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Use mk_ty_from_kind a bit less, clean up lifetime handling in borrowck #137763

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Use mk_ty_from_kind a bit less, clean up lifetime handling in borrowck #137763

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44 changes: 13 additions & 31 deletions compiler/rustc_borrowck/src/type_check/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -38,7 +38,7 @@ use rustc_mir_dataflow::move_paths::MoveData;
use rustc_mir_dataflow::points::DenseLocationMap;
use rustc_span::def_id::CRATE_DEF_ID;
use rustc_span::source_map::Spanned;
use rustc_span::{DUMMY_SP, Span, sym};
use rustc_span::{Span, sym};
use rustc_trait_selection::traits::query::type_op::custom::scrape_region_constraints;
use rustc_trait_selection::traits::query::type_op::{TypeOp, TypeOpOutput};
use tracing::{debug, instrument, trace};
Expand All @@ -51,7 +51,6 @@ use crate::polonius::legacy::{PoloniusFacts, PoloniusLocationTable};
use crate::polonius::{PoloniusContext, PoloniusLivenessContext};
use crate::region_infer::TypeTest;
use crate::region_infer::values::{LivenessValues, PlaceholderIndex, PlaceholderIndices};
use crate::renumber::RegionCtxt;
use crate::session_diagnostics::{MoveUnsized, SimdIntrinsicArgConst};
use crate::type_check::free_region_relations::{CreateResult, UniversalRegionRelations};
use crate::universal_regions::{DefiningTy, UniversalRegions};
Expand Down Expand Up @@ -2121,35 +2120,31 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
//
// Note that other checks (such as denying `dyn Send` -> `dyn
// Debug`) are in `rustc_hir_typeck`.
if let ty::Dynamic(src_tty, ..) = src_tail.kind()
&& let ty::Dynamic(dst_tty, ..) = dst_tail.kind()
if let ty::Dynamic(src_tty, _src_lt, _) = *src_tail.kind()
&& let ty::Dynamic(dst_tty, dst_lt, _) = *dst_tail.kind()
&& src_tty.principal().is_some()
&& dst_tty.principal().is_some()
{
// Remove auto traits.
// Auto trait checks are handled in `rustc_hir_typeck` as FCW.
let src_obj = tcx.mk_ty_from_kind(ty::Dynamic(
let src_obj = Ty::new_dynamic(
tcx,
tcx.mk_poly_existential_predicates(
&src_tty.without_auto_traits().collect::<Vec<_>>(),
),
tcx.lifetimes.re_static,
// FIXME: Once we disallow casting `*const dyn Trait + 'short`
// to `*const dyn Trait + 'long`, then this can just be `src_lt`.
dst_lt,
ty::Dyn,
));
let dst_obj = tcx.mk_ty_from_kind(ty::Dynamic(
);
let dst_obj = Ty::new_dynamic(
tcx,
tcx.mk_poly_existential_predicates(
&dst_tty.without_auto_traits().collect::<Vec<_>>(),
),
tcx.lifetimes.re_static,
dst_lt,
ty::Dyn,
));

// Replace trait object lifetimes with fresh vars, to allow
// casts like
// `*mut dyn FnOnce() + 'a` -> `*mut dyn FnOnce() + 'static`
let src_obj =
freshen_single_trait_object_lifetime(self.infcx, src_obj);
let dst_obj =
freshen_single_trait_object_lifetime(self.infcx, dst_obj);
);

debug!(?src_tty, ?dst_tty, ?src_obj, ?dst_obj);

Expand Down Expand Up @@ -2707,16 +2702,3 @@ impl<'tcx> TypeOp<'tcx> for InstantiateOpaqueType<'tcx> {
Ok(output)
}
}

fn freshen_single_trait_object_lifetime<'tcx>(
infcx: &BorrowckInferCtxt<'tcx>,
ty: Ty<'tcx>,
) -> Ty<'tcx> {
let &ty::Dynamic(tty, _, dyn_kind @ ty::Dyn) = ty.kind() else { bug!("expected trait object") };

let fresh = infcx
.next_region_var(rustc_infer::infer::RegionVariableOrigin::MiscVariable(DUMMY_SP), || {
RegionCtxt::Unknown
});
infcx.tcx.mk_ty_from_kind(ty::Dynamic(tty, fresh, dyn_kind))
}
10 changes: 6 additions & 4 deletions compiler/rustc_hir_typeck/src/cast.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -895,20 +895,22 @@ impl<'a, 'tcx> CastCheck<'tcx> {
// e.g. we want to allow `dyn T -> (dyn T,)`, etc.
//
// We also need to skip auto traits to emit an FCW and not an error.
let src_obj = tcx.mk_ty_from_kind(ty::Dynamic(
let src_obj = Ty::new_dynamic(
tcx,
tcx.mk_poly_existential_predicates(
&src_tty.without_auto_traits().collect::<Vec<_>>(),
),
tcx.lifetimes.re_erased,
ty::Dyn,
));
let dst_obj = tcx.mk_ty_from_kind(ty::Dynamic(
);
let dst_obj = Ty::new_dynamic(
tcx,
tcx.mk_poly_existential_predicates(
&dst_tty.without_auto_traits().collect::<Vec<_>>(),
),
tcx.lifetimes.re_erased,
ty::Dyn,
));
);

// `dyn Src = dyn Dst`, this checks for matching traits/generics/projections
// This is `fcx.demand_eqtype`, but inlined to give a better error.
Expand Down
2 changes: 1 addition & 1 deletion compiler/rustc_middle/src/ty/codec.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -224,7 +224,7 @@ impl<'tcx, D: TyDecoder<I = TyCtxt<'tcx>>> Decodable<D> for Ty<'tcx> {
})
} else {
let tcx = decoder.interner();
tcx.mk_ty_from_kind(rustc_type_ir::TyKind::decode(decoder))
tcx.mk_ty_from_kind(ty::TyKind::decode(decoder))
}
}
}
Expand Down
2 changes: 1 addition & 1 deletion compiler/rustc_middle/src/ty/sty.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -461,7 +461,7 @@ impl<'tcx> Ty<'tcx> {

#[inline]
pub fn new_param(tcx: TyCtxt<'tcx>, index: u32, name: Symbol) -> Ty<'tcx> {
tcx.mk_ty_from_kind(Param(ParamTy { index, name }))
Ty::new(tcx, Param(ParamTy { index, name }))
}

#[inline]
Expand Down
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