1 use rustc::infer::{InferCtxt, NLLRegionVariableOrigin};
2 use rustc::mir::visit::{MutVisitor, TyContext};
3 use rustc::mir::{BodyAndCache, Location, PlaceElem, Promoted};
4 use rustc::ty::subst::SubstsRef;
5 use rustc::ty::{self, Ty, TyCtxt, TypeFoldable};
6 use rustc_index::vec::IndexVec;
8 /// Replaces all free regions appearing in the MIR with fresh
9 /// inference variables, returning the number of variables created.
10 pub fn renumber_mir<'tcx>(
11 infcx: &InferCtxt<'_, 'tcx>,
12 body: &mut BodyAndCache<'tcx>,
13 promoted: &mut IndexVec<Promoted, BodyAndCache<'tcx>>,
15 debug!("renumber_mir()");
16 debug!("renumber_mir: body.arg_count={:?}", body.arg_count);
18 let mut visitor = NLLVisitor { infcx };
20 for body in promoted.iter_mut() {
21 visitor.visit_body(body);
24 visitor.visit_body(body);
27 /// Replaces all regions appearing in `value` with fresh inference
29 pub fn renumber_regions<'tcx, T>(infcx: &InferCtxt<'_, 'tcx>, value: &T) -> T
31 T: TypeFoldable<'tcx>,
33 debug!("renumber_regions(value={:?})", value);
35 infcx.tcx.fold_regions(value, &mut false, |_region, _depth| {
36 let origin = NLLRegionVariableOrigin::Existential { from_forall: false };
37 infcx.next_nll_region_var(origin)
41 struct NLLVisitor<'a, 'tcx> {
42 infcx: &'a InferCtxt<'a, 'tcx>,
45 impl<'a, 'tcx> NLLVisitor<'a, 'tcx> {
46 fn renumber_regions<T>(&mut self, value: &T) -> T
48 T: TypeFoldable<'tcx>,
50 renumber_regions(self.infcx, value)
54 impl<'a, 'tcx> MutVisitor<'tcx> for NLLVisitor<'a, 'tcx> {
55 fn tcx(&self) -> TyCtxt<'tcx> {
59 fn visit_ty(&mut self, ty: &mut Ty<'tcx>, ty_context: TyContext) {
60 debug!("visit_ty(ty={:?}, ty_context={:?})", ty, ty_context);
62 *ty = self.renumber_regions(ty);
64 debug!("visit_ty: ty={:?}", ty);
67 fn process_projection_elem(&mut self, elem: &PlaceElem<'tcx>) -> Option<PlaceElem<'tcx>> {
68 if let PlaceElem::Field(field, ty) = elem {
69 let new_ty = self.renumber_regions(ty);
72 return Some(PlaceElem::Field(*field, new_ty));
79 fn visit_substs(&mut self, substs: &mut SubstsRef<'tcx>, location: Location) {
80 debug!("visit_substs(substs={:?}, location={:?})", substs, location);
82 *substs = self.renumber_regions(&{ *substs });
84 debug!("visit_substs: substs={:?}", substs);
87 fn visit_region(&mut self, region: &mut ty::Region<'tcx>, location: Location) {
88 debug!("visit_region(region={:?}, location={:?})", region, location);
90 let old_region = *region;
91 *region = self.renumber_regions(&old_region);
93 debug!("visit_region: region={:?}", region);
96 fn visit_const(&mut self, constant: &mut &'tcx ty::Const<'tcx>, _location: Location) {
97 *constant = self.renumber_regions(&*constant);