Add sym::anon.

Author: nnethercote

Diff for: compiler/rustc_borrowck/src/type_check/mod.rs

@@ -1339,14 +1339,11 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
                 };
                 let (sig, map) = tcx.replace_late_bound_regions(sig, |br| {
                     use crate::renumber::{BoundRegionInfo, RegionCtxt};
-                    use rustc_span::Symbol;
 
                     let region_ctxt_fn = || {
                         let reg_info = match br.kind {
                             ty::BoundRegionKind::BrAnon(Some(span)) => BoundRegionInfo::Span(span),
-                            ty::BoundRegionKind::BrAnon(..) => {
-                                BoundRegionInfo::Name(Symbol::intern("anon"))
-                            }
+                            ty::BoundRegionKind::BrAnon(..) => BoundRegionInfo::Name(sym::anon),
                             ty::BoundRegionKind::BrNamed(_, name) => BoundRegionInfo::Name(name),
                             ty::BoundRegionKind::BrEnv => BoundRegionInfo::Name(sym::env),
                         };

Diff for: compiler/rustc_borrowck/src/type_check/relate_tys.rs

@@ -126,7 +126,7 @@ impl<'tcx> TypeRelatingDelegate<'tcx> for NllTypeRelatingDelegate<'_, '_, 'tcx>
 
         let reg_info = match placeholder.bound.kind {
             ty::BoundRegionKind::BrAnon(Some(span)) => BoundRegionInfo::Span(span),
-            ty::BoundRegionKind::BrAnon(..) => BoundRegionInfo::Name(Symbol::intern("anon")),
+            ty::BoundRegionKind::BrAnon(..) => BoundRegionInfo::Name(sym::anon),
             ty::BoundRegionKind::BrNamed(_, name) => BoundRegionInfo::Name(name),
             ty::BoundRegionKind::BrEnv => BoundRegionInfo::Name(sym::env),
         };

Diff for: compiler/rustc_borrowck/src/universal_regions.rs

@@ -24,7 +24,7 @@ use rustc_infer::infer::NllRegionVariableOrigin;
 use rustc_middle::ty::fold::TypeFoldable;
 use rustc_middle::ty::{self, InlineConstSubsts, InlineConstSubstsParts, RegionVid, Ty, TyCtxt};
 use rustc_middle::ty::{InternalSubsts, SubstsRef};
-use rustc_span::symbol::kw;
+use rustc_span::symbol::{kw, sym};
 use rustc_span::Symbol;
 use std::iter;
 
@@ -783,7 +783,7 @@ impl<'cx, 'tcx> InferCtxtExt<'tcx> for BorrowckInferCtxt<'cx, 'tcx> {
             let region_vid = {
                 let name = match br.kind.get_name() {
                     Some(name) => name,
-                    _ => Symbol::intern("anon"),
+                    _ => sym::anon,
                 };
 
                 self.next_nll_region_var(origin, || RegionCtxt::Bound(BoundRegionInfo::Name(name)))

Diff for: compiler/rustc_middle/src/ty/sty.rs

@@ -1637,7 +1637,7 @@ impl<'tcx> Region<'tcx> {
     pub fn get_name_or_anon(self) -> Symbol {
         match self.get_name() {
             Some(name) => name,
-            None => Symbol::intern("anon"),
+            None => sym::anon,
         }
     }
 

Diff for: compiler/rustc_span/src/symbol.rs

@@ -357,6 +357,7 @@ symbols! {
         always,
         and,
         and_then,
+        anon,
         anonymous_lifetime_in_impl_trait,
         any,
         append_const_msg,