Drive-by cleanup in region naming

src/librustc_mir/borrow_check/nll/region_infer/error_reporting/region_name.rs

@@ -77,17 +77,30 @@ impl RegionErrorNamingCtx {
  }
  }
 
+ /// Get the name of `region` if it has previously been named.
  crate fn get(&self, region: &RegionVid) -> Option<&RegionName> {
  self.renctx.get(region)
  }
 
+ /// Give `region` the name `name`.
  crate fn insert(&mut self, region: RegionVid, name: RegionName) {
  self.renctx.insert(region, name);
  }
+
+ /// Creates a synthetic region named `'N`, where `N` is the next value of the counter. Then,
+ /// increment the counter.
+ ///
+ /// The name is not memoized. A separate call to `insert` should be made later. (Currently,
+ /// this happens at the end of `give_region_a_name`).
+ crate fn synthesize_region_name(&mut self) -> Symbol {
+ let c = self.counter;
+ self.counter += 1;
+
+ Symbol::intern(&format!("'{:?}", c))
+ }
 }
 
 impl RegionName {
- #[allow(dead_code)]
  crate fn was_named(&self) -> bool {
  match self.source {
  RegionNameSource::NamedEarlyBoundRegion(..) |
@@ -103,12 +116,6 @@ impl RegionName {
  }
  }
 
- #[allow(dead_code)]
- crate fn was_synthesized(&self) -> bool {
- !self.was_named()
- }
-
- #[allow(dead_code)]
  crate fn name(&self) -> Symbol {
  self.name
  }
@@ -298,7 +305,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
  } else {
  bug!("Closure is not defined by a closure expr");
  };
- let region_name = self.synthesize_region_name(renctx);
+ let region_name = renctx.synthesize_region_name();
 
  let closure_kind_ty = substs.as_closure().kind_ty(def_id, tcx);
  let note = match closure_kind_ty.to_opt_closure_kind() {
@@ -478,7 +485,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
  // This counter value will already have been used, so this function will increment
  // it so the next value will be used next and return the region name that would
  // have been used.
- name: self.synthesize_region_name(renctx),
+ name: renctx.synthesize_region_name(),
  source: RegionNameSource::CannotMatchHirTy(span, type_name),
  })
  } else {
@@ -533,7 +540,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
  hir::TyKind::Rptr(_lifetime, referent_hir_ty),
  ) => {
  if region.to_region_vid() == needle_fr {
- let region_name = self.synthesize_region_name(renctx);
+ let region_name = renctx.synthesize_region_name();
 
  // Just grab the first character, the `&`.
  let source_map = tcx.sess.source_map();
@@ -621,7 +628,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
  | hir::LifetimeName::Error
  | hir::LifetimeName::Static
  | hir::LifetimeName::Underscore => {
- let region_name = self.synthesize_region_name(renctx);
+ let region_name = renctx.synthesize_region_name();
  let ampersand_span = lifetime.span;
  Some(RegionName {
  name: region_name,
@@ -713,7 +720,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
  let upvar_index = self.get_upvar_index_for_region(tcx, fr)?;
  let (upvar_name, upvar_span) =
  self.get_upvar_name_and_span_for_region(tcx, upvars, upvar_index);
- let region_name = self.synthesize_region_name(renctx);
+ let region_name = renctx.synthesize_region_name();
 
  Some(RegionName {
  name: region_name,
@@ -776,7 +783,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
  // This counter value will already have been used, so this function will increment it
  // so the next value will be used next and return the region name that would have been
  // used.
- name: self.synthesize_region_name(renctx),
+ name: renctx.synthesize_region_name(),
  source: RegionNameSource::AnonRegionFromOutput(
  return_span,
  mir_description.to_string(),
@@ -831,16 +838,8 @@ impl<'tcx> RegionInferenceContext<'tcx> {
  );
 
  Some(RegionName {
- name: self.synthesize_region_name(renctx),
+ name: renctx.synthesize_region_name(),
  source: RegionNameSource::AnonRegionFromYieldTy(yield_span, type_name),
  })
  }
-
- /// Creates a synthetic region named `'1`, incrementing the counter.
- fn synthesize_region_name(&self, renctx: &mut RegionErrorNamingCtx) -> Symbol {
- let c = renctx.counter;
- renctx.counter += 1;
-
- Symbol::intern(&format!("'{:?}", c))
- }
 }