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Rollup merge of #122027 - compiler-errors:rpitit-cycle, r=spastorino

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Uplift some feeding out of `associated_type_for_impl_trait_in_impl` and into queries

This PR moves the `type_of` and `generics_of` query feeding out of `associated_type_for_impl_trait_in_impl`, since eagerly feeding results in query cycles due to a subtle interaction with `resolve_bound_vars`.

Fixes #122019

r? spastorino
This commit is contained in:
Matthias Krüger 2024-03-06 22:41:55 +01:00 • committed by GitHub
commit 34cffae24c
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GPG key ID: B5690EEEBB952194
5 changed files with 85 additions and 60 deletions
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47
compiler/rustc_ty_utils/src/assoc.rs
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@ -4,7 +4,7 @@ use rustc_hir::def::DefKind;
use rustc_hir::def_id::{DefId, DefIdMap, LocalDefId};
use rustc_hir::intravisit::{self, Visitor};
use rustc_middle::query::Providers;
use rustc_middle::ty::{self, GenericArgs, ImplTraitInTraitData, Ty, TyCtxt};
use rustc_middle::ty::{self, ImplTraitInTraitData, TyCtxt};
use rustc_span::symbol::kw;
pub(crate) fn provide(providers: &mut Providers) {
@ -284,48 +284,8 @@ fn associated_type_for_impl_trait_in_trait(
// Copy defaultness of the containing function.
trait_assoc_ty.defaultness(tcx.defaultness(fn_def_id));
// Copy type_of of the opaque.
trait_assoc_ty.type_of(ty::EarlyBinder::bind(Ty::new_opaque(
tcx,
opaque_ty_def_id.to_def_id(),
GenericArgs::identity_for_item(tcx, opaque_ty_def_id),
)));
trait_assoc_ty.is_type_alias_impl_trait(false);
// Copy generics_of of the opaque type item but the trait is the parent.
trait_assoc_ty.generics_of({
let opaque_ty_generics = tcx.generics_of(opaque_ty_def_id);
let opaque_ty_parent_count = opaque_ty_generics.parent_count;
let mut params = opaque_ty_generics.params.clone();
let parent_generics = tcx.generics_of(trait_def_id);
let parent_count = parent_generics.parent_count + parent_generics.params.len();
let mut trait_fn_params = tcx.generics_of(fn_def_id).params.clone();
for param in &mut params {
param.index = param.index + parent_count as u32 + trait_fn_params.len() as u32
- opaque_ty_parent_count as u32;
}
trait_fn_params.extend(params);
params = trait_fn_params;
let param_def_id_to_index =
params.iter().map(|param| (param.def_id, param.index)).collect();
ty::Generics {
parent: Some(trait_def_id.to_def_id()),
parent_count,
params,
param_def_id_to_index,
has_self: opaque_ty_generics.has_self,
has_late_bound_regions: opaque_ty_generics.has_late_bound_regions,
host_effect_index: parent_generics.host_effect_index,
}
});
// There are no inferred outlives for the synthesized associated type.
trait_assoc_ty.inferred_outlives_of(&[]);
@ -382,8 +342,9 @@ fn associated_type_for_impl_trait_in_impl(
impl_assoc_ty.defaultness(tcx.defaultness(impl_fn_def_id));
// Copy generics_of the trait's associated item but the impl as the parent.
// FIXME(-Zlower-impl-trait-in-trait-to-assoc-ty) resolves to the trait instead of the impl
// generics.
// FIXME: This may be detrimental to diagnostics, as we resolve the early-bound vars
// here to paramswhose parent are items in the trait. We could synthesize new params
// here, but it seems overkill.
impl_assoc_ty.generics_of({
let trait_assoc_generics = tcx.generics_of(trait_assoc_def_id);
let trait_assoc_parent_count = trait_assoc_generics.parent_count;