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Rollup merge of #118396 - compiler-errors:ast-lang-items, r=cjgillot

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Collect lang items from AST, get rid of `GenericBound::LangItemTrait`

r? `@cjgillot`
cc #115178

Looking forward, the work to remove `QPath::LangItem` will also be significantly more difficult, but I plan on doing it as well. Specifically, we have to change:
1. A lot of `rustc_ast_lowering` for things like expr `..`
2. A lot of astconv, since we actually instantiate lang and non-lang paths quite differently.
3. A ton of diagnostics and clippy lints that are special-cased via `QPath::LangItem`

Meanwhile, it was pretty easy to remove `GenericBound::LangItemTrait`, so I just did that here.
This commit is contained in:
Jubilee 2023-12-15 14:08:15 -08:00 • committed by GitHub
commit 1d54949765
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31 changed files with 504 additions and 412 deletions
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11
compiler/rustc_hir_analysis/src/astconv/bounds.rs
View file

@ -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(

145
compiler/rustc_hir_analysis/src/astconv/mod.rs
View file

@ -678,36 +678,57 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
)
}
fn instantiate_poly_trait_ref_inner(
/// Given a trait bound like `Debug`, applies that trait bound the given self-type to construct
/// a full trait reference. The resulting trait reference is returned. This may also generate
/// auxiliary bounds, which are added to `bounds`.
///
/// Example:
///
/// ```ignore (illustrative)
/// poly_trait_ref = Iterator<Item = u32>
/// self_ty = Foo
/// ```
///
/// this would return `Foo: Iterator` and add `<Foo as Iterator>::Item = u32` into `bounds`.
///
/// **A note on binders:** against our usual convention, there is an implied binder around
/// the `self_ty` and `poly_trait_ref` parameters here. So they may reference bound regions.
/// If for example you had `for<'a> Foo<'a>: Bar<'a>`, then the `self_ty` would be `Foo<'a>`
/// where `'a` is a bound region at depth 0. Similarly, the `poly_trait_ref` would be
/// `Bar<'a>`. The returned poly-trait-ref will have this binder instantiated explicitly,
/// however.
#[instrument(level = "debug", skip(self, span, constness, bounds, speculative))]
pub(crate) fn instantiate_poly_trait_ref(
&self,
hir_id: hir::HirId,
trait_ref: &hir::TraitRef<'_>,
span: Span,
binding_span: Option<Span>,
constness: ty::BoundConstness,
polarity: ty::ImplPolarity,
self_ty: Ty<'tcx>,
bounds: &mut Bounds<'tcx>,
speculative: bool,
trait_ref_span: Span,
trait_def_id: DefId,
trait_segment: &hir::PathSegment<'_>,
args: &GenericArgs<'_>,
infer_args: bool,
self_ty: Ty<'tcx>,
only_self_bounds: OnlySelfBounds,
) -> GenericArgCountResult {
let trait_def_id = trait_ref.trait_def_id().unwrap_or_else(|| FatalError.raise());
let trait_segment = trait_ref.path.segments.last().unwrap();
let args = trait_segment.args();
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);
let (generic_args, arg_count) = self.create_args_for_ast_path(
trait_ref_span,
trait_ref.path.span,
trait_def_id,
&[],
trait_segment,
args,
infer_args,
trait_segment.infer_args,
Some(self_ty),
constness,
);
let tcx = self.tcx();
let bound_vars = tcx.late_bound_vars(hir_id);
let bound_vars = tcx.late_bound_vars(trait_ref.hir_ref_id);
debug!(?bound_vars);
let assoc_bindings = self.create_assoc_bindings_for_generic_args(args);
@ -735,13 +756,13 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
// Specify type to assert that error was already reported in `Err` case.
let _: Result<_, ErrorGuaranteed> = self.add_predicates_for_ast_type_binding(
hir_id,
trait_ref.hir_ref_id,
poly_trait_ref,
binding,
bounds,
speculative,
&mut dup_bindings,
binding_span.unwrap_or(binding.span),
binding.span,
constness,
only_self_bounds,
polarity,
@ -752,102 +773,6 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
arg_count
}
/// Given a trait bound like `Debug`, applies that trait bound the given self-type to construct
/// a full trait reference. The resulting trait reference is returned. This may also generate
/// auxiliary bounds, which are added to `bounds`.
///
/// Example:
///
/// ```ignore (illustrative)
/// poly_trait_ref = Iterator<Item = u32>
/// self_ty = Foo
/// ```
///
/// this would return `Foo: Iterator` and add `<Foo as Iterator>::Item = u32` into `bounds`.
///
/// **A note on binders:** against our usual convention, there is an implied bounder around
/// the `self_ty` and `poly_trait_ref` parameters here. So they may reference bound regions.
/// If for example you had `for<'a> Foo<'a>: Bar<'a>`, then the `self_ty` would be `Foo<'a>`
/// where `'a` is a bound region at depth 0. Similarly, the `poly_trait_ref` would be
/// `Bar<'a>`. The returned poly-trait-ref will have this binder instantiated explicitly,
/// however.
#[instrument(level = "debug", skip(self, span, constness, bounds, speculative))]
pub(crate) fn instantiate_poly_trait_ref(
&self,
trait_ref: &hir::TraitRef<'_>,
span: Span,
constness: ty::BoundConstness,
polarity: ty::ImplPolarity,
self_ty: Ty<'tcx>,
bounds: &mut Bounds<'tcx>,
speculative: bool,
only_self_bounds: OnlySelfBounds,
) -> GenericArgCountResult {
let hir_id = trait_ref.hir_ref_id;
let binding_span = None;
let trait_ref_span = trait_ref.path.span;
let trait_def_id = trait_ref.trait_def_id().unwrap_or_else(|| FatalError.raise());
let trait_segment = trait_ref.path.segments.last().unwrap();
let args = trait_segment.args();
let infer_args = trait_segment.infer_args;
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);
self.instantiate_poly_trait_ref_inner(
hir_id,
span,
binding_span,
constness,
polarity,
bounds,
speculative,
trait_ref_span,
trait_def_id,
trait_segment,
args,
infer_args,
self_ty,
only_self_bounds,
)
}
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,

26
compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs
View file

@ -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);
}