN_INFERRED_BOUND]);
impl<'tcx> LateLintPass<'tcx> for OpaqueHiddenInferredBound { impl<'tcx> LateLintPass<'tcx> for OpaqueHiddenInferredBound {
fn check_ty(&mut self, cx: &LateContext<'tcx>, ty: &'tcx hir::Ty<'tcx>) { fn check_ty(&mut self, cx: &LateContext<'tcx>, ty: &'tcx hir::Ty<'tcx>) {
let hir::TyKind::OpaqueDef(opaque, _) = &ty.kind else { let hir::TyKind::OpaqueDef(opaque) = &ty.kind else {
return; return;
}; };

4
compiler/rustc_middle/src/middle/resolve_bound_vars.rs
View file

@ -3,7 +3,7 @@
use rustc_data_structures::sorted_map::SortedMap; use rustc_data_structures::sorted_map::SortedMap;
use rustc_errors::ErrorGuaranteed; use rustc_errors::ErrorGuaranteed;
use rustc_hir::ItemLocalId; use rustc_hir::ItemLocalId;
use rustc_hir::def_id::{DefId, LocalDefId}; use rustc_hir::def_id::{DefId, LocalDefId, LocalDefIdMap};
use rustc_macros::{Decodable, Encodable, HashStable, TyDecodable, TyEncodable}; use rustc_macros::{Decodable, Encodable, HashStable, TyDecodable, TyEncodable};
use crate::ty; use crate::ty;
@ -54,4 +54,6 @@ pub struct ResolveBoundVars {
pub defs: SortedMap<ItemLocalId, ResolvedArg>, pub defs: SortedMap<ItemLocalId, ResolvedArg>,
pub late_bound_vars: SortedMap<ItemLocalId, Vec<ty::BoundVariableKind>>, pub late_bound_vars: SortedMap<ItemLocalId, Vec<ty::BoundVariableKind>>,
pub opaque_captured_lifetimes: LocalDefIdMap<Vec<(ResolvedArg, LocalDefId)>>,
} }

17
compiler/rustc_middle/src/query/mod.rs
View file

@ -1781,6 +1781,23 @@ rustc_queries! {
-> &'tcx SortedMap<ItemLocalId, Vec<ty::BoundVariableKind>> { -> &'tcx SortedMap<ItemLocalId, Vec<ty::BoundVariableKind>> {
desc { |tcx| "looking up late bound vars inside `{}`", tcx.def_path_str(owner_id) } desc { |tcx| "looking up late bound vars inside `{}`", tcx.def_path_str(owner_id) }
} }
/// For an opaque type, return the list of (captured lifetime, inner generic param).
/// ```ignore (illustrative)
/// fn foo<'a: 'a, 'b, T>(&'b u8) -> impl Into<Self> + 'b { ... }
/// ```
///
/// We would return `[('a, '_a), ('b, '_b)]`, with `'a` early-bound and `'b` late-bound.
///
/// After hir_ty_lowering, we get:
/// ```ignore (pseudo-code)
/// opaque foo::<'a>::opaque<'_a, '_b>: Into<Foo<'_a>> + '_b;
/// ^^^^^^^^ inner generic params
/// fn foo<'a>: for<'b> fn(&'b u8) -> foo::<'a>::opaque::<'a, 'b>
/// ^^^^^^ captured lifetimes
/// ```
query opaque_captured_lifetimes(def_id: LocalDefId) -> &'tcx [(ResolvedArg, LocalDefId)] {
desc { |tcx| "listing captured lifetimes for opaque `{}`", tcx.def_path_str(def_id) }
}
/// Computes the visibility of the provided `def_id`. /// Computes the visibility of the provided `def_id`.
/// ///

12
compiler/rustc_middle/src/ty/context.rs
View file

@ -3060,7 +3060,7 @@ impl<'tcx> TyCtxt<'tcx> {
loop { loop {
let parent = self.local_parent(opaque_lifetime_param_def_id); let parent = self.local_parent(opaque_lifetime_param_def_id);
let hir::OpaqueTy { lifetime_mapping, .. } = self.hir().expect_opaque_ty(parent); let lifetime_mapping = self.opaque_captured_lifetimes(parent);
let Some((lifetime, _)) = lifetime_mapping let Some((lifetime, _)) = lifetime_mapping
.iter() .iter()
@ -3069,8 +3069,8 @@ impl<'tcx> TyCtxt<'tcx> {
bug!("duplicated lifetime param should be present"); bug!("duplicated lifetime param should be present");
}; };
match self.named_bound_var(lifetime.hir_id) { match *lifetime {
Some(resolve_bound_vars::ResolvedArg::EarlyBound(ebv)) => { resolve_bound_vars::ResolvedArg::EarlyBound(ebv) => {
let new_parent = self.local_parent(ebv); let new_parent = self.local_parent(ebv);
// If we map to another opaque, then it should be a parent // If we map to another opaque, then it should be a parent
@ -3089,7 +3089,7 @@ impl<'tcx> TyCtxt<'tcx> {
name: self.item_name(ebv.to_def_id()), name: self.item_name(ebv.to_def_id()),
}); });
} }
Some(resolve_bound_vars::ResolvedArg::LateBound(_, _, lbv)) => { resolve_bound_vars::ResolvedArg::LateBound(_, _, lbv) => {
let new_parent = self.local_parent(lbv); let new_parent = self.local_parent(lbv);
return ty::Region::new_late_param( return ty::Region::new_late_param(
self, self,
@ -3100,13 +3100,13 @@ impl<'tcx> TyCtxt<'tcx> {
), ),
); );
} }
Some(resolve_bound_vars::ResolvedArg::Error(guar)) => { resolve_bound_vars::ResolvedArg::Error(guar) => {
return ty::Region::new_error(self, guar); return ty::Region::new_error(self, guar);
} }
_ => { _ => {
return ty::Region::new_error_with_message( return ty::Region::new_error_with_message(
self, self,
lifetime.ident.span, self.def_span(opaque_lifetime_param_def_id),
"cannot resolve lifetime", "cannot resolve lifetime",
); );
} }

1
compiler/rustc_middle/src/ty/sty.rs
View file

@ -1354,6 +1354,7 @@ impl<'tcx> Ty<'tcx> {
} }
} }
#[tracing::instrument(level = "trace", skip(tcx))]
pub fn fn_sig(self, tcx: TyCtxt<'tcx>) -> PolyFnSig<'tcx> { pub fn fn_sig(self, tcx: TyCtxt<'tcx>) -> PolyFnSig<'tcx> {
match self.kind() { match self.kind() {
FnDef(def_id, args) => tcx.fn_sig(*def_id).instantiate(tcx, args), FnDef(def_id, args) => tcx.fn_sig(*def_id).instantiate(tcx, args),

40
compiler/rustc_resolve/src/late.rs
View file

@ -841,10 +841,9 @@ impl<'ra: 'ast, 'ast, 'tcx> Visitor<'ast> for LateResolutionVisitor<'_, 'ast, 'r
self.r.record_partial_res(ty.id, PartialRes::new(res)); self.r.record_partial_res(ty.id, PartialRes::new(res));
visit::walk_ty(self, ty) visit::walk_ty(self, ty)
} }
TyKind::ImplTrait(node_id, _) => { TyKind::ImplTrait(_, _) => {
let candidates = self.lifetime_elision_candidates.take(); let candidates = self.lifetime_elision_candidates.take();
visit::walk_ty(self, ty); visit::walk_ty(self, ty);
self.record_lifetime_params_for_impl_trait(*node_id);
self.lifetime_elision_candidates = candidates; self.lifetime_elision_candidates = candidates;
} }
TyKind::TraitObject(bounds, ..) => { TyKind::TraitObject(bounds, ..) => {
@ -977,14 +976,6 @@ impl<'ra: 'ast, 'ast, 'tcx> Visitor<'ast> for LateResolutionVisitor<'_, 'ast, 'r
sig.decl.inputs.iter().map(|Param { ty, .. }| (None, &**ty)), sig.decl.inputs.iter().map(|Param { ty, .. }| (None, &**ty)),
&sig.decl.output, &sig.decl.output,
); );
if let Some((coro_node_id, _)) = sig
.header
.coroutine_kind
.map(|coroutine_kind| coroutine_kind.return_id())
{
this.record_lifetime_params_for_impl_trait(coro_node_id);
}
}, },
); );
return; return;
@ -1026,10 +1017,6 @@ impl<'ra: 'ast, 'ast, 'tcx> Visitor<'ast> for LateResolutionVisitor<'_, 'ast, 'r
.map(|Param { pat, ty, .. }| (Some(&**pat), &**ty)), .map(|Param { pat, ty, .. }| (Some(&**pat), &**ty)),
&declaration.output, &declaration.output,
); );
if let Some((async_node_id, _)) = coro_node_id {
this.record_lifetime_params_for_impl_trait(async_node_id);
}
}, },
); );
@ -1220,7 +1207,6 @@ impl<'ra: 'ast, 'ast, 'tcx> Visitor<'ast> for LateResolutionVisitor<'_, 'ast, 'r
} }
}, },
AssocItemConstraintKind::Bound { ref bounds } => { AssocItemConstraintKind::Bound { ref bounds } => {
self.record_lifetime_params_for_impl_trait(constraint.id);
walk_list!(self, visit_param_bound, bounds, BoundKind::Bound); walk_list!(self, visit_param_bound, bounds, BoundKind::Bound);
} }
} }
@ -4795,30 +4781,6 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
) )
} }
/// Construct the list of in-scope lifetime parameters for impl trait lowering.
/// We include all lifetime parameters, either named or "Fresh".
/// The order of those parameters does not matter, as long as it is
/// deterministic.
fn record_lifetime_params_for_impl_trait(&mut self, impl_trait_node_id: NodeId) {
let mut extra_lifetime_params = vec![];
for rib in self.lifetime_ribs.iter().rev() {
extra_lifetime_params
.extend(rib.bindings.iter().map(|(&ident, &(node_id, res))| (ident, node_id, res)));
match rib.kind {
LifetimeRibKind::Item => break,
LifetimeRibKind::AnonymousCreateParameter { binder, .. } => {
if let Some(earlier_fresh) = self.r.extra_lifetime_params_map.get(&binder) {
extra_lifetime_params.extend(earlier_fresh);
}
}
_ => {}
}
}
self.r.extra_lifetime_params_map.insert(impl_trait_node_id, extra_lifetime_params);
}
fn resolve_and_cache_rustdoc_path(&mut self, path_str: &str, ns: Namespace) -> Option<Res> { fn resolve_and_cache_rustdoc_path(&mut self, path_str: &str, ns: Namespace) -> Option<Res> {
// FIXME: This caching may be incorrect in case of multiple `macro_rules` // FIXME: This caching may be incorrect in case of multiple `macro_rules`
// items with the same name in the same module. // items with the same name in the same module.

2
compiler/rustc_trait_selection/src/error_reporting/infer/nice_region_error/static_impl_trait.rs
View file

@ -284,7 +284,7 @@ pub fn suggest_new_region_bound(
} }
match fn_return.kind { match fn_return.kind {
// FIXME(precise_captures): Suggest adding to `use<...>` list instead. // FIXME(precise_captures): Suggest adding to `use<...>` list instead.
TyKind::OpaqueDef(opaque, _) => { TyKind::OpaqueDef(opaque) => {
// Get the identity type for this RPIT // Get the identity type for this RPIT
let did = opaque.def_id.to_def_id(); let did = opaque.def_id.to_def_id();
let ty = Ty::new_opaque(tcx, did, ty::GenericArgs::identity_for_item(tcx, did)); let ty = Ty::new_opaque(tcx, did, ty::GenericArgs::identity_for_item(tcx, did));

16
compiler/rustc_trait_selection/src/error_reporting/infer/region.rs
View file

@ -862,22 +862,6 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
self.add_lt_suggs.push(lt.suggestion(self.new_lt)); self.add_lt_suggs.push(lt.suggestion(self.new_lt));
} }
} }
fn visit_ty(&mut self, ty: &'hir hir::Ty<'hir>) {
let hir::TyKind::OpaqueDef(opaque_ty, _) = ty.kind else {
return hir::intravisit::walk_ty(self, ty);
};
if let Some(&(_, b)) =
opaque_ty.lifetime_mapping.iter().find(|&(a, _)| a.res == self.needle)
{
let prev_needle =
std::mem::replace(&mut self.needle, hir::LifetimeName::Param(b));
for bound in opaque_ty.bounds {
self.visit_param_bound(bound);
}
self.needle = prev_needle;
}
}
} }
let (lifetime_def_id, lifetime_scope) = let (lifetime_def_id, lifetime_scope) =

6
compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs
View file

@ -361,7 +361,6 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
}) })
| hir::Node::TraitItem(hir::TraitItem { generics, .. }) | hir::Node::TraitItem(hir::TraitItem { generics, .. })
| hir::Node::ImplItem(hir::ImplItem { generics, .. }) | hir::Node::ImplItem(hir::ImplItem { generics, .. })
| hir::Node::OpaqueTy(hir::OpaqueTy { generics, .. })
if param_ty => if param_ty =>
{ {
// We skip the 0'th arg (self) because we do not want // We skip the 0'th arg (self) because we do not want
@ -424,10 +423,7 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
| hir::ItemKind::Const(_, generics, _) | hir::ItemKind::Const(_, generics, _)
| hir::ItemKind::TraitAlias(generics, _), | hir::ItemKind::TraitAlias(generics, _),
.. ..
}) }) if !param_ty => {
| hir::Node::OpaqueTy(hir::OpaqueTy { generics, .. })
if !param_ty =>
{
// Missing generic type parameter bound. // Missing generic type parameter bound.
if suggest_arbitrary_trait_bound( if suggest_arbitrary_trait_bound(
self.tcx, self.tcx,

2
compiler/rustc_ty_utils/src/assoc.rs
View file

@ -190,7 +190,7 @@ fn associated_types_for_impl_traits_in_associated_fn(
impl<'tcx> Visitor<'tcx> for RPITVisitor { impl<'tcx> Visitor<'tcx> for RPITVisitor {
fn visit_ty(&mut self, ty: &'tcx hir::Ty<'tcx>) { fn visit_ty(&mut self, ty: &'tcx hir::Ty<'tcx>) {
if let hir::TyKind::OpaqueDef(opaq, _) = ty.kind if let hir::TyKind::OpaqueDef(opaq) = ty.kind
&& self.rpits.insert(opaq.def_id) && self.rpits.insert(opaq.def_id)
{ {
for bound in opaq.bounds { for bound in opaq.bounds {

2
src/librustdoc/clean/mod.rs
View file

@ -1829,7 +1829,7 @@ pub(crate) fn clean_ty<'tcx>(ty: &hir::Ty<'tcx>, cx: &mut DocContext<'tcx>) -> T
Array(Box::new(clean_ty(ty, cx)), length.into()) Array(Box::new(clean_ty(ty, cx)), length.into())
} }
TyKind::Tup(tys) => Tuple(tys.iter().map(|ty| clean_ty(ty, cx)).collect()), TyKind::Tup(tys) => Tuple(tys.iter().map(|ty| clean_ty(ty, cx)).collect()),
TyKind::OpaqueDef(ty, _) => { TyKind::OpaqueDef(ty) => {
ImplTrait(ty.bounds.iter().filter_map(|x| clean_generic_bound(x, cx)).collect()) ImplTrait(ty.bounds.iter().filter_map(|x| clean_generic_bound(x, cx)).collect())
} }
TyKind::Path(_) => clean_qpath(ty, cx), TyKind::Path(_) => clean_qpath(ty, cx),

9
src/tools/clippy/clippy_lints/src/lifetimes.rs
View file

@ -420,15 +420,6 @@ impl<'tcx> Visitor<'tcx> for RefVisitor<'_, 'tcx> {
fn visit_ty(&mut self, ty: &'tcx Ty<'_>) { fn visit_ty(&mut self, ty: &'tcx Ty<'_>) {
match ty.kind { match ty.kind {
TyKind::OpaqueDef(opaque, bounds) => {
let len = self.lts.len();
self.visit_opaque_ty(opaque);
self.lts.truncate(len);
self.lts.extend(bounds.iter().filter_map(|bound| match bound {
GenericArg::Lifetime(&l) => Some(l),
_ => None,
}));
},
TyKind::BareFn(&BareFnTy { decl, .. }) => { TyKind::BareFn(&BareFnTy { decl, .. }) => {
let mut sub_visitor = RefVisitor::new(self.cx); let mut sub_visitor = RefVisitor::new(self.cx);
sub_visitor.visit_fn_decl(decl); sub_visitor.visit_fn_decl(decl);

80
src/tools/clippy/clippy_lints/src/manual_async_fn.rs
View file

@ -4,9 +4,11 @@ use rustc_errors::Applicability;
use rustc_hir::intravisit::FnKind; use rustc_hir::intravisit::FnKind;
use rustc_hir::{ use rustc_hir::{
Block, Body, Closure, ClosureKind, CoroutineDesugaring, CoroutineKind, CoroutineSource, Expr, ExprKind, FnDecl, Block, Body, Closure, ClosureKind, CoroutineDesugaring, CoroutineKind, CoroutineSource, Expr, ExprKind, FnDecl,
FnRetTy, GenericArg, GenericBound, ImplItem, Item, LifetimeName, Node, TraitRef, Ty, TyKind, FnRetTy, GenericBound, ImplItem, Item, Node, OpaqueTy, TraitRef, Ty, TyKind,
}; };
use rustc_lint::{LateContext, LateLintPass}; use rustc_lint::{LateContext, LateLintPass};
use rustc_middle::middle::resolve_bound_vars::ResolvedArg;
use rustc_middle::ty;
use rustc_session::declare_lint_pass; use rustc_session::declare_lint_pass;
use rustc_span::def_id::LocalDefId; use rustc_span::def_id::LocalDefId;
use rustc_span::{Span, sym}; use rustc_span::{Span, sym};
@ -44,21 +46,22 @@ impl<'tcx> LateLintPass<'tcx> for ManualAsyncFn {
decl: &'tcx FnDecl<'_>, decl: &'tcx FnDecl<'_>,
body: &'tcx Body<'_>, body: &'tcx Body<'_>,
span: Span, span: Span,
def_id: LocalDefId, fn_def_id: LocalDefId,
) { ) {
if let Some(header) = kind.header() if let Some(header) = kind.header()
&& !header.asyncness.is_async() && !header.asyncness.is_async()
// Check that this function returns `impl Future` // Check that this function returns `impl Future`
&& let FnRetTy::Return(ret_ty) = decl.output && let FnRetTy::Return(ret_ty) = decl.output
&& let Some((trait_ref, output_lifetimes)) = future_trait_ref(cx, ret_ty) && let TyKind::OpaqueDef(opaque) = ret_ty.kind
&& let Some(trait_ref) = future_trait_ref(cx, opaque)
&& let Some(output) = future_output_ty(trait_ref) && let Some(output) = future_output_ty(trait_ref)
&& captures_all_lifetimes(decl.inputs, &output_lifetimes) && captures_all_lifetimes(cx, fn_def_id, opaque.def_id)
// Check that the body of the function consists of one async block // Check that the body of the function consists of one async block
&& let ExprKind::Block(block, _) = body.value.kind && let ExprKind::Block(block, _) = body.value.kind
&& block.stmts.is_empty() && block.stmts.is_empty()
&& let Some(closure_body) = desugared_async_block(cx, block) && let Some(closure_body) = desugared_async_block(cx, block)
&& let Node::Item(Item {vis_span, ..}) | Node::ImplItem(ImplItem {vis_span, ..}) = && let Node::Item(Item {vis_span, ..}) | Node::ImplItem(ImplItem {vis_span, ..}) =
cx.tcx.hir_node_by_def_id(def_id) cx.tcx.hir_node_by_def_id(fn_def_id)
{ {
let header_span = span.with_hi(ret_ty.span.hi()); let header_span = span.with_hi(ret_ty.span.hi());
@ -101,12 +104,8 @@ impl<'tcx> LateLintPass<'tcx> for ManualAsyncFn {
} }
} }
fn future_trait_ref<'tcx>( fn future_trait_ref<'tcx>(cx: &LateContext<'tcx>, opaque: &'tcx OpaqueTy<'tcx>) -> Option<&'tcx TraitRef<'tcx>> {
cx: &LateContext<'tcx>, if let Some(trait_ref) = opaque.bounds.iter().find_map(|bound| {
ty: &'tcx Ty<'tcx>,
) -> Option<(&'tcx TraitRef<'tcx>, Vec<LifetimeName>)> {
if let TyKind::OpaqueDef(opaque, bounds) = ty.kind
&& let Some(trait_ref) = opaque.bounds.iter().find_map(|bound| {
if let GenericBound::Trait(poly) = bound { if let GenericBound::Trait(poly) = bound {
Some(&poly.trait_ref) Some(&poly.trait_ref)
} else { } else {
@ -115,18 +114,7 @@ fn future_trait_ref<'tcx>(
}) })
&& trait_ref.trait_def_id() == cx.tcx.lang_items().future_trait() && trait_ref.trait_def_id() == cx.tcx.lang_items().future_trait()
{ {
let output_lifetimes = bounds return Some(trait_ref);
.iter()
.filter_map(|bound| {
if let GenericArg::Lifetime(lt) = bound {
Some(lt.res)
} else {
None
}
})
.collect();
return Some((trait_ref, output_lifetimes));
} }
None None
@ -145,27 +133,35 @@ fn future_output_ty<'tcx>(trait_ref: &'tcx TraitRef<'tcx>) -> Option<&'tcx Ty<'t
None None
} }
fn captures_all_lifetimes(inputs: &[Ty<'_>], output_lifetimes: &[LifetimeName]) -> bool { fn captures_all_lifetimes(cx: &LateContext<'_>, fn_def_id: LocalDefId, opaque_def_id: LocalDefId) -> bool {
let input_lifetimes: Vec<LifetimeName> = inputs let early_input_params = ty::GenericArgs::identity_for_item(cx.tcx, fn_def_id);
.iter() let late_input_params = cx.tcx.late_bound_vars(cx.tcx.local_def_id_to_hir_id(fn_def_id));
.filter_map(|ty| {
if let TyKind::Ref(lt, _) = ty.kind {
Some(lt.res)
} else {
None
}
})
.collect();
// The lint should trigger in one of these cases: let num_early_lifetimes = early_input_params
// - There are no input lifetimes
// - There's only one output lifetime bound using `+ '_`
// - All input lifetimes are explicitly bound to the output
input_lifetimes.is_empty()
|| (output_lifetimes.len() == 1 && matches!(output_lifetimes[0], LifetimeName::Infer))
|| input_lifetimes
.iter() .iter()
.all(|in_lt| output_lifetimes.iter().any(|out_lt| in_lt == out_lt)) .filter(|param| param.as_region().is_some())
.count();
let num_late_lifetimes = late_input_params
.iter()
.filter(|param_kind| matches!(param_kind, ty::BoundVariableKind::Region(_)))
.count();
// There is no lifetime, so they are all captured.
if num_early_lifetimes == 0 && num_late_lifetimes == 0 {
return true;
}
// By construction, each captured lifetime only appears once in `opaque_captured_lifetimes`.
let num_captured_lifetimes = cx
.tcx
.opaque_captured_lifetimes(opaque_def_id)
.iter()
.filter(|&(lifetime, _)| match *lifetime {
ResolvedArg::EarlyBound(_) | ResolvedArg::LateBound(ty::INNERMOST, _, _) => true,
_ => false,
})
.count();
num_captured_lifetimes == num_early_lifetimes + num_late_lifetimes
} }
fn desugared_async_block<'tcx>(cx: &LateContext<'tcx>, block: &'tcx Block<'tcx>) -> Option<&'tcx Body<'tcx>> { fn desugared_async_block<'tcx>(cx: &LateContext<'tcx>, block: &'tcx Block<'tcx>) -> Option<&'tcx Body<'tcx>> {

5
src/tools/clippy/clippy_utils/src/hir_utils.rs
View file

@ -1231,16 +1231,13 @@ impl<'a, 'tcx> SpanlessHash<'a, 'tcx> {
} }
}, },
TyKind::Path(ref qpath) => self.hash_qpath(qpath), TyKind::Path(ref qpath) => self.hash_qpath(qpath),
TyKind::OpaqueDef(_, arg_list) => {
self.hash_generic_args(arg_list);
},
TyKind::TraitObject(_, lifetime, _) => { TyKind::TraitObject(_, lifetime, _) => {
self.hash_lifetime(lifetime); self.hash_lifetime(lifetime);
}, },
TyKind::Typeof(anon_const) => { TyKind::Typeof(anon_const) => {
self.hash_body(anon_const.body); self.hash_body(anon_const.body);
}, },
TyKind::Err(_) | TyKind::Infer | TyKind::Never | TyKind::InferDelegation(..) | TyKind::AnonAdt(_) => {}, TyKind::Err(_) | TyKind::Infer | TyKind::Never | TyKind::InferDelegation(..) | TyKind::OpaqueDef(_) | TyKind::AnonAdt(_) => {},
} }
} }

2
src/tools/clippy/tests/ui/issue_4266.stderr
View file

@ -11,7 +11,7 @@ error: the following explicit lifetimes could be elided: 'a
--> tests/ui/issue_4266.rs:10:21 --> tests/ui/issue_4266.rs:10:21
| |
LL | async fn one_to_one<'a>(s: &'a str) -> &'a str { LL | async fn one_to_one<'a>(s: &'a str) -> &'a str {
| ^^ ^^ | ^^ ^^ ^^
error: methods called `new` usually take no `self` error: methods called `new` usually take no `self`
--> tests/ui/issue_4266.rs:31:22 --> tests/ui/issue_4266.rs:31:22

6
tests/ui/impl-trait/in-trait/variance.rs
View file

@ -4,7 +4,7 @@
trait Foo<'i> { trait Foo<'i> {
fn implicit_capture_early<'a: 'a>() -> impl Sized {} fn implicit_capture_early<'a: 'a>() -> impl Sized {}
//~^ [Self: o, 'i: o, 'a: *, 'a: o, 'i: o] //~^ [Self: o, 'i: o, 'a: *, 'i: o, 'a: o]
fn explicit_capture_early<'a: 'a>() -> impl Sized + use<'i, 'a, Self> {} fn explicit_capture_early<'a: 'a>() -> impl Sized + use<'i, 'a, Self> {}
//~^ [Self: o, 'i: o, 'a: *, 'i: o, 'a: o] //~^ [Self: o, 'i: o, 'a: *, 'i: o, 'a: o]
@ -13,12 +13,12 @@ trait Foo<'i> {
//~^ [Self: o, 'i: o, 'a: *, 'i: o] //~^ [Self: o, 'i: o, 'a: *, 'i: o]
fn implicit_capture_late<'a>(_: &'a ()) -> impl Sized {} fn implicit_capture_late<'a>(_: &'a ()) -> impl Sized {}
//~^ [Self: o, 'i: o, 'a: o, 'i: o] //~^ [Self: o, 'i: o, 'i: o, 'a: o]
fn explicit_capture_late<'a>(_: &'a ()) -> impl Sized + use<'i, 'a, Self> {} fn explicit_capture_late<'a>(_: &'a ()) -> impl Sized + use<'i, 'a, Self> {}
//~^ [Self: o, 'i: o, 'i: o, 'a: o] //~^ [Self: o, 'i: o, 'i: o, 'a: o]
fn not_cpatured_late<'a>(_: &'a ()) -> impl Sized + use<'i, Self> {} fn not_captured_late<'a>(_: &'a ()) -> impl Sized + use<'i, Self> {}
//~^ [Self: o, 'i: o, 'i: o] //~^ [Self: o, 'i: o, 'i: o]
} }

6
tests/ui/impl-trait/in-trait/variance.stderr
View file

@ -1,4 +1,4 @@
error: [Self: o, 'i: o, 'a: *, 'a: o, 'i: o] error: [Self: o, 'i: o, 'a: *, 'i: o, 'a: o]
--> $DIR/variance.rs:6:44 --> $DIR/variance.rs:6:44
| |
LL | fn implicit_capture_early<'a: 'a>() -> impl Sized {} LL | fn implicit_capture_early<'a: 'a>() -> impl Sized {}
@ -16,7 +16,7 @@ error: [Self: o, 'i: o, 'a: *, 'i: o]
LL | fn not_captured_early<'a: 'a>() -> impl Sized + use<'i, Self> {} LL | fn not_captured_early<'a: 'a>() -> impl Sized + use<'i, Self> {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^ | ^^^^^^^^^^^^^^^^^^^^^^^^^^
error: [Self: o, 'i: o, 'a: o, 'i: o] error: [Self: o, 'i: o, 'i: o, 'a: o]
--> $DIR/variance.rs:15:48 --> $DIR/variance.rs:15:48
| |
LL | fn implicit_capture_late<'a>(_: &'a ()) -> impl Sized {} LL | fn implicit_capture_late<'a>(_: &'a ()) -> impl Sized {}
@ -31,7 +31,7 @@ LL | fn explicit_capture_late<'a>(_: &'a ()) -> impl Sized + use<'i, 'a, Sel
error: [Self: o, 'i: o, 'i: o] error: [Self: o, 'i: o, 'i: o]
--> $DIR/variance.rs:21:44 --> $DIR/variance.rs:21:44
| |
LL | fn not_cpatured_late<'a>(_: &'a ()) -> impl Sized + use<'i, Self> {} LL | fn not_captured_late<'a>(_: &'a ()) -> impl Sized + use<'i, Self> {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^ | ^^^^^^^^^^^^^^^^^^^^^^^^^^
error: aborting due to 6 previous errors error: aborting due to 6 previous errors

5
tests/ui/impl-trait/precise-capturing/capturing-implicit.rs
View file

@ -6,9 +6,8 @@
#![rustc_variance_of_opaques] #![rustc_variance_of_opaques]
fn foo(x: &()) -> impl IntoIterator<Item = impl Sized> + use<> { fn foo(x: &()) -> impl IntoIterator<Item = impl Sized> + use<> {
//~^ ERROR ['_: o] //~^ ERROR []
//~| ERROR ['_: o] //~| ERROR []
//~| ERROR `impl Trait` captures lifetime parameter
[*x] [*x]
} }

14
tests/ui/impl-trait/precise-capturing/capturing-implicit.stderr
View file

@ -1,22 +1,14 @@
error: `impl Trait` captures lifetime parameter, but it is not mentioned in `use<...>` precise captures list error: []
--> $DIR/capturing-implicit.rs:8:11
|
LL | fn foo(x: &()) -> impl IntoIterator<Item = impl Sized> + use<> {
| ^ -------------------------------------------- lifetime captured due to being mentioned in the bounds of the `impl Trait`
| |
| this lifetime parameter is captured
error: ['_: o]
--> $DIR/capturing-implicit.rs:8:19 --> $DIR/capturing-implicit.rs:8:19
| |
LL | fn foo(x: &()) -> impl IntoIterator<Item = impl Sized> + use<> { LL | fn foo(x: &()) -> impl IntoIterator<Item = impl Sized> + use<> {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error: ['_: o] error: []
--> $DIR/capturing-implicit.rs:8:44 --> $DIR/capturing-implicit.rs:8:44
| |
LL | fn foo(x: &()) -> impl IntoIterator<Item = impl Sized> + use<> { LL | fn foo(x: &()) -> impl IntoIterator<Item = impl Sized> + use<> {
| ^^^^^^^^^^ | ^^^^^^^^^^
error: aborting due to 3 previous errors error: aborting due to 2 previous errors

3
tests/ui/type-alias-impl-trait/bound-lifetime-through-dyn-trait.rs
View file

@ -5,6 +5,7 @@ impl<T> Captures<'_> for T {}
fn dyn_hoops<T: Sized>() -> dyn for<'a> Iterator<Item = impl Captures<'a>> { fn dyn_hoops<T: Sized>() -> dyn for<'a> Iterator<Item = impl Captures<'a>> {
//~^ ERROR `impl Trait` cannot capture higher-ranked lifetime from `dyn` type //~^ ERROR `impl Trait` cannot capture higher-ranked lifetime from `dyn` type
//~| ERROR return type cannot have an unboxed trait object
loop {} loop {}
} }
@ -12,7 +13,9 @@ pub fn main() {
//~^ ERROR item does not constrain `Opaque::{opaque#0}`, but has it in its signature //~^ ERROR item does not constrain `Opaque::{opaque#0}`, but has it in its signature
type Opaque = impl Sized; type Opaque = impl Sized;
fn define() -> Opaque { fn define() -> Opaque {
//~^ ERROR the size for values of type `(dyn Iterator<Item = impl Captures<'_>> + 'static)`
let x: Opaque = dyn_hoops::<()>(); let x: Opaque = dyn_hoops::<()>();
//~^ ERROR the size for values of type `(dyn Iterator<Item = impl Captures<'_>> + 'static)`
x x
} }
} }

46
tests/ui/type-alias-impl-trait/bound-lifetime-through-dyn-trait.stderr
View file

@ -10,19 +10,57 @@ note: lifetime declared here
LL | fn dyn_hoops<T: Sized>() -> dyn for<'a> Iterator<Item = impl Captures<'a>> { LL | fn dyn_hoops<T: Sized>() -> dyn for<'a> Iterator<Item = impl Captures<'a>> {
| ^^ | ^^
error[E0746]: return type cannot have an unboxed trait object
--> $DIR/bound-lifetime-through-dyn-trait.rs:6:29
|
LL | fn dyn_hoops<T: Sized>() -> dyn for<'a> Iterator<Item = impl Captures<'a>> {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time
|
help: consider returning an `impl Trait` instead of a `dyn Trait`
|
LL | fn dyn_hoops<T: Sized>() -> impl for<'a> Iterator<Item = impl Captures<'a>> {
| ~~~~
help: alternatively, box the return type, and wrap all of the returned values in `Box::new`
|
LL ~ fn dyn_hoops<T: Sized>() -> Box<dyn for<'a> Iterator<Item = impl Captures<'a>>> {
LL |
LL |
LL ~ Box::new(loop {})
|
error: item does not constrain `Opaque::{opaque#0}`, but has it in its signature error: item does not constrain `Opaque::{opaque#0}`, but has it in its signature
--> $DIR/bound-lifetime-through-dyn-trait.rs:11:8 --> $DIR/bound-lifetime-through-dyn-trait.rs:12:8
| |
LL | pub fn main() { LL | pub fn main() {
| ^^^^ | ^^^^
| |
= note: consider moving the opaque type's declaration and defining uses into a separate module = note: consider moving the opaque type's declaration and defining uses into a separate module
note: this opaque type is in the signature note: this opaque type is in the signature
--> $DIR/bound-lifetime-through-dyn-trait.rs:13:19 --> $DIR/bound-lifetime-through-dyn-trait.rs:14:19
| |
LL | type Opaque = impl Sized; LL | type Opaque = impl Sized;
| ^^^^^^^^^^ | ^^^^^^^^^^
error: aborting due to 2 previous errors error[E0277]: the size for values of type `(dyn Iterator<Item = impl Captures<'_>> + 'static)` cannot be known at compilation time
--> $DIR/bound-lifetime-through-dyn-trait.rs:15:20
|
LL | fn define() -> Opaque {
| ^^^^^^ doesn't have a size known at compile-time
...
LL | x
| - return type was inferred to be `(dyn Iterator<Item = impl Captures<'_>> + 'static)` here
|
= help: the trait `Sized` is not implemented for `(dyn Iterator<Item = impl Captures<'_>> + 'static)`
For more information about this error, try `rustc --explain E0657`. error[E0277]: the size for values of type `(dyn Iterator<Item = impl Captures<'_>> + 'static)` cannot be known at compilation time
--> $DIR/bound-lifetime-through-dyn-trait.rs:17:25
|
LL | let x: Opaque = dyn_hoops::<()>();
| ^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time
|
= help: the trait `Sized` is not implemented for `(dyn Iterator<Item = impl Captures<'_>> + 'static)`
error: aborting due to 5 previous errors
Some errors have detailed explanations: E0277, E0657, E0746.
For more information about an error, try `rustc --explain E0277`.

1
tests/ui/type-alias-impl-trait/escaping-bound-var.rs
View file

@ -8,6 +8,7 @@ trait Test<'a> {}
pub type Foo = impl for<'a> Trait<'a, Assoc = impl Test<'a>>; pub type Foo = impl for<'a> Trait<'a, Assoc = impl Test<'a>>;
//~^ ERROR `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait` //~^ ERROR `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
//~| ERROR `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
impl Trait<'_> for () { impl Trait<'_> for () {
type Assoc = (); type Assoc = ();

14
tests/ui/type-alias-impl-trait/escaping-bound-var.stderr
View file

@ -10,6 +10,18 @@ note: lifetime declared here
LL | pub type Foo = impl for<'a> Trait<'a, Assoc = impl Test<'a>>; LL | pub type Foo = impl for<'a> Trait<'a, Assoc = impl Test<'a>>;
| ^^ | ^^
error: aborting due to 1 previous error error[E0657]: `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
--> $DIR/escaping-bound-var.rs:9:57
|
LL | pub type Foo = impl for<'a> Trait<'a, Assoc = impl Test<'a>>;
| ^^
|
note: lifetime declared here
--> $DIR/escaping-bound-var.rs:9:25
|
LL | pub type Foo = impl for<'a> Trait<'a, Assoc = impl Test<'a>>;
| ^^
error: aborting due to 2 previous errors
For more information about this error, try `rustc --explain E0657`. For more information about this error, try `rustc --explain E0657`.

16
tests/ui/type-alias-impl-trait/variance.rs
View file

@ -11,11 +11,11 @@ type NotCapturedEarly<'a> = impl Sized; //~ ['a: *, 'a: o]
type CapturedEarly<'a> = impl Sized + Captures<'a>; //~ ['a: *, 'a: o] type CapturedEarly<'a> = impl Sized + Captures<'a>; //~ ['a: *, 'a: o]
//~^ ERROR: unconstrained opaque type //~^ ERROR: unconstrained opaque type
type NotCapturedLate<'a> = dyn for<'b> Iterator<Item = impl Sized>; //~ ['a: *, 'b: o, 'a: o] type NotCapturedLate<'a> = dyn for<'b> Iterator<Item = impl Sized>; //~ ['a: *, 'a: o, 'b: o]
//~^ ERROR `impl Trait` cannot capture higher-ranked lifetime from `dyn` type //~^ ERROR `impl Trait` cannot capture higher-ranked lifetime from `dyn` type
//~| ERROR: unconstrained opaque type //~| ERROR: unconstrained opaque type
type Captured<'a> = dyn for<'b> Iterator<Item = impl Sized + Captures<'a>>; //~ ['a: *, 'b: o, 'a: o] type Captured<'a> = dyn for<'b> Iterator<Item = impl Sized + Captures<'a>>; //~ ['a: *, 'a: o, 'b: o]
//~^ ERROR `impl Trait` cannot capture higher-ranked lifetime from `dyn` type //~^ ERROR `impl Trait` cannot capture higher-ranked lifetime from `dyn` type
//~| ERROR: unconstrained opaque type //~| ERROR: unconstrained opaque type
@ -31,24 +31,24 @@ trait Foo<'i> {
} }
impl<'i> Foo<'i> for &'i () { impl<'i> Foo<'i> for &'i () {
type ImplicitCapture<'a> = impl Sized; //~ ['i: *, 'a: *, 'a: o, 'i: o] type ImplicitCapture<'a> = impl Sized; //~ ['i: *, 'a: *, 'i: o, 'a: o]
//~^ ERROR: unconstrained opaque type //~^ ERROR: unconstrained opaque type
type ExplicitCaptureFromHeader<'a> = impl Sized + Captures<'i>; //~ ['i: *, 'a: *, 'a: o, 'i: o] type ExplicitCaptureFromHeader<'a> = impl Sized + Captures<'i>; //~ ['i: *, 'a: *, 'i: o, 'a: o]
//~^ ERROR: unconstrained opaque type //~^ ERROR: unconstrained opaque type
type ExplicitCaptureFromGat<'a> = impl Sized + Captures<'a>; //~ ['i: *, 'a: *, 'a: o, 'i: o] type ExplicitCaptureFromGat<'a> = impl Sized + Captures<'a>; //~ ['i: *, 'a: *, 'i: o, 'a: o]
//~^ ERROR: unconstrained opaque type //~^ ERROR: unconstrained opaque type
} }
impl<'i> Foo<'i> for () { impl<'i> Foo<'i> for () {
type ImplicitCapture<'a> = impl Sized; //~ ['i: *, 'a: *, 'a: o, 'i: o] type ImplicitCapture<'a> = impl Sized; //~ ['i: *, 'a: *, 'i: o, 'a: o]
//~^ ERROR: unconstrained opaque type //~^ ERROR: unconstrained opaque type
type ExplicitCaptureFromHeader<'a> = impl Sized + Captures<'i>; //~ ['i: *, 'a: *, 'a: o, 'i: o] type ExplicitCaptureFromHeader<'a> = impl Sized + Captures<'i>; //~ ['i: *, 'a: *, 'i: o, 'a: o]
//~^ ERROR: unconstrained opaque type //~^ ERROR: unconstrained opaque type
type ExplicitCaptureFromGat<'a> = impl Sized + Captures<'a>; //~ ['i: *, 'a: *, 'a: o, 'i: o] type ExplicitCaptureFromGat<'a> = impl Sized + Captures<'a>; //~ ['i: *, 'a: *, 'i: o, 'a: o]
//~^ ERROR: unconstrained opaque type //~^ ERROR: unconstrained opaque type
} }

16
tests/ui/type-alias-impl-trait/variance.stderr
View file

@ -122,13 +122,13 @@ error: ['a: *, 'a: o]
LL | type CapturedEarly<'a> = impl Sized + Captures<'a>; LL | type CapturedEarly<'a> = impl Sized + Captures<'a>;
| ^^^^^^^^^^^^^^^^^^^^^^^^^ | ^^^^^^^^^^^^^^^^^^^^^^^^^
error: ['a: *, 'b: o, 'a: o] error: ['a: *, 'a: o, 'b: o]
--> $DIR/variance.rs:14:56 --> $DIR/variance.rs:14:56
| |
LL | type NotCapturedLate<'a> = dyn for<'b> Iterator<Item = impl Sized>; LL | type NotCapturedLate<'a> = dyn for<'b> Iterator<Item = impl Sized>;
| ^^^^^^^^^^ | ^^^^^^^^^^
error: ['a: *, 'b: o, 'a: o] error: ['a: *, 'a: o, 'b: o]
--> $DIR/variance.rs:18:49 --> $DIR/variance.rs:18:49
| |
LL | type Captured<'a> = dyn for<'b> Iterator<Item = impl Sized + Captures<'a>>; LL | type Captured<'a> = dyn for<'b> Iterator<Item = impl Sized + Captures<'a>>;
@ -140,37 +140,37 @@ error: ['a: *, 'b: *, T: o, 'a: o, 'b: o]
LL | type Bar<'a, 'b: 'b, T> = impl Sized; LL | type Bar<'a, 'b: 'b, T> = impl Sized;
| ^^^^^^^^^^ | ^^^^^^^^^^
error: ['i: *, 'a: *, 'a: o, 'i: o] error: ['i: *, 'a: *, 'i: o, 'a: o]
--> $DIR/variance.rs:34:32 --> $DIR/variance.rs:34:32
| |
LL | type ImplicitCapture<'a> = impl Sized; LL | type ImplicitCapture<'a> = impl Sized;
| ^^^^^^^^^^ | ^^^^^^^^^^
error: ['i: *, 'a: *, 'a: o, 'i: o] error: ['i: *, 'a: *, 'i: o, 'a: o]
--> $DIR/variance.rs:37:42 --> $DIR/variance.rs:37:42
| |
LL | type ExplicitCaptureFromHeader<'a> = impl Sized + Captures<'i>; LL | type ExplicitCaptureFromHeader<'a> = impl Sized + Captures<'i>;
| ^^^^^^^^^^^^^^^^^^^^^^^^^ | ^^^^^^^^^^^^^^^^^^^^^^^^^
error: ['i: *, 'a: *, 'a: o, 'i: o] error: ['i: *, 'a: *, 'i: o, 'a: o]
--> $DIR/variance.rs:40:39 --> $DIR/variance.rs:40:39
| |
LL | type ExplicitCaptureFromGat<'a> = impl Sized + Captures<'a>; LL | type ExplicitCaptureFromGat<'a> = impl Sized + Captures<'a>;
| ^^^^^^^^^^^^^^^^^^^^^^^^^ | ^^^^^^^^^^^^^^^^^^^^^^^^^
error: ['i: *, 'a: *, 'a: o, 'i: o] error: ['i: *, 'a: *, 'i: o, 'a: o]
--> $DIR/variance.rs:45:32 --> $DIR/variance.rs:45:32
| |
LL | type ImplicitCapture<'a> = impl Sized; LL | type ImplicitCapture<'a> = impl Sized;
| ^^^^^^^^^^ | ^^^^^^^^^^
error: ['i: *, 'a: *, 'a: o, 'i: o] error: ['i: *, 'a: *, 'i: o, 'a: o]
--> $DIR/variance.rs:48:42 --> $DIR/variance.rs:48:42
| |
LL | type ExplicitCaptureFromHeader<'a> = impl Sized + Captures<'i>; LL | type ExplicitCaptureFromHeader<'a> = impl Sized + Captures<'i>;
| ^^^^^^^^^^^^^^^^^^^^^^^^^ | ^^^^^^^^^^^^^^^^^^^^^^^^^
error: ['i: *, 'a: *, 'a: o, 'i: o] error: ['i: *, 'a: *, 'i: o, 'a: o]
--> $DIR/variance.rs:51:39 --> $DIR/variance.rs:51:39
| |
LL | type ExplicitCaptureFromGat<'a> = impl Sized + Captures<'a>; LL | type ExplicitCaptureFromGat<'a> = impl Sized + Captures<'a>;