Auto merge of #28642 - petrochenkov:name3, r=nrc

This PR removes random remaining `Ident`s outside of libsyntax and performs general cleanup
In particular, interfaces of `Name` and `Ident` are tidied up, `Name`s and `Ident`s being small `Copy` aggregates are always passed to functions by value, and `Ident`s are never used as keys in maps, because `Ident` comparisons are tricky.

Although this PR closes #6993 there's still work related to it:
- `Name` can be made `NonZero` to compress numerous `Option<Name>`s and `Option<Ident>`s but it requires const unsafe functions.
- Implementation of `PartialEq` on `Ident` should be eliminated and replaced with explicit hygienic, non-hygienic or member-wise comparisons.
- Finally, large parts of AST can potentially be converted to `Name`s in the same way as HIR to clearly separate identifiers used in hygienic and non-hygienic contexts.

r? @nrc

Author: bors

src/grammar/verify.rs

@@ -35,7 +35,7 @@ use syntax::parse::lexer::TokenAndSpan;
 
 fn parse_token_list(file: &str) -> HashMap<String, token::Token> {
     fn id() -> token::Token {
-        token::Ident(ast::Ident { name: Name(0), ctxt: 0, }, token::Plain)
+        token::Ident(ast::Ident::with_empty_ctxt(Name(0))), token::Plain)
     }
 
     let mut res = HashMap::new();
@@ -75,7 +75,7 @@ fn parse_token_list(file: &str) -> HashMap<String, token::Token> {
             "RPAREN"            => token::CloseDelim(token::Paren),
             "SLASH"             => token::BinOp(token::Slash),
             "COMMA"             => token::Comma,
-            "LIFETIME"          => token::Lifetime(ast::Ident { name: Name(0), ctxt: 0 }),
+            "LIFETIME"          => token::Lifetime(ast::Ident::with_empty_ctxt(Name(0))),
             "CARET"             => token::BinOp(token::Caret),
             "TILDE"             => token::Tilde,
             "IDENT"             => id(),
@@ -208,9 +208,9 @@ fn parse_antlr_token(s: &str, tokens: &HashMap<String, token::Token>, surrogate_
         token::Literal(token::ByteStr(..), n)    => token::Literal(token::ByteStr(nm), n),
         token::Literal(token::ByteStrRaw(..), n) => token::Literal(token::ByteStrRaw(fix(content),
                                                                                 count(content)), n),
-        token::Ident(..)           => token::Ident(ast::Ident { name: nm, ctxt: 0 },
+        token::Ident(..)           => token::Ident(ast::Ident::with_empty_ctxt(nm)),
                                                    token::ModName),
-        token::Lifetime(..)        => token::Lifetime(ast::Ident { name: nm, ctxt: 0 }),
+        token::Lifetime(..)        => token::Lifetime(ast::Ident::with_empty_ctxt(nm)),
         ref t => t.clone()
     };
 

src/librustc/metadata/creader.rs

@@ -482,7 +482,7 @@ impl<'a> CrateReader<'a> {
                 let span = mk_sp(lo, p.last_span.hi);
                 p.abort_if_errors();
                 macros.push(ast::MacroDef {
-                    ident: name.ident(),
+                    ident: ast::Ident::with_empty_ctxt(name),
                     attrs: attrs,
                     id: ast::DUMMY_NODE_ID,
                     span: span,

src/librustc/metadata/encoder.rs

@@ -520,9 +520,9 @@ fn encode_info_for_mod(ecx: &EncodeContext,
         });
 
         if let hir::ItemImpl(..) = item.node {
-            let (ident, did) = (item.name, item.id);
+            let (name, did) = (item.name, item.id);
             debug!("(encoding info for module) ... encoding impl {} ({}/{})",
-                   ident,
+                   name,
                    did, ecx.tcx.map.node_to_string(did));
 
             rbml_w.wr_tagged_u64(tag_mod_impl, def_to_u64(DefId::local(did)));

src/librustc/metadata/tydecode.rs

@@ -184,8 +184,8 @@ impl<'a,'tcx> TyDecoder<'a,'tcx> {
             }
             '[' => {
                 let def = self.parse_def(RegionParameter);
-                let ident = token::str_to_ident(&self.parse_str(']'));
-                ty::BrNamed(def, ident.name)
+                let name = token::intern(&self.parse_str(']'));
+                ty::BrNamed(def, name)
             }
             'f' => {
                 let id = self.parse_u32();
@@ -219,12 +219,12 @@ impl<'a,'tcx> TyDecoder<'a,'tcx> {
                 assert_eq!(self.next(), '|');
                 let index = self.parse_u32();
                 assert_eq!(self.next(), '|');
-                let nm = token::str_to_ident(&self.parse_str(']'));
+                let name = token::intern(&self.parse_str(']'));
                 ty::ReEarlyBound(ty::EarlyBoundRegion {
                     param_id: node_id,
                     space: space,
                     index: index,
-                    name: nm.name
+                    name: name
                 })
             }
             'f' => {
@@ -598,7 +598,7 @@ impl<'a,'tcx> TyDecoder<'a,'tcx> {
         ty::ProjectionPredicate {
             projection_ty: ty::ProjectionTy {
                 trait_ref: self.parse_trait_ref(),
-                item_name: token::str_to_ident(&self.parse_str('|')).name,
+                item_name: token::intern(&self.parse_str('|')),
             },
             ty: self.parse_ty(),
         }

src/librustc/middle/cfg/construct.rs

@@ -284,15 +284,15 @@ impl<'a, 'tcx> CFGBuilder<'a, 'tcx> {
             }
 
             hir::ExprBreak(label) => {
-                let loop_scope = self.find_scope(expr, label.map(|l| l.node));
+                let loop_scope = self.find_scope(expr, label.map(|l| l.node.name));
                 let b = self.add_ast_node(expr.id, &[pred]);
                 self.add_exiting_edge(expr, b,
                                       loop_scope, loop_scope.break_index);
                 self.add_unreachable_node()
             }
 
             hir::ExprAgain(label) => {
-                let loop_scope = self.find_scope(expr, label.map(|l| l.node));
+                let loop_scope = self.find_scope(expr, label.map(|l| l.node.name));
                 let a = self.add_ast_node(expr.id, &[pred]);
                 self.add_exiting_edge(expr, a,
                                       loop_scope, loop_scope.continue_index);
@@ -585,7 +585,7 @@ impl<'a, 'tcx> CFGBuilder<'a, 'tcx> {
 
     fn find_scope(&self,
                   expr: &hir::Expr,
-                  label: Option<ast::Ident>) -> LoopScope {
+                  label: Option<ast::Name>) -> LoopScope {
         if label.is_none() {
             return *self.loop_scopes.last().unwrap();
         }

src/librustc/middle/dataflow.rs

@@ -114,7 +114,7 @@ impl<'a, 'tcx, O:DataFlowOperator> pprust::PpAnn for DataFlowContext<'a, 'tcx, O
            ps: &mut pprust::State,
            node: pprust::AnnNode) -> io::Result<()> {
         let id = match node {
-            pprust::NodeIdent(_) | pprust::NodeName(_) => 0,
+            pprust::NodeName(_) => 0,
             pprust::NodeExpr(expr) => expr.id,
             pprust::NodeBlock(blk) => blk.id,
             pprust::NodeItem(_) | pprust::NodeSubItem(_) => 0,

src/librustc/middle/entry.rs

@@ -85,7 +85,7 @@ fn entry_point_type(item: &Item, depth: usize) -> EntryPointType {
                 EntryPointType::Start
             } else if attr::contains_name(&item.attrs, "main") {
                 EntryPointType::MainAttr
-            } else if item.name == "main" {
+            } else if item.name.as_str() == "main" {
                 if depth == 1 {
                     // This is a top-level function so can be 'main'
                     EntryPointType::MainNamed

src/librustc/middle/infer/error_reporting.rs

@@ -1015,12 +1015,12 @@ impl<'a, 'tcx> ErrorReporting<'tcx> for InferCtxt<'a, 'tcx> {
             },
             None => None
         };
-        let (fn_decl, generics, unsafety, constness, ident, expl_self, span)
+        let (fn_decl, generics, unsafety, constness, name, expl_self, span)
                                     = node_inner.expect("expect item fn");
         let rebuilder = Rebuilder::new(self.tcx, fn_decl, expl_self,
                                        generics, same_regions, &life_giver);
         let (fn_decl, expl_self, generics) = rebuilder.rebuild();
-        self.give_expl_lifetime_param(&fn_decl, unsafety, constness, ident,
+        self.give_expl_lifetime_param(&fn_decl, unsafety, constness, name,
                                       expl_self.as_ref(), &generics, span);
     }
 }
@@ -1127,7 +1127,7 @@ impl<'a, 'tcx> Rebuilder<'a, 'tcx> {
                 names.push(lt_name);
             }
             names.sort();
-            let name = token::str_to_ident(&names[0]).name;
+            let name = token::intern(&names[0]);
             return (name_to_dummy_lifetime(name), Kept);
         }
         return (self.life_giver.give_lifetime(), Fresh);
@@ -1938,8 +1938,7 @@ impl LifeGiver {
             let mut s = String::from("'");
             s.push_str(&num_to_string(self.counter.get()));
             if !self.taken.contains(&s) {
-                lifetime = name_to_dummy_lifetime(
-                                    token::str_to_ident(&s[..]).name);
+                lifetime = name_to_dummy_lifetime(token::intern(&s[..]));
                 self.generated.borrow_mut().push(lifetime);
                 break;
             }

src/librustc/middle/intrinsicck.rs

@@ -55,7 +55,7 @@ impl<'a, 'tcx> IntrinsicCheckingVisitor<'a, 'tcx> {
             ty::TyBareFn(_, ref bfty) => bfty.abi == RustIntrinsic,
             _ => return false
         };
-        intrinsic && self.tcx.item_name(def_id) == "transmute"
+        intrinsic && self.tcx.item_name(def_id).as_str() == "transmute"
     }
 
     fn check_transmute(&self, span: Span, from: Ty<'tcx>, to: Ty<'tcx>, id: ast::NodeId) {

src/librustc/middle/liveness.rs

@@ -383,7 +383,7 @@ fn visit_fn(ir: &mut IrMaps,
                                &*arg.pat,
                                |_bm, arg_id, _x, path1| {
             debug!("adding argument {}", arg_id);
-            let name = path1.node.name;
+            let name = path1.node;
             fn_maps.add_variable(Arg(arg_id, name));
         })
     };
@@ -416,7 +416,7 @@ fn visit_fn(ir: &mut IrMaps,
 fn visit_local(ir: &mut IrMaps, local: &hir::Local) {
     pat_util::pat_bindings(&ir.tcx.def_map, &*local.pat, |_, p_id, sp, path1| {
         debug!("adding local variable {}", p_id);
-        let name = path1.node.name;
+        let name = path1.node;
         ir.add_live_node_for_node(p_id, VarDefNode(sp));
         ir.add_variable(Local(LocalInfo {
           id: p_id,
@@ -431,7 +431,7 @@ fn visit_arm(ir: &mut IrMaps, arm: &hir::Arm) {
         pat_util::pat_bindings(&ir.tcx.def_map, &**pat, |bm, p_id, sp, path1| {
             debug!("adding local variable {} from match with bm {:?}",
                    p_id, bm);
-            let name = path1.node.name;
+            let name = path1.node;
             ir.add_live_node_for_node(p_id, VarDefNode(sp));
             ir.add_variable(Local(LocalInfo {
                 id: p_id,
@@ -688,7 +688,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
     }
 
     fn find_loop_scope(&self,
-                       opt_label: Option<ast::Ident>,
+                       opt_label: Option<ast::Name>,
                        id: NodeId,
                        sp: Span)
                        -> NodeId {
@@ -1049,7 +1049,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
 
           hir::ExprBreak(opt_label) => {
               // Find which label this break jumps to
-              let sc = self.find_loop_scope(opt_label.map(|l| l.node), expr.id, expr.span);
+              let sc = self.find_loop_scope(opt_label.map(|l| l.node.name), expr.id, expr.span);
 
               // Now that we know the label we're going to,
               // look it up in the break loop nodes table
@@ -1063,7 +1063,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
 
           hir::ExprAgain(opt_label) => {
               // Find which label this expr continues to
-              let sc = self.find_loop_scope(opt_label.map(|l| l.node), expr.id, expr.span);
+              let sc = self.find_loop_scope(opt_label.map(|l| l.node.name), expr.id, expr.span);
 
               // Now that we know the label we're going to,
               // look it up in the continue loop nodes table
@@ -1553,8 +1553,8 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
                                    |_bm, p_id, sp, path1| {
                 let var = self.variable(p_id, sp);
                 // Ignore unused self.
-                let ident = path1.node;
-                if ident.name != special_idents::self_.name {
+                let name = path1.node;
+                if name != special_idents::self_.name {
                     self.warn_about_unused(sp, p_id, entry_ln, var);
                 }
             })

src/librustc/middle/pat_util.rs

@@ -16,9 +16,9 @@ use util::nodemap::FnvHashMap;
 use syntax::ast;
 use rustc_front::hir;
 use rustc_front::util::walk_pat;
-use syntax::codemap::{Span, Spanned, DUMMY_SP};
+use syntax::codemap::{respan, Span, Spanned, DUMMY_SP};
 
-pub type PatIdMap = FnvHashMap<ast::Ident, ast::NodeId>;
+pub type PatIdMap = FnvHashMap<ast::Name, ast::NodeId>;
 
 // This is used because same-named variables in alternative patterns need to
 // use the NodeId of their namesake in the first pattern.
@@ -109,12 +109,26 @@ pub fn pat_is_binding_or_wild(dm: &DefMap, pat: &hir::Pat) -> bool {
 /// Call `it` on every "binding" in a pattern, e.g., on `a` in
 /// `match foo() { Some(a) => (), None => () }`
 pub fn pat_bindings<I>(dm: &DefMap, pat: &hir::Pat, mut it: I) where
+    I: FnMut(hir::BindingMode, ast::NodeId, Span, &Spanned<ast::Name>),
+{
+    walk_pat(pat, |p| {
+        match p.node {
+          hir::PatIdent(binding_mode, ref pth, _) if pat_is_binding(dm, p) => {
+            it(binding_mode, p.id, p.span, &respan(pth.span, pth.node.name));
+          }
+          _ => {}
+        }
+        true
+    });
+}
+
+pub fn pat_bindings_hygienic<I>(dm: &DefMap, pat: &hir::Pat, mut it: I) where
     I: FnMut(hir::BindingMode, ast::NodeId, Span, &Spanned<ast::Ident>),
 {
     walk_pat(pat, |p| {
         match p.node {
           hir::PatIdent(binding_mode, ref pth, _) if pat_is_binding(dm, p) => {
-            it(binding_mode, p.id, p.span, pth);
+            it(binding_mode, p.id, p.span, &respan(pth.span, pth.node));
           }
           _ => {}
         }
@@ -182,10 +196,10 @@ pub fn pat_contains_bindings_or_wild(dm: &DefMap, pat: &hir::Pat) -> bool {
     contains_bindings
 }
 
-pub fn simple_identifier<'a>(pat: &'a hir::Pat) -> Option<&'a ast::Ident> {
+pub fn simple_name<'a>(pat: &'a hir::Pat) -> Option<ast::Name> {
     match pat.node {
         hir::PatIdent(hir::BindByValue(_), ref path1, None) => {
-            Some(&path1.node)
+            Some(path1.node.name)
         }
         _ => {
             None
@@ -197,7 +211,7 @@ pub fn def_to_path(tcx: &ty::ctxt, id: DefId) -> hir::Path {
     tcx.with_path(id, |path| hir::Path {
         global: false,
         segments: path.last().map(|elem| hir::PathSegment {
-            identifier: ast::Ident::new(elem.name()),
+            identifier: ast::Ident::with_empty_ctxt(elem.name()),
             parameters: hir::PathParameters::none(),
         }).into_iter().collect(),
         span: DUMMY_SP,

src/librustc/middle/resolve_lifetime.rs

@@ -73,7 +73,7 @@ struct LifetimeContext<'a> {
     trait_ref_hack: bool,
 
     // List of labels in the function/method currently under analysis.
-    labels_in_fn: Vec<(ast::Ident, Span)>,
+    labels_in_fn: Vec<(ast::Name, Span)>,
 }
 
 enum ScopeChain<'a> {
@@ -381,7 +381,7 @@ fn extract_labels<'v, 'a>(ctxt: &mut LifetimeContext<'a>, b: &'v hir::Block) {
     struct GatherLabels<'a> {
         sess: &'a Session,
         scope: Scope<'a>,
-        labels_in_fn: &'a mut Vec<(ast::Ident, Span)>,
+        labels_in_fn: &'a mut Vec<(ast::Name, Span)>,
     }
 
     let mut gather = GatherLabels {
@@ -403,9 +403,9 @@ fn extract_labels<'v, 'a>(ctxt: &mut LifetimeContext<'a>, b: &'v hir::Block) {
             if let Some(label) = expression_label(ex) {
                 for &(prior, prior_span) in &self.labels_in_fn[..] {
                     // FIXME (#24278): non-hygienic comparison
-                    if label.name == prior.name {
+                    if label == prior {
                         signal_shadowing_problem(self.sess,
-                                                 label.name,
+                                                 label,
                                                  original_label(prior_span),
                                                  shadower_label(ex.span));
                     }
@@ -426,17 +426,17 @@ fn extract_labels<'v, 'a>(ctxt: &mut LifetimeContext<'a>, b: &'v hir::Block) {
         }
     }
 
-    fn expression_label(ex: &hir::Expr) -> Option<ast::Ident> {
+    fn expression_label(ex: &hir::Expr) -> Option<ast::Name> {
         match ex.node {
             hir::ExprWhile(_, _, Some(label)) |
-            hir::ExprLoop(_, Some(label)) => Some(label),
+            hir::ExprLoop(_, Some(label)) => Some(label.name),
             _ => None,
         }
     }
 
     fn check_if_label_shadows_lifetime<'a>(sess: &'a Session,
                                            mut scope: Scope<'a>,
-                                           label: ast::Ident,
+                                           label: ast::Name,
                                            label_span: Span) {
         loop {
             match *scope {
@@ -447,10 +447,10 @@ fn extract_labels<'v, 'a>(ctxt: &mut LifetimeContext<'a>, b: &'v hir::Block) {
                 LateScope(lifetimes, s) => {
                     for lifetime_def in lifetimes {
                         // FIXME (#24278): non-hygienic comparison
-                        if label.name == lifetime_def.lifetime.name {
+                        if label == lifetime_def.lifetime.name {
                             signal_shadowing_problem(
                                 sess,
-                                label.name,
+                                label,
                                 original_lifetime(&lifetime_def.lifetime),
                                 shadower_label(label_span));
                             return;
@@ -703,7 +703,7 @@ impl<'a> LifetimeContext<'a> {
     {
         for &(label, label_span) in &self.labels_in_fn {
             // FIXME (#24278): non-hygienic comparison
-            if lifetime.name == label.name {
+            if lifetime.name == label {
                 signal_shadowing_problem(self.sess,
                                          lifetime.name,
                                          original_label(label_span),

src/librustc/middle/stability.rs

@@ -336,7 +336,7 @@ impl<'a, 'v, 'tcx> Visitor<'v> for Checker<'a, 'tcx> {
         // When compiling with --test we don't enforce stability on the
         // compiler-generated test module, demarcated with `DUMMY_SP` plus the
         // name `__test`
-        if item.span == DUMMY_SP && item.name == "__test" { return }
+        if item.span == DUMMY_SP && item.name.as_str() == "__test" { return }
 
         check_item(self.tcx, item, true,
                    &mut |id, sp, stab| self.check(id, sp, stab));

src/librustc_borrowck/borrowck/gather_loans/gather_moves.rs

@@ -99,7 +99,7 @@ pub fn gather_move_from_pat<'a, 'tcx>(bccx: &BorrowckCtxt<'a, 'tcx>,
     let pat_span_path_opt = match move_pat.node {
         hir::PatIdent(_, ref path1, _) => {
             Some(MoveSpanAndPath{span: move_pat.span,
-                                 ident: path1.node})
+                                 name: path1.node.name})
         },
         _ => None,
     };