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use infer::outlives::free_region_map::{FreeRegionMap, FreeRegionRelations};
use hir::def_id::DefId;
use middle::region;
use ty::{self, TyCtxt, Region};
pub struct RegionRelations<'a, 'gcx: 'tcx, 'tcx: 'a> {
pub tcx: TyCtxt<'a, 'gcx, 'tcx>,
pub context: DefId,
pub region_scope_tree: &'a region::ScopeTree,
pub free_regions: &'a FreeRegionMap<'tcx>,
}
impl<'a, 'gcx, 'tcx> RegionRelations<'a, 'gcx, 'tcx> {
pub fn new(
tcx: TyCtxt<'a, 'gcx, 'tcx>,
context: DefId,
region_scope_tree: &'a region::ScopeTree,
free_regions: &'a FreeRegionMap<'tcx>,
) -> Self {
Self {
tcx,
context,
region_scope_tree,
free_regions,
}
}
pub fn is_subregion_of(&self,
sub_region: ty::Region<'tcx>,
super_region: ty::Region<'tcx>)
-> bool {
let result = sub_region == super_region || {
match (sub_region, super_region) {
(ty::ReEmpty, _) |
(_, ty::ReStatic) =>
true,
(ty::ReScope(sub_scope), ty::ReScope(super_scope)) =>
self.region_scope_tree.is_subscope_of(*sub_scope, *super_scope),
(ty::ReScope(sub_scope), ty::ReEarlyBound(ref br)) => {
let fr_scope = self.region_scope_tree.early_free_scope(self.tcx, br);
self.region_scope_tree.is_subscope_of(*sub_scope, fr_scope)
}
(ty::ReScope(sub_scope), ty::ReFree(fr)) => {
let fr_scope = self.region_scope_tree.free_scope(self.tcx, fr);
self.region_scope_tree.is_subscope_of(*sub_scope, fr_scope)
}
(ty::ReEarlyBound(_), ty::ReEarlyBound(_)) |
(ty::ReFree(_), ty::ReEarlyBound(_)) |
(ty::ReEarlyBound(_), ty::ReFree(_)) |
(ty::ReFree(_), ty::ReFree(_)) =>
self.free_regions.sub_free_regions(sub_region, super_region),
_ =>
false,
}
};
let result = result || self.is_static(super_region);
debug!("is_subregion_of(sub_region={:?}, super_region={:?}) = {:?}",
sub_region, super_region, result);
result
}
fn is_static(&self, super_region: ty::Region<'tcx>) -> bool {
debug!("is_static(super_region={:?})", super_region);
match *super_region {
ty::ReStatic => true,
ty::ReEarlyBound(_) | ty::ReFree(_) => {
let re_static = self.tcx.mk_region(ty::ReStatic);
self.free_regions.sub_free_regions(&re_static, &super_region)
}
_ => false
}
}
pub fn lub_free_regions(&self,
r_a: Region<'tcx>,
r_b: Region<'tcx>)
-> Region<'tcx> {
self.free_regions.lub_free_regions(self.tcx, r_a, r_b)
}
}