diff options
| -rw-r--r-- | src/librustc_mir/borrow_check/nll/type_check/relate_tys.rs | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/src/librustc_mir/borrow_check/nll/type_check/relate_tys.rs b/src/librustc_mir/borrow_check/nll/type_check/relate_tys.rs index 0badef49f66..0e945ad3341 100644 --- a/src/librustc_mir/borrow_check/nll/type_check/relate_tys.rs +++ b/src/librustc_mir/borrow_check/nll/type_check/relate_tys.rs @@ -194,6 +194,14 @@ impl<'cx, 'bccx, 'gcx, 'tcx> TypeRelating<'cx, 'bccx, 'gcx, 'tcx> { scope } + /// When we encounter binders during the type traversal, we record + /// the value to substitute for each of the things contained in + /// that binder. (This will be either a universal placeholder or + /// an existential inference variable.) Given the debruijn index + /// `debruijn` (and name `br`) of some binder we have now + /// encountered, this routine finds the value that we instantiated + /// the region with; to do so, it indexes backwards into the list + /// of ambient scopes `scopes`. fn lookup_bound_region( &self, debruijn: ty::DebruijnIndex, @@ -211,6 +219,9 @@ impl<'cx, 'bccx, 'gcx, 'tcx> TypeRelating<'cx, 'bccx, 'gcx, 'tcx> { scope.map[br] } + /// If `r` is a bound region, find the scope in which it is bound + /// (from `scopes`) and return the value that we instantiated it + /// with. Otherwise just return `r`. fn replace_bound_region( &self, universal_regions: &UniversalRegions<'tcx>, @@ -226,6 +237,8 @@ impl<'cx, 'bccx, 'gcx, 'tcx> TypeRelating<'cx, 'bccx, 'gcx, 'tcx> { } } + /// Push a new outlives requirement into our output set of + /// constraints. fn push_outlives(&mut self, sup: RegionVid, sub: RegionVid) { debug!("push_outlives({:?}: {:?})", sup, sub); @@ -243,6 +256,9 @@ impl<'cx, 'bccx, 'gcx, 'tcx> TypeRelating<'cx, 'bccx, 'gcx, 'tcx> { } } + /// When we encounter a canonical variable `var` in the output, + /// equate it with `kind`. If the variable has been previously + /// equated, then equate it again. fn equate_var( &mut self, var: CanonicalVar, |