diff --git a/compiler/rustc_ast/src/mut_visit.rs b/compiler/rustc_ast/src/mut_visit.rs index f673ab2f3ef..74def2bab1b 100644 --- a/compiler/rustc_ast/src/mut_visit.rs +++ b/compiler/rustc_ast/src/mut_visit.rs @@ -37,9 +37,7 @@ pub trait MutVisitor: Sized { /// Mutable token visiting only exists for the `macro_rules` token marker and should not be /// used otherwise. Token visitor would be entirely separate from the regular visitor if /// the marker didn't have to visit AST fragments in nonterminal tokens. - fn token_visiting_enabled(&self) -> bool { - false - } + const VISIT_TOKENS: bool = false; // Methods in this trait have one of three forms: // @@ -363,7 +361,7 @@ pub fn visit_mac_args(args: &mut MacArgs, vis: &mut T) { } MacArgs::Eq(eq_span, token) => { vis.visit_span(eq_span); - if vis.token_visiting_enabled() { + if T::VISIT_TOKENS { visit_token(token, vis); } else { // The value in `#[key = VALUE]` must be visited as an expression for backward @@ -682,7 +680,7 @@ pub fn visit_tt(tt: &mut TokenTree, vis: &mut T) { // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`. pub fn visit_tts(TokenStream(tts): &mut TokenStream, vis: &mut T) { - if vis.token_visiting_enabled() && !tts.is_empty() { + if T::VISIT_TOKENS && !tts.is_empty() { let tts = Lrc::make_mut(tts); visit_vec(tts, |(tree, _is_joint)| visit_tt(tree, vis)); } @@ -692,14 +690,14 @@ pub fn visit_attr_annotated_tts( AttrAnnotatedTokenStream(tts): &mut AttrAnnotatedTokenStream, vis: &mut T, ) { - if vis.token_visiting_enabled() && !tts.is_empty() { + if T::VISIT_TOKENS && !tts.is_empty() { let tts = Lrc::make_mut(tts); visit_vec(tts, |(tree, _is_joint)| visit_attr_annotated_tt(tree, vis)); } } pub fn visit_lazy_tts_opt_mut(lazy_tts: Option<&mut LazyTokenStream>, vis: &mut T) { - if vis.token_visiting_enabled() { + if T::VISIT_TOKENS { if let Some(lazy_tts) = lazy_tts { let mut tts = lazy_tts.create_token_stream(); visit_attr_annotated_tts(&mut tts, vis); diff --git a/compiler/rustc_expand/src/mbe/transcribe.rs b/compiler/rustc_expand/src/mbe/transcribe.rs index 4663dd80fa8..88e1623012b 100644 --- a/compiler/rustc_expand/src/mbe/transcribe.rs +++ b/compiler/rustc_expand/src/mbe/transcribe.rs @@ -19,9 +19,7 @@ use std::mem; struct Marker(LocalExpnId, Transparency); impl MutVisitor for Marker { - fn token_visiting_enabled(&self) -> bool { - true - } + const VISIT_TOKENS: bool = true; fn visit_span(&mut self, span: &mut Span) { *span = span.apply_mark(self.0.to_expn_id(), self.1) diff --git a/compiler/rustc_expand/src/mut_visit/tests.rs b/compiler/rustc_expand/src/mut_visit/tests.rs index 0068539fb3b..8974d45b4d8 100644 --- a/compiler/rustc_expand/src/mut_visit/tests.rs +++ b/compiler/rustc_expand/src/mut_visit/tests.rs @@ -15,9 +15,8 @@ fn print_crate_items(krate: &ast::Crate) -> String { struct ToZzIdentMutVisitor; impl MutVisitor for ToZzIdentMutVisitor { - fn token_visiting_enabled(&self) -> bool { - true - } + const VISIT_TOKENS: bool = true; + fn visit_ident(&mut self, ident: &mut Ident) { *ident = Ident::from_str("zz"); }