| use rustc::infer::{InferCtxt, NLLRegionVariableOrigin}; |
| use rustc::mir::visit::{MutVisitor, TyContext}; |
| use rustc::mir::{BodyAndCache, Location, PlaceElem, Promoted}; |
| use rustc::ty::subst::SubstsRef; |
| use rustc::ty::{self, Ty, TyCtxt, TypeFoldable}; |
| use rustc_index::vec::IndexVec; |
| |
| /// Replaces all free regions appearing in the MIR with fresh |
| /// inference variables, returning the number of variables created. |
| pub fn renumber_mir<'tcx>( |
| infcx: &InferCtxt<'_, 'tcx>, |
| body: &mut BodyAndCache<'tcx>, |
| promoted: &mut IndexVec<Promoted, BodyAndCache<'tcx>>, |
| ) { |
| debug!("renumber_mir()"); |
| debug!("renumber_mir: body.arg_count={:?}", 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. |
| pub fn renumber_regions<'tcx, T>(infcx: &InferCtxt<'_, 'tcx>, value: &T) -> T |
| where |
| T: TypeFoldable<'tcx>, |
| { |
| debug!("renumber_regions(value={:?})", value); |
| |
| infcx.tcx.fold_regions(value, &mut false, |_region, _depth| { |
| let origin = NLLRegionVariableOrigin::Existential { from_forall: false }; |
| infcx.next_nll_region_var(origin) |
| }) |
| } |
| |
| struct NLLVisitor<'a, 'tcx> { |
| infcx: &'a InferCtxt<'a, 'tcx>, |
| } |
| |
| impl<'a, 'tcx> NLLVisitor<'a, 'tcx> { |
| fn renumber_regions<T>(&mut self, value: &T) -> T |
| where |
| T: TypeFoldable<'tcx>, |
| { |
| renumber_regions(self.infcx, value) |
| } |
| } |
| |
| impl<'a, 'tcx> MutVisitor<'tcx> for NLLVisitor<'a, 'tcx> { |
| fn tcx(&self) -> TyCtxt<'tcx> { |
| self.infcx.tcx |
| } |
| |
| fn visit_ty(&mut self, ty: &mut Ty<'tcx>, ty_context: TyContext) { |
| debug!("visit_ty(ty={:?}, ty_context={:?})", ty, ty_context); |
| |
| *ty = self.renumber_regions(ty); |
| |
| debug!("visit_ty: ty={:?}", ty); |
| } |
| |
| fn process_projection_elem(&mut self, elem: &PlaceElem<'tcx>) -> Option<PlaceElem<'tcx>> { |
| if let PlaceElem::Field(field, ty) = elem { |
| let new_ty = self.renumber_regions(ty); |
| |
| if new_ty != *ty { |
| return Some(PlaceElem::Field(*field, new_ty)); |
| } |
| } |
| |
| None |
| } |
| |
| fn visit_substs(&mut self, substs: &mut SubstsRef<'tcx>, location: Location) { |
| debug!("visit_substs(substs={:?}, location={:?})", substs, location); |
| |
| *substs = self.renumber_regions(&{ *substs }); |
| |
| debug!("visit_substs: substs={:?}", substs); |
| } |
| |
| fn visit_region(&mut self, region: &mut ty::Region<'tcx>, location: Location) { |
| debug!("visit_region(region={:?}, location={:?})", region, location); |
| |
| let old_region = *region; |
| *region = self.renumber_regions(&old_region); |
| |
| debug!("visit_region: region={:?}", region); |
| } |
| |
| fn visit_const(&mut self, constant: &mut &'tcx ty::Const<'tcx>, _location: Location) { |
| *constant = self.renumber_regions(&*constant); |
| } |
| } |