Introduce Region::get_name_or_anon.

For a common pattern.

Author: nnethercote

compiler/rustc_borrowck/src/universal_regions.rs

@@ -440,11 +440,7 @@ impl<'cx, 'tcx> UniversalRegionsBuilder<'cx, 'tcx> {
                     debug!(?r);
                     if !indices.indices.contains_key(&r) {
                         let region_vid = {
-                            let name = match r.get_name() {
-                                Some(name) => name,
-                                _ => Symbol::intern("anon"),
-                            };
-
+                            let name = r.get_name_or_anon();
                             self.infcx.next_nll_region_var(FR, || {
                                 RegionCtxt::LateBound(BoundRegionInfo::Name(name))
                             })
@@ -478,11 +474,7 @@ impl<'cx, 'tcx> UniversalRegionsBuilder<'cx, 'tcx> {
             debug!(?r);
             if !indices.indices.contains_key(&r) {
                 let region_vid = {
-                    let name = match r.get_name() {
-                        Some(name) => name,
-                        _ => Symbol::intern("anon"),
-                    };
-
+                    let name = r.get_name_or_anon();
                     self.infcx.next_nll_region_var(FR, || {
                         RegionCtxt::LateBound(BoundRegionInfo::Name(name))
                     })
@@ -768,15 +760,10 @@ impl<'cx, 'tcx> InferCtxtExt<'tcx> for BorrowckInferCtxt<'cx, 'tcx> {
         T: TypeFoldable<TyCtxt<'tcx>>,
     {
         self.infcx.tcx.fold_regions(value, |region, _depth| {
-            let name = match region.get_name() {
-                Some(name) => name,
-                _ => Symbol::intern("anon"),
-            };
+            let name = region.get_name_or_anon();
             debug!(?region, ?name);
 
-            let reg_var = self.next_nll_region_var(origin, || RegionCtxt::Free(name));
-
-            reg_var
+            self.next_nll_region_var(origin, || RegionCtxt::Free(name))
         })
     }
 
@@ -829,11 +816,7 @@ impl<'cx, 'tcx> InferCtxtExt<'tcx> for BorrowckInferCtxt<'cx, 'tcx> {
             debug!(?r);
             if !indices.indices.contains_key(&r) {
                 let region_vid = {
-                    let name = match r.get_name() {
-                        Some(name) => name,
-                        _ => Symbol::intern("anon"),
-                    };
-
+                    let name = r.get_name_or_anon();
                     self.next_nll_region_var(FR, || {
                         RegionCtxt::LateBound(BoundRegionInfo::Name(name))
                     })
@@ -855,11 +838,7 @@ impl<'cx, 'tcx> InferCtxtExt<'tcx> for BorrowckInferCtxt<'cx, 'tcx> {
             debug!(?r);
             if !indices.indices.contains_key(&r) {
                 let region_vid = {
-                    let name = match r.get_name() {
-                        Some(name) => name,
-                        _ => Symbol::intern("anon"),
-                    };
-
+                    let name = r.get_name_or_anon();
                     self.next_nll_region_var(FR, || {
                         RegionCtxt::LateBound(BoundRegionInfo::Name(name))
                     })

compiler/rustc_middle/src/ty/sty.rs

@@ -1621,19 +1621,24 @@ impl<'tcx> Region<'tcx> {
 
     pub fn get_name(self) -> Option<Symbol> {
         if self.has_name() {
-            let name = match *self {
+            match *self {
                 ty::ReEarlyBound(ebr) => Some(ebr.name),
                 ty::ReLateBound(_, br) => br.kind.get_name(),
                 ty::ReFree(fr) => fr.bound_region.get_name(),
                 ty::ReStatic => Some(kw::StaticLifetime),
                 ty::RePlaceholder(placeholder) => placeholder.bound.kind.get_name(),
                 _ => None,
-            };
-
-            return name;
+            }
+        } else {
+            None
         }
+    }
 
-        None
+    pub fn get_name_or_anon(self) -> Symbol {
+        match self.get_name() {
+            Some(name) => name,
+            None => Symbol::intern("anon"),
+        }
     }
 
     /// Is this region named by the user?