Make HasTokens a sub-trait of HasAttrs.

compiler/rustc_ast/src/ast_traits.rs

@@ -62,7 +62,7 @@ impl<T: HasNodeId> HasNodeId for Box<T> {
 }
 
 /// A trait for AST nodes having (or not having) collected tokens.
-pub trait HasTokens {
+pub trait HasTokens: HasAttrs {
     fn tokens(&self) -> Option<&LazyAttrTokenStream>;
     fn tokens_mut(&mut self) -> Option<&mut Option<LazyAttrTokenStream>>;
 }
@@ -109,7 +109,7 @@ impl_has_tokens_none!(
     WherePredicate
 );
 
-impl<T> HasTokens for WithTokens<T> {
+impl<T: HasAttrs> HasTokens for WithTokens<T> {
     fn tokens(&self) -> Option<&LazyAttrTokenStream> {
         self.tokens.as_ref()
     }

compiler/rustc_ast/src/tokenstream.rs

@@ -18,7 +18,7 @@ use rustc_span::{DUMMY_SP, Span, SpanDecoder, SpanEncoder, Symbol, sym};
 use thin_vec::ThinVec;
 
 use crate::ast::AttrStyle;
-use crate::ast_traits::{HasAttrs, HasTokens};
+use crate::ast_traits::HasTokens;
 use crate::token::{self, Delimiter, Token, TokenKind};
 use crate::{AttrVec, Attribute};
 
@@ -653,7 +653,7 @@ impl TokenStream {
         TokenStream::new(vec![TokenTree::token_alone(kind, span)])
     }
 
-    pub fn from_ast(node: &(impl HasAttrs + HasTokens + fmt::Debug)) -> TokenStream {
+    pub fn from_ast(node: &(impl HasTokens + fmt::Debug)) -> TokenStream {
         let tokens = node.tokens().unwrap_or_else(|| panic!("missing tokens for node: {:?}", node));
         let mut tts = vec![];
         attrs_and_tokens_to_token_trees(node.attrs(), tokens, &mut tts);

compiler/rustc_builtin_macros/src/cfg_eval.rs

@@ -3,7 +3,7 @@ use core::ops::ControlFlow;
 use rustc_ast as ast;
 use rustc_ast::mut_visit::MutVisitor;
 use rustc_ast::visit::{AssocCtxt, Visitor};
-use rustc_ast::{Attribute, HasAttrs, HasTokens, NodeId, mut_visit, visit};
+use rustc_ast::{Attribute, HasTokens, NodeId, mut_visit, visit};
 use rustc_errors::PResult;
 use rustc_expand::base::{Annotatable, ExtCtxt};
 use rustc_expand::config::StripUnconfigured;
@@ -67,7 +67,7 @@ fn has_cfg_or_cfg_attr(annotatable: &Annotatable) -> bool {
 }
 
 impl CfgEval<'_> {
-    fn configure<T: HasAttrs + HasTokens>(&mut self, node: T) -> Option<T> {
+    fn configure<T: HasTokens>(&mut self, node: T) -> Option<T> {
         self.0.configure(node)
     }
 

compiler/rustc_expand/src/config.rs

@@ -167,7 +167,7 @@ macro_rules! configure {
 }
 
 impl<'a> StripUnconfigured<'a> {
-    pub fn configure<T: HasAttrs + HasTokens>(&self, mut node: T) -> Option<T> {
+    pub fn configure<T: HasTokens>(&self, mut node: T) -> Option<T> {
         self.process_cfg_attrs(&mut node);
         self.in_cfg(node.attrs()).then(|| {
             self.try_configure_tokens(&mut node);

compiler/rustc_parse/src/parser/attr_wrapper.rs

@@ -5,7 +5,7 @@ use rustc_ast::token::Token;
 use rustc_ast::tokenstream::{
     AttrsTarget, LazyAttrTokenStream, NodeRange, ParserRange, Spacing, TokenCursor,
 };
-use rustc_ast::{self as ast, AttrVec, Attribute, HasAttrs, HasTokens};
+use rustc_ast::{self as ast, AttrVec, Attribute, HasTokens};
 use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::PResult;
 use rustc_session::parse::ParseSess;
@@ -137,7 +137,7 @@ impl<'a> Parser<'a> {
     ///     }                               //  32..33
     /// }                                   //  33..34
     /// ```
-    pub(super) fn collect_tokens<R: HasAttrs + HasTokens>(
+    pub(super) fn collect_tokens<R: HasTokens>(
         &mut self,
         pre_attr_pos: Option<CollectPos>,
         attrs: AttrWrapper,

compiler/rustc_parse/src/parser/mod.rs

@@ -36,9 +36,8 @@ use rustc_ast::util::case::Case;
 use rustc_ast::util::classify;
 use rustc_ast::{
     self as ast, AnonConst, AttrArgs, AttrId, BinOpKind, ByRef, Const, CoroutineKind,
-    DUMMY_NODE_ID, DelimArgs, Expr, ExprKind, Extern, HasAttrs, HasTokens, ImplRestriction,
-    MutRestriction, Mutability, Recovered, RestrictionKind, Safety, StrLit, Visibility,
-    VisibilityKind,
+    DUMMY_NODE_ID, DelimArgs, Expr, ExprKind, Extern, HasTokens, ImplRestriction, MutRestriction,
+    Mutability, Recovered, RestrictionKind, Safety, StrLit, Visibility, VisibilityKind,
 };
 use rustc_ast_pretty::pprust;
 use rustc_data_structures::fx::FxHashMap;
@@ -1662,7 +1661,7 @@ impl<'a> Parser<'a> {
         }
     }
 
-    fn collect_tokens_no_attrs<R: HasAttrs + HasTokens>(
+    fn collect_tokens_no_attrs<R: HasTokens>(
         &mut self,
         f: impl FnOnce(&mut Self) -> PResult<'a, R>,
     ) -> PResult<'a, R> {