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banish hir::GenericBound::LangItemTrait
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@compiler-errors
compiler-errors committed Dec 15, 2023
1 parent ad00641 commit fc010de
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Showing 12 changed files with 68 additions and 135 deletions.
43 changes: 37 additions & 6 deletions compiler/rustc_ast_lowering/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -766,6 +766,28 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
self.resolver.get_import_res(id).present_items()
}

fn make_lang_item_path(
&mut self,
lang_item: hir::LangItem,
span: Span,
args: Option<&'hir hir::GenericArgs<'hir>>,
) -> &'hir hir::Path<'hir> {
let def_id = self.tcx.require_lang_item(lang_item, Some(span));
let def_kind = self.tcx.def_kind(def_id);
let res = Res::Def(def_kind, def_id);
self.arena.alloc(hir::Path {
span,
res,
segments: self.arena.alloc_from_iter([hir::PathSegment {
ident: Ident::new(lang_item.name(), span),
hir_id: self.next_id(),
res,
args,
infer_args: false,
}]),
})
}

/// Reuses the span but adds information like the kind of the desugaring and features that are
/// allowed inside this span.
fn mark_span_with_reason(
Expand Down Expand Up @@ -1977,18 +1999,27 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
CoroutineKind::AsyncGen { .. } => (sym::Item, hir::LangItem::AsyncIterator),
};

let future_args = self.arena.alloc(hir::GenericArgs {
let bound_args = self.arena.alloc(hir::GenericArgs {
args: &[],
bindings: arena_vec![self; self.assoc_ty_binding(assoc_ty_name, opaque_ty_span, output_ty)],
parenthesized: hir::GenericArgsParentheses::No,
span_ext: DUMMY_SP,
});

hir::GenericBound::LangItemTrait(
trait_lang_item,
opaque_ty_span,
self.next_id(),
future_args,
hir::GenericBound::Trait(
hir::PolyTraitRef {
bound_generic_params: &[],
trait_ref: hir::TraitRef {
path: self.make_lang_item_path(
trait_lang_item,
opaque_ty_span,
Some(bound_args),
),
hir_ref_id: self.next_id(),
},
span: opaque_ty_span,
},
hir::TraitBoundModifier::None,
)
}

Expand Down
30 changes: 10 additions & 20 deletions compiler/rustc_borrowck/src/diagnostics/region_name.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -788,28 +788,18 @@ impl<'tcx> MirBorrowckCtxt<'_, 'tcx> {
};
let opaque_ty = hir.item(id);
if let hir::ItemKind::OpaqueTy(hir::OpaqueTy {
bounds:
[
hir::GenericBound::LangItemTrait(
hir::LangItem::Future,
_,
_,
hir::GenericArgs {
bindings:
[
hir::TypeBinding {
ident: Ident { name: sym::Output, .. },
kind:
hir::TypeBindingKind::Equality { term: hir::Term::Ty(ty) },
..
},
],
..
},
),
],
bounds: [hir::GenericBound::Trait(trait_ref, _)],
..
}) = opaque_ty.kind
&& let Some(segment) = trait_ref.trait_ref.path.segments.last()
&& let Some(args) = segment.args
&& let [
hir::TypeBinding {
ident: Ident { name: sym::Output, .. },
kind: hir::TypeBindingKind::Equality { term: hir::Term::Ty(ty) },
..
},
] = args.bindings
{
ty
} else {
Expand Down
3 changes: 0 additions & 3 deletions compiler/rustc_hir/src/hir.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -435,8 +435,6 @@ pub enum TraitBoundModifier {
#[derive(Clone, Copy, Debug, HashStable_Generic)]
pub enum GenericBound<'hir> {
Trait(PolyTraitRef<'hir>, TraitBoundModifier),
// FIXME(davidtwco): Introduce `PolyTraitRef::LangItem`
LangItemTrait(LangItem, Span, HirId, &'hir GenericArgs<'hir>),
Outlives(&'hir Lifetime),
}

Expand All @@ -451,7 +449,6 @@ impl GenericBound<'_> {
pub fn span(&self) -> Span {
match self {
GenericBound::Trait(t, ..) => t.span,
GenericBound::LangItemTrait(_, span, ..) => *span,
GenericBound::Outlives(l) => l.ident.span,
}
}
Expand Down
4 changes: 0 additions & 4 deletions compiler/rustc_hir/src/intravisit.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1075,10 +1075,6 @@ pub fn walk_param_bound<'v, V: Visitor<'v>>(visitor: &mut V, bound: &'v GenericB
GenericBound::Trait(ref typ, _modifier) => {
visitor.visit_poly_trait_ref(typ);
}
GenericBound::LangItemTrait(_, _span, hir_id, args) => {
visitor.visit_id(hir_id);
visitor.visit_generic_args(args);
}
GenericBound::Outlives(ref lifetime) => visitor.visit_lifetime(lifetime),
}
}
Expand Down
11 changes: 0 additions & 11 deletions compiler/rustc_hir_analysis/src/astconv/bounds.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -134,17 +134,6 @@ impl<'tcx> dyn AstConv<'tcx> + '_ {
only_self_bounds,
);
}
&hir::GenericBound::LangItemTrait(lang_item, span, hir_id, args) => {
self.instantiate_lang_item_trait_ref(
lang_item,
span,
hir_id,
args,
param_ty,
bounds,
only_self_bounds,
);
}
hir::GenericBound::Outlives(lifetime) => {
let region = self.ast_region_to_region(lifetime, None);
bounds.push_region_bound(
Expand Down
37 changes: 1 addition & 36 deletions compiler/rustc_hir_analysis/src/astconv/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -791,6 +791,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
self.prohibit_generics(trait_ref.path.segments.split_last().unwrap().1.iter(), |_| {});
self.complain_about_internal_fn_trait(span, trait_def_id, trait_segment, false);

// TODO: inline
self.instantiate_poly_trait_ref_inner(
hir_id,
span,
Expand All @@ -809,42 +810,6 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
)
}

pub(crate) fn instantiate_lang_item_trait_ref(
&self,
lang_item: hir::LangItem,
span: Span,
hir_id: hir::HirId,
args: &GenericArgs<'_>,
self_ty: Ty<'tcx>,
bounds: &mut Bounds<'tcx>,
only_self_bounds: OnlySelfBounds,
) {
let binding_span = Some(span);
let constness = ty::BoundConstness::NotConst;
let speculative = false;
let trait_ref_span = span;
let trait_def_id = self.tcx().require_lang_item(lang_item, Some(span));
let trait_segment = &hir::PathSegment::invalid();
let infer_args = false;

self.instantiate_poly_trait_ref_inner(
hir_id,
span,
binding_span,
constness,
ty::ImplPolarity::Positive,
bounds,
speculative,
trait_ref_span,
trait_def_id,
trait_segment,
args,
infer_args,
self_ty,
only_self_bounds,
);
}

fn ast_path_to_mono_trait_ref(
&self,
span: Span,
Expand Down
26 changes: 0 additions & 26 deletions compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -938,32 +938,6 @@ impl<'a, 'tcx> Visitor<'tcx> for BoundVarContext<'a, 'tcx> {
}
}

fn visit_param_bound(&mut self, bound: &'tcx hir::GenericBound<'tcx>) {
match bound {
hir::GenericBound::LangItemTrait(_, _, hir_id, _) => {
// FIXME(jackh726): This is pretty weird. `LangItemTrait` doesn't go
// through the regular poly trait ref code, so we don't get another
// chance to introduce a binder. For now, I'm keeping the existing logic
// of "if there isn't a Binder scope above us, add one", but I
// imagine there's a better way to go about this.
let (binders, scope_type) = self.poly_trait_ref_binder_info();

self.record_late_bound_vars(*hir_id, binders);
let scope = Scope::Binder {
hir_id: *hir_id,
bound_vars: FxIndexMap::default(),
s: self.scope,
scope_type,
where_bound_origin: None,
};
self.with(scope, |this| {
intravisit::walk_param_bound(this, bound);
});
}
_ => intravisit::walk_param_bound(self, bound),
}
}

fn visit_poly_trait_ref(&mut self, trait_ref: &'tcx hir::PolyTraitRef<'tcx>) {
self.visit_poly_trait_ref_inner(trait_ref, NonLifetimeBinderAllowed::Allow);
}
Expand Down
5 changes: 0 additions & 5 deletions compiler/rustc_hir_pretty/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2088,11 +2088,6 @@ impl<'a> State<'a> {
}
self.print_poly_trait_ref(tref);
}
GenericBound::LangItemTrait(lang_item, span, ..) => {
self.word("#[lang = \"");
self.print_ident(Ident::new(lang_item.name(), *span));
self.word("\"]");
}
GenericBound::Outlives(lt) => {
self.print_lifetime(lt);
}
Expand Down
6 changes: 3 additions & 3 deletions compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -825,9 +825,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
&& let hir::Node::Item(hir::Item {
kind: hir::ItemKind::OpaqueTy(op_ty), ..
}) = self.tcx.hir_node(item_id.hir_id())
&& let [
hir::GenericBound::LangItemTrait(hir::LangItem::Future, _, _, generic_args),
] = op_ty.bounds
&& let [hir::GenericBound::Trait(trait_ref, _)] = op_ty.bounds
&& let Some(hir::PathSegment { args: Some(generic_args), .. }) =
trait_ref.trait_ref.path.segments.last()
&& let hir::GenericArgs { bindings: [ty_binding], .. } = generic_args
&& let hir::TypeBindingKind::Equality { term: hir::Term::Ty(term) } =
ty_binding.kind
Expand Down
26 changes: 8 additions & 18 deletions compiler/rustc_infer/src/infer/error_reporting/suggest.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -668,26 +668,16 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
(
hir::ItemKind::OpaqueTy(hir::OpaqueTy { bounds: last_bounds, .. }),
hir::ItemKind::OpaqueTy(hir::OpaqueTy { bounds: exp_bounds, .. }),
) if std::iter::zip(*last_bounds, *exp_bounds).all(|(left, right)| {
match (left, right) {
(
hir::GenericBound::Trait(tl, ml),
hir::GenericBound::Trait(tr, mr),
) if tl.trait_ref.trait_def_id() == tr.trait_ref.trait_def_id()
) if std::iter::zip(*last_bounds, *exp_bounds).all(|(left, right)| match (
left, right,
) {
(hir::GenericBound::Trait(tl, ml), hir::GenericBound::Trait(tr, mr))
if tl.trait_ref.trait_def_id() == tr.trait_ref.trait_def_id()
&& ml == mr =>
{
true
}
(
hir::GenericBound::LangItemTrait(langl, _, _, argsl),
hir::GenericBound::LangItemTrait(langr, _, _, argsr),
) if langl == langr => {
// FIXME: consider the bounds!
debug!("{:?} {:?}", argsl, argsr);
true
}
_ => false,
{
true
}
_ => false,
}) =>
{
StatementAsExpression::NeedsBoxing
Expand Down
2 changes: 1 addition & 1 deletion compiler/rustc_passes/src/hir_stats.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -429,7 +429,7 @@ impl<'v> hir_visit::Visitor<'v> for StatCollector<'v> {
fn visit_param_bound(&mut self, b: &'v hir::GenericBound<'v>) {
record_variants!(
(self, b, b, Id::None, hir, GenericBound, GenericBound),
[Trait, LangItemTrait, Outlives]
[Trait, Outlives]
);
hir_visit::walk_param_bound(self, b)
}
Expand Down
10 changes: 8 additions & 2 deletions compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -4783,8 +4783,14 @@ pub fn suggest_desugaring_async_fn_to_impl_future_in_trait<'tcx>(
};

let future = tcx.hir_node_by_def_id(opaque_def_id).expect_item().expect_opaque_ty();
let Some(hir::GenericBound::LangItemTrait(_, _, _, generics)) = future.bounds.get(0) else {
// `async fn` should always lower to a lang item bound... but don't ICE.
let [hir::GenericBound::Trait(trait_ref, _)] = future.bounds else {
// `async fn` should always lower to a single bound... but don't ICE.
return None;
};
let Some(hir::PathSegment { args: Some(generics), .. }) =
trait_ref.trait_ref.path.segments.last()
else {
// desugaring to a single path segment for `Future<...>`.
return None;
};
let Some(hir::TypeBindingKind::Equality { term: hir::Term::Ty(future_output_ty) }) =
Expand Down

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