Auto merge of #37824 - jseyfried:symbols, r=eddyb

Clean up `ast::Attribute`, `ast::CrateConfig`, and string interning

This PR
 - removes `ast::Attribute_` (changing `Attribute` from `Spanned<Attribute_>` to a struct),
 - moves a `MetaItem`'s name from the `MetaItemKind` variants to a field of `MetaItem`,
 - avoids needlessly wrapping `ast::MetaItem` with `P`,
 - moves string interning into `syntax::symbol` (`ast::Name` is a reexport of `symbol::Symbol` for now),
 - replaces `InternedString` with `Symbol` in the AST, HIR, and various other places, and
 - refactors `ast::CrateConfig` from a `Vec` to a `HashSet`.

r? @eddyb

Author: bors

src/libproc_macro_plugin/qquote.rs

@@ -34,8 +34,9 @@ use syntax::codemap::Span;
 use syntax::ext::base::*;
 use syntax::ext::base;
 use syntax::ext::proc_macro_shim::build_block_emitter;
-use syntax::parse::token::{self, Token, gensym_ident, str_to_ident};
+use syntax::parse::token::{self, Token};
 use syntax::print::pprust;
+use syntax::symbol::Symbol;
 use syntax::tokenstream::{TokenTree, TokenStream};
 
 // ____________________________________________________________________________________________
@@ -124,7 +125,7 @@ fn qquote_iter<'cx>(cx: &'cx mut ExtCtxt, depth: i64, ts: TokenStream) -> (Bindi
                     } // produce an error or something first
                     let exp = vec![exp.unwrap().to_owned()];
                     debug!("RHS: {:?}", exp.clone());
-                    let new_id = gensym_ident("tmp");
+                    let new_id = Ident::with_empty_ctxt(Symbol::gensym("tmp"));
                     debug!("RHS TS: {:?}", TokenStream::from_tts(exp.clone()));
                     debug!("RHS TS TT: {:?}", TokenStream::from_tts(exp.clone()).to_vec());
                     bindings.push((new_id, TokenStream::from_tts(exp)));
@@ -179,7 +180,7 @@ fn unravel_concats(tss: Vec<TokenStream>) -> TokenStream {
     };
 
     while let Some(ts) = pushes.pop() {
-        output = build_fn_call(str_to_ident("concat"),
+        output = build_fn_call(Ident::from_str("concat"),
                                concat(concat(ts,
                                              from_tokens(vec![Token::Comma])),
                                       output));
@@ -209,18 +210,19 @@ fn convert_complex_tts<'cx>(cx: &'cx mut ExtCtxt, tts: Vec<QTT>) -> (Bindings, T
             // FIXME handle sequence repetition tokens
             QTT::QDL(qdl) => {
                 debug!("  QDL: {:?} ", qdl.tts);
-                let new_id = gensym_ident("qdl_tmp");
+                let new_id = Ident::with_empty_ctxt(Symbol::gensym("qdl_tmp"));
                 let mut cct_rec = convert_complex_tts(cx, qdl.tts);
                 bindings.append(&mut cct_rec.0);
                 bindings.push((new_id, cct_rec.1));
 
                 let sep = build_delim_tok(qdl.delim);
 
-                pushes.push(build_mod_call(vec![str_to_ident("proc_macro_tokens"),
-                                               str_to_ident("build"),
-                                               str_to_ident("build_delimited")],
-                                          concat(from_tokens(vec![Token::Ident(new_id)]),
-                                                 concat(lex(","), sep))));
+                pushes.push(build_mod_call(
+                    vec![Ident::from_str("proc_macro_tokens"),
+                         Ident::from_str("build"),
+                         Ident::from_str("build_delimited")],
+                    concat(from_tokens(vec![Token::Ident(new_id)]), concat(lex(","), sep)),
+                ));
             }
             QTT::QIdent(t) => {
                 pushes.push(TokenStream::from_tts(vec![t]));
@@ -250,13 +252,13 @@ fn unravel(binds: Bindings) -> TokenStream {
 
 /// Checks if the Ident is `unquote`.
 fn is_unquote(id: Ident) -> bool {
-    let qq = str_to_ident("unquote");
+    let qq = Ident::from_str("unquote");
     id.name == qq.name  // We disregard context; unquote is _reserved_
 }
 
 /// Checks if the Ident is `quote`.
 fn is_qquote(id: Ident) -> bool {
-    let qq = str_to_ident("qquote");
+    let qq = Ident::from_str("qquote");
     id.name == qq.name  // We disregard context; qquote is _reserved_
 }
 
@@ -266,7 +268,8 @@ mod int_build {
 
     use syntax::ast::{self, Ident};
     use syntax::codemap::{DUMMY_SP};
-    use syntax::parse::token::{self, Token, keywords, str_to_ident};
+    use syntax::parse::token::{self, Token, Lit};
+    use syntax::symbol::keywords;
     use syntax::tokenstream::{TokenTree, TokenStream};
 
     // ____________________________________________________________________________________________
@@ -277,19 +280,19 @@ mod int_build {
                build_paren_delimited(build_vec(build_token_tt(t))))
     }
 
-    pub fn emit_lit(l: token::Lit, n: Option<ast::Name>) -> TokenStream {
+    pub fn emit_lit(l: Lit, n: Option<ast::Name>) -> TokenStream {
         let suf = match n {
-            Some(n) => format!("Some(ast::Name({}))", n.0),
+            Some(n) => format!("Some(ast::Name({}))", n.as_u32()),
             None => "None".to_string(),
         };
 
         let lit = match l {
-            token::Lit::Byte(n) => format!("Lit::Byte(token::intern(\"{}\"))", n.to_string()),
-            token::Lit::Char(n) => format!("Lit::Char(token::intern(\"{}\"))", n.to_string()),
-            token::Lit::Integer(n) => format!("Lit::Integer(token::intern(\"{}\"))", n.to_string()),
-            token::Lit::Float(n) => format!("Lit::Float(token::intern(\"{}\"))", n.to_string()),
-            token::Lit::Str_(n) => format!("Lit::Str_(token::intern(\"{}\"))", n.to_string()),
-            token::Lit::ByteStr(n) => format!("Lit::ByteStr(token::intern(\"{}\"))", n.to_string()),
+            Lit::Byte(n) => format!("Lit::Byte(Symbol::intern(\"{}\"))", n.to_string()),
+            Lit::Char(n) => format!("Lit::Char(Symbol::intern(\"{}\"))", n.to_string()),
+            Lit::Float(n) => format!("Lit::Float(Symbol::intern(\"{}\"))", n.to_string()),
+            Lit::Str_(n) => format!("Lit::Str_(Symbol::intern(\"{}\"))", n.to_string()),
+            Lit::Integer(n) => format!("Lit::Integer(Symbol::intern(\"{}\"))", n.to_string()),
+            Lit::ByteStr(n) => format!("Lit::ByteStr(Symbol::intern(\"{}\"))", n.to_string()),
             _ => panic!("Unsupported literal"),
         };
 
@@ -388,9 +391,10 @@ mod int_build {
             Token::Underscore => lex("_"),
             Token::Literal(lit, sfx) => emit_lit(lit, sfx),
             // fix ident expansion information... somehow
-            Token::Ident(ident) => lex(&format!("Token::Ident(str_to_ident(\"{}\"))", ident.name)),
-            Token::Lifetime(ident) => lex(&format!("Token::Ident(str_to_ident(\"{}\"))",
-                                                   ident.name)),
+            Token::Ident(ident) =>
+                lex(&format!("Token::Ident(Ident::from_str(\"{}\"))", ident.name)),
+            Token::Lifetime(ident) =>
+                lex(&format!("Token::Ident(Ident::from_str(\"{}\"))", ident.name)),
             _ => panic!("Unhandled case!"),
         }
     }
@@ -408,7 +412,7 @@ mod int_build {
 
     /// Takes `input` and returns `vec![input]`.
     pub fn build_vec(ts: TokenStream) -> TokenStream {
-        build_mac_call(str_to_ident("vec"), ts)
+        build_mac_call(Ident::from_str("vec"), ts)
         // tts.clone().to_owned()
     }
 

src/libproc_macro_tokens/build.rs

@@ -13,7 +13,8 @@ extern crate syntax_pos;
 
 use syntax::ast::Ident;
 use syntax::codemap::DUMMY_SP;
-use syntax::parse::token::{self, Token, keywords, str_to_ident};
+use syntax::parse::token::{self, Token};
+use syntax::symbol::keywords;
 use syntax::tokenstream::{self, TokenTree, TokenStream};
 use std::rc::Rc;
 
@@ -43,13 +44,13 @@ pub fn ident_eq(tident: &TokenTree, id: Ident) -> bool {
 
 /// Convert a `&str` into a Token.
 pub fn str_to_token_ident(s: &str) -> Token {
-    Token::Ident(str_to_ident(s))
+    Token::Ident(Ident::from_str(s))
 }
 
 /// Converts a keyword (from `syntax::parse::token::keywords`) into a Token that
 /// corresponds to it.
 pub fn keyword_to_token_ident(kw: keywords::Keyword) -> Token {
-    Token::Ident(str_to_ident(&kw.name().as_str()[..]))
+    Token::Ident(Ident::from_str(&kw.name().as_str()[..]))
 }
 
 // ____________________________________________________________________________________________

src/librustc/hir/check_attr.rs

@@ -64,7 +64,7 @@ impl<'a> CheckAttrVisitor<'a> {
                 None => continue,
             };
 
-            let (message, label) = match &*name {
+            let (message, label) = match &*name.as_str() {
                 "C" => {
                     conflicting_reprs += 1;
                     if target != Target::Struct &&
@@ -120,7 +120,7 @@ impl<'a> CheckAttrVisitor<'a> {
     }
 
     fn check_attribute(&self, attr: &ast::Attribute, target: Target) {
-        let name: &str = &attr.name();
+        let name: &str = &attr.name().as_str();
         match name {
             "inline" => self.check_inline(attr, target),
             "repr" => self.check_repr(attr, target),

src/librustc/hir/lowering.rs

@@ -53,8 +53,8 @@ use syntax::ast::*;
 use syntax::errors;
 use syntax::ptr::P;
 use syntax::codemap::{respan, Spanned};
-use syntax::parse::token;
 use syntax::std_inject;
+use syntax::symbol::{Symbol, keywords};
 use syntax::visit::{self, Visitor};
 use syntax_pos::Span;
 
@@ -149,7 +149,7 @@ impl<'a> LoweringContext<'a> {
     }
 
     fn str_to_ident(&self, s: &'static str) -> Name {
-        token::gensym(s)
+        Symbol::gensym(s)
     }
 
     fn with_parent_def<T, F>(&mut self, parent_id: NodeId, f: F) -> T
@@ -400,8 +400,8 @@ impl<'a> LoweringContext<'a> {
         // Don't expose `Self` (recovered "keyword used as ident" parse error).
         // `rustc::ty` expects `Self` to be only used for a trait's `Self`.
         // Instead, use gensym("Self") to create a distinct name that looks the same.
-        if name == token::keywords::SelfType.name() {
-            name = token::gensym("Self");
+        if name == keywords::SelfType.name() {
+            name = Symbol::gensym("Self");
         }
 
         hir::TyParam {
@@ -540,7 +540,7 @@ impl<'a> LoweringContext<'a> {
         hir::StructField {
             span: f.span,
             id: f.id,
-            name: f.ident.map(|ident| ident.name).unwrap_or(token::intern(&index.to_string())),
+            name: f.ident.map(|ident| ident.name).unwrap_or(Symbol::intern(&index.to_string())),
             vis: self.lower_visibility(&f.vis),
             ty: self.lower_ty(&f.ty),
             attrs: self.lower_attrs(&f.attrs),
@@ -1189,7 +1189,7 @@ impl<'a> LoweringContext<'a> {
                                                                           e.span,
                                                                           hir::PopUnstableBlock,
                                                                           ThinVec::new());
-                                this.field(token::intern(s), signal_block, ast_expr.span)
+                                this.field(Symbol::intern(s), signal_block, ast_expr.span)
                             }).collect();
                             let attrs = ast_expr.attrs.clone();
 
@@ -1953,9 +1953,9 @@ impl<'a> LoweringContext<'a> {
     fn std_path_components(&mut self, components: &[&str]) -> Vec<Name> {
         let mut v = Vec::new();
         if let Some(s) = self.crate_root {
-            v.push(token::intern(s));
+            v.push(Symbol::intern(s));
         }
-        v.extend(components.iter().map(|s| token::intern(s)));
+        v.extend(components.iter().map(|s| Symbol::intern(s)));
         return v;
     }
 

src/librustc/hir/map/def_collector.rs

@@ -19,7 +19,7 @@ use middle::cstore::InlinedItem;
 use syntax::ast::*;
 use syntax::ext::hygiene::Mark;
 use syntax::visit;
-use syntax::parse::token::{self, keywords};
+use syntax::symbol::{Symbol, keywords};
 
 /// Creates def ids for nodes in the HIR.
 pub struct DefCollector<'a> {
@@ -169,7 +169,7 @@ impl<'a> visit::Visitor for DefCollector<'a> {
                         this.with_parent(variant_def_index, |this| {
                             for (index, field) in v.node.data.fields().iter().enumerate() {
                                 let name = field.ident.map(|ident| ident.name)
-                                    .unwrap_or_else(|| token::intern(&index.to_string()));
+                                    .unwrap_or_else(|| Symbol::intern(&index.to_string()));
                                 this.create_def(field.id, DefPathData::Field(name.as_str()));
                             }
 
@@ -188,7 +188,7 @@ impl<'a> visit::Visitor for DefCollector<'a> {
 
                     for (index, field) in struct_def.fields().iter().enumerate() {
                         let name = field.ident.map(|ident| ident.name.as_str())
-                            .unwrap_or(token::intern(&index.to_string()).as_str());
+                            .unwrap_or(Symbol::intern(&index.to_string()).as_str());
                         this.create_def(field.id, DefPathData::Field(name));
                     }
                 }

src/librustc/hir/map/definitions.rs

@@ -14,7 +14,7 @@ use std::fmt::Write;
 use std::hash::{Hash, Hasher};
 use std::collections::hash_map::DefaultHasher;
 use syntax::ast;
-use syntax::parse::token::{self, InternedString};
+use syntax::symbol::{Symbol, InternedString};
 use ty::TyCtxt;
 use util::nodemap::NodeMap;
 
@@ -115,9 +115,9 @@ impl DefPath {
     pub fn to_string(&self, tcx: TyCtxt) -> String {
         let mut s = String::with_capacity(self.data.len() * 16);
 
-        s.push_str(&tcx.original_crate_name(self.krate));
+        s.push_str(&tcx.original_crate_name(self.krate).as_str());
         s.push_str("/");
-        s.push_str(&tcx.crate_disambiguator(self.krate));
+        s.push_str(&tcx.crate_disambiguator(self.krate).as_str());
 
         for component in &self.data {
             write!(s,
@@ -137,8 +137,8 @@ impl DefPath {
     }
 
     pub fn deterministic_hash_to<H: Hasher>(&self, tcx: TyCtxt, state: &mut H) {
-        tcx.original_crate_name(self.krate).hash(state);
-        tcx.crate_disambiguator(self.krate).hash(state);
+        tcx.original_crate_name(self.krate).as_str().hash(state);
+        tcx.crate_disambiguator(self.krate).as_str().hash(state);
         self.data.hash(state);
     }
 }
@@ -328,7 +328,7 @@ impl DefPathData {
             LifetimeDef(ref name) |
             EnumVariant(ref name) |
             Binding(ref name) |
-            Field(ref name) => Some(token::intern(name)),
+            Field(ref name) => Some(Symbol::intern(name)),
 
             Impl |
             CrateRoot |
@@ -343,7 +343,7 @@ impl DefPathData {
 
     pub fn as_interned_str(&self) -> InternedString {
         use self::DefPathData::*;
-        match *self {
+        let s = match *self {
             TypeNs(ref name) |
             ValueNs(ref name) |
             Module(ref name) |
@@ -353,43 +353,24 @@ impl DefPathData {
             EnumVariant(ref name) |
             Binding(ref name) |
             Field(ref name) => {
-                name.clone()
-            }
-
-            Impl => {
-                InternedString::new("{{impl}}")
+                return name.clone();
             }
 
             // note that this does not show up in user printouts
-            CrateRoot => {
-                InternedString::new("{{root}}")
-            }
+            CrateRoot => "{{root}}",
 
             // note that this does not show up in user printouts
-            InlinedRoot(_) => {
-                InternedString::new("{{inlined-root}}")
-            }
-
-            Misc => {
-                InternedString::new("{{?}}")
-            }
-
-            ClosureExpr => {
-                InternedString::new("{{closure}}")
-            }
-
-            StructCtor => {
-                InternedString::new("{{constructor}}")
-            }
-
-            Initializer => {
-                InternedString::new("{{initializer}}")
-            }
+            InlinedRoot(_) => "{{inlined-root}}",
+
+            Impl => "{{impl}}",
+            Misc => "{{?}}",
+            ClosureExpr => "{{closure}}",
+            StructCtor => "{{constructor}}",
+            Initializer => "{{initializer}}",
+            ImplTrait => "{{impl-Trait}}",
+        };
 
-            ImplTrait => {
-                InternedString::new("{{impl-Trait}}")
-            }
-        }
+        Symbol::intern(s).as_str()
     }
 
     pub fn to_string(&self) -> String {

src/librustc/hir/map/mod.rs

@@ -765,7 +765,7 @@ impl<'a, 'ast> NodesMatchingSuffix<'a, 'ast> {
                 None => return false,
                 Some((node_id, name)) => (node_id, name),
             };
-            if &part[..] != mod_name.as_str() {
+            if mod_name != &**part {
                 return false;
             }
             cursor = self.map.get_parent(mod_id);
@@ -803,8 +803,7 @@ impl<'a, 'ast> NodesMatchingSuffix<'a, 'ast> {
     // We are looking at some node `n` with a given name and parent
     // id; do their names match what I am seeking?
     fn matches_names(&self, parent_of_n: NodeId, name: Name) -> bool {
-        name.as_str() == &self.item_name[..] &&
-            self.suffix_matches(parent_of_n)
+        name == &**self.item_name && self.suffix_matches(parent_of_n)
     }
 }