Rename UniversalRegionRelationsBuilder.

Rename it as `CreateResultBuilder`, because it builds a `CreateResult`.
(`CreateResult` contains a `UniversalRegionRelations`, so maybe the name
made more sense in the past.) Also rename the `create` method as
`build`, to match the `Builder` in the name.

Author: nnethercote

compiler/rustc_borrowck/src/type_check/free_region_relations.rs

@@ -57,7 +57,7 @@ pub(crate) fn create<'tcx>(
     universal_regions: Rc<UniversalRegions<'tcx>>,
     constraints: &mut MirTypeckRegionConstraints<'tcx>,
 ) -> CreateResult<'tcx> {
-    UniversalRegionRelationsBuilder {
+    CreateResultBuilder {
         infcx,
         param_env,
         implicit_region_bound,
@@ -67,7 +67,7 @@ pub(crate) fn create<'tcx>(
         outlives: Default::default(),
         inverse_outlives: Default::default(),
     }
-    .create()
+    .build()
 }
 
 impl UniversalRegionRelations<'_> {
@@ -181,7 +181,7 @@ impl UniversalRegionRelations<'_> {
     }
 }
 
-struct UniversalRegionRelationsBuilder<'a, 'tcx> {
+struct CreateResultBuilder<'a, 'tcx> {
     infcx: &'a InferCtxt<'tcx>,
     param_env: ty::ParamEnv<'tcx>,
     universal_regions: Rc<UniversalRegions<'tcx>>,
@@ -194,7 +194,7 @@ struct UniversalRegionRelationsBuilder<'a, 'tcx> {
     region_bound_pairs: RegionBoundPairs<'tcx>,
 }
 
-impl<'tcx> UniversalRegionRelationsBuilder<'_, 'tcx> {
+impl<'tcx> CreateResultBuilder<'_, 'tcx> {
     /// Records in the `outlives_relation` (and
     /// `inverse_outlives_relation`) that `fr_a: fr_b`.
     fn relate_universal_regions(&mut self, fr_a: RegionVid, fr_b: RegionVid) {
@@ -204,7 +204,7 @@ impl<'tcx> UniversalRegionRelationsBuilder<'_, 'tcx> {
     }
 
     #[instrument(level = "debug", skip(self))]
-    pub(crate) fn create(mut self) -> CreateResult<'tcx> {
+    pub(crate) fn build(mut self) -> CreateResult<'tcx> {
         let tcx = self.infcx.tcx;
         let defining_ty_def_id = self.universal_regions.defining_ty.def_id().expect_local();
         let span = tcx.def_span(defining_ty_def_id);