diff options
| -rw-r--r-- | compiler/rustc_infer/src/infer/lexical_region_resolve/mod.rs | 111 |
1 files changed, 46 insertions, 65 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 0ed57706790..5f13b2b3deb 100644 --- a/compiler/rustc_infer/src/infer/lexical_region_resolve/mod.rs +++ b/compiler/rustc_infer/src/infer/lexical_region_resolve/mod.rs @@ -15,6 +15,7 @@ use rustc_data_structures::graph::implementation::{ use rustc_data_structures::intern::Interned; use rustc_index::vec::{Idx, 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, ReFree, ReStatic}; use rustc_middle::ty::{ReLateBound, RePlaceholder, ReVar}; @@ -195,6 +196,36 @@ 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) + } + + 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 @@ -237,40 +268,15 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> { true } VarValue::Value(cur_region) => { - let lub = match *cur_region { - ReLateBound(..) | ReErased => { - bug!("cannot relate region: {:?}", cur_region); - } - - ReVar(v_id) => { - span_bug!( - self.var_infos[v_id].origin.span(), - "lub_concrete_regions invoked with non-concrete regions: {:?}", - cur_region, - ); - } - - ReStatic => { - // nothing lives longer than `'static` - self.tcx().lifetimes.re_static - } - - ReEarlyBound(_) | ReFree(_) => { - // All empty regions are less than early-bound, free, - // and scope regions. + 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 } - - RePlaceholder(placeholder) => { - // 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. - if a_universe == placeholder.universe { - cur_region - } else { - self.tcx().lifetimes.re_static - } - } + Err(_) => self.tcx().lifetimes.re_static, }; if lub == cur_region { @@ -368,40 +374,15 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> { match *b_data { VarValue::Empty(empty_ui) => { - let lub = match *a_region { - ReLateBound(..) | ReErased => { - bug!("cannot relate region: {:?}", a_region); - } - - ReVar(v_id) => { - span_bug!( - self.var_infos[v_id].origin.span(), - "expand_node invoked with non-concrete regions: {:?}", - a_region, - ); - } - - ReStatic => { - // nothing lives longer than `'static` - self.tcx().lifetimes.re_static - } - - ReEarlyBound(_) | ReFree(_) => { - // All empty regions are less than early-bound, free, - // and scope regions. - 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) { - self.tcx().mk_region(RePlaceholder(placeholder)) - } else { - self.tcx().lifetimes.re_static - } + 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) => { + self.tcx().mk_region(RePlaceholder(placeholder)) } + Err(_) => self.tcx().lifetimes.re_static, }; debug!("Expanding value of {:?} from empty lifetime to {:?}", b_vid, lub); |