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

1 files changed, 5 insertions, 4 deletions

diff --git a/src/libsyntax_ext/format.rs b/src/libsyntax_ext/format.rs
index 6eba8baf5b8..d2afa08cada 100644
--- a/src/libsyntax_ext/format.rs
+++ b/src/libsyntax_ext/format.rs
@@ -17,8 +17,9 @@ use syntax::ast;
 use syntax::ext::base::*;
 use syntax::ext::base;
 use syntax::ext::build::AstBuilder;
-use syntax::parse::token::{self, keywords};
+use syntax::parse::token;
 use syntax::ptr::P;
+use syntax::symbol::{Symbol, keywords};
 use syntax_pos::{Span, DUMMY_SP};
 use syntax::tokenstream;
 
@@ -369,7 +370,7 @@ impl<'a, 'b> Context<'a, 'b> {
     /// Translate the accumulated string literals to a literal expression
     fn trans_literal_string(&mut self) -> P<ast::Expr> {
         let sp = self.fmtsp;
-        let s = token::intern_and_get_ident(&self.literal);
+        let s = Symbol::intern(&self.literal);
         self.literal.clear();
         self.ecx.expr_str(sp, s)
     }
@@ -727,7 +728,8 @@ pub fn expand_preparsed_format_args(ecx: &mut ExtCtxt,
         fmtsp: fmt.span,
     };
 
-    let mut parser = parse::Parser::new(&fmt.node.0);
+    let fmt_str = &*fmt.node.0.as_str();
+    let mut parser = parse::Parser::new(fmt_str);
     let mut pieces = vec![];
 
     loop {
@@ -808,7 +810,6 @@ pub fn expand_preparsed_format_args(ecx: &mut ExtCtxt,
         // Decide if we want to look for foreign formatting directives.
         if args_used < args_unused {
             use super::format_foreign as foreign;
-            let fmt_str = &fmt.node.0[..];
 
             // The set of foreign substitutions we've explained.  This prevents spamming the user
             // with `%d should be written as {}` over and over again.