Remove `token::Lit` from `ast::MetaItemLit`.

`token::Lit` contains a `kind` field that indicates what kind of literal
it is. `ast::MetaItemLit` currently wraps a `token::Lit` but also has
its own `kind` field. This means that `ast::MetaItemLit` encodes the
literal kind in two different ways.

This commit changes `ast::MetaItemLit` so it no longer wraps
`token::Lit`. It now contains the `symbol` and `suffix` fields from
`token::Lit`, but not the `kind` field, eliminating the redundancy.

1 files changed, 6 insertions, 4 deletions

diff --git a/compiler/rustc_builtin_macros/src/derive.rs b/compiler/rustc_builtin_macros/src/derive.rs
index fa5a45730ac..2a8dc02849e 100644
--- a/compiler/rustc_builtin_macros/src/derive.rs
+++ b/compiler/rustc_builtin_macros/src/derive.rs
@@ -1,7 +1,7 @@
 use crate::cfg_eval::cfg_eval;
 
 use rustc_ast as ast;
-use rustc_ast::{token, GenericParamKind, ItemKind, MetaItemKind, NestedMetaItem, StmtKind};
+use rustc_ast::{GenericParamKind, ItemKind, MetaItemKind, NestedMetaItem, StmtKind};
 use rustc_errors::{struct_span_err, Applicability};
 use rustc_expand::base::{Annotatable, ExpandResult, ExtCtxt, Indeterminate, MultiItemModifier};
 use rustc_feature::AttributeTemplate;
@@ -130,9 +130,11 @@ fn report_bad_target(sess: &Session, item: &Annotatable, span: Span) -> bool {
 }
 
 fn report_unexpected_meta_item_lit(sess: &Session, lit: &ast::MetaItemLit) {
-    let help_msg = match lit.token_lit.kind {
-        token::Str if rustc_lexer::is_ident(lit.token_lit.symbol.as_str()) => {
-            format!("try using `#[derive({})]`", lit.token_lit.symbol)
+    let help_msg = match lit.kind {
+        ast::LitKind::Str(_, ast::StrStyle::Cooked)
+            if rustc_lexer::is_ident(lit.symbol.as_str()) =>
+        {
+            format!("try using `#[derive({})]`", lit.symbol)
         }
         _ => "for example, write `#[derive(Debug)]` for `Debug`".to_string(),
     };