Avoid as_str() in ParamTy::is_self.

It's a hot function, and a direct `Symbol` comparison is faster.

The patch also converts some `&InternedString`s to `InternedString`.

Author: nnethercote

src/librustc/hir/mod.rs

@@ -609,9 +609,9 @@ impl Generics {
         own_counts
     }
 
-    pub fn get_named(&self, name: &InternedString) -> Option<&GenericParam> {
+    pub fn get_named(&self, name: InternedString) -> Option<&GenericParam> {
         for param in &self.params {
-            if *name == param.name.ident().as_interned_str() {
+            if name == param.name.ident().as_interned_str() {
                 return Some(param);
             }
         }

src/librustc/infer/error_reporting/mod.rs

@@ -194,20 +194,20 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
                 let mut sp = cm.def_span(self.hir().span_by_hir_id(node));
                 if let Some(param) = self.hir()
                     .get_generics(scope)
-                    .and_then(|generics| generics.get_named(&br.name))
+                    .and_then(|generics| generics.get_named(br.name))
                 {
                     sp = param.span;
                 }
                 (format!("the lifetime {} as defined on", br.name), sp)
             }
             ty::ReFree(ty::FreeRegion {
-                bound_region: ty::BoundRegion::BrNamed(_, ref name),
+                bound_region: ty::BoundRegion::BrNamed(_, name),
                 ..
             }) => {
                 let mut sp = cm.def_span(self.hir().span_by_hir_id(node));
                 if let Some(param) = self.hir()
                     .get_generics(scope)
-                    .and_then(|generics| generics.get_named(&name))
+                    .and_then(|generics| generics.get_named(name))
                 {
                     sp = param.span;
                 }

src/librustc/infer/error_reporting/nice_region_error/util.rs

@@ -43,7 +43,7 @@ impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
     ) -> Option<AnonymousArgInfo<'_>> {
         let (id, bound_region) = match *anon_region {
             ty::ReFree(ref free_region) => (free_region.scope, free_region.bound_region),
-            ty::ReEarlyBound(ref ebr) => (
+            ty::ReEarlyBound(ebr) => (
                 self.tcx().parent(ebr.def_id).unwrap(),
                 ty::BoundRegion::BrNamed(ebr.def_id, ebr.name),
             ),

src/librustc/ty/sty.rs

@@ -1136,7 +1136,7 @@ impl<'a, 'gcx, 'tcx> ParamTy {
         // FIXME(#50125): Ignoring `Self` with `index != 0` might lead to weird behavior elsewhere,
         // but this should only be possible when using `-Z continue-parse-after-error` like
         // `compile-fail/issue-36638.rs`.
-        self.name == keywords::SelfUpper.name().as_str() && self.index == 0
+        self.name.as_symbol() == keywords::SelfUpper.name() && self.index == 0
     }
 }
 

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

@@ -60,8 +60,8 @@ impl RegionName {
     }
 
     #[allow(dead_code)]
-    crate fn name(&self) -> &InternedString {
-        &self.name
+    crate fn name(&self) -> InternedString {
+        self.name
     }
 
     crate fn highlight_region_name(
@@ -206,7 +206,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         match error_region {
             ty::ReEarlyBound(ebr) => {
                 if ebr.has_name() {
-                    let span = self.get_named_span(tcx, error_region, &ebr.name);
+                    let span = self.get_named_span(tcx, error_region, ebr.name);
                     Some(RegionName {
                         name: ebr.name,
                         source: RegionNameSource::NamedEarlyBoundRegion(span)
@@ -223,7 +223,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
 
             ty::ReFree(free_region) => match free_region.bound_region {
                 ty::BoundRegion::BrNamed(_, name) => {
-                    let span = self.get_named_span(tcx, error_region, &name);
+                    let span = self.get_named_span(tcx, error_region, name);
                     Some(RegionName {
                         name,
                         source: RegionNameSource::NamedFreeRegion(span),
@@ -306,7 +306,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         &self,
         tcx: TyCtxt<'_, '_, 'tcx>,
         error_region: &RegionKind,
-        name: &InternedString,
+        name: InternedString,
     ) -> Span {
         let scope = error_region.free_region_binding_scope(tcx);
         let node = tcx.hir().as_local_hir_id(scope).unwrap_or(hir::DUMMY_HIR_ID);