diff --git a/compiler/rustc_ast/src/ast.rs b/compiler/rustc_ast/src/ast.rs
index 727c6bc82fe..af246e31371 100644
--- a/compiler/rustc_ast/src/ast.rs
+++ b/compiler/rustc_ast/src/ast.rs
@@ -2786,6 +2786,7 @@ pub enum AttrKind {
 #[derive(Clone, Encodable, Decodable, Debug)]
 pub struct NormalAttr {
     pub item: AttrItem,
+    // Tokens for the full attribute, e.g. `#[foo]`, `#![bar]`.
     pub tokens: Option<LazyAttrTokenStream>,
 }
 
@@ -2802,6 +2803,7 @@ pub fn from_ident(ident: Ident) -> Self {
 pub struct AttrItem {
     pub path: Path,
     pub args: AttrArgs,
+    // Tokens for the meta item, e.g. just the `foo` within `#[foo]` or `#![foo]`.
     pub tokens: Option<LazyAttrTokenStream>,
 }
 
diff --git a/compiler/rustc_ast/src/attr/mod.rs b/compiler/rustc_ast/src/attr/mod.rs
index 5e3fc7e3357..0f12fd31975 100644
--- a/compiler/rustc_ast/src/attr/mod.rs
+++ b/compiler/rustc_ast/src/attr/mod.rs
@@ -298,7 +298,10 @@ pub fn name_value_literal_span(&self) -> Option<Span> {
     }
 
     pub fn value_str(&self) -> Option<Symbol> {
-        self.kind.value_str()
+        match &self.kind {
+            MetaItemKind::NameValue(v) => v.kind.str(),
+            _ => None,
+        }
     }
 
     fn from_tokens<'a, I>(tokens: &mut iter::Peekable<I>) -> Option<MetaItem>
@@ -362,13 +365,6 @@ fn from_tokens<'a, I>(tokens: &mut iter::Peekable<I>) -> Option<MetaItem>
 }
 
 impl MetaItemKind {
-    pub fn value_str(&self) -> Option<Symbol> {
-        match self {
-            MetaItemKind::NameValue(v) => v.kind.str(),
-            _ => None,
-        }
-    }
-
     fn list_from_tokens(tokens: TokenStream) -> Option<ThinVec<NestedMetaItem>> {
         let mut tokens = tokens.trees().peekable();
         let mut result = ThinVec::new();
@@ -468,8 +464,9 @@ pub fn meta_item_list(&self) -> Option<&[NestedMetaItem]> {
         self.meta_item().and_then(|meta_item| meta_item.meta_item_list())
     }
 
-    /// Returns a name and single literal value tuple of the `MetaItem`.
-    pub fn name_value_literal(&self) -> Option<(Symbol, &MetaItemLit)> {
+    /// If it's a singleton list of the form `foo(lit)`, returns the `foo` and
+    /// the `lit`.
+    pub fn singleton_lit_list(&self) -> Option<(Symbol, &MetaItemLit)> {
         self.meta_item().and_then(|meta_item| {
             meta_item.meta_item_list().and_then(|meta_item_list| {
                 if meta_item_list.len() == 1
diff --git a/compiler/rustc_ast/src/mut_visit.rs b/compiler/rustc_ast/src/mut_visit.rs
index 7dbfb7c7364..1cceca33c17 100644
--- a/compiler/rustc_ast/src/mut_visit.rs
+++ b/compiler/rustc_ast/src/mut_visit.rs
@@ -335,7 +335,7 @@ pub fn visit_clobber<T: DummyAstNode>(t: &mut T, f: impl FnOnce(T) -> T) {
 
 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
 #[inline]
-pub fn visit_vec<T, F>(elems: &mut Vec<T>, mut visit_elem: F)
+fn visit_vec<T, F>(elems: &mut Vec<T>, mut visit_elem: F)
 where
     F: FnMut(&mut T),
 {
@@ -346,7 +346,7 @@ pub fn visit_vec<T, F>(elems: &mut Vec<T>, mut visit_elem: F)
 
 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
 #[inline]
-pub fn visit_thin_vec<T, F>(elems: &mut ThinVec<T>, mut visit_elem: F)
+fn visit_thin_vec<T, F>(elems: &mut ThinVec<T>, mut visit_elem: F)
 where
     F: FnMut(&mut T),
 {
@@ -357,7 +357,7 @@ pub fn visit_thin_vec<T, F>(elems: &mut ThinVec<T>, mut visit_elem: F)
 
 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
 #[inline]
-pub fn visit_opt<T, F>(opt: &mut Option<T>, mut visit_elem: F)
+fn visit_opt<T, F>(opt: &mut Option<T>, mut visit_elem: F)
 where
     F: FnMut(&mut T),
 {
@@ -367,36 +367,37 @@ pub fn visit_opt<T, F>(opt: &mut Option<T>, mut visit_elem: F)
 }
 
 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
-pub fn visit_attrs<T: MutVisitor>(attrs: &mut AttrVec, vis: &mut T) {
+fn visit_attrs<T: MutVisitor>(attrs: &mut AttrVec, vis: &mut T) {
     for attr in attrs.iter_mut() {
         vis.visit_attribute(attr);
     }
 }
 
 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
-pub fn visit_exprs<T: MutVisitor>(exprs: &mut Vec<P<Expr>>, vis: &mut T) {
+#[allow(unused)]
+fn visit_exprs<T: MutVisitor>(exprs: &mut Vec<P<Expr>>, vis: &mut T) {
     exprs.flat_map_in_place(|expr| vis.filter_map_expr(expr))
 }
 
 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
-pub fn visit_thin_exprs<T: MutVisitor>(exprs: &mut ThinVec<P<Expr>>, vis: &mut T) {
+fn visit_thin_exprs<T: MutVisitor>(exprs: &mut ThinVec<P<Expr>>, vis: &mut T) {
     exprs.flat_map_in_place(|expr| vis.filter_map_expr(expr))
 }
 
 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
-pub fn visit_bounds<T: MutVisitor>(bounds: &mut GenericBounds, vis: &mut T) {
+fn visit_bounds<T: MutVisitor>(bounds: &mut GenericBounds, vis: &mut T) {
     visit_vec(bounds, |bound| vis.visit_param_bound(bound));
 }
 
 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
-pub fn visit_fn_sig<T: MutVisitor>(FnSig { header, decl, span }: &mut FnSig, vis: &mut T) {
+fn visit_fn_sig<T: MutVisitor>(FnSig { header, decl, span }: &mut FnSig, vis: &mut T) {
     vis.visit_fn_header(header);
     vis.visit_fn_decl(decl);
     vis.visit_span(span);
 }
 
 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
-pub fn visit_attr_args<T: MutVisitor>(args: &mut AttrArgs, vis: &mut T) {
+fn visit_attr_args<T: MutVisitor>(args: &mut AttrArgs, vis: &mut T) {
     match args {
         AttrArgs::Empty => {}
         AttrArgs::Delimited(args) => visit_delim_args(args, vis),
@@ -411,7 +412,7 @@ pub fn visit_attr_args<T: MutVisitor>(args: &mut AttrArgs, vis: &mut T) {
 }
 
 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
-pub fn visit_delim_args<T: MutVisitor>(args: &mut DelimArgs, vis: &mut T) {
+fn visit_delim_args<T: MutVisitor>(args: &mut DelimArgs, vis: &mut T) {
     let DelimArgs { dspan, delim: _, tokens } = args;
     visit_delim_span(dspan, vis);
     visit_tts(tokens, vis);
@@ -435,7 +436,7 @@ pub fn noop_flat_map_pat_field<T: MutVisitor>(
     smallvec![fp]
 }
 
-pub fn noop_visit_use_tree<T: MutVisitor>(use_tree: &mut UseTree, vis: &mut T) {
+fn noop_visit_use_tree<T: MutVisitor>(use_tree: &mut UseTree, vis: &mut T) {
     let UseTree { prefix, kind, span } = use_tree;
     vis.visit_path(prefix);
     match kind {
@@ -462,7 +463,7 @@ pub fn noop_visit_use_tree<T: MutVisitor>(use_tree: &mut UseTree, vis: &mut T) {
     smallvec![arm]
 }
 
-pub fn noop_visit_constraint<T: MutVisitor>(
+fn noop_visit_constraint<T: MutVisitor>(
     AssocConstraint { id, ident, gen_args, kind, span }: &mut AssocConstraint,
     vis: &mut T,
 ) {
@@ -541,7 +542,7 @@ pub fn noop_visit_ty<T: MutVisitor>(ty: &mut P<Ty>, vis: &mut T) {
     visit_lazy_tts(tokens, vis);
 }
 
-pub fn noop_visit_foreign_mod<T: MutVisitor>(foreign_mod: &mut ForeignMod, vis: &mut T) {
+fn noop_visit_foreign_mod<T: MutVisitor>(foreign_mod: &mut ForeignMod, vis: &mut T) {
     let ForeignMod { unsafety, abi: _, items } = foreign_mod;
     visit_unsafety(unsafety, vis);
     items.flat_map_in_place(|item| vis.flat_map_foreign_item(item));
@@ -562,11 +563,11 @@ pub fn noop_flat_map_variant<T: MutVisitor>(
     smallvec![variant]
 }
 
-pub fn noop_visit_ident<T: MutVisitor>(Ident { name: _, span }: &mut Ident, vis: &mut T) {
+fn noop_visit_ident<T: MutVisitor>(Ident { name: _, span }: &mut Ident, vis: &mut T) {
     vis.visit_span(span);
 }
 
-pub fn noop_visit_path<T: MutVisitor>(Path { segments, span, tokens }: &mut Path, vis: &mut T) {
+fn noop_visit_path<T: MutVisitor>(Path { segments, span, tokens }: &mut Path, vis: &mut T) {
     vis.visit_span(span);
     for PathSegment { ident, id, args } in segments {
         vis.visit_ident(ident);
@@ -576,7 +577,7 @@ pub fn noop_visit_path<T: MutVisitor>(Path { segments, span, tokens }: &mut Path
     visit_lazy_tts(tokens, vis);
 }
 
-pub fn noop_visit_qself<T: MutVisitor>(qself: &mut Option<P<QSelf>>, vis: &mut T) {
+fn noop_visit_qself<T: MutVisitor>(qself: &mut Option<P<QSelf>>, vis: &mut T) {
     visit_opt(qself, |qself| {
         let QSelf { ty, path_span, position: _ } = &mut **qself;
         vis.visit_ty(ty);
@@ -584,14 +585,14 @@ pub fn noop_visit_qself<T: MutVisitor>(qself: &mut Option<P<QSelf>>, vis: &mut T
     })
 }
 
-pub fn noop_visit_generic_args<T: MutVisitor>(generic_args: &mut GenericArgs, vis: &mut T) {
+fn noop_visit_generic_args<T: MutVisitor>(generic_args: &mut GenericArgs, vis: &mut T) {
     match generic_args {
         GenericArgs::AngleBracketed(data) => vis.visit_angle_bracketed_parameter_data(data),
         GenericArgs::Parenthesized(data) => vis.visit_parenthesized_parameter_data(data),
     }
 }
 
-pub fn noop_visit_generic_arg<T: MutVisitor>(arg: &mut GenericArg, vis: &mut T) {
+fn noop_visit_generic_arg<T: MutVisitor>(arg: &mut GenericArg, vis: &mut T) {
     match arg {
         GenericArg::Lifetime(lt) => vis.visit_lifetime(lt),
         GenericArg::Type(ty) => vis.visit_ty(ty),
@@ -599,7 +600,7 @@ pub fn noop_visit_generic_arg<T: MutVisitor>(arg: &mut GenericArg, vis: &mut T)
     }
 }
 
-pub fn noop_visit_angle_bracketed_parameter_data<T: MutVisitor>(
+fn noop_visit_angle_bracketed_parameter_data<T: MutVisitor>(
     data: &mut AngleBracketedArgs,
     vis: &mut T,
 ) {
@@ -611,7 +612,7 @@ pub fn noop_visit_angle_bracketed_parameter_data<T: MutVisitor>(
     vis.visit_span(span);
 }
 
-pub fn noop_visit_parenthesized_parameter_data<T: MutVisitor>(
+fn noop_visit_parenthesized_parameter_data<T: MutVisitor>(
     args: &mut ParenthesizedArgs,
     vis: &mut T,
 ) {
@@ -621,7 +622,7 @@ pub fn noop_visit_parenthesized_parameter_data<T: MutVisitor>(
     vis.visit_span(span);
 }
 
-pub fn noop_visit_local<T: MutVisitor>(local: &mut P<Local>, vis: &mut T) {
+fn noop_visit_local<T: MutVisitor>(local: &mut P<Local>, vis: &mut T) {
     let Local { id, pat, ty, kind, span, colon_sp, attrs, tokens } = local.deref_mut();
     vis.visit_id(id);
     vis.visit_pat(pat);
@@ -642,7 +643,7 @@ pub fn noop_visit_local<T: MutVisitor>(local: &mut P<Local>, vis: &mut T) {
     visit_lazy_tts(tokens, vis);
 }
 
-pub fn noop_visit_attribute<T: MutVisitor>(attr: &mut Attribute, vis: &mut T) {
+fn noop_visit_attribute<T: MutVisitor>(attr: &mut Attribute, vis: &mut T) {
     let Attribute { kind, id: _, style: _, span } = attr;
     match kind {
         AttrKind::Normal(normal) => {
@@ -658,25 +659,25 @@ pub fn noop_visit_attribute<T: MutVisitor>(attr: &mut Attribute, vis: &mut T) {
     vis.visit_span(span);
 }
 
-pub fn noop_visit_mac<T: MutVisitor>(mac: &mut MacCall, vis: &mut T) {
+fn noop_visit_mac<T: MutVisitor>(mac: &mut MacCall, vis: &mut T) {
     let MacCall { path, args } = mac;
     vis.visit_path(path);
     visit_delim_args(args, vis);
 }
 
-pub fn noop_visit_macro_def<T: MutVisitor>(macro_def: &mut MacroDef, vis: &mut T) {
+fn noop_visit_macro_def<T: MutVisitor>(macro_def: &mut MacroDef, vis: &mut T) {
     let MacroDef { body, macro_rules: _ } = macro_def;
     visit_delim_args(body, vis);
 }
 
-pub fn noop_visit_meta_list_item<T: MutVisitor>(li: &mut NestedMetaItem, vis: &mut T) {
+fn noop_visit_meta_list_item<T: MutVisitor>(li: &mut NestedMetaItem, vis: &mut T) {
     match li {
         NestedMetaItem::MetaItem(mi) => vis.visit_meta_item(mi),
         NestedMetaItem::Lit(_lit) => {}
     }
 }
 
-pub fn noop_visit_meta_item<T: MutVisitor>(mi: &mut MetaItem, vis: &mut T) {
+fn noop_visit_meta_item<T: MutVisitor>(mi: &mut MetaItem, vis: &mut T) {
     let MetaItem { path: _, kind, span } = mi;
     match kind {
         MetaItemKind::Word => {}
@@ -697,7 +698,7 @@ pub fn noop_visit_meta_item<T: MutVisitor>(mi: &mut MetaItem, vis: &mut T) {
 }
 
 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
-pub fn visit_attr_tt<T: MutVisitor>(tt: &mut AttrTokenTree, vis: &mut T) {
+fn visit_attr_tt<T: MutVisitor>(tt: &mut AttrTokenTree, vis: &mut T) {
     match tt {
         AttrTokenTree::Token(token, _) => {
             visit_token(token, vis);
@@ -724,7 +725,7 @@ pub fn visit_attr_tt<T: MutVisitor>(tt: &mut AttrTokenTree, vis: &mut T) {
 }
 
 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
-pub fn visit_tt<T: MutVisitor>(tt: &mut TokenTree, vis: &mut T) {
+fn visit_tt<T: MutVisitor>(tt: &mut TokenTree, vis: &mut T) {
     match tt {
         TokenTree::Token(token, _) => {
             visit_token(token, vis);
@@ -738,24 +739,21 @@ pub fn visit_tt<T: MutVisitor>(tt: &mut TokenTree, vis: &mut T) {
 }
 
 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
-pub fn visit_tts<T: MutVisitor>(TokenStream(tts): &mut TokenStream, vis: &mut T) {
+fn visit_tts<T: MutVisitor>(TokenStream(tts): &mut TokenStream, vis: &mut T) {
     if T::VISIT_TOKENS && !tts.is_empty() {
         let tts = Lrc::make_mut(tts);
         visit_vec(tts, |tree| visit_tt(tree, vis));
     }
 }
 
-pub fn visit_attr_tts<T: MutVisitor>(AttrTokenStream(tts): &mut AttrTokenStream, vis: &mut T) {
+fn visit_attr_tts<T: MutVisitor>(AttrTokenStream(tts): &mut AttrTokenStream, vis: &mut T) {
     if T::VISIT_TOKENS && !tts.is_empty() {
         let tts = Lrc::make_mut(tts);
         visit_vec(tts, |tree| visit_attr_tt(tree, vis));
     }
 }
 
-pub fn visit_lazy_tts_opt_mut<T: MutVisitor>(
-    lazy_tts: Option<&mut LazyAttrTokenStream>,
-    vis: &mut T,
-) {
+fn visit_lazy_tts_opt_mut<T: MutVisitor>(lazy_tts: Option<&mut LazyAttrTokenStream>, vis: &mut T) {
     if T::VISIT_TOKENS {
         if let Some(lazy_tts) = lazy_tts {
             let mut tts = lazy_tts.to_attr_token_stream();
@@ -765,7 +763,7 @@ pub fn visit_lazy_tts_opt_mut<T: MutVisitor>(
     }
 }
 
-pub fn visit_lazy_tts<T: MutVisitor>(lazy_tts: &mut Option<LazyAttrTokenStream>, vis: &mut T) {
+fn visit_lazy_tts<T: MutVisitor>(lazy_tts: &mut Option<LazyAttrTokenStream>, vis: &mut T) {
     visit_lazy_tts_opt_mut(lazy_tts.as_mut(), vis);
 }
 
@@ -818,7 +816,7 @@ pub fn visit_token<T: MutVisitor>(t: &mut Token, vis: &mut T) {
 // contain multiple items, but decided against it when I looked at
 // `parse_item_or_view_item` and tried to figure out what I would do with
 // multiple items there....
-pub fn visit_nonterminal<T: MutVisitor>(nt: &mut token::Nonterminal, vis: &mut T) {
+fn visit_nonterminal<T: MutVisitor>(nt: &mut token::Nonterminal, vis: &mut T) {
     match nt {
         token::NtItem(item) => visit_clobber(item, |item| {
             // This is probably okay, because the only visitors likely to
@@ -851,7 +849,7 @@ pub fn visit_nonterminal<T: MutVisitor>(nt: &mut token::Nonterminal, vis: &mut T
 }
 
 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
-pub fn visit_defaultness<T: MutVisitor>(defaultness: &mut Defaultness, vis: &mut T) {
+fn visit_defaultness<T: MutVisitor>(defaultness: &mut Defaultness, vis: &mut T) {
     match defaultness {
         Defaultness::Default(span) => vis.visit_span(span),
         Defaultness::Final => {}
@@ -859,7 +857,7 @@ pub fn visit_defaultness<T: MutVisitor>(defaultness: &mut Defaultness, vis: &mut
 }
 
 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
-pub fn visit_unsafety<T: MutVisitor>(unsafety: &mut Unsafe, vis: &mut T) {
+fn visit_unsafety<T: MutVisitor>(unsafety: &mut Unsafe, vis: &mut T) {
     match unsafety {
         Unsafe::Yes(span) => vis.visit_span(span),
         Unsafe::No => {}
@@ -867,7 +865,7 @@ pub fn visit_unsafety<T: MutVisitor>(unsafety: &mut Unsafe, vis: &mut T) {
 }
 
 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
-pub fn visit_polarity<T: MutVisitor>(polarity: &mut ImplPolarity, vis: &mut T) {
+fn visit_polarity<T: MutVisitor>(polarity: &mut ImplPolarity, vis: &mut T) {
     match polarity {
         ImplPolarity::Positive => {}
         ImplPolarity::Negative(span) => vis.visit_span(span),
@@ -875,14 +873,14 @@ pub fn visit_polarity<T: MutVisitor>(polarity: &mut ImplPolarity, vis: &mut T) {
 }
 
 // No `noop_` prefix because there isn't a corresponding method in `MutVisitor`.
-pub fn visit_constness<T: MutVisitor>(constness: &mut Const, vis: &mut T) {
+fn visit_constness<T: MutVisitor>(constness: &mut Const, vis: &mut T) {
     match constness {
         Const::Yes(span) => vis.visit_span(span),
         Const::No => {}
     }
 }
 
-pub fn noop_visit_closure_binder<T: MutVisitor>(binder: &mut ClosureBinder, vis: &mut T) {
+fn noop_visit_closure_binder<T: MutVisitor>(binder: &mut ClosureBinder, vis: &mut T) {
     match binder {
         ClosureBinder::NotPresent => {}
         ClosureBinder::For { span: _, generic_params } => {
@@ -891,7 +889,7 @@ pub fn noop_visit_closure_binder<T: MutVisitor>(binder: &mut ClosureBinder, vis:
     }
 }
 
-pub fn noop_visit_coroutine_kind<T: MutVisitor>(coroutine_kind: &mut CoroutineKind, vis: &mut T) {
+fn noop_visit_coroutine_kind<T: MutVisitor>(coroutine_kind: &mut CoroutineKind, vis: &mut T) {
     match coroutine_kind {
         CoroutineKind::Async { span, closure_id, return_impl_trait_id }
         | CoroutineKind::Gen { span, closure_id, return_impl_trait_id }
@@ -903,27 +901,27 @@ pub fn noop_visit_coroutine_kind<T: MutVisitor>(coroutine_kind: &mut CoroutineKi
     }
 }
 
-pub fn noop_visit_fn_decl<T: MutVisitor>(decl: &mut P<FnDecl>, vis: &mut T) {
+fn noop_visit_fn_decl<T: MutVisitor>(decl: &mut P<FnDecl>, vis: &mut T) {
     let FnDecl { inputs, output } = decl.deref_mut();
     inputs.flat_map_in_place(|param| vis.flat_map_param(param));
     noop_visit_fn_ret_ty(output, vis);
 }
 
-pub fn noop_visit_fn_ret_ty<T: MutVisitor>(fn_ret_ty: &mut FnRetTy, vis: &mut T) {
+fn noop_visit_fn_ret_ty<T: MutVisitor>(fn_ret_ty: &mut FnRetTy, vis: &mut T) {
     match fn_ret_ty {
         FnRetTy::Default(span) => vis.visit_span(span),
         FnRetTy::Ty(ty) => vis.visit_ty(ty),
     }
 }
 
-pub fn noop_visit_param_bound<T: MutVisitor>(pb: &mut GenericBound, vis: &mut T) {
+fn noop_visit_param_bound<T: MutVisitor>(pb: &mut GenericBound, vis: &mut T) {
     match pb {
         GenericBound::Trait(ty, _modifier) => vis.visit_poly_trait_ref(ty),
         GenericBound::Outlives(lifetime) => noop_visit_lifetime(lifetime, vis),
     }
 }
 
-pub fn noop_visit_precise_capturing_arg<T: MutVisitor>(arg: &mut PreciseCapturingArg, vis: &mut T) {
+fn noop_visit_precise_capturing_arg<T: MutVisitor>(arg: &mut PreciseCapturingArg, vis: &mut T) {
     match arg {
         PreciseCapturingArg::Lifetime(lt) => {
             vis.visit_lifetime(lt);
@@ -960,7 +958,7 @@ pub fn noop_flat_map_generic_param<T: MutVisitor>(
     smallvec![param]
 }
 
-pub fn noop_visit_label<T: MutVisitor>(Label { ident }: &mut Label, vis: &mut T) {
+fn noop_visit_label<T: MutVisitor>(Label { ident }: &mut Label, vis: &mut T) {
     vis.visit_ident(ident);
 }
 
@@ -969,20 +967,20 @@ fn noop_visit_lifetime<T: MutVisitor>(Lifetime { id, ident }: &mut Lifetime, vis
     vis.visit_ident(ident);
 }
 
-pub fn noop_visit_generics<T: MutVisitor>(generics: &mut Generics, vis: &mut T) {
+fn noop_visit_generics<T: MutVisitor>(generics: &mut Generics, vis: &mut T) {
     let Generics { params, where_clause, span } = generics;
     params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
     vis.visit_where_clause(where_clause);
     vis.visit_span(span);
 }
 
-pub fn noop_visit_where_clause<T: MutVisitor>(wc: &mut WhereClause, vis: &mut T) {
+fn noop_visit_where_clause<T: MutVisitor>(wc: &mut WhereClause, vis: &mut T) {
     let WhereClause { has_where_token: _, predicates, span } = wc;
     visit_thin_vec(predicates, |predicate| vis.visit_where_predicate(predicate));
     vis.visit_span(span);
 }
 
-pub fn noop_visit_where_predicate<T: MutVisitor>(pred: &mut WherePredicate, vis: &mut T) {
+fn noop_visit_where_predicate<T: MutVisitor>(pred: &mut WherePredicate, vis: &mut T) {
     match pred {
         WherePredicate::BoundPredicate(bp) => {
             let WhereBoundPredicate { span, bound_generic_params, bounded_ty, bounds } = bp;
@@ -1006,7 +1004,7 @@ pub fn noop_visit_where_predicate<T: MutVisitor>(pred: &mut WherePredicate, vis:
     }
 }
 
-pub fn noop_visit_variant_data<T: MutVisitor>(vdata: &mut VariantData, vis: &mut T) {
+fn noop_visit_variant_data<T: MutVisitor>(vdata: &mut VariantData, vis: &mut T) {
     match vdata {
         VariantData::Struct { fields, .. } => {
             fields.flat_map_in_place(|field| vis.flat_map_field_def(field));
@@ -1019,12 +1017,12 @@ pub fn noop_visit_variant_data<T: MutVisitor>(vdata: &mut VariantData, vis: &mut
     }
 }
 
-pub fn noop_visit_trait_ref<T: MutVisitor>(TraitRef { path, ref_id }: &mut TraitRef, vis: &mut T) {
+fn noop_visit_trait_ref<T: MutVisitor>(TraitRef { path, ref_id }: &mut TraitRef, vis: &mut T) {
     vis.visit_path(path);
     vis.visit_id(ref_id);
 }
 
-pub fn noop_visit_poly_trait_ref<T: MutVisitor>(p: &mut PolyTraitRef, vis: &mut T) {
+fn noop_visit_poly_trait_ref<T: MutVisitor>(p: &mut PolyTraitRef, vis: &mut T) {
     let PolyTraitRef { bound_generic_params, trait_ref, span } = p;
     bound_generic_params.flat_map_in_place(|param| vis.flat_map_generic_param(param));
     vis.visit_trait_ref(trait_ref);
@@ -1058,7 +1056,7 @@ pub fn noop_flat_map_expr_field<T: MutVisitor>(
     smallvec![f]
 }
 
-pub fn noop_visit_mt<T: MutVisitor>(MutTy { ty, mutbl: _ }: &mut MutTy, vis: &mut T) {
+fn noop_visit_mt<T: MutVisitor>(MutTy { ty, mutbl: _ }: &mut MutTy, vis: &mut T) {
     vis.visit_ty(ty);
 }
 
@@ -1225,7 +1223,7 @@ fn visit_const_item<T: MutVisitor>(
     visit_opt(expr, |expr| visitor.visit_expr(expr));
 }
 
-pub fn noop_visit_fn_header<T: MutVisitor>(header: &mut FnHeader, vis: &mut T) {
+fn noop_visit_fn_header<T: MutVisitor>(header: &mut FnHeader, vis: &mut T) {
     let FnHeader { unsafety, coroutine_kind, constness, ext: _ } = header;
     visit_constness(constness, vis);
     coroutine_kind.as_mut().map(|coroutine_kind| vis.visit_coroutine_kind(coroutine_kind));
@@ -1343,12 +1341,12 @@ pub fn noop_visit_pat<T: MutVisitor>(pat: &mut P<Pat>, vis: &mut T) {
     visit_lazy_tts(tokens, vis);
 }
 
-pub fn noop_visit_anon_const<T: MutVisitor>(AnonConst { id, value }: &mut AnonConst, vis: &mut T) {
+fn noop_visit_anon_const<T: MutVisitor>(AnonConst { id, value }: &mut AnonConst, vis: &mut T) {
     vis.visit_id(id);
     vis.visit_expr(value);
 }
 
-pub fn noop_visit_inline_asm<T: MutVisitor>(asm: &mut InlineAsm, vis: &mut T) {
+fn noop_visit_inline_asm<T: MutVisitor>(asm: &mut InlineAsm, vis: &mut T) {
     for (op, _) in &mut asm.operands {
         match op {
             InlineAsmOperand::In { expr, .. }
@@ -1368,7 +1366,7 @@ pub fn noop_visit_inline_asm<T: MutVisitor>(asm: &mut InlineAsm, vis: &mut T) {
     }
 }
 
-pub fn noop_visit_inline_asm_sym<T: MutVisitor>(
+fn noop_visit_inline_asm_sym<T: MutVisitor>(
     InlineAsmSym { id, qself, path }: &mut InlineAsmSym,
     vis: &mut T,
 ) {
@@ -1377,7 +1375,7 @@ pub fn noop_visit_inline_asm_sym<T: MutVisitor>(
     vis.visit_path(path);
 }
 
-pub fn noop_visit_format_args<T: MutVisitor>(fmt: &mut FormatArgs, vis: &mut T) {
+fn noop_visit_format_args<T: MutVisitor>(fmt: &mut FormatArgs, vis: &mut T) {
     for arg in fmt.arguments.all_args_mut() {
         if let FormatArgumentKind::Named(name) = &mut arg.kind {
             vis.visit_ident(name);
@@ -1594,10 +1592,7 @@ pub fn noop_flat_map_stmt<T: MutVisitor>(
     stmts
 }
 
-pub fn noop_flat_map_stmt_kind<T: MutVisitor>(
-    kind: StmtKind,
-    vis: &mut T,
-) -> SmallVec<[StmtKind; 1]> {
+fn noop_flat_map_stmt_kind<T: MutVisitor>(kind: StmtKind, vis: &mut T) -> SmallVec<[StmtKind; 1]> {
     match kind {
         StmtKind::Let(mut local) => smallvec![StmtKind::Let({
             vis.visit_local(&mut local);
@@ -1617,7 +1612,7 @@ pub fn noop_flat_map_stmt_kind<T: MutVisitor>(
     }
 }
 
-pub fn noop_visit_vis<T: MutVisitor>(visibility: &mut Visibility, vis: &mut T) {
+fn noop_visit_vis<T: MutVisitor>(visibility: &mut Visibility, vis: &mut T) {
     match &mut visibility.kind {
         VisibilityKind::Public | VisibilityKind::Inherited => {}
         VisibilityKind::Restricted { path, id, shorthand: _ } => {
@@ -1628,7 +1623,7 @@ pub fn noop_visit_vis<T: MutVisitor>(visibility: &mut Visibility, vis: &mut T) {
     vis.visit_span(&mut visibility.span);
 }
 
-pub fn noop_visit_capture_by<T: MutVisitor>(capture_by: &mut CaptureBy, vis: &mut T) {
+fn noop_visit_capture_by<T: MutVisitor>(capture_by: &mut CaptureBy, vis: &mut T) {
     match capture_by {
         CaptureBy::Ref => {}
         CaptureBy::Value { move_kw } => {
diff --git a/compiler/rustc_ast/src/tokenstream.rs b/compiler/rustc_ast/src/tokenstream.rs
index 880f92bbe7b..08d65a5ffa5 100644
--- a/compiler/rustc_ast/src/tokenstream.rs
+++ b/compiler/rustc_ast/src/tokenstream.rs
@@ -140,9 +140,8 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
 }
 
 impl<S: SpanEncoder> Encodable<S> for LazyAttrTokenStream {
-    fn encode(&self, s: &mut S) {
-        // Used by AST json printing.
-        Encodable::encode(&self.to_attr_token_stream(), s);
+    fn encode(&self, _s: &mut S) {
+        panic!("Attempted to encode LazyAttrTokenStream");
     }
 }
 
diff --git a/compiler/rustc_attr/src/builtin.rs b/compiler/rustc_attr/src/builtin.rs
index 439f13e7635..1c2077372e1 100644
--- a/compiler/rustc_attr/src/builtin.rs
+++ b/compiler/rustc_attr/src/builtin.rs
@@ -986,7 +986,7 @@ pub fn parse_repr_attr(sess: &Session, attr: &Attribute) -> Vec<ReprAttr> {
                     recognised = true;
                     acc.push(h);
                 }
-            } else if let Some((name, value)) = item.name_value_literal() {
+            } else if let Some((name, value)) = item.singleton_lit_list() {
                 let mut literal_error = None;
                 let mut err_span = item.span();
                 if name == sym::align {
diff --git a/compiler/rustc_codegen_ssa/src/codegen_attrs.rs b/compiler/rustc_codegen_ssa/src/codegen_attrs.rs
index 9c9e134f033..c28b0d644e6 100644
--- a/compiler/rustc_codegen_ssa/src/codegen_attrs.rs
+++ b/compiler/rustc_codegen_ssa/src/codegen_attrs.rs
@@ -435,7 +435,7 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
             sym::repr => {
                 codegen_fn_attrs.alignment = if let Some(items) = attr.meta_item_list()
                     && let [item] = items.as_slice()
-                    && let Some((sym::align, literal)) = item.name_value_literal()
+                    && let Some((sym::align, literal)) = item.singleton_lit_list()
                 {
                     rustc_attr::parse_alignment(&literal.kind)
                         .map_err(|msg| {
diff --git a/compiler/rustc_session/src/options.rs b/compiler/rustc_session/src/options.rs
index d5108058948..6a556e2a1f5 100644
--- a/compiler/rustc_session/src/options.rs
+++ b/compiler/rustc_session/src/options.rs
@@ -1,5 +1,4 @@
 use crate::config::*;
-
 use crate::search_paths::SearchPath;
 use crate::utils::NativeLib;
 use crate::{lint, EarlyDiagCtxt};
@@ -8,20 +7,17 @@
 use rustc_data_structures::stable_hasher::Hash64;
 use rustc_errors::ColorConfig;
 use rustc_errors::{LanguageIdentifier, TerminalUrl};
+use rustc_feature::UnstableFeatures;
+use rustc_span::edition::Edition;
+use rustc_span::RealFileName;
+use rustc_span::SourceFileHashAlgorithm;
 use rustc_target::spec::{
     CodeModel, LinkerFlavorCli, MergeFunctions, PanicStrategy, SanitizerSet, WasmCAbi,
 };
 use rustc_target::spec::{
     RelocModel, RelroLevel, SplitDebuginfo, StackProtector, TargetTriple, TlsModel,
 };
-
-use rustc_feature::UnstableFeatures;
-use rustc_span::edition::Edition;
-use rustc_span::RealFileName;
-use rustc_span::SourceFileHashAlgorithm;
-
 use std::collections::BTreeMap;
-
 use std::hash::{DefaultHasher, Hasher};
 use std::num::{IntErrorKind, NonZero};
 use std::path::PathBuf;
@@ -118,8 +114,8 @@ pub fn dep_tracking_hash(&self, for_crate_hash: bool) -> u64 {
     /// incremental compilation cache before proceeding.
     ///
     /// - `[TRACKED_NO_CRATE_HASH]`
-    /// Same as `[TRACKED]`, but will not affect the crate hash. This is useful for options that only
-    /// affect the incremental cache.
+    /// Same as `[TRACKED]`, but will not affect the crate hash. This is useful for options that
+    /// only affect the incremental cache.
     ///
     /// - `[UNTRACKED]`
     /// Incremental compilation is not influenced by this option.