syntax: Pre-intern names of all built-in macros

They always end up interned anyway

src/libsyntax/ext/derive.rs

@@ -63,11 +63,11 @@ pub fn add_derived_markers<T>(cx: &mut ExtCtxt<'_>, span: Span, traits: &[ast::P
 
     let span = span.with_ctxt(cx.backtrace());
     item.visit_attrs(|attrs| {
-        if names.contains(&Symbol::intern("Eq")) && names.contains(&Symbol::intern("PartialEq")) {
-            let meta = cx.meta_word(span, Symbol::intern("structural_match"));
+        if names.contains(&sym::Eq) && names.contains(&sym::PartialEq) {
+            let meta = cx.meta_word(span, sym::structural_match);
             attrs.push(cx.attribute(span, meta));
         }
-        if names.contains(&Symbol::intern("Copy")) {
+        if names.contains(&sym::Copy) {
             let meta = cx.meta_word(span, sym::rustc_copy_clone_marker);
             attrs.push(cx.attribute(span, meta));
         }

src/libsyntax/parse/lexer/mod.rs

@@ -613,7 +613,7 @@ fn scan_number(&mut self, c: char) -> (token::LitKind, Symbol) {
         if num_digits == 0 {
             self.err_span_(start_bpos, self.pos, "no valid digits found for number");
 
-            return (token::Integer, Symbol::intern("0"));
+            return (token::Integer, sym::integer(0));
         }
 
         // might be a float, but don't be greedy if this is actually an

src/libsyntax_ext/deriving/mod.rs

@@ -61,10 +61,10 @@ fn expand(&self,
 }
 
 macro_rules! derive_traits {
-    ($( [$deprecation:expr] $name:expr => $func:path, )+) => {
+    ($( [$deprecation:expr] $name:ident => $func:path, )+) => {
         pub fn is_builtin_trait(name: ast::Name) -> bool {
-            match &*name.as_str() {
-                $( $name )|+ => true,
+            match name {
+                $( sym::$name )|+ => true,
                 _ => false,
             }
         }
@@ -80,7 +80,7 @@ pub fn register_builtin_derives(resolver: &mut dyn Resolver, edition: Edition) {
 
             $(
                 resolver.add_builtin(
-                    ast::Ident::with_empty_ctxt(Symbol::intern($name)),
+                    ast::Ident::with_empty_ctxt(sym::$name),
                     Lrc::new(SyntaxExtension {
                         deprecation: $deprecation.map(|msg| Deprecation {
                             since: Some(Symbol::intern("1.0.0")),
@@ -100,40 +100,40 @@ pub fn register_builtin_derives(resolver: &mut dyn Resolver, edition: Edition) {
 
 derive_traits! {
     [None]
-    "Clone" => clone::expand_deriving_clone,
+    Clone => clone::expand_deriving_clone,
 
     [None]
-    "Hash" => hash::expand_deriving_hash,
+    Hash => hash::expand_deriving_hash,
 
     [None]
-    "RustcEncodable" => encodable::expand_deriving_rustc_encodable,
+    RustcEncodable => encodable::expand_deriving_rustc_encodable,
 
     [None]
-    "RustcDecodable" => decodable::expand_deriving_rustc_decodable,
+    RustcDecodable => decodable::expand_deriving_rustc_decodable,
 
     [None]
-    "PartialEq" => partial_eq::expand_deriving_partial_eq,
+    PartialEq => partial_eq::expand_deriving_partial_eq,
     [None]
-    "Eq" => eq::expand_deriving_eq,
+    Eq => eq::expand_deriving_eq,
     [None]
-    "PartialOrd" => partial_ord::expand_deriving_partial_ord,
+    PartialOrd => partial_ord::expand_deriving_partial_ord,
     [None]
-    "Ord" => ord::expand_deriving_ord,
+    Ord => ord::expand_deriving_ord,
 
     [None]
-    "Debug" => debug::expand_deriving_debug,
+    Debug => debug::expand_deriving_debug,
 
     [None]
-    "Default" => default::expand_deriving_default,
+    Default => default::expand_deriving_default,
 
     [None]
-    "Copy" => bounds::expand_deriving_copy,
+    Copy => bounds::expand_deriving_copy,
 
     // deprecated
     [Some("derive(Encodable) is deprecated in favor of derive(RustcEncodable)")]
-    "Encodable" => encodable::expand_deriving_encodable,
+    Encodable => encodable::expand_deriving_encodable,
     [Some("derive(Decodable) is deprecated in favor of derive(RustcDecodable)")]
-    "Decodable" => decodable::expand_deriving_decodable,
+    Decodable => decodable::expand_deriving_decodable,
 }
 
 /// Construct a name for the inner type parameter that can't collide with any type parameters of

src/libsyntax_ext/lib.rs

@@ -74,14 +74,14 @@ pub fn register_builtins(resolver: &mut dyn syntax::ext::base::Resolver,
     };
     macro_rules! register {
         ($( $name:ident: $f:expr, )*) => { $(
-            register(Symbol::intern(stringify!($name)), SyntaxExtension::default(
+            register(sym::$name, SyntaxExtension::default(
                 SyntaxExtensionKind::LegacyBang(Box::new($f as MacroExpanderFn)), edition
             ));
         )* }
     }
     macro_rules! register_unstable {
         ($( [$feature:expr, $reason:expr, $issue:expr] $name:ident: $f:expr, )*) => { $(
-            register(Symbol::intern(stringify!($name)), SyntaxExtension {
+            register(sym::$name, SyntaxExtension {
                 stability: Some(Stability::unstable(
                     $feature, Some(Symbol::intern($reason)), $issue
                 )),
@@ -144,7 +144,7 @@ pub fn register_builtins(resolver: &mut dyn syntax::ext::base::Resolver,
 
     // format_args uses `unstable` things internally.
     let allow_internal_unstable = Some([sym::fmt_internals][..].into());
-    register(Symbol::intern("format_args"), SyntaxExtension {
+    register(sym::format_args, SyntaxExtension {
         allow_internal_unstable: allow_internal_unstable.clone(),
         ..SyntaxExtension::default(
             SyntaxExtensionKind::LegacyBang(Box::new(format::expand_format_args)), edition

src/libsyntax_ext/proc_macro_server.rs

@@ -548,10 +548,10 @@ fn float(&mut self, n: &str) -> Self::Literal {
         self.lit(token::Float, Symbol::intern(n), None)
     }
     fn f32(&mut self, n: &str) -> Self::Literal {
-        self.lit(token::Float, Symbol::intern(n), Some(Symbol::intern("f32")))
+        self.lit(token::Float, Symbol::intern(n), Some(sym::f32))
     }
     fn f64(&mut self, n: &str) -> Self::Literal {
-        self.lit(token::Float, Symbol::intern(n), Some(Symbol::intern("f64")))
+        self.lit(token::Float, Symbol::intern(n), Some(sym::f64))
     }
     fn string(&mut self, string: &str) -> Self::Literal {
         let mut escaped = String::new();

src/libsyntax_pos/symbol.rs

@@ -141,6 +141,7 @@
         ArgumentV1,
         arm_target_feature,
         asm,
+        assert,
         associated_consts,
         associated_type_bounds,
         associated_type_defaults,
@@ -184,8 +185,10 @@
         cmp,
         cmpxchg16b_target_feature,
         cold,
+        column,
         compile_error,
         compiler_builtins,
+        concat,
         concat_idents,
         conservative_impl_trait,
         console,
@@ -203,6 +206,7 @@
         contents,
         context,
         convert,
+        Copy,
         copy_closures,
         core,
         core_intrinsics,
@@ -217,8 +221,10 @@
         custom_inner_attributes,
         custom_test_frameworks,
         c_variadic,
+        Debug,
         declare_lint_pass,
         decl_macro,
+        Decodable,
         Default,
         default_lib_allocator,
         default_type_parameter_fallback,
@@ -253,9 +259,12 @@
         eh_personality,
         eh_unwind_resume,
         enable,
+        Encodable,
+        env,
         eq,
         err,
         Err,
+        Eq,
         Equal,
         except,
         exclusive_range_pattern,
@@ -284,6 +293,7 @@
         fmt_internals,
         fn_must_use,
         forbid,
+        format_args,
         format_args_nl,
         from,
         From,
@@ -335,6 +345,8 @@
         index_mut,
         in_band_lifetimes,
         include,
+        include_bytes,
+        include_str,
         inclusive_range_syntax,
         infer_outlives_requirements,
         infer_static_outlives_requirements,
@@ -363,6 +375,7 @@
         lhs,
         lib,
         lifetime,
+        line,
         link,
         linkage,
         link_args,
@@ -402,6 +415,7 @@
         mips_target_feature,
         mmx_target_feature,
         module,
+        module_path,
         more_struct_aliases,
         movbe_target_feature,
         must_use,
@@ -447,6 +461,7 @@
         optin_builtin_traits,
         option,
         Option,
+        option_env,
         opt_out_copy,
         or,
         Ord,
@@ -462,6 +477,7 @@
         parent_trait,
         partial_cmp,
         param_attrs,
+        PartialEq,
         PartialOrd,
         passes,
         pat,
@@ -532,6 +548,8 @@
         rust_2018_preview,
         rust_begin_unwind,
         rustc,
+        RustcDecodable,
+        RustcEncodable,
         rustc_allocator,
         rustc_allocator_nounwind,
         rustc_allow_const_fn_ptr,
@@ -591,7 +609,6 @@
         _Self,
         self_in_typedefs,
         self_struct_ctor,
-        Send,
         should_panic,
         simd,
         simd_ffi,
@@ -613,6 +630,7 @@
         static_recursion,
         std,
         str,
+        stringify,
         stmt,
         stmt_expr_attributes,
         stop_after_dataflow,