get rid of RefCell in TransitiveRelation

compiler/rustc_typeck/src/check/compare_method.rs

@@ -401,8 +401,9 @@ fn compare_predicate_entailment<'tcx>(
 
         // Finally, resolve all regions. This catches wily misuses of
         // lifetime parameters.
-        let mut outlives_environment = OutlivesEnvironment::new(param_env);
+        let mut outlives_environment = OutlivesEnvironment::builder(param_env);
         outlives_environment.add_implied_bounds(infcx, wf_tys, impl_m_hir_id);
+        let outlives_environment = outlives_environment.build();
         infcx.check_region_obligations_and_report_errors(
             impl_m.def_id.expect_local(),
             &outlives_environment,
@@ -1513,8 +1514,9 @@ pub fn check_type_bounds<'tcx>(
 
         // Finally, resolve all regions. This catches wily misuses of
         // lifetime parameters.
-        let mut outlives_environment = OutlivesEnvironment::new(param_env);
+        let mut outlives_environment = OutlivesEnvironment::builder(param_env);
         outlives_environment.add_implied_bounds(&infcx, assumed_wf_types, impl_ty_hir_id);
+        let outlives_environment = outlives_environment.build();
         infcx.check_region_obligations_and_report_errors(
             impl_ty.def_id.expect_local(),
             &outlives_environment,

compiler/rustc_typeck/src/check/regionck.rs

@@ -1,7 +1,7 @@
 use crate::outlives::outlives_bounds::InferCtxtExt as _;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir as hir;
-use rustc_infer::infer::outlives::env::OutlivesEnvironment;
+use rustc_infer::infer::outlives::env::OutlivesEnvironmentBuilder;
 use rustc_infer::infer::InferCtxt;
 use rustc_middle::ty::Ty;
 
@@ -14,7 +14,7 @@ pub(crate) trait OutlivesEnvironmentExt<'tcx> {
     );
 }
 
-impl<'tcx> OutlivesEnvironmentExt<'tcx> for OutlivesEnvironment<'tcx> {
+impl<'tcx> OutlivesEnvironmentExt<'tcx> for OutlivesEnvironmentBuilder<'tcx> {
     /// This method adds "implied bounds" into the outlives environment.
     /// Implied bounds are outlives relationships that we can deduce
     /// on the basis that certain types must be well-formed -- these are

compiler/rustc_typeck/src/check/wfcheck.rs

@@ -104,8 +104,9 @@ pub(super) fn enter_wf_checking_ctxt<'tcx, F>(
             return;
         }
 
-        let mut outlives_environment = OutlivesEnvironment::new(param_env);
+        let mut outlives_environment = OutlivesEnvironment::builder(param_env);
         outlives_environment.add_implied_bounds(infcx, assumed_wf_types, body_id);
+        let outlives_environment = outlives_environment.build();
         infcx.check_region_obligations_and_report_errors(body_def_id, &outlives_environment);
     })
 }
@@ -694,8 +695,9 @@ fn resolve_regions_with_wf_tys<'tcx>(
     // region constraints get added and solved there and we need to test each
     // call individually.
     tcx.infer_ctxt().enter(|infcx| {
-        let mut outlives_environment = OutlivesEnvironment::new(param_env);
+        let mut outlives_environment = OutlivesEnvironment::builder(param_env);
         outlives_environment.add_implied_bounds(&infcx, wf_tys.clone(), id);
+        let outlives_environment = outlives_environment.build();
         let region_bound_pairs = outlives_environment.region_bound_pairs();
 
         add_constraints(&infcx, region_bound_pairs);

compiler/rustc_typeck/src/impl_wf_check/min_specialization.rs

@@ -166,8 +166,7 @@ fn get_impl_substs<'tcx>(
             return None;
         };
         Some((impl1_substs, impl2_substs))
-    })
-}
+    })}
 
 /// Returns a list of all of the unconstrained subst of the given impl.
 ///