Remove free_region_map from TypeckTables

It was unused.

Author: matthewjasper

src/librustc/ty/context.rs

@@ -23,7 +23,6 @@ use crate::mir::{
 };
 use crate::traits;
 use crate::traits::{Clause, Clauses, Goal, GoalKind, Goals};
-use crate::ty::free_region_map::FreeRegionMap;
 use crate::ty::layout::{LayoutDetails, TargetDataLayout, VariantIdx};
 use crate::ty::query;
 use crate::ty::steal::Steal;
@@ -416,11 +415,6 @@ pub struct TypeckTables<'tcx> {
     /// this field will be set to `true`.
     pub tainted_by_errors: bool,
 
-    /// Stores the free-region relationships that were deduced from
-    /// its where-clauses and parameter types. These are then
-    /// read-again by borrowck.
-    pub free_region_map: FreeRegionMap<'tcx>,
-
     /// All the opaque types that are restricted to concrete types
     /// by this function.
     pub concrete_opaque_types: FxHashMap<DefId, ResolvedOpaqueTy<'tcx>>,
@@ -456,7 +450,6 @@ impl<'tcx> TypeckTables<'tcx> {
             coercion_casts: Default::default(),
             used_trait_imports: Lrc::new(Default::default()),
             tainted_by_errors: false,
-            free_region_map: Default::default(),
             concrete_opaque_types: Default::default(),
             upvar_list: Default::default(),
             generator_interior_types: Default::default(),
@@ -719,7 +712,6 @@ impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for TypeckTables<'tcx> {
 
             ref used_trait_imports,
             tainted_by_errors,
-            ref free_region_map,
             ref concrete_opaque_types,
             ref upvar_list,
             ref generator_interior_types,
@@ -757,7 +749,6 @@ impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for TypeckTables<'tcx> {
             coercion_casts.hash_stable(hcx, hasher);
             used_trait_imports.hash_stable(hcx, hasher);
             tainted_by_errors.hash_stable(hcx, hasher);
-            free_region_map.hash_stable(hcx, hasher);
             concrete_opaque_types.hash_stable(hcx, hasher);
             upvar_list.hash_stable(hcx, hasher);
             generator_interior_types.hash_stable(hcx, hasher);

src/librustc_typeck/check/regionck.rs

@@ -125,9 +125,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             rcx.visit_region_obligations(id);
         }
         rcx.resolve_regions_and_report_errors(SuppressRegionErrors::when_nll_is_enabled(self.tcx));
-
-        assert!(self.tables.borrow().free_region_map.is_empty());
-        self.tables.borrow_mut().free_region_map = rcx.outlives_environment.into_free_region_map();
     }
 
     /// Region checking during the WF phase for items. `wf_tys` are the
@@ -169,12 +166,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
 
         rcx.resolve_regions_and_report_errors(SuppressRegionErrors::when_nll_is_enabled(self.tcx));
-
-        // In this mode, we also copy the free-region-map into the
-        // tables of the enclosing fcx. In the other regionck modes
-        // (e.g., `regionck_item`), we don't have an enclosing tables.
-        assert!(self.tables.borrow().free_region_map.is_empty());
-        self.tables.borrow_mut().free_region_map = rcx.outlives_environment.into_free_region_map();
     }
 }
 

src/librustc_typeck/check/writeback.rs

@@ -62,7 +62,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         wbcx.visit_fru_field_types();
         wbcx.visit_opaque_types(body.value.span);
         wbcx.visit_coercion_casts();
-        wbcx.visit_free_region_map();
         wbcx.visit_user_provided_tys();
         wbcx.visit_user_provided_sigs();
         wbcx.visit_generator_interior_types();
@@ -358,11 +357,6 @@ impl<'cx, 'tcx> WritebackCx<'cx, 'tcx> {
         }
     }
 
-    fn visit_free_region_map(&mut self) {
-        self.tables.free_region_map = self.fcx.tables.borrow().free_region_map.clone();
-        debug_assert!(!self.tables.free_region_map.elements().any(|r| r.has_local_value()));
-    }
-
     fn visit_user_provided_tys(&mut self) {
         let fcx_tables = self.fcx.tables.borrow();
         debug_assert_eq!(fcx_tables.local_id_root, self.tables.local_id_root);