diff options
| -rw-r--r-- | compiler/rustc_infer/src/infer/lexical_region_resolve/mod.rs | 91 |
1 files changed, 30 insertions, 61 deletions
diff --git a/compiler/rustc_infer/src/infer/lexical_region_resolve/mod.rs b/compiler/rustc_infer/src/infer/lexical_region_resolve/mod.rs index 60d9d6578f5..cb651363982 100644 --- a/compiler/rustc_infer/src/infer/lexical_region_resolve/mod.rs +++ b/compiler/rustc_infer/src/infer/lexical_region_resolve/mod.rs @@ -15,7 +15,6 @@ use rustc_data_structures::graph::implementation::{ use rustc_data_structures::intern::Interned; use rustc_index::{IndexSlice, IndexVec}; use rustc_middle::ty::fold::TypeFoldable; -use rustc_middle::ty::PlaceholderRegion; use rustc_middle::ty::{self, Ty, TyCtxt}; use rustc_middle::ty::{ReEarlyBound, ReErased, ReError, ReFree, ReStatic}; use rustc_middle::ty::{ReLateBound, RePlaceholder, ReVar}; @@ -173,38 +172,6 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> { } } - /// Gets the LUb of a given region and the empty region - fn lub_empty(&self, a_region: Region<'tcx>) -> Result<Region<'tcx>, PlaceholderRegion> { - match *a_region { - ReLateBound(..) | ReErased => { - bug!("cannot relate region: {:?}", a_region); - } - - ReVar(v_id) => { - span_bug!( - self.var_infos[v_id].origin.span(), - "lub invoked with non-concrete regions: {:?}", - a_region, - ); - } - - ReStatic => { - // nothing lives longer than `'static` - Ok(self.tcx().lifetimes.re_static) - } - - ReError(_) => Ok(a_region), - - ReEarlyBound(_) | ReFree(_) => { - // All empty regions are less than early-bound, free, - // and scope regions. - Ok(a_region) - } - - RePlaceholder(placeholder) => Err(placeholder), - } - } - fn expansion(&self, var_values: &mut LexicalRegionResolutions<'tcx>) { // In the first pass, we expand region vids according to constraints we // have previously found. In the second pass, we loop through the region @@ -247,27 +214,25 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> { true } VarValue::Value(cur_region) => { - let lub = match self.lub_empty(cur_region) { - Ok(r) => r, - // If the empty and placeholder regions are in the same universe, - // then the LUB is the Placeholder region (which is the cur_region). - // If they are not in the same universe, the LUB is the Static lifetime. - Err(placeholder) if a_universe == placeholder.universe => { - cur_region + match *cur_region { + // If this empty region is from a universe that can name the + // placeholder universe, then the LUB is the Placeholder region + // (which is the cur_region). Otherwise, the LUB is the Static + // lifetime. + RePlaceholder(placeholder) + if !a_universe.can_name(placeholder.universe) => + { + let lub = self.tcx().lifetimes.re_static; + debug!( + "Expanding value of {:?} from {:?} to {:?}", + b_vid, cur_region, lub + ); + + *b_data = VarValue::Value(lub); + true } - Err(_) => self.tcx().lifetimes.re_static, - }; - - if lub == cur_region { - false - } else { - debug!( - "Expanding value of {:?} from {:?} to {:?}", - b_vid, cur_region, lub - ); - - *b_data = VarValue::Value(lub); - true + + _ => false, } } @@ -341,15 +306,19 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> { match *b_data { VarValue::Empty(empty_ui) => { - let lub = match self.lub_empty(a_region) { - Ok(r) => r, - // If this empty region is from a universe that can - // name the placeholder, then the placeholder is - // larger; otherwise, the only ancestor is `'static`. - Err(placeholder) if empty_ui.can_name(placeholder.universe) => { - ty::Region::new_placeholder(self.tcx(), placeholder) + let lub = match *a_region { + RePlaceholder(placeholder) => { + // If this empty region is from a universe that can + // name the placeholder, then the placeholder is + // larger; otherwise, the only ancestor is `'static`. + if empty_ui.can_name(placeholder.universe) { + ty::Region::new_placeholder(self.tcx(), placeholder) + } else { + self.tcx().lifetimes.re_static + } } - Err(_) => self.tcx().lifetimes.re_static, + + _ => a_region, }; debug!("Expanding value of {:?} from empty lifetime to {:?}", b_vid, lub); |