Skip to content

Remove variances_of on RPITIT GATs, remove its one use-case #113427

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Jul 8, 2023
Merged

Remove variances_of on RPITIT GATs, remove its one use-case #113427

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
12 changes: 3 additions & 9 deletions compiler/rustc_hir_analysis/src/variance/mod.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -7,7 +7,7 @@ use rustc_arena::DroplessArena;
use rustc_hir::def::DefKind;
use rustc_hir::def_id::{DefId, LocalDefId};
use rustc_middle::query::Providers;
use rustc_middle::ty::{self, CrateVariancesMap, ImplTraitInTraitData, SubstsRef, Ty, TyCtxt};
use rustc_middle::ty::{self, CrateVariancesMap, SubstsRef, Ty, TyCtxt};
use rustc_middle::ty::{TypeSuperVisitable, TypeVisitable};
use std::ops::ControlFlow;

Expand Down Expand Up @@ -59,13 +59,6 @@ fn variances_of(tcx: TyCtxt<'_>, item_def_id: LocalDefId) -> &[ty::Variance] {
DefKind::OpaqueTy | DefKind::ImplTraitPlaceholder => {
return variance_of_opaque(tcx, item_def_id);
}
DefKind::AssocTy => {
Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This is unreachable given the deleted code below.

if let Some(ImplTraitInTraitData::Trait { .. }) =
tcx.opt_rpitit_info(item_def_id.to_def_id())
{
return variance_of_opaque(tcx, item_def_id);
}
}
_ => {}
}

Expand Down Expand Up @@ -125,7 +118,8 @@ fn variance_of_opaque(tcx: TyCtxt<'_>, item_def_id: LocalDefId) -> &[ty::Varianc
// FIXME(-Zlower-impl-trait-in-trait-to-assoc-ty) check whether this is necessary
// at all for RPITITs.
ty::Alias(_, ty::AliasTy { def_id, substs, .. })
if self.tcx.is_impl_trait_in_trait(*def_id) =>
if self.tcx.is_impl_trait_in_trait(*def_id)
&& !self.tcx.lower_impl_trait_in_trait_to_assoc_ty() =>
Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

In the new lowering scheme, we should never need to consider the variances on a RPITIT GAT.

{
self.visit_opaque(*def_id, substs)
}
Expand Down
11 changes: 0 additions & 11 deletions compiler/rustc_infer/src/infer/opaque_types.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -473,17 +473,6 @@ where
}
}

ty::Alias(ty::Projection, proj) if self.tcx.is_impl_trait_in_trait(proj.def_id) => {
Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

In the new lowering scheme, we should never need to consider the variances of a RPITIT GAT.

// Skip lifetime parameters that are not captures.
let variances = self.tcx.variances_of(proj.def_id);

for (v, s) in std::iter::zip(variances, proj.substs.iter()) {
if *v != ty::Variance::Bivariant {
s.visit_with(self);
}
}
}

_ => {
ty.super_visit_with(self);
}
Expand Down