Auto merge of #60815 - nnethercote:use-Symbol-more-2, r=<try>

Use `Symbol` even more

These patches simplify the code a bit (fewer conversions) and also speed things up a bit (fewer `with_interner` calls).

r? @petrochenkov

src/librustc/hir/map/definitions.rs

@@ -593,7 +593,7 @@ impl DefPathData {
             ImplTrait => "{{opaque}}",
         };
 
-        Symbol::intern(s).as_interned_str()
+        InternedString::intern(s)
     }
 
     pub fn to_string(&self) -> String {

src/librustc/hir/mod.rs

@@ -16,7 +16,7 @@ use crate::util::nodemap::{NodeMap, FxHashSet};
 use crate::mir::mono::Linkage;
 
 use errors::FatalError;
-use syntax_pos::{Span, DUMMY_SP, symbol::InternedString};
+use syntax_pos::{Span, DUMMY_SP};
 use syntax::source_map::Spanned;
 use rustc_target::spec::abi::Abi;
 use syntax::ast::{self, CrateSugar, Ident, Name, NodeId, AsmDialect};
@@ -609,9 +609,9 @@ impl Generics {
         own_counts
     }
 
-    pub fn get_named(&self, name: &InternedString) -> Option<&GenericParam> {
+    pub fn get_named(&self, name: Symbol) -> Option<&GenericParam> {
         for param in &self.params {
-            if *name == param.name.ident().as_interned_str() {
+            if name == param.name.ident().name {
                 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/mod.rs

@@ -32,7 +32,7 @@ use std::cell::{Cell, Ref, RefCell, RefMut};
 use std::collections::BTreeMap;
 use std::fmt;
 use syntax::ast;
-use syntax_pos::symbol::InternedString;
+use syntax_pos::symbol::Symbol;
 use syntax_pos::Span;
 
 use self::combine::CombineFields;
@@ -383,7 +383,7 @@ pub enum RegionVariableOrigin {
     Coercion(Span),
 
     /// Region variables created as the values for early-bound regions
-    EarlyBoundRegion(Span, InternedString),
+    EarlyBoundRegion(Span, Symbol),
 
     /// Region variables created for bound regions
     /// in a function or method that is called

src/librustc/infer/type_variable.rs

@@ -1,4 +1,4 @@
-use syntax::symbol::InternedString;
+use syntax::symbol::Symbol;
 use syntax_pos::Span;
 use crate::ty::{self, Ty, TyVid};
 
@@ -43,7 +43,7 @@ pub enum TypeVariableOrigin {
     MiscVariable(Span),
     NormalizeProjectionType(Span),
     TypeInference(Span),
-    TypeParameterDefinition(Span, InternedString),
+    TypeParameterDefinition(Span, Symbol),
 
     /// one of the upvars or closure kind parameters in a `ClosureSubsts`
     /// (before it has been determined)

src/librustc/infer/unify_key.rs

@@ -3,7 +3,7 @@ use crate::mir::interpret::ConstValue;
 use rustc_data_structures::unify::{NoError, EqUnifyValue, UnifyKey, UnifyValue, UnificationTable};
 use rustc_data_structures::unify::InPlace;
 use syntax_pos::{Span, DUMMY_SP};
-use syntax::symbol::InternedString;
+use syntax::symbol::Symbol;
 
 use std::cmp;
 use std::marker::PhantomData;
@@ -84,7 +84,7 @@ impl ToType for FloatVarValue {
 pub enum ConstVariableOrigin {
     MiscVariable(Span),
     ConstInference(Span),
-    ConstParameterDefinition(Span, InternedString),
+    ConstParameterDefinition(Span, Symbol),
     SubstitutionPlaceholder(Span),
 }
 

src/librustc/lint/context.rs

@@ -828,8 +828,8 @@ impl<'a, 'tcx> LateContext<'a, 'tcx> {
 
                 // This shouldn't ever be needed, but just in case:
                 Ok(vec![match trait_ref {
-                    Some(trait_ref) => Symbol::intern(&format!("{:?}", trait_ref)).as_str(),
-                    None => Symbol::intern(&format!("<{}>", self_ty)).as_str(),
+                    Some(trait_ref) => LocalInternedString::intern(&format!("{:?}", trait_ref)),
+                    None => LocalInternedString::intern(&format!("<{}>", self_ty)),
                 }])
             }
 
@@ -845,9 +845,10 @@ impl<'a, 'tcx> LateContext<'a, 'tcx> {
                 // This shouldn't ever be needed, but just in case:
                 path.push(match trait_ref {
                     Some(trait_ref) => {
-                        Symbol::intern(&format!("<impl {} for {}>", trait_ref, self_ty)).as_str()
+                        LocalInternedString::intern(&format!("<impl {} for {}>", trait_ref,
+                                                    self_ty))
                     },
-                    None => Symbol::intern(&format!("<impl {}>", self_ty)).as_str(),
+                    None => LocalInternedString::intern(&format!("<impl {}>", self_ty)),
                 });
 
                 Ok(path)

src/librustc/mir/mono.rs

@@ -1,6 +1,6 @@
 use crate::hir::def_id::{DefId, CrateNum, LOCAL_CRATE};
 use crate::hir::HirId;
-use syntax::symbol::{Symbol, InternedString};
+use syntax::symbol::InternedString;
 use crate::ty::{Instance, TyCtxt};
 use crate::util::nodemap::FxHashMap;
 use rustc_data_structures::base_n;
@@ -280,7 +280,7 @@ impl<'a, 'gcx: 'tcx, 'tcx: 'a> CodegenUnitNameBuilder<'a, 'gcx, 'tcx> {
             cgu_name
         } else {
             let cgu_name = &cgu_name.as_str()[..];
-            Symbol::intern(&CodegenUnit::mangle_name(cgu_name)).as_interned_str()
+            InternedString::intern(&CodegenUnit::mangle_name(cgu_name))
         }
     }
 
@@ -336,6 +336,6 @@ impl<'a, 'gcx: 'tcx, 'tcx: 'a> CodegenUnitNameBuilder<'a, 'gcx, 'tcx> {
             write!(cgu_name, ".{}", special_suffix).unwrap();
         }
 
-        Symbol::intern(&cgu_name[..]).as_interned_str()
+        InternedString::intern(&cgu_name[..])
     }
 }

src/librustc/traits/object_safety.rs

@@ -539,7 +539,7 @@ impl<'a, 'tcx> TyCtxt<'a, 'tcx, 'tcx> {
         // are implemented
         let unsized_self_ty: Ty<'tcx> = self.mk_ty_param(
             ::std::u32::MAX,
-            Name::intern("RustaceansAreAwesome").as_interned_str(),
+            Name::intern("RustaceansAreAwesome"),
         );
 
         // `Receiver[Self => U]`

src/librustc/traits/on_unimplemented.rs

@@ -250,7 +250,7 @@ impl<'a, 'gcx, 'tcx> OnUnimplementedFormatString {
                     Position::ArgumentNamed(s) if s == "from_desugaring" => (),
                     // So is `{A}` if A is a type parameter
                     Position::ArgumentNamed(s) => match generics.params.iter().find(|param|
-                        param.name == s
+                        param.name.as_str() == s
                     ) {
                         Some(_) => (),
                         None => {

src/librustc/traits/structural_impls.rs

@@ -4,7 +4,7 @@ use crate::traits;
 use crate::traits::project::Normalized;
 use crate::ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
 use crate::ty::{self, Lift, Ty, TyCtxt};
-use syntax::symbol::InternedString;
+use syntax::symbol::Symbol;
 
 use std::fmt;
 use std::rc::Rc;
@@ -261,11 +261,11 @@ impl fmt::Display for traits::QuantifierKind {
 /// for debug output in tests anyway.
 struct BoundNamesCollector {
     // Just sort by name because `BoundRegion::BrNamed` does not have a `BoundVar` index anyway.
-    regions: BTreeSet<InternedString>,
+    regions: BTreeSet<Symbol>,
 
     // Sort by `BoundVar` index, so usually this should be equivalent to the order given
     // by the list of type parameters.
-    types: BTreeMap<u32, InternedString>,
+    types: BTreeMap<u32, Symbol>,
 
     binder_index: ty::DebruijnIndex,
 }
@@ -312,8 +312,6 @@ impl<'tcx> TypeVisitor<'tcx> for BoundNamesCollector {
     }
 
     fn visit_ty(&mut self, t: Ty<'tcx>) -> bool {
-        use syntax::symbol::Symbol;
-
         match t.sty {
             ty::Bound(debruijn, bound_ty) if debruijn == self.binder_index => {
                 self.types.insert(
@@ -322,7 +320,7 @@ impl<'tcx> TypeVisitor<'tcx> for BoundNamesCollector {
                         ty::BoundTyKind::Param(name) => name,
                         ty::BoundTyKind::Anon => Symbol::intern(
                             &format!("^{}", bound_ty.var.as_u32())
-                        ).as_interned_str(),
+                        ),
                     }
                 );
             }
@@ -334,8 +332,6 @@ impl<'tcx> TypeVisitor<'tcx> for BoundNamesCollector {
     }
 
     fn visit_region(&mut self, r: ty::Region<'tcx>) -> bool {
-        use syntax::symbol::Symbol;
-
         match r {
             ty::ReLateBound(index, br) if *index == self.binder_index => {
                 match br {
@@ -346,7 +342,7 @@ impl<'tcx> TypeVisitor<'tcx> for BoundNamesCollector {
                     ty::BoundRegion::BrAnon(var) => {
                         self.regions.insert(Symbol::intern(
                             &format!("'^{}", var)
-                        ).as_interned_str());
+                        ));
                     }
 
                     _ => (),

src/librustc/ty/context.rs

@@ -74,7 +74,7 @@ use syntax::ast;
 use syntax::attr;
 use syntax::source_map::MultiSpan;
 use syntax::feature_gate;
-use syntax::symbol::{Symbol, keywords, InternedString, sym};
+use syntax::symbol::{Symbol, keywords, sym};
 use syntax_pos::Span;
 
 use crate::hir;
@@ -2716,15 +2716,15 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
     }
 
     #[inline]
-    pub fn mk_ty_param(self, index: u32, name: InternedString) -> Ty<'tcx> {
+    pub fn mk_ty_param(self, index: u32, name: Symbol) -> Ty<'tcx> {
         self.mk_ty(Param(ParamTy { index, name: name }))
     }
 
     #[inline]
     pub fn mk_const_param(
         self,
         index: u32,
-        name: InternedString,
+        name: Symbol,
         ty: Ty<'tcx>
     ) -> &'tcx Const<'tcx> {
         self.mk_const(ty::Const {
@@ -2735,7 +2735,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
 
     #[inline]
     pub fn mk_self_type(self) -> Ty<'tcx> {
-        self.mk_ty_param(0, keywords::SelfUpper.name().as_interned_str())
+        self.mk_ty_param(0, keywords::SelfUpper.name())
     }
 
     pub fn mk_param_from_def(self, param: &ty::GenericParamDef) -> Kind<'tcx> {

src/librustc/ty/mod.rs

@@ -835,7 +835,7 @@ impl ty::EarlyBoundRegion {
     /// Does this early bound region have a name? Early bound regions normally
     /// always have names except when using anonymous lifetimes (`'_`).
     pub fn has_name(&self) -> bool {
-        self.name != keywords::UnderscoreLifetime.name().as_interned_str()
+        self.name != keywords::UnderscoreLifetime.name()
     }
 }
 
@@ -852,7 +852,7 @@ pub enum GenericParamDefKind {
 
 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
 pub struct GenericParamDef {
-    pub name: InternedString,
+    pub name: Symbol,
     pub def_id: DefId,
     pub index: u32,
 
@@ -3405,7 +3405,7 @@ impl_stable_hash_for!(struct self::SymbolName {
 impl SymbolName {
     pub fn new(name: &str) -> SymbolName {
         SymbolName {
-            name: Symbol::intern(name).as_interned_str()
+            name: InternedString::intern(name)
         }
     }
 

src/librustc/ty/print/pretty.rs

@@ -10,7 +10,6 @@ use crate::mir::interpret::ConstValue;
 use syntax::symbol::{keywords, Symbol};
 
 use rustc_target::spec::abi::Abi;
-use syntax::symbol::InternedString;
 
 use std::cell::Cell;
 use std::fmt::{self, Write as _};
@@ -818,7 +817,7 @@ pub struct FmtPrinterData<'a, 'gcx, 'tcx, F> {
     empty_path: bool,
     in_value: bool,
 
-    used_region_names: FxHashSet<InternedString>,
+    used_region_names: FxHashSet<Symbol>,
     region_index: usize,
     binder_depth: usize,
 
@@ -1142,14 +1141,16 @@ impl<F: fmt::Write> PrettyPrinter<'gcx, 'tcx> for FmtPrinter<'_, 'gcx, 'tcx, F>
 
         match *region {
             ty::ReEarlyBound(ref data) => {
-                data.name != "" && data.name != "'_"
+                data.name != keywords::Invalid.name() &&
+                data.name != keywords::UnderscoreLifetime.name()
             }
 
             ty::ReLateBound(_, br) |
             ty::ReFree(ty::FreeRegion { bound_region: br, .. }) |
             ty::RePlaceholder(ty::Placeholder { name: br, .. }) => {
                 if let ty::BrNamed(_, name) = br {
-                    if name != "" && name != "'_" {
+                    if name != keywords::Invalid.name() &&
+                       name != keywords::UnderscoreLifetime.name() {
                         return true;
                     }
                 }
@@ -1205,7 +1206,7 @@ impl<F: fmt::Write> FmtPrinter<'_, '_, '_, F> {
         // `explain_region()` or `note_and_explain_region()`.
         match *region {
             ty::ReEarlyBound(ref data) => {
-                if data.name != "" {
+                if data.name != keywords::Invalid.name() {
                     p!(write("{}", data.name));
                     return Ok(self);
                 }
@@ -1214,7 +1215,8 @@ impl<F: fmt::Write> FmtPrinter<'_, '_, '_, F> {
             ty::ReFree(ty::FreeRegion { bound_region: br, .. }) |
             ty::RePlaceholder(ty::Placeholder { name: br, .. }) => {
                 if let ty::BrNamed(_, name) = br {
-                    if name != "" && name != "'_" {
+                    if name != keywords::Invalid.name() &&
+                       name != keywords::UnderscoreLifetime.name() {
                         p!(write("{}", name));
                         return Ok(self);
                     }
@@ -1283,12 +1285,12 @@ impl<F: fmt::Write> FmtPrinter<'_, 'gcx, 'tcx, F> {
     ) -> Result<Self, fmt::Error>
         where T: Print<'gcx, 'tcx, Self, Output = Self, Error = fmt::Error> + TypeFoldable<'tcx>
     {
-        fn name_by_region_index(index: usize) -> InternedString {
+        fn name_by_region_index(index: usize) -> Symbol {
             match index {
                 0 => Symbol::intern("'r"),
                 1 => Symbol::intern("'s"),
                 i => Symbol::intern(&format!("'t{}", i-2)),
-            }.as_interned_str()
+            }
         }
 
         // Replace any anonymous late-bound regions with named
@@ -1351,7 +1353,7 @@ impl<F: fmt::Write> FmtPrinter<'_, 'gcx, 'tcx, F> {
         where T: TypeFoldable<'tcx>
     {
 
-        struct LateBoundRegionNameCollector<'a>(&'a mut FxHashSet<InternedString>);
+        struct LateBoundRegionNameCollector<'a>(&'a mut FxHashSet<Symbol>);
         impl<'tcx> ty::fold::TypeVisitor<'tcx> for LateBoundRegionNameCollector<'_> {
             fn visit_region(&mut self, r: ty::Region<'tcx>) -> bool {
                 match *r {

src/librustc/ty/query/values.rs

@@ -1,7 +1,7 @@
 use crate::ty::{self, Ty, TyCtxt, AdtSizedConstraint};
 use crate::ty::util::NeedsDrop;
 
-use syntax::symbol::Symbol;
+use syntax::symbol::InternedString;
 
 pub(super) trait Value<'tcx>: Sized {
     fn from_cycle_error<'a>(tcx: TyCtxt<'a, 'tcx, 'tcx>) -> Self;
@@ -28,7 +28,7 @@ impl<'tcx> Value<'tcx> for Ty<'tcx> {
 
 impl<'tcx> Value<'tcx> for ty::SymbolName {
     fn from_cycle_error<'a>(_: TyCtxt<'a, 'tcx, 'tcx>) -> Self {
-        ty::SymbolName { name: Symbol::intern("<error>").as_interned_str() }
+        ty::SymbolName { name: InternedString::intern("<error>") }
     }
 }