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Lower and resolve precise captures in HIR

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This commit is contained in:
Michael Goulet 2024-04-04 10:48:47 -04:00
parent c897092654
commit 41cf87b71b
8 changed files with 108 additions and 46 deletions
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47
compiler/rustc_ast_lowering/src/lib.rs
View file

@ -48,6 +48,7 @@ use rustc_ast::{self as ast, *};
use rustc_ast_pretty::pprust;
use rustc_data_structures::captures::Captures;
use rustc_data_structures::fingerprint::Fingerprint;
use rustc_data_structures::fx::FxIndexSet;
use rustc_data_structures::sorted_map::SortedMap;
use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
use rustc_data_structures::sync::Lrc;
@ -1525,7 +1526,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
bounds: &GenericBounds,
fn_kind: Option<FnDeclKind>,
itctx: ImplTraitContext,
precise_capturing: Option<&[ast::PreciseCapturingArg]>,
precise_capturing_args: Option<&[PreciseCapturingArg]>,
) -> hir::TyKind<'hir> {
// Make sure we know that some funky desugaring has been going on here.
// This is a first: there is code in other places like for loop
@ -1541,9 +1542,13 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
precise_capturing
.iter()
.filter_map(|arg| match arg {
ast::PreciseCapturingArg::Lifetime(lt) => Some(*lt),
ast::PreciseCapturingArg::Arg(..) => None,
PreciseCapturingArg::Lifetime(lt) => Some(*lt),
PreciseCapturingArg::Arg(..) => None,
})
// Add in all the lifetimes mentioned in the bounds. We will error
// them out later, but capturing them here is important to make sure
// they actually get resolved in resolve_bound_vars.
.chain(lifetime_collector::lifetimes_in_bounds(self.resolver, bounds))
.collect()
} else {
match origin {
@ -1592,6 +1597,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
captured_lifetimes_to_duplicate,
span,
opaque_ty_span,
precise_capturing_args,
|this| this.lower_param_bounds(bounds, itctx),
)
}
@ -1601,9 +1607,10 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
opaque_ty_node_id: NodeId,
origin: hir::OpaqueTyOrigin,
in_trait: bool,
captured_lifetimes_to_duplicate: Vec<Lifetime>,
captured_lifetimes_to_duplicate: FxIndexSet<Lifetime>,
span: Span,
opaque_ty_span: Span,
precise_capturing_args: Option<&[PreciseCapturingArg]>,
lower_item_bounds: impl FnOnce(&mut Self) -> &'hir [hir::GenericBound<'hir>],
) -> hir::TyKind<'hir> {
let opaque_ty_def_id = self.create_def(
@ -1690,8 +1697,15 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
// Install the remapping from old to new (if any). This makes sure that
// 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 (bounds, precise_capturing_args) =
this.with_remapping(captured_to_synthesized_mapping, |this| {
(
lower_item_bounds(this),
precise_capturing_args.map(|precise_capturing| {
this.lower_precise_capturing_args(precise_capturing)
}),
)
});
let generic_params =
this.arena.alloc_from_iter(synthesized_lifetime_definitions.iter().map(
@ -1736,6 +1750,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
origin,
lifetime_mapping,
in_trait,
precise_capturing_args,
};
// Generate an `type Foo = impl Trait;` declaration.
@ -1768,6 +1783,23 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
)
}
fn lower_precise_capturing_args(
&mut self,
precise_capturing_args: &[PreciseCapturingArg],
) -> &'hir [hir::PreciseCapturingArg<'hir>] {
self.arena.alloc_from_iter(precise_capturing_args.iter().map(|arg| match arg {
PreciseCapturingArg::Lifetime(lt) => {
hir::PreciseCapturingArg::Lifetime(self.lower_lifetime(lt))
}
PreciseCapturingArg::Arg(_, node_id) => {
let res = self.resolver.get_partial_res(*node_id).map_or(Res::Err, |partial_res| {
partial_res.full_res().expect("no partial res expected for precise capture arg")
});
hir::PreciseCapturingArg::Param(self.lower_res(res), self.lower_node_id(*node_id))
}
}))
}
fn lower_fn_params_to_names(&mut self, decl: &FnDecl) -> &'hir [Ident] {
self.arena.alloc_from_iter(decl.inputs.iter().map(|param| match param.pat.kind {
PatKind::Ident(_, ident, _) => self.lower_ident(ident),
@ -1908,7 +1940,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
let opaque_ty_span =
self.mark_span_with_reason(DesugaringKind::Async, span, allowed_features);
let captured_lifetimes: Vec<_> = self
let captured_lifetimes = self
.resolver
.take_extra_lifetime_params(opaque_ty_node_id)
.into_iter()
@ -1922,6 +1954,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
captured_lifetimes,
span,
opaque_ty_span,
None,
|this| {
let bound = this.lower_coroutine_fn_output_type_to_bound(
output,

15
compiler/rustc_ast_lowering/src/lifetime_collector.rs
View file

@ -1,6 +1,7 @@
use super::ResolverAstLoweringExt;
use rustc_ast::visit::{self, BoundKind, LifetimeCtxt, Visitor};
use rustc_ast::{GenericBounds, Lifetime, NodeId, PathSegment, PolyTraitRef, Ty, TyKind};
use rustc_data_structures::fx::FxIndexSet;
use rustc_hir::def::{DefKind, LifetimeRes, Res};
use rustc_middle::span_bug;
use rustc_middle::ty::ResolverAstLowering;
@ -10,27 +11,23 @@ use rustc_span::Span;
struct LifetimeCollectVisitor<'ast> {
resolver: &'ast ResolverAstLowering,
current_binders: Vec<NodeId>,
collected_lifetimes: Vec<Lifetime>,
collected_lifetimes: FxIndexSet<Lifetime>,
}
impl<'ast> LifetimeCollectVisitor<'ast> {
fn new(resolver: &'ast ResolverAstLowering) -> Self {
Self { resolver, current_binders: Vec::new(), collected_lifetimes: Vec::new() }
Self { resolver, current_binders: Vec::new(), collected_lifetimes: FxIndexSet::default() }
}
fn record_lifetime_use(&mut self, lifetime: Lifetime) {
match self.resolver.get_lifetime_res(lifetime.id).unwrap_or(LifetimeRes::Error) {
LifetimeRes::Param { binder, .. } | LifetimeRes::Fresh { binder, .. } => {
if !self.current_binders.contains(&binder) {
if !self.collected_lifetimes.contains(&lifetime) {
self.collected_lifetimes.push(lifetime);
}
self.collected_lifetimes.insert(lifetime);
}
}
LifetimeRes::Static | LifetimeRes::Error => {
if !self.collected_lifetimes.contains(&lifetime) {
self.collected_lifetimes.push(lifetime);
}
self.collected_lifetimes.insert(lifetime);
}
LifetimeRes::Infer => {}
res => {
@ -111,7 +108,7 @@ impl<'ast> Visitor<'ast> for LifetimeCollectVisitor<'ast> {
pub(crate) fn lifetimes_in_bounds(
resolver: &ResolverAstLowering,
bounds: &GenericBounds,
) -> Vec<Lifetime> {
) -> FxIndexSet<Lifetime> {
let mut visitor = LifetimeCollectVisitor::new(resolver);
for bound in bounds {
visitor.visit_param_bound(bound, BoundKind::Bound);