diff --git a/clippy_lints/src/undocumented_unsafe_blocks.rs b/clippy_lints/src/undocumented_unsafe_blocks.rs
index 6cc4b589a720..8906e654c972 100644
--- a/clippy_lints/src/undocumented_unsafe_blocks.rs
+++ b/clippy_lints/src/undocumented_unsafe_blocks.rs
@@ -9,7 +9,7 @@ use clippy_utils::visitors::{Descend, for_each_expr};
 use hir::HirId;
 use rustc_hir as hir;
 use rustc_hir::{Block, BlockCheckMode, ItemKind, Node, UnsafeSource};
-use rustc_lexer::{TokenKind, tokenize};
+use rustc_lexer::{FrontmatterAllowed, TokenKind, tokenize};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_session::impl_lint_pass;
 use rustc_span::{BytePos, Pos, RelativeBytePos, Span, SyntaxContext};
@@ -746,7 +746,7 @@ fn text_has_safety_comment(src: &str, line_starts: &[RelativeBytePos], start_pos
     loop {
         if line.starts_with("/*") {
             let src = &src[line_start..line_starts.last().unwrap().to_usize()];
-            let mut tokens = tokenize(src);
+            let mut tokens = tokenize(src, FrontmatterAllowed::No);
             return (src[..tokens.next().unwrap().len as usize]
                 .to_ascii_uppercase()
                 .contains("SAFETY:")
diff --git a/clippy_lints/src/utils/format_args_collector.rs b/clippy_lints/src/utils/format_args_collector.rs
index 8f314ce7a60c..6629a67f78bd 100644
--- a/clippy_lints/src/utils/format_args_collector.rs
+++ b/clippy_lints/src/utils/format_args_collector.rs
@@ -3,7 +3,7 @@ use clippy_utils::source::SpanRangeExt;
 use itertools::Itertools;
 use rustc_ast::{Crate, Expr, ExprKind, FormatArgs};
 use rustc_data_structures::fx::FxHashMap;
-use rustc_lexer::{TokenKind, tokenize};
+use rustc_lexer::{FrontmatterAllowed, TokenKind, tokenize};
 use rustc_lint::{EarlyContext, EarlyLintPass};
 use rustc_session::impl_lint_pass;
 use rustc_span::{Span, hygiene};
@@ -82,7 +82,7 @@ fn has_span_from_proc_macro(cx: &EarlyContext<'_>, args: &FormatArgs) -> bool {
         .all(|sp| {
             sp.check_source_text(cx, |src| {
                 // text should be either `, name` or `, name =`
-                let mut iter = tokenize(src).filter(|t| {
+                let mut iter = tokenize(src, FrontmatterAllowed::No).filter(|t| {
                     !matches!(
                         t.kind,
                         TokenKind::LineComment { .. } | TokenKind::BlockComment { .. } | TokenKind::Whitespace
diff --git a/clippy_utils/src/consts.rs b/clippy_utils/src/consts.rs
index ba0376e4d406..25afa12e95d6 100644
--- a/clippy_utils/src/consts.rs
+++ b/clippy_utils/src/consts.rs
@@ -15,7 +15,7 @@ use rustc_hir::def::{DefKind, Res};
 use rustc_hir::{
     BinOpKind, Block, ConstBlock, Expr, ExprKind, HirId, Item, ItemKind, Node, PatExpr, PatExprKind, QPath, UnOp,
 };
-use rustc_lexer::tokenize;
+use rustc_lexer::{FrontmatterAllowed, tokenize};
 use rustc_lint::LateContext;
 use rustc_middle::mir::ConstValue;
 use rustc_middle::mir::interpret::{Scalar, alloc_range};
@@ -304,9 +304,7 @@ pub fn lit_to_mir_constant<'tcx>(lit: &LitKind, ty: Option<Ty<'tcx>>) -> Constan
     match *lit {
         LitKind::Str(ref is, _) => Constant::Str(is.to_string()),
         LitKind::Byte(b) => Constant::Int(u128::from(b)),
-        LitKind::ByteStr(ref s, _) | LitKind::CStr(ref s, _) => {
-            Constant::Binary(s.as_byte_str().to_vec())
-        }
+        LitKind::ByteStr(ref s, _) | LitKind::CStr(ref s, _) => Constant::Binary(s.as_byte_str().to_vec()),
         LitKind::Char(c) => Constant::Char(c),
         LitKind::Int(n, _) => Constant::Int(n.get()),
         LitKind::Float(ref is, LitFloatType::Suffixed(fty)) => match fty {
@@ -568,9 +566,7 @@ impl<'tcx> ConstEvalCtxt<'tcx> {
                 } else {
                     match &lit.node {
                         LitKind::Str(is, _) => Some(is.is_empty()),
-                        LitKind::ByteStr(s, _) | LitKind::CStr(s, _) => {
-                            Some(s.as_byte_str().is_empty())
-                        }
+                        LitKind::ByteStr(s, _) | LitKind::CStr(s, _) => Some(s.as_byte_str().is_empty()),
                         _ => None,
                     }
                 }
@@ -715,7 +711,7 @@ impl<'tcx> ConstEvalCtxt<'tcx> {
                     && let Some(src) = src.as_str()
                 {
                     use rustc_lexer::TokenKind::{BlockComment, LineComment, OpenBrace, Semi, Whitespace};
-                    if !tokenize(src)
+                    if !tokenize(src, FrontmatterAllowed::No)
                         .map(|t| t.kind)
                         .filter(|t| !matches!(t, Whitespace | LineComment { .. } | BlockComment { .. } | Semi))
                         .eq([OpenBrace])
diff --git a/clippy_utils/src/hir_utils.rs b/clippy_utils/src/hir_utils.rs
index 0ca494f16e31..6e8dccbccd51 100644
--- a/clippy_utils/src/hir_utils.rs
+++ b/clippy_utils/src/hir_utils.rs
@@ -12,7 +12,7 @@ use rustc_hir::{
     Pat, PatExpr, PatExprKind, PatField, PatKind, Path, PathSegment, PrimTy, QPath, Stmt, StmtKind, StructTailExpr,
     TraitBoundModifiers, Ty, TyKind, TyPat, TyPatKind,
 };
-use rustc_lexer::{TokenKind, tokenize};
+use rustc_lexer::{FrontmatterAllowed, TokenKind, tokenize};
 use rustc_lint::LateContext;
 use rustc_middle::ty::TypeckResults;
 use rustc_span::{BytePos, ExpnKind, MacroKind, Symbol, SyntaxContext, sym};
@@ -686,7 +686,7 @@ fn reduce_exprkind<'hir>(cx: &LateContext<'_>, kind: &'hir ExprKind<'hir>) -> &'
             // `{}` => `()`
             ([], None)
                 if block.span.check_source_text(cx, |src| {
-                    tokenize(src)
+                    tokenize(src, FrontmatterAllowed::No)
                         .map(|t| t.kind)
                         .filter(|t| {
                             !matches!(
diff --git a/clippy_utils/src/lib.rs b/clippy_utils/src/lib.rs
index c01f0ffaac9a..98b4c183b120 100644
--- a/clippy_utils/src/lib.rs
+++ b/clippy_utils/src/lib.rs
@@ -106,7 +106,7 @@ use rustc_hir::{
     Param, Pat, PatExpr, PatExprKind, PatKind, Path, PathSegment, QPath, Stmt, StmtKind, TraitFn, TraitItem,
     TraitItemKind, TraitRef, TyKind, UnOp, def,
 };
-use rustc_lexer::{TokenKind, tokenize};
+use rustc_lexer::{FrontmatterAllowed, TokenKind, tokenize};
 use rustc_lint::{LateContext, Level, Lint, LintContext};
 use rustc_middle::hir::nested_filter;
 use rustc_middle::hir::place::PlaceBase;
@@ -2764,7 +2764,7 @@ pub fn expr_use_ctxt<'tcx>(cx: &LateContext<'tcx>, e: &Expr<'tcx>) -> ExprUseCtx
 /// Tokenizes the input while keeping the text associated with each token.
 pub fn tokenize_with_text(s: &str) -> impl Iterator<Item = (TokenKind, &str, InnerSpan)> {
     let mut pos = 0;
-    tokenize(s).map(move |t| {
+    tokenize(s, FrontmatterAllowed::No).map(move |t| {
         let end = pos + t.len;
         let range = pos as usize..end as usize;
         let inner = InnerSpan::new(range.start, range.end);
@@ -2779,7 +2779,7 @@ pub fn span_contains_comment(sm: &SourceMap, span: Span) -> bool {
     let Ok(snippet) = sm.span_to_snippet(span) else {
         return false;
     };
-    return tokenize(&snippet).any(|token| {
+    return tokenize(&snippet, FrontmatterAllowed::No).any(|token| {
         matches!(
             token.kind,
             TokenKind::BlockComment { .. } | TokenKind::LineComment { .. }
diff --git a/clippy_utils/src/source.rs b/clippy_utils/src/source.rs
index 7f2bf99daff2..7d21336be1cd 100644
--- a/clippy_utils/src/source.rs
+++ b/clippy_utils/src/source.rs
@@ -7,7 +7,7 @@ use std::sync::Arc;
 use rustc_ast::{LitKind, StrStyle};
 use rustc_errors::Applicability;
 use rustc_hir::{BlockCheckMode, Expr, ExprKind, UnsafeSource};
-use rustc_lexer::{LiteralKind, TokenKind, tokenize};
+use rustc_lexer::{FrontmatterAllowed, LiteralKind, TokenKind, tokenize};
 use rustc_lint::{EarlyContext, LateContext};
 use rustc_middle::ty::TyCtxt;
 use rustc_session::Session;
@@ -277,7 +277,7 @@ fn map_range(
 }
 
 fn ends_with_line_comment_or_broken(text: &str) -> bool {
-    let Some(last) = tokenize(text).last() else {
+    let Some(last) = tokenize(text, FrontmatterAllowed::No).last() else {
         return false;
     };
     match last.kind {
@@ -310,7 +310,8 @@ fn with_leading_whitespace_inner(lines: &[RelativeBytePos], src: &str, range: Ra
         && ends_with_line_comment_or_broken(&start[prev_start..])
         && let next_line = lines.partition_point(|&pos| pos.to_usize() < range.end)
         && let next_start = lines.get(next_line).map_or(src.len(), |&x| x.to_usize())
-        && tokenize(src.get(range.end..next_start)?).any(|t| !matches!(t.kind, TokenKind::Whitespace))
+        && tokenize(src.get(range.end..next_start)?, FrontmatterAllowed::No)
+            .any(|t| !matches!(t.kind, TokenKind::Whitespace))
     {
         Some(range.start)
     } else {