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#![deny(rustc::untranslatable_diagnostic)]
#![deny(rustc::diagnostic_outside_of_impl)]
use crate::BorrowckInferCtxt;
use rustc_index::vec::IndexVec;
use rustc_infer::infer::NllRegionVariableOrigin;
use rustc_middle::mir::visit::{MutVisitor, TyContext};
use rustc_middle::mir::Constant;
use rustc_middle::mir::{Body, Location, Promoted};
use rustc_middle::ty::subst::SubstsRef;
use rustc_middle::ty::{self, Ty, TyCtxt, TypeFoldable};
use rustc_span::{Span, Symbol};
/// Replaces all free regions appearing in the MIR with fresh
/// inference variables, returning the number of variables created.
#[instrument(skip(infcx, body, promoted), level = "debug")]
pub fn renumber_mir<'tcx>(
infcx: &BorrowckInferCtxt<'_, 'tcx>,
body: &mut Body<'tcx>,
promoted: &mut IndexVec<Promoted, Body<'tcx>>,
) {
debug!(?body.arg_count);
let mut visitor = NllVisitor { infcx };
for body in promoted.iter_mut() {
visitor.visit_body(body);
}
visitor.visit_body(body);
}
/// Replaces all regions appearing in `value` with fresh inference
/// variables.
#[instrument(skip(infcx, get_ctxt_fn), level = "debug")]
pub(crate) fn renumber_regions<'tcx, T, F>(
infcx: &BorrowckInferCtxt<'_, 'tcx>,
value: T,
get_ctxt_fn: F,
) -> T
where
T: TypeFoldable<TyCtxt<'tcx>>,
F: Fn() -> RegionCtxt,
{
infcx.tcx.fold_regions(value, |_region, _depth| {
let origin = NllRegionVariableOrigin::Existential { from_forall: false };
infcx.next_nll_region_var(origin, || get_ctxt_fn())
})
}
#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
pub(crate) enum BoundRegionInfo {
Name(Symbol),
Span(Span),
}
#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
pub(crate) enum RegionCtxt {
Location(Location),
TyContext(TyContext),
Free(Symbol),
Bound(BoundRegionInfo),
LateBound(BoundRegionInfo),
Existential(Option<Symbol>),
Placeholder(BoundRegionInfo),
Unknown,
}
impl RegionCtxt {
/// Used to determine the representative of a component in the strongly connected
/// constraint graph
pub(crate) fn preference_value(self) -> usize {
let _anon = Symbol::intern("anon");
match self {
RegionCtxt::Unknown => 1,
RegionCtxt::Existential(None) => 2,
RegionCtxt::Existential(Some(_anon)) | RegionCtxt::Free(_anon) => 2,
RegionCtxt::Location(_) => 3,
RegionCtxt::TyContext(_) => 4,
_ => 5,
}
}
}
struct NllVisitor<'a, 'tcx> {
infcx: &'a BorrowckInferCtxt<'a, 'tcx>,
}
impl<'a, 'tcx> NllVisitor<'a, 'tcx> {
fn renumber_regions<T, F>(&mut self, value: T, region_ctxt_fn: F) -> T
where
T: TypeFoldable<TyCtxt<'tcx>>,
F: Fn() -> RegionCtxt,
{
renumber_regions(self.infcx, value, region_ctxt_fn)
}
}
impl<'a, 'tcx> MutVisitor<'tcx> for NllVisitor<'a, 'tcx> {
fn tcx(&self) -> TyCtxt<'tcx> {
self.infcx.tcx
}
#[instrument(skip(self), level = "debug")]
fn visit_ty(&mut self, ty: &mut Ty<'tcx>, ty_context: TyContext) {
*ty = self.renumber_regions(*ty, || RegionCtxt::TyContext(ty_context));
debug!(?ty);
}
#[instrument(skip(self), level = "debug")]
fn visit_substs(&mut self, substs: &mut SubstsRef<'tcx>, location: Location) {
*substs = self.renumber_regions(*substs, || RegionCtxt::Location(location));
debug!(?substs);
}
#[instrument(skip(self), level = "debug")]
fn visit_region(&mut self, region: &mut ty::Region<'tcx>, location: Location) {
let old_region = *region;
*region = self.renumber_regions(old_region, || RegionCtxt::Location(location));
debug!(?region);
}
#[instrument(skip(self), level = "debug")]
fn visit_constant(&mut self, constant: &mut Constant<'tcx>, _location: Location) {
let literal = constant.literal;
constant.literal = self.renumber_regions(literal, || RegionCtxt::Location(_location));
debug!("constant: {:#?}", constant);
}
}
|
