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use rustc_data_structures::fx::FxHashMap;
use rustc_hir as hir;
use rustc_hir::def::DefKind;
use rustc_hir::def_id::LocalDefId;
use rustc_middle::middle::resolve_bound_vars as rbv;
use rustc_middle::query::Providers;
use rustc_middle::ty::{self, Ty, TyCtxt};
use rustc_span::Span;
use std::iter;
pub fn provide(providers: &mut Providers) {
*providers = Providers { assumed_wf_types, ..*providers };
}
fn assumed_wf_types<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> &'tcx [(Ty<'tcx>, Span)] {
match tcx.def_kind(def_id) {
DefKind::Fn => {
let sig = tcx.fn_sig(def_id).instantiate_identity();
let liberated_sig = tcx.liberate_late_bound_regions(def_id.to_def_id(), sig);
tcx.arena.alloc_from_iter(itertools::zip_eq(
liberated_sig.inputs_and_output,
fn_sig_spans(tcx, def_id),
))
}
DefKind::AssocFn => {
let sig = tcx.fn_sig(def_id).instantiate_identity();
let liberated_sig = tcx.liberate_late_bound_regions(def_id.to_def_id(), sig);
let mut assumed_wf_types: Vec<_> =
tcx.assumed_wf_types(tcx.local_parent(def_id)).into();
assumed_wf_types.extend(itertools::zip_eq(
liberated_sig.inputs_and_output,
fn_sig_spans(tcx, def_id),
));
tcx.arena.alloc_slice(&assumed_wf_types)
}
DefKind::Impl { .. } => {
// Trait arguments and the self type for trait impls or only the self type for
// inherent impls.
let tys = match tcx.impl_trait_ref(def_id) {
Some(trait_ref) => trait_ref.skip_binder().args.types().collect(),
None => vec![tcx.type_of(def_id).instantiate_identity()],
};
let mut impl_spans = impl_spans(tcx, def_id);
tcx.arena.alloc_from_iter(tys.into_iter().map(|ty| (ty, impl_spans.next().unwrap())))
}
DefKind::AssocTy if let Some(ty::ImplTraitInTraitData::Trait { fn_def_id, opaque_def_id }) = tcx.opt_rpitit_info(def_id.to_def_id()) => {
let hir::OpaqueTy { lifetime_mapping, .. } =
*tcx.hir().expect_item(opaque_def_id.expect_local()).expect_opaque_ty();
let mut mapping = FxHashMap::default();
let generics = tcx.generics_of(def_id);
for &(lifetime, new_early_bound_def_id) in lifetime_mapping {
if let Some(rbv::ResolvedArg::LateBound(_, _, def_id)) =
tcx.named_bound_var(lifetime.hir_id)
{
let name = tcx.hir().name(lifetime.hir_id);
let index = generics
.param_def_id_to_index(tcx, new_early_bound_def_id.to_def_id())
.unwrap();
mapping.insert(
ty::Region::new_free(
tcx,
fn_def_id,
ty::BoundRegionKind::BrNamed(def_id, name),
),
ty::Region::new_early_bound(
tcx,
ty::EarlyBoundRegion {
def_id: new_early_bound_def_id.to_def_id(),
index,
name,
},
),
);
}
}
let a = tcx.fold_regions(tcx.assumed_wf_types(fn_def_id.expect_local()).to_vec(), |re, _| {
if let Some(re) = mapping.get(&re) { *re } else { re }
});
tcx.arena.alloc_from_iter(a)
}
DefKind::AssocConst | DefKind::AssocTy => tcx.assumed_wf_types(tcx.local_parent(def_id)),
DefKind::OpaqueTy => match tcx.def_kind(tcx.local_parent(def_id)) {
DefKind::TyAlias => ty::List::empty(),
DefKind::AssocTy => tcx.assumed_wf_types(tcx.local_parent(def_id)),
// Nested opaque types only occur in associated types:
// ` type Opaque<T> = impl Trait<&'static T, AssocTy = impl Nested>; `
// assumed_wf_types should include those of `Opaque<T>`, `Opaque<T>` itself
// and `&'static T`.
DefKind::OpaqueTy => bug!("unimplemented implied bounds for nested opaque types"),
def_kind => {
bug!("unimplemented implied bounds for opaque types with parent {def_kind:?}")
}
},
DefKind::Mod
| DefKind::Struct
| DefKind::Union
| DefKind::Enum
| DefKind::Variant
| DefKind::Trait
| DefKind::TyAlias
| DefKind::ForeignTy
| DefKind::TraitAlias
| DefKind::TyParam
| DefKind::Const
| DefKind::ConstParam
| DefKind::Static(_)
| DefKind::Ctor(_, _)
| DefKind::Macro(_)
| DefKind::ExternCrate
| DefKind::Use
| DefKind::ForeignMod
| DefKind::AnonConst
| DefKind::InlineConst
| DefKind::Field
| DefKind::LifetimeParam
| DefKind::GlobalAsm
| DefKind::Closure
| DefKind::Generator => ty::List::empty(),
}
}
fn fn_sig_spans(tcx: TyCtxt<'_>, def_id: LocalDefId) -> impl Iterator<Item = Span> + '_ {
let node = tcx.hir().get(tcx.local_def_id_to_hir_id(def_id));
if let Some(decl) = node.fn_decl() {
decl.inputs.iter().map(|ty| ty.span).chain(iter::once(decl.output.span()))
} else {
bug!("unexpected item for fn {def_id:?}: {node:?}")
}
}
fn impl_spans(tcx: TyCtxt<'_>, def_id: LocalDefId) -> impl Iterator<Item = Span> + '_ {
let item = tcx.hir().expect_item(def_id);
if let hir::ItemKind::Impl(impl_) = item.kind {
let trait_args = impl_
.of_trait
.into_iter()
.flat_map(|trait_ref| trait_ref.path.segments.last().unwrap().args().args)
.map(|arg| arg.span());
let dummy_spans_for_default_args =
impl_.of_trait.into_iter().flat_map(|trait_ref| iter::repeat(trait_ref.path.span));
iter::once(impl_.self_ty.span).chain(trait_args).chain(dummy_spans_for_default_args)
} else {
bug!("unexpected item for impl {def_id:?}: {item:?}")
}
}
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