From ca4c006f7daeaba68a6292df8af16a37449fed35 Mon Sep 17 00:00:00 2001
From: Micha Reiser <micha@reiser.io>
Date: Sat, 26 Oct 2024 12:26:18 +0200
Subject: [PATCH] Experiment with Located trait

---
 crates/red_knot_test/src/assertion.rs         |   2 +-
 .../src/checkers/ast/analyze/bindings.rs      |   6 +-
 .../ast/analyze/unresolved_references.rs      |   6 +-
 crates/ruff_linter/src/checkers/ast/mod.rs    |   4 +
 .../src/checkers/physical_lines.rs            |   4 +-
 crates/ruff_linter/src/directives.rs          |   2 +-
 crates/ruff_linter/src/fix/edits.rs           |   8 +-
 crates/ruff_linter/src/importer/insertion.rs  |   4 +-
 crates/ruff_linter/src/linter.rs              |  65 +--
 crates/ruff_linter/src/noqa.rs                |   2 +-
 .../rules/mutable_argument_default.rs         |   6 +-
 .../rules/string_in_exception.rs              |   7 +-
 .../rules/unconventional_import_alias.rs      |   2 +-
 .../rules/unnecessary_placeholder.rs          |   2 +-
 .../unaliased_collections_abc_set_import.rs   |   2 +-
 .../flake8_pytest_style/rules/assertion.rs    |   8 +-
 .../src/rules/flake8_return/rules/function.rs |   6 +-
 .../flake8_simplify/rules/ast_bool_op.rs      |   2 +-
 .../flake8_simplify/rules/collapsible_if.rs   |   2 +-
 .../rules/flake8_simplify/rules/fix_with.rs   |   2 +-
 .../if_else_block_instead_of_dict_get.rs      |   4 +-
 .../rules/if_else_block_instead_of_if_exp.rs  |   2 +-
 .../flake8_simplify/rules/needless_bool.rs    |   2 +-
 .../rules/suppressible_exception.rs           |   2 +-
 .../src/rules/isort/rules/organize_imports.rs |   8 +-
 .../pycodestyle/rules/compound_statements.rs  |   2 +-
 .../pycodestyle/rules/lambda_assignment.rs    |   4 +-
 .../pycodestyle/rules/literal_comparisons.rs  |   2 +-
 .../rules/multiple_imports_on_one_line.rs     |   5 +-
 .../src/rules/pycodestyle/rules/not_tests.rs  |   4 +-
 .../pycodestyle/rules/trailing_whitespace.rs  |   2 +-
 .../rules/blank_before_after_class.rs         |   2 +-
 crates/ruff_linter/src/rules/pyflakes/mod.rs  |   4 +-
 .../src/rules/pyflakes/rules/unused_import.rs |   2 +-
 .../rules/pyflakes/rules/unused_variable.rs   |   2 +-
 .../rules/pylint/rules/collapsible_else_if.rs |   2 +-
 .../src/rules/pylint/rules/empty_comment.rs   |   2 +-
 .../src/rules/pylint/rules/nested_min_max.rs  |   2 +-
 .../rules/pylint/rules/no_method_decorator.rs |   2 +-
 .../src/rules/pylint/rules/non_ascii_name.rs  |   5 +-
 .../pylint/rules/useless_else_on_loop.rs      |   4 +-
 .../pyupgrade/rules/deprecated_import.rs      |   2 +-
 .../pyupgrade/rules/deprecated_mock_import.rs |   4 +-
 .../pyupgrade/rules/outdated_version_block.rs |   8 +-
 .../rules/printf_string_formatting.rs         |   2 +-
 .../rules/unnecessary_coding_comment.rs       |   2 +-
 .../rules/single_item_membership_test.rs      |   2 +-
 .../rules/collection_literal_concatenation.rs |   2 +-
 .../invalid_formatter_suppression_comment.rs  |   9 +-
 .../src/rules/ruff/rules/post_init_default.rs |   2 +-
 .../ruff/rules/suppression_comment_visitor.rs |   6 +-
 .../src/rules/ruff/rules/test_rules.rs        |  38 +-
 crates/ruff_linter/src/test.rs                |   8 +-
 crates/ruff_python_ast/src/helpers.rs         |  32 +-
 crates/ruff_python_ast/src/whitespace.rs      |  18 +-
 crates/ruff_python_codegen/src/lib.rs         |   4 +-
 crates/ruff_python_codegen/src/stylist.rs     |  77 ++--
 .../ruff_python_formatter/src/comments/mod.rs |   4 +-
 .../src/comments/placement.rs                 | 287 ++++++------
 .../src/comments/visitor.rs                   |   9 +-
 crates/ruff_python_formatter/src/context.rs   |   5 -
 .../src/expression/expr_f_string.rs           |  18 +-
 .../src/expression/expr_number_literal.rs     |   7 +-
 crates/ruff_python_formatter/src/lib.rs       |  20 +-
 .../src/other/f_string.rs                     |  10 +-
 .../src/other/f_string_element.rs             |   3 +-
 crates/ruff_python_formatter/src/range.rs     |   9 +-
 .../src/string/docstring.rs                   |   4 +-
 .../src/string/implicit.rs                    |  20 +-
 .../ruff_python_formatter/src/string/mod.rs   |   7 +-
 .../src/string/normalize.rs                   |  17 +-
 crates/ruff_python_formatter/src/verbatim.rs  |   6 +-
 crates/ruff_python_index/src/indexer.rs       |  67 ++-
 crates/ruff_python_semantic/src/binding.rs    |   6 +-
 crates/ruff_python_semantic/src/reference.rs  |   6 +-
 .../ruff_python_trivia/src/comment_ranges.rs  |  40 +-
 crates/ruff_python_trivia/src/whitespace.rs   |  29 +-
 .../tests/block_comments.rs                   |  22 +-
 .../tests/whitespace.rs                       |  16 +-
 crates/ruff_server/src/lint.rs                |   4 +-
 crates/ruff_source_file/src/lib.rs            |   2 +
 crates/ruff_source_file/src/located.rs        | 422 ++++++++++++++++++
 crates/ruff_source_file/src/locator.rs        |  59 +--
 crates/ruff_wasm/src/lib.rs                   |   4 +-
 84 files changed, 926 insertions(+), 599 deletions(-)
 create mode 100644 crates/ruff_source_file/src/located.rs

diff --git a/crates/red_knot_test/src/assertion.rs b/crates/red_knot_test/src/assertion.rs
index 2355b19f2f..d9191b5d30 100644
--- a/crates/red_knot_test/src/assertion.rs
+++ b/crates/red_knot_test/src/assertion.rs
@@ -76,7 +76,7 @@ impl InlineFileAssertions {
     }
 
     fn is_own_line_comment(&self, ranged_assertion: &AssertionWithRange) -> bool {
-        CommentRanges::is_own_line(ranged_assertion.start(), &self.locator())
+        CommentRanges::is_own_line(ranged_assertion.start(), self.source.as_str())
     }
 }
 
diff --git a/crates/ruff_linter/src/checkers/ast/analyze/bindings.rs b/crates/ruff_linter/src/checkers/ast/analyze/bindings.rs
index fe6faeafa6..04ed28fb44 100644
--- a/crates/ruff_linter/src/checkers/ast/analyze/bindings.rs
+++ b/crates/ruff_linter/src/checkers/ast/analyze/bindings.rs
@@ -26,11 +26,11 @@ pub(crate) fn bindings(checker: &mut Checker) {
                 && !checker
                     .settings
                     .dummy_variable_rgx
-                    .is_match(binding.name(checker.locator))
+                    .is_match(binding.name(checker.source()))
             {
                 let mut diagnostic = Diagnostic::new(
                     pyflakes::rules::UnusedVariable {
-                        name: binding.name(checker.locator).to_string(),
+                        name: binding.name(checker.source()).to_string(),
                     },
                     binding.range(),
                 );
@@ -52,7 +52,7 @@ pub(crate) fn bindings(checker: &mut Checker) {
             }
         }
         if checker.enabled(Rule::NonAsciiName) {
-            if let Some(diagnostic) = pylint::rules::non_ascii_name(binding, checker.locator) {
+            if let Some(diagnostic) = pylint::rules::non_ascii_name(binding, checker.source()) {
                 checker.diagnostics.push(diagnostic);
             }
         }
diff --git a/crates/ruff_linter/src/checkers/ast/analyze/unresolved_references.rs b/crates/ruff_linter/src/checkers/ast/analyze/unresolved_references.rs
index e0d7705204..22bfd90568 100644
--- a/crates/ruff_linter/src/checkers/ast/analyze/unresolved_references.rs
+++ b/crates/ruff_linter/src/checkers/ast/analyze/unresolved_references.rs
@@ -17,7 +17,7 @@ pub(crate) fn unresolved_references(checker: &mut Checker) {
             if checker.enabled(Rule::UndefinedLocalWithImportStarUsage) {
                 checker.diagnostics.push(Diagnostic::new(
                     pyflakes::rules::UndefinedLocalWithImportStarUsage {
-                        name: reference.name(checker.locator).to_string(),
+                        name: reference.name(checker.source()).to_string(),
                     },
                     reference.range(),
                 ));
@@ -31,12 +31,12 @@ pub(crate) fn unresolved_references(checker: &mut Checker) {
 
                 // Allow __path__.
                 if checker.path.ends_with("__init__.py") {
-                    if reference.name(checker.locator) == "__path__" {
+                    if reference.name(checker.source()) == "__path__" {
                         continue;
                     }
                 }
 
-                let symbol_name = reference.name(checker.locator);
+                let symbol_name = reference.name(checker.source());
 
                 checker.diagnostics.push(Diagnostic::new(
                     pyflakes::rules::UndefinedName {
diff --git a/crates/ruff_linter/src/checkers/ast/mod.rs b/crates/ruff_linter/src/checkers/ast/mod.rs
index 821d74eb4d..1f36c92a4a 100644
--- a/crates/ruff_linter/src/checkers/ast/mod.rs
+++ b/crates/ruff_linter/src/checkers/ast/mod.rs
@@ -352,6 +352,10 @@ impl<'a> Checker<'a> {
         self.locator
     }
 
+    pub(crate) const fn source(&self) -> &'a str {
+        self.locator.contents()
+    }
+
     /// The [`Stylist`] for the current file, which detects the current line ending, quote, and
     /// indentation style.
     pub(crate) const fn stylist(&self) -> &'a Stylist<'a> {
diff --git a/crates/ruff_linter/src/checkers/physical_lines.rs b/crates/ruff_linter/src/checkers/physical_lines.rs
index 7f1940a61b..087962b93e 100644
--- a/crates/ruff_linter/src/checkers/physical_lines.rs
+++ b/crates/ruff_linter/src/checkers/physical_lines.rs
@@ -106,8 +106,8 @@ mod tests {
         let line = "'\u{4e9c}' * 2"; // 7 in UTF-32, 9 in UTF-8.
         let locator = Locator::new(line);
         let parsed = parse_module(line).unwrap();
-        let indexer = Indexer::from_tokens(parsed.tokens(), &locator);
-        let stylist = Stylist::from_tokens(parsed.tokens(), &locator);
+        let indexer = Indexer::from_tokens(parsed.tokens(), line);
+        let stylist = Stylist::from_tokens(parsed.tokens(), line);
 
         let check_with_max_line_length = |line_length: LineLength| {
             check_physical_lines(
diff --git a/crates/ruff_linter/src/directives.rs b/crates/ruff_linter/src/directives.rs
index 50d23c40bc..ce7291741a 100644
--- a/crates/ruff_linter/src/directives.rs
+++ b/crates/ruff_linter/src/directives.rs
@@ -377,7 +377,7 @@ mod tests {
     fn noqa_mappings(contents: &str) -> NoqaMapping {
         let parsed = parse_module(contents).unwrap();
         let locator = Locator::new(contents);
-        let indexer = Indexer::from_tokens(parsed.tokens(), &locator);
+        let indexer = Indexer::from_tokens(parsed.tokens(), contents);
 
         extract_noqa_line_for(parsed.tokens(), &locator, &indexer)
     }
diff --git a/crates/ruff_linter/src/fix/edits.rs b/crates/ruff_linter/src/fix/edits.rs
index 7b1fa7ebb7..459d2067d9 100644
--- a/crates/ruff_linter/src/fix/edits.rs
+++ b/crates/ruff_linter/src/fix/edits.rs
@@ -48,9 +48,11 @@ pub(crate) fn delete_stmt(
         if let Some(semicolon) = trailing_semicolon(stmt.end(), locator) {
             let next = next_stmt_break(semicolon, locator);
             Edit::deletion(stmt.start(), next)
-        } else if has_leading_content(stmt.start(), locator) {
+        } else if has_leading_content(stmt.start(), locator.contents()) {
             Edit::range_deletion(stmt.range())
-        } else if let Some(start) = indexer.preceded_by_continuations(stmt.start(), locator) {
+        } else if let Some(start) =
+            indexer.preceded_by_continuations(stmt.start(), locator.contents())
+        {
             Edit::deletion(start, stmt.end())
         } else {
             let range = locator.full_lines_range(stmt.range());
@@ -726,7 +728,7 @@ x = 1 \
         let locator = Locator::new(raw);
         let edits = {
             let parsed = parse_expression(raw)?;
-            let stylist = Stylist::from_tokens(parsed.tokens(), &locator);
+            let stylist = Stylist::from_tokens(parsed.tokens(), raw);
             add_to_dunder_all(names.iter().copied(), parsed.expr(), &stylist)
         };
         let diag = {
diff --git a/crates/ruff_linter/src/importer/insertion.rs b/crates/ruff_linter/src/importer/insertion.rs
index 715405e19e..3a621aede2 100644
--- a/crates/ruff_linter/src/importer/insertion.rs
+++ b/crates/ruff_linter/src/importer/insertion.rs
@@ -329,7 +329,7 @@ mod tests {
         fn insert(contents: &str) -> Result<Insertion> {
             let parsed = parse_module(contents)?;
             let locator = Locator::new(contents);
-            let stylist = Stylist::from_tokens(parsed.tokens(), &locator);
+            let stylist = Stylist::from_tokens(parsed.tokens(), contents);
             Ok(Insertion::start_of_file(parsed.suite(), &locator, &stylist))
         }
 
@@ -440,7 +440,7 @@ x = 1
         fn insert(contents: &str, offset: TextSize) -> Insertion {
             let parsed = parse_module(contents).unwrap();
             let locator = Locator::new(contents);
-            let stylist = Stylist::from_tokens(parsed.tokens(), &locator);
+            let stylist = Stylist::from_tokens(parsed.tokens(), contents);
             Insertion::start_of_block(offset, &locator, &stylist, parsed.tokens())
         }
 
diff --git a/crates/ruff_linter/src/linter.rs b/crates/ruff_linter/src/linter.rs
index 6958b298cf..996b59aa7d 100644
--- a/crates/ruff_linter/src/linter.rs
+++ b/crates/ruff_linter/src/linter.rs
@@ -206,40 +206,53 @@ pub fn check_path(
             }
             let diagnostic = match test_rule {
                 Rule::StableTestRule => {
-                    test_rules::StableTestRule::diagnostic(locator, comment_ranges)
-                }
-                Rule::StableTestRuleSafeFix => {
-                    test_rules::StableTestRuleSafeFix::diagnostic(locator, comment_ranges)
-                }
-                Rule::StableTestRuleUnsafeFix => {
-                    test_rules::StableTestRuleUnsafeFix::diagnostic(locator, comment_ranges)
+                    test_rules::StableTestRule::diagnostic(locator.contents(), comment_ranges)
                 }
+                Rule::StableTestRuleSafeFix => test_rules::StableTestRuleSafeFix::diagnostic(
+                    locator.contents(),
+                    comment_ranges,
+                ),
+                Rule::StableTestRuleUnsafeFix => test_rules::StableTestRuleUnsafeFix::diagnostic(
+                    locator.contents(),
+                    comment_ranges,
+                ),
                 Rule::StableTestRuleDisplayOnlyFix => {
-                    test_rules::StableTestRuleDisplayOnlyFix::diagnostic(locator, comment_ranges)
+                    test_rules::StableTestRuleDisplayOnlyFix::diagnostic(
+                        locator.contents(),
+                        comment_ranges,
+                    )
                 }
                 Rule::PreviewTestRule => {
-                    test_rules::PreviewTestRule::diagnostic(locator, comment_ranges)
+                    test_rules::PreviewTestRule::diagnostic(locator.contents(), comment_ranges)
                 }
                 Rule::DeprecatedTestRule => {
-                    test_rules::DeprecatedTestRule::diagnostic(locator, comment_ranges)
+                    test_rules::DeprecatedTestRule::diagnostic(locator.contents(), comment_ranges)
                 }
                 Rule::AnotherDeprecatedTestRule => {
-                    test_rules::AnotherDeprecatedTestRule::diagnostic(locator, comment_ranges)
+                    test_rules::AnotherDeprecatedTestRule::diagnostic(
+                        locator.contents(),
+                        comment_ranges,
+                    )
                 }
                 Rule::RemovedTestRule => {
-                    test_rules::RemovedTestRule::diagnostic(locator, comment_ranges)
-                }
-                Rule::AnotherRemovedTestRule => {
-                    test_rules::AnotherRemovedTestRule::diagnostic(locator, comment_ranges)
+                    test_rules::RemovedTestRule::diagnostic(locator.contents(), comment_ranges)
                 }
+                Rule::AnotherRemovedTestRule => test_rules::AnotherRemovedTestRule::diagnostic(
+                    locator.contents(),
+                    comment_ranges,
+                ),
                 Rule::RedirectedToTestRule => {
-                    test_rules::RedirectedToTestRule::diagnostic(locator, comment_ranges)
-                }
-                Rule::RedirectedFromTestRule => {
-                    test_rules::RedirectedFromTestRule::diagnostic(locator, comment_ranges)
+                    test_rules::RedirectedToTestRule::diagnostic(locator.contents(), comment_ranges)
                 }
+                Rule::RedirectedFromTestRule => test_rules::RedirectedFromTestRule::diagnostic(
+                    locator.contents(),
+                    comment_ranges,
+                ),
                 Rule::RedirectedFromPrefixTestRule => {
-                    test_rules::RedirectedFromPrefixTestRule::diagnostic(locator, comment_ranges)
+                    test_rules::RedirectedFromPrefixTestRule::diagnostic(
+                        locator.contents(),
+                        comment_ranges,
+                    )
                 }
                 _ => unreachable!("All test rules must have an implementation"),
             };
@@ -335,10 +348,10 @@ pub fn add_noqa_to_path(
     let locator = Locator::new(source_kind.source_code());
 
     // Detect the current code style (lazily).
-    let stylist = Stylist::from_tokens(parsed.tokens(), &locator);
+    let stylist = Stylist::from_tokens(parsed.tokens(), source_kind.source_code());
 
     // Extra indices from the code.
-    let indexer = Indexer::from_tokens(parsed.tokens(), &locator);
+    let indexer = Indexer::from_tokens(parsed.tokens(), source_kind.source_code());
 
     // Extract the `# noqa` and `# isort: skip` directives from the source.
     let directives = directives::extract_directives(
@@ -393,10 +406,10 @@ pub fn lint_only(
     let locator = Locator::new(source_kind.source_code());
 
     // Detect the current code style (lazily).
-    let stylist = Stylist::from_tokens(parsed.tokens(), &locator);
+    let stylist = Stylist::from_tokens(parsed.tokens(), source_kind.source_code());
 
     // Extra indices from the code.
-    let indexer = Indexer::from_tokens(parsed.tokens(), &locator);
+    let indexer = Indexer::from_tokens(parsed.tokens(), source_kind.source_code());
 
     // Extract the `# noqa` and `# isort: skip` directives from the source.
     let directives = directives::extract_directives(
@@ -495,10 +508,10 @@ pub fn lint_fix<'a>(
         let locator = Locator::new(transformed.source_code());
 
         // Detect the current code style (lazily).
-        let stylist = Stylist::from_tokens(parsed.tokens(), &locator);
+        let stylist = Stylist::from_tokens(parsed.tokens(), transformed.source_code());
 
         // Extra indices from the code.
-        let indexer = Indexer::from_tokens(parsed.tokens(), &locator);
+        let indexer = Indexer::from_tokens(parsed.tokens(), transformed.source_code());
 
         // Extract the `# noqa` and `# isort: skip` directives from the source.
         let directives = directives::extract_directives(
diff --git a/crates/ruff_linter/src/noqa.rs b/crates/ruff_linter/src/noqa.rs
index bfacc88a63..e1cfa33331 100644
--- a/crates/ruff_linter/src/noqa.rs
+++ b/crates/ruff_linter/src/noqa.rs
@@ -369,7 +369,7 @@ impl<'a> FileNoqaDirectives<'a> {
                     warn!("Invalid `# ruff: noqa` directive at {path_display}:{line}: {err}");
                 }
                 Ok(Some(exemption)) => {
-                    if indentation_at_offset(range.start(), locator).is_none() {
+                    if indentation_at_offset(range.start(), contents).is_none() {
                         #[allow(deprecated)]
                         let line = locator.compute_line_index(range.start());
                         let path_display = relativize_path(path);
diff --git a/crates/ruff_linter/src/rules/flake8_bugbear/rules/mutable_argument_default.rs b/crates/ruff_linter/src/rules/flake8_bugbear/rules/mutable_argument_default.rs
index e15ca868ab..dfbebf979a 100644
--- a/crates/ruff_linter/src/rules/flake8_bugbear/rules/mutable_argument_default.rs
+++ b/crates/ruff_linter/src/rules/flake8_bugbear/rules/mutable_argument_default.rs
@@ -145,7 +145,7 @@ fn move_initialization(
 
     // Avoid attempting to fix single-line functions.
     let statement = body.peek()?;
-    if indexer.preceded_by_multi_statement_line(statement, locator) {
+    if indexer.preceded_by_multi_statement_line(statement, locator.contents()) {
         return None;
     }
 
@@ -170,7 +170,7 @@ fn move_initialization(
     content.push_str(stylist.line_ending().as_str());
 
     // Determine the indentation depth of the function body.
-    let indentation = indentation_at_offset(statement.start(), locator)?;
+    let indentation = indentation_at_offset(statement.start(), locator.contents())?;
 
     // Indent the edit to match the body indentation.
     let mut content = textwrap::indent(&content, indentation).to_string();
@@ -186,7 +186,7 @@ fn move_initialization(
             if let Some(next) = body.peek() {
                 // If there's a second statement, insert _before_ it, but ensure this isn't a
                 // multi-statement line.
-                if indexer.in_multi_statement_line(statement, locator) {
+                if indexer.in_multi_statement_line(statement, locator.contents()) {
                     continue;
                 }
                 pos = locator.line_start(next.start());
diff --git a/crates/ruff_linter/src/rules/flake8_errmsg/rules/string_in_exception.rs b/crates/ruff_linter/src/rules/flake8_errmsg/rules/string_in_exception.rs
index 23f2bf5881..df5dddd6cc 100644
--- a/crates/ruff_linter/src/rules/flake8_errmsg/rules/string_in_exception.rs
+++ b/crates/ruff_linter/src/rules/flake8_errmsg/rules/string_in_exception.rs
@@ -190,7 +190,7 @@ pub(crate) fn string_in_exception(checker: &mut Checker, stmt: &Stmt, exc: &Expr
                             let mut diagnostic =
                                 Diagnostic::new(RawStringInException, first.range());
                             if let Some(indentation) =
-                                whitespace::indentation(checker.locator(), stmt)
+                                whitespace::indentation(checker.source(), stmt)
                             {
                                 diagnostic.set_fix(generate_fix(
                                     stmt,
@@ -208,8 +208,7 @@ pub(crate) fn string_in_exception(checker: &mut Checker, stmt: &Stmt, exc: &Expr
                 Expr::FString(_) => {
                     if checker.enabled(Rule::FStringInException) {
                         let mut diagnostic = Diagnostic::new(FStringInException, first.range());
-                        if let Some(indentation) = whitespace::indentation(checker.locator(), stmt)
-                        {
+                        if let Some(indentation) = whitespace::indentation(checker.source(), stmt) {
                             diagnostic.set_fix(generate_fix(
                                 stmt,
                                 first,
@@ -231,7 +230,7 @@ pub(crate) fn string_in_exception(checker: &mut Checker, stmt: &Stmt, exc: &Expr
                                 let mut diagnostic =
                                     Diagnostic::new(DotFormatInException, first.range());
                                 if let Some(indentation) =
-                                    whitespace::indentation(checker.locator(), stmt)
+                                    whitespace::indentation(checker.source(), stmt)
                                 {
                                     diagnostic.set_fix(generate_fix(
                                         stmt,
diff --git a/crates/ruff_linter/src/rules/flake8_import_conventions/rules/unconventional_import_alias.rs b/crates/ruff_linter/src/rules/flake8_import_conventions/rules/unconventional_import_alias.rs
index 9a16bb8ed3..2ebe87f48d 100644
--- a/crates/ruff_linter/src/rules/flake8_import_conventions/rules/unconventional_import_alias.rs
+++ b/crates/ruff_linter/src/rules/flake8_import_conventions/rules/unconventional_import_alias.rs
@@ -65,7 +65,7 @@ pub(crate) fn unconventional_import_alias(
     let qualified_name = import.qualified_name().to_string();
     let expected_alias = conventions.get(qualified_name.as_str())?;
 
-    let name = binding.name(checker.locator());
+    let name = binding.name(checker.source());
     if name == expected_alias {
         return None;
     }
diff --git a/crates/ruff_linter/src/rules/flake8_pie/rules/unnecessary_placeholder.rs b/crates/ruff_linter/src/rules/flake8_pie/rules/unnecessary_placeholder.rs
index 09a58552d6..85fafcac08 100644
--- a/crates/ruff_linter/src/rules/flake8_pie/rules/unnecessary_placeholder.rs
+++ b/crates/ruff_linter/src/rules/flake8_pie/rules/unnecessary_placeholder.rs
@@ -105,7 +105,7 @@ pub(crate) fn unnecessary_placeholder(checker: &mut Checker, body: &[Stmt]) {
         };
 
         let mut diagnostic = Diagnostic::new(UnnecessaryPlaceholder { kind }, stmt.range());
-        let edit = if let Some(index) = trailing_comment_start_offset(stmt, checker.locator()) {
+        let edit = if let Some(index) = trailing_comment_start_offset(stmt, checker.source()) {
             Edit::range_deletion(stmt.range().add_end(index))
         } else {
             fix::edits::delete_stmt(stmt, None, checker.locator(), checker.indexer())
diff --git a/crates/ruff_linter/src/rules/flake8_pyi/rules/unaliased_collections_abc_set_import.rs b/crates/ruff_linter/src/rules/flake8_pyi/rules/unaliased_collections_abc_set_import.rs
index 24aa32e1ad..bb24ed01f0 100644
--- a/crates/ruff_linter/src/rules/flake8_pyi/rules/unaliased_collections_abc_set_import.rs
+++ b/crates/ruff_linter/src/rules/flake8_pyi/rules/unaliased_collections_abc_set_import.rs
@@ -73,7 +73,7 @@ pub(crate) fn unaliased_collections_abc_set_import(
         return None;
     }
 
-    let name = binding.name(checker.locator());
+    let name = binding.name(checker.source());
     if name == "AbstractSet" {
         return None;
     }
diff --git a/crates/ruff_linter/src/rules/flake8_pytest_style/rules/assertion.rs b/crates/ruff_linter/src/rules/flake8_pytest_style/rules/assertion.rs
index dc520f1738..ebf8285861 100644
--- a/crates/ruff_linter/src/rules/flake8_pytest_style/rules/assertion.rs
+++ b/crates/ruff_linter/src/rules/flake8_pytest_style/rules/assertion.rs
@@ -386,7 +386,7 @@ pub(crate) fn unittest_raises_assertion(
     );
     if !checker
         .comment_ranges()
-        .has_comments(call, checker.locator())
+        .has_comments(call, checker.source())
     {
         if let Some(args) = to_pytest_raises_args(checker, attr.as_str(), &call.arguments) {
             diagnostic.try_set_fix(|| {
@@ -622,8 +622,8 @@ fn parenthesize<'a>(expression: &Expression<'a>, parent: &Expression<'a>) -> Exp
 /// `assert a == "hello"` and `assert b == "world"`.
 fn fix_composite_condition(stmt: &Stmt, locator: &Locator, stylist: &Stylist) -> Result<Edit> {
     // Infer the indentation of the outer block.
-    let outer_indent =
-        whitespace::indentation(locator, stmt).context("Unable to fix multiline statement")?;
+    let outer_indent = whitespace::indentation(locator.contents(), stmt)
+        .context("Unable to fix multiline statement")?;
 
     // Extract the module text.
     let contents = locator.lines(stmt.range());
@@ -747,7 +747,7 @@ pub(crate) fn composite_condition(
             && !checker.comment_ranges().intersects(stmt.range())
             && !checker
                 .indexer()
-                .in_multi_statement_line(stmt, checker.locator())
+                .in_multi_statement_line(stmt, checker.source())
         {
             diagnostic.try_set_fix(|| {
                 fix_composite_condition(stmt, checker.locator(), checker.stylist())
diff --git a/crates/ruff_linter/src/rules/flake8_return/rules/function.rs b/crates/ruff_linter/src/rules/flake8_return/rules/function.rs
index 35a4553f91..3bc9fc6f09 100644
--- a/crates/ruff_linter/src/rules/flake8_return/rules/function.rs
+++ b/crates/ruff_linter/src/rules/flake8_return/rules/function.rs
@@ -453,7 +453,7 @@ fn is_noreturn_func(func: &Expr, semantic: &SemanticModel) -> bool {
 
 fn add_return_none(checker: &mut Checker, stmt: &Stmt, range: TextRange) {
     let mut diagnostic = Diagnostic::new(ImplicitReturn, range);
-    if let Some(indent) = indentation(checker.locator(), stmt) {
+    if let Some(indent) = indentation(checker.source(), stmt) {
         let mut content = String::new();
         content.push_str(checker.stylist().line_ending().as_str());
         content.push_str(indent);
@@ -851,14 +851,14 @@ fn remove_else(
         };
 
         // get the indentation of the `else`, since that is the indent level we want to end with
-        let Some(desired_indentation) = indentation(locator, elif_else) else {
+        let Some(desired_indentation) = indentation(locator.contents(), elif_else) else {
             return Err(anyhow::anyhow!("Compound statement cannot be inlined"));
         };
 
         // If the statement is on the same line as the `else`, just remove the `else: `.
         // Ex) `else: return True` -> `return True`
         if let Some(first) = elif_else.body.first() {
-            if indexer.preceded_by_multi_statement_line(first, locator) {
+            if indexer.preceded_by_multi_statement_line(first, locator.contents()) {
                 return Ok(Fix::safe_edit(Edit::deletion(
                     elif_else.start(),
                     first.start(),
diff --git a/crates/ruff_linter/src/rules/flake8_simplify/rules/ast_bool_op.rs b/crates/ruff_linter/src/rules/flake8_simplify/rules/ast_bool_op.rs
index f7d8c3b924..d61dd56bed 100644
--- a/crates/ruff_linter/src/rules/flake8_simplify/rules/ast_bool_op.rs
+++ b/crates/ruff_linter/src/rules/flake8_simplify/rules/ast_bool_op.rs
@@ -536,7 +536,7 @@ pub(crate) fn compare_with_tuple(checker: &mut Checker, expr: &Expr) {
         // Avoid removing comments.
         if checker
             .comment_ranges()
-            .has_comments(expr, checker.locator())
+            .has_comments(expr, checker.source())
         {
             continue;
         }
diff --git a/crates/ruff_linter/src/rules/flake8_simplify/rules/collapsible_if.rs b/crates/ruff_linter/src/rules/flake8_simplify/rules/collapsible_if.rs
index b4516f7dfa..a4cdad0b77 100644
--- a/crates/ruff_linter/src/rules/flake8_simplify/rules/collapsible_if.rs
+++ b/crates/ruff_linter/src/rules/flake8_simplify/rules/collapsible_if.rs
@@ -292,7 +292,7 @@ pub(super) fn collapse_nested_if(
     nested_if: NestedIf,
 ) -> Result<Edit> {
     // Infer the indentation of the outer block.
-    let Some(outer_indent) = whitespace::indentation(locator, &nested_if) else {
+    let Some(outer_indent) = whitespace::indentation(locator.contents(), &nested_if) else {
         bail!("Unable to fix multiline statement");
     };
 
diff --git a/crates/ruff_linter/src/rules/flake8_simplify/rules/fix_with.rs b/crates/ruff_linter/src/rules/flake8_simplify/rules/fix_with.rs
index 9360b5fcfb..cd9ab4d314 100644
--- a/crates/ruff_linter/src/rules/flake8_simplify/rules/fix_with.rs
+++ b/crates/ruff_linter/src/rules/flake8_simplify/rules/fix_with.rs
@@ -18,7 +18,7 @@ pub(crate) fn fix_multiple_with_statements(
     with_stmt: &ast::StmtWith,
 ) -> Result<Edit> {
     // Infer the indentation of the outer block.
-    let Some(outer_indent) = whitespace::indentation(locator, with_stmt) else {
+    let Some(outer_indent) = whitespace::indentation(locator.contents(), with_stmt) else {
         bail!("Unable to fix multiline statement");
     };
 
diff --git a/crates/ruff_linter/src/rules/flake8_simplify/rules/if_else_block_instead_of_dict_get.rs b/crates/ruff_linter/src/rules/flake8_simplify/rules/if_else_block_instead_of_dict_get.rs
index 4a754ac30c..f14374dfa9 100644
--- a/crates/ruff_linter/src/rules/flake8_simplify/rules/if_else_block_instead_of_dict_get.rs
+++ b/crates/ruff_linter/src/rules/flake8_simplify/rules/if_else_block_instead_of_dict_get.rs
@@ -211,7 +211,7 @@ pub(crate) fn if_else_block_instead_of_dict_get(checker: &mut Checker, stmt_if:
     );
     if !checker
         .comment_ranges()
-        .has_comments(stmt_if, checker.locator())
+        .has_comments(stmt_if, checker.source())
     {
         diagnostic.set_fix(Fix::unsafe_edit(Edit::range_replacement(
             contents,
@@ -300,7 +300,7 @@ pub(crate) fn if_exp_instead_of_dict_get(
     );
     if !checker
         .comment_ranges()
-        .has_comments(expr, checker.locator())
+        .has_comments(expr, checker.source())
     {
         diagnostic.set_fix(Fix::unsafe_edit(Edit::range_replacement(
             contents,
diff --git a/crates/ruff_linter/src/rules/flake8_simplify/rules/if_else_block_instead_of_if_exp.rs b/crates/ruff_linter/src/rules/flake8_simplify/rules/if_else_block_instead_of_if_exp.rs
index 03e0dacec0..d113bd46c9 100644
--- a/crates/ruff_linter/src/rules/flake8_simplify/rules/if_else_block_instead_of_if_exp.rs
+++ b/crates/ruff_linter/src/rules/flake8_simplify/rules/if_else_block_instead_of_if_exp.rs
@@ -227,7 +227,7 @@ pub(crate) fn if_else_block_instead_of_if_exp(checker: &mut Checker, stmt_if: &a
     );
     if !checker
         .comment_ranges()
-        .has_comments(stmt_if, checker.locator())
+        .has_comments(stmt_if, checker.source())
     {
         diagnostic.set_fix(Fix::unsafe_edit(Edit::range_replacement(
             contents,
diff --git a/crates/ruff_linter/src/rules/flake8_simplify/rules/needless_bool.rs b/crates/ruff_linter/src/rules/flake8_simplify/rules/needless_bool.rs
index 8f7a474551..b6dedfd098 100644
--- a/crates/ruff_linter/src/rules/flake8_simplify/rules/needless_bool.rs
+++ b/crates/ruff_linter/src/rules/flake8_simplify/rules/needless_bool.rs
@@ -200,7 +200,7 @@ pub(crate) fn needless_bool(checker: &mut Checker, stmt: &Stmt) {
     // Generate the replacement condition.
     let condition = if checker
         .comment_ranges()
-        .has_comments(&range, checker.locator())
+        .has_comments(&range, checker.source())
     {
         None
     } else {
diff --git a/crates/ruff_linter/src/rules/flake8_simplify/rules/suppressible_exception.rs b/crates/ruff_linter/src/rules/flake8_simplify/rules/suppressible_exception.rs
index d8bd58a5d3..8cd1136a18 100644
--- a/crates/ruff_linter/src/rules/flake8_simplify/rules/suppressible_exception.rs
+++ b/crates/ruff_linter/src/rules/flake8_simplify/rules/suppressible_exception.rs
@@ -127,7 +127,7 @@ pub(crate) fn suppressible_exception(
     );
     if !checker
         .comment_ranges()
-        .has_comments(stmt, checker.locator())
+        .has_comments(stmt, checker.source())
     {
         diagnostic.try_set_fix(|| {
             // let range = statement_range(stmt, checker.locator(), checker.indexer());
diff --git a/crates/ruff_linter/src/rules/isort/rules/organize_imports.rs b/crates/ruff_linter/src/rules/isort/rules/organize_imports.rs
index 88af0b9055..95ec37615b 100644
--- a/crates/ruff_linter/src/rules/isort/rules/organize_imports.rs
+++ b/crates/ruff_linter/src/rules/isort/rules/organize_imports.rs
@@ -1,7 +1,6 @@
 use std::path::Path;
 
 use itertools::{EitherOrBoth, Itertools};
-
 use ruff_diagnostics::{Diagnostic, Edit, Fix, FixAvailability, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_ast::whitespace::trailing_lines_end;
@@ -98,8 +97,9 @@ pub(crate) fn organize_imports(
 
     // Special-cases: there's leading or trailing content in the import block. These
     // are too hard to get right, and relatively rare, so flag but don't fix.
-    if indexer.preceded_by_multi_statement_line(block.imports.first().unwrap(), locator)
-        || indexer.followed_by_multi_statement_line(block.imports.last().unwrap(), locator)
+    if indexer.preceded_by_multi_statement_line(block.imports.first().unwrap(), locator.contents())
+        || indexer
+            .followed_by_multi_statement_line(block.imports.last().unwrap(), locator.contents())
     {
         return Some(Diagnostic::new(UnsortedImports, range));
     }
@@ -114,7 +114,7 @@ pub(crate) fn organize_imports(
     let trailing_line_end = if block.trailer.is_none() {
         locator.full_line_end(range.end())
     } else {
-        trailing_lines_end(block.imports.last().unwrap(), locator)
+        trailing_lines_end(block.imports.last().unwrap(), locator.contents())
     };
 
     // Generate the sorted import block.
diff --git a/crates/ruff_linter/src/rules/pycodestyle/rules/compound_statements.rs b/crates/ruff_linter/src/rules/pycodestyle/rules/compound_statements.rs
index 98278ae0c4..e98dbe9c9f 100644
--- a/crates/ruff_linter/src/rules/pycodestyle/rules/compound_statements.rs
+++ b/crates/ruff_linter/src/rules/pycodestyle/rules/compound_statements.rs
@@ -170,7 +170,7 @@ pub(crate) fn compound_statements(
                         let mut diagnostic = Diagnostic::new(UselessSemicolon, range);
                         diagnostic.set_fix(Fix::safe_edit(Edit::deletion(
                             indexer
-                                .preceded_by_continuations(range.start(), locator)
+                                .preceded_by_continuations(range.start(), locator.contents())
                                 .unwrap_or(range.start()),
                             range.end(),
                         )));
diff --git a/crates/ruff_linter/src/rules/pycodestyle/rules/lambda_assignment.rs b/crates/ruff_linter/src/rules/pycodestyle/rules/lambda_assignment.rs
index 5c41c5c44a..3eec15c49a 100644
--- a/crates/ruff_linter/src/rules/pycodestyle/rules/lambda_assignment.rs
+++ b/crates/ruff_linter/src/rules/pycodestyle/rules/lambda_assignment.rs
@@ -79,8 +79,8 @@ pub(crate) fn lambda_assignment(
         stmt.range(),
     );
 
-    if !has_leading_content(stmt.start(), checker.locator())
-        && !has_trailing_content(stmt.end(), checker.locator())
+    if !has_leading_content(stmt.start(), checker.source())
+        && !has_trailing_content(stmt.end(), checker.source())
     {
         let first_line = checker.locator().line(stmt.start());
         let indentation = leading_indentation(first_line);
diff --git a/crates/ruff_linter/src/rules/pycodestyle/rules/literal_comparisons.rs b/crates/ruff_linter/src/rules/pycodestyle/rules/literal_comparisons.rs
index 0a59cdb866..0ae56cdf44 100644
--- a/crates/ruff_linter/src/rules/pycodestyle/rules/literal_comparisons.rs
+++ b/crates/ruff_linter/src/rules/pycodestyle/rules/literal_comparisons.rs
@@ -336,7 +336,7 @@ pub(crate) fn literal_comparisons(checker: &mut Checker, compare: &ast::ExprComp
             &compare.comparators,
             compare.into(),
             checker.comment_ranges(),
-            checker.locator(),
+            checker.source(),
         );
         for diagnostic in &mut diagnostics {
             diagnostic.set_fix(Fix::unsafe_edit(Edit::range_replacement(
diff --git a/crates/ruff_linter/src/rules/pycodestyle/rules/multiple_imports_on_one_line.rs b/crates/ruff_linter/src/rules/pycodestyle/rules/multiple_imports_on_one_line.rs
index e54715330c..cac044cc58 100644
--- a/crates/ruff_linter/src/rules/pycodestyle/rules/multiple_imports_on_one_line.rs
+++ b/crates/ruff_linter/src/rules/pycodestyle/rules/multiple_imports_on_one_line.rs
@@ -68,7 +68,7 @@ fn split_imports(
     indexer: &Indexer,
     stylist: &Stylist,
 ) -> Fix {
-    if indexer.in_multi_statement_line(stmt, locator) {
+    if indexer.in_multi_statement_line(stmt, locator.contents()) {
         // Ex) `x = 1; import os, sys` (convert to `x = 1; import os; import sys`)
         let replacement = names
             .iter()
@@ -90,7 +90,8 @@ fn split_imports(
         Fix::safe_edit(Edit::range_replacement(replacement, stmt.range()))
     } else {
         // Ex) `import os, sys` (convert to `import os\nimport sys`)
-        let indentation = indentation_at_offset(stmt.start(), locator).unwrap_or_default();
+        let indentation =
+            indentation_at_offset(stmt.start(), locator.contents()).unwrap_or_default();
 
         // Generate newline-delimited imports.
         let replacement = names
diff --git a/crates/ruff_linter/src/rules/pycodestyle/rules/not_tests.rs b/crates/ruff_linter/src/rules/pycodestyle/rules/not_tests.rs
index 50022dee78..7a479ac834 100644
--- a/crates/ruff_linter/src/rules/pycodestyle/rules/not_tests.rs
+++ b/crates/ruff_linter/src/rules/pycodestyle/rules/not_tests.rs
@@ -105,7 +105,7 @@ pub(crate) fn not_tests(checker: &mut Checker, unary_op: &ast::ExprUnaryOp) {
                             comparators,
                             unary_op.into(),
                             checker.comment_ranges(),
-                            checker.locator(),
+                            checker.source(),
                         ),
                         unary_op.range(),
                         checker.locator(),
@@ -126,7 +126,7 @@ pub(crate) fn not_tests(checker: &mut Checker, unary_op: &ast::ExprUnaryOp) {
                             comparators,
                             unary_op.into(),
                             checker.comment_ranges(),
-                            checker.locator(),
+                            checker.source(),
                         ),
                         unary_op.range(),
                         checker.locator(),
diff --git a/crates/ruff_linter/src/rules/pycodestyle/rules/trailing_whitespace.rs b/crates/ruff_linter/src/rules/pycodestyle/rules/trailing_whitespace.rs
index fee7bc5ffb..2741b0d8b4 100644
--- a/crates/ruff_linter/src/rules/pycodestyle/rules/trailing_whitespace.rs
+++ b/crates/ruff_linter/src/rules/pycodestyle/rules/trailing_whitespace.rs
@@ -100,7 +100,7 @@ pub(crate) fn trailing_whitespace(
                 diagnostic.set_fix(Fix::applicable_edit(
                     Edit::range_deletion(TextRange::new(
                         indexer
-                            .preceded_by_continuations(line.start(), locator)
+                            .preceded_by_continuations(line.start(), locator.contents())
                             .unwrap_or(range.start()),
                         range.end(),
                     )),
diff --git a/crates/ruff_linter/src/rules/pydocstyle/rules/blank_before_after_class.rs b/crates/ruff_linter/src/rules/pydocstyle/rules/blank_before_after_class.rs
index 299d6f44b4..ef5c9181ce 100644
--- a/crates/ruff_linter/src/rules/pydocstyle/rules/blank_before_after_class.rs
+++ b/crates/ruff_linter/src/rules/pydocstyle/rules/blank_before_after_class.rs
@@ -240,7 +240,7 @@ pub(crate) fn blank_before_after_class(checker: &mut Checker, docstring: &Docstr
         if let Some(first_line) = &first_line {
             let trailing = first_line.as_str().trim_whitespace_start();
             if let Some(next_statement) = trailing.strip_prefix(';') {
-                let indentation = indentation_at_offset(docstring.start(), checker.locator())
+                let indentation = indentation_at_offset(docstring.start(), checker.source())
                     .expect("Own line docstring must have indentation");
                 let mut diagnostic = Diagnostic::new(OneBlankLineAfterClass, docstring.range());
                 let line_ending = checker.stylist().line_ending().as_str();
diff --git a/crates/ruff_linter/src/rules/pyflakes/mod.rs b/crates/ruff_linter/src/rules/pyflakes/mod.rs
index 5e42a7e0e2..22a23a7bf2 100644
--- a/crates/ruff_linter/src/rules/pyflakes/mod.rs
+++ b/crates/ruff_linter/src/rules/pyflakes/mod.rs
@@ -712,8 +712,8 @@ mod tests {
         let parsed =
             ruff_python_parser::parse_unchecked_source(source_kind.source_code(), source_type);
         let locator = Locator::new(&contents);
-        let stylist = Stylist::from_tokens(parsed.tokens(), &locator);
-        let indexer = Indexer::from_tokens(parsed.tokens(), &locator);
+        let stylist = Stylist::from_tokens(parsed.tokens(), &contents);
+        let indexer = Indexer::from_tokens(parsed.tokens(), &contents);
         let directives = directives::extract_directives(
             parsed.tokens(),
             directives::Flags::from_settings(&settings),
diff --git a/crates/ruff_linter/src/rules/pyflakes/rules/unused_import.rs b/crates/ruff_linter/src/rules/pyflakes/rules/unused_import.rs
index ecba0975d0..3f6efbba07 100644
--- a/crates/ruff_linter/src/rules/pyflakes/rules/unused_import.rs
+++ b/crates/ruff_linter/src/rules/pyflakes/rules/unused_import.rs
@@ -295,7 +295,7 @@ pub(crate) fn unused_import(checker: &Checker, scope: &Scope, diagnostics: &mut
             continue;
         };
 
-        let name = binding.name(checker.locator());
+        let name = binding.name(checker.source());
 
         // If an import is marked as required, avoid treating it as unused, regardless of whether
         // it was _actually_ used.
diff --git a/crates/ruff_linter/src/rules/pyflakes/rules/unused_variable.rs b/crates/ruff_linter/src/rules/pyflakes/rules/unused_variable.rs
index 6da056c137..1bd813f65a 100644
--- a/crates/ruff_linter/src/rules/pyflakes/rules/unused_variable.rs
+++ b/crates/ruff_linter/src/rules/pyflakes/rules/unused_variable.rs
@@ -183,7 +183,7 @@ fn remove_unused_variable(binding: &Binding, checker: &Checker) -> Option<Fix> {
                 };
             }
         } else {
-            let name = binding.name(checker.locator());
+            let name = binding.name(checker.source());
             let renamed = format!("_{name}");
             if checker.settings.dummy_variable_rgx.is_match(&renamed) {
                 let edit = Edit::range_replacement(renamed, binding.range());
diff --git a/crates/ruff_linter/src/rules/pylint/rules/collapsible_else_if.rs b/crates/ruff_linter/src/rules/pylint/rules/collapsible_else_if.rs
index aae432959f..eba064b579 100644
--- a/crates/ruff_linter/src/rules/pylint/rules/collapsible_else_if.rs
+++ b/crates/ruff_linter/src/rules/pylint/rules/collapsible_else_if.rs
@@ -113,7 +113,7 @@ fn convert_to_elif(
     let trivia_range = TextRange::new(else_line_end, inner_if_line_start);
 
     // Identify the indentation of the outer clause
-    let Some(indentation) = indentation(locator, else_clause) else {
+    let Some(indentation) = indentation(locator.contents(), else_clause) else {
         return Err(anyhow::anyhow!("`else` is expected to be on its own line"));
     };
 
diff --git a/crates/ruff_linter/src/rules/pylint/rules/empty_comment.rs b/crates/ruff_linter/src/rules/pylint/rules/empty_comment.rs
index 1c741cf322..eb3c6fcf21 100644
--- a/crates/ruff_linter/src/rules/pylint/rules/empty_comment.rs
+++ b/crates/ruff_linter/src/rules/pylint/rules/empty_comment.rs
@@ -47,7 +47,7 @@ pub(crate) fn empty_comments(
     comment_ranges: &CommentRanges,
     locator: &Locator,
 ) {
-    let block_comments = comment_ranges.block_comments(locator);
+    let block_comments = comment_ranges.block_comments(locator.contents());
 
     for range in comment_ranges {
         // Ignore comments that are part of multi-line "comment blocks".
diff --git a/crates/ruff_linter/src/rules/pylint/rules/nested_min_max.rs b/crates/ruff_linter/src/rules/pylint/rules/nested_min_max.rs
index 039e4ace21..c6799864ba 100644
--- a/crates/ruff_linter/src/rules/pylint/rules/nested_min_max.rs
+++ b/crates/ruff_linter/src/rules/pylint/rules/nested_min_max.rs
@@ -157,7 +157,7 @@ pub(crate) fn nested_min_max(
         let mut diagnostic = Diagnostic::new(NestedMinMax { func: min_max }, expr.range());
         if !checker
             .comment_ranges()
-            .has_comments(expr, checker.locator())
+            .has_comments(expr, checker.source())
         {
             let flattened_expr = Expr::Call(ast::ExprCall {
                 func: Box::new(func.clone()),
diff --git a/crates/ruff_linter/src/rules/pylint/rules/no_method_decorator.rs b/crates/ruff_linter/src/rules/pylint/rules/no_method_decorator.rs
index 10d3390553..dc01fb788f 100644
--- a/crates/ruff_linter/src/rules/pylint/rules/no_method_decorator.rs
+++ b/crates/ruff_linter/src/rules/pylint/rules/no_method_decorator.rs
@@ -175,7 +175,7 @@ fn get_undecorated_methods(checker: &mut Checker, class_stmt: &Stmt, method_type
                 TextRange::new(stmt.range().start(), stmt.range().start()),
             );
 
-            let indentation = indentation_at_offset(stmt.range().start(), checker.locator());
+            let indentation = indentation_at_offset(stmt.range().start(), checker.source());
 
             match indentation {
                 Some(indentation) => {
diff --git a/crates/ruff_linter/src/rules/pylint/rules/non_ascii_name.rs b/crates/ruff_linter/src/rules/pylint/rules/non_ascii_name.rs
index 02ba51ae59..141878f8fb 100644
--- a/crates/ruff_linter/src/rules/pylint/rules/non_ascii_name.rs
+++ b/crates/ruff_linter/src/rules/pylint/rules/non_ascii_name.rs
@@ -3,7 +3,6 @@ use std::fmt;
 use ruff_diagnostics::{Diagnostic, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_semantic::{Binding, BindingKind};
-use ruff_source_file::Locator;
 use ruff_text_size::Ranged;
 
 /// ## What it does
@@ -43,8 +42,8 @@ impl Violation for NonAsciiName {
 }
 
 /// PLC2401
-pub(crate) fn non_ascii_name(binding: &Binding, locator: &Locator) -> Option<Diagnostic> {
-    let name = binding.name(locator);
+pub(crate) fn non_ascii_name(binding: &Binding, source: &str) -> Option<Diagnostic> {
+    let name = binding.name(source);
     if name.is_ascii() {
         return None;
     }
diff --git a/crates/ruff_linter/src/rules/pylint/rules/useless_else_on_loop.rs b/crates/ruff_linter/src/rules/pylint/rules/useless_else_on_loop.rs
index 818b9e4a8a..731c652ac0 100644
--- a/crates/ruff_linter/src/rules/pylint/rules/useless_else_on_loop.rs
+++ b/crates/ruff_linter/src/rules/pylint/rules/useless_else_on_loop.rs
@@ -146,7 +146,7 @@ fn remove_else(
         return Err(anyhow::anyhow!("Empty `else` clause"));
     };
 
-    let start_indentation = indentation(locator, start);
+    let start_indentation = indentation(locator.contents(), start);
     if start_indentation.is_none() {
         // Inline `else` block (e.g., `else: x = 1`).
         Ok(Fix::safe_edit(Edit::deletion(
@@ -155,7 +155,7 @@ fn remove_else(
         )))
     } else {
         // Identify the indentation of the loop itself (e.g., the `while` or `for`).
-        let Some(desired_indentation) = indentation(locator, stmt) else {
+        let Some(desired_indentation) = indentation(locator.contents(), stmt) else {
             return Err(anyhow::anyhow!("Compound statement cannot be inlined"));
         };
 
diff --git a/crates/ruff_linter/src/rules/pyupgrade/rules/deprecated_import.rs b/crates/ruff_linter/src/rules/pyupgrade/rules/deprecated_import.rs
index 8f1f005671..78a71440f7 100644
--- a/crates/ruff_linter/src/rules/pyupgrade/rules/deprecated_import.rs
+++ b/crates/ruff_linter/src/rules/pyupgrade/rules/deprecated_import.rs
@@ -617,7 +617,7 @@ impl<'a> ImportReplacer<'a> {
             let fix = Some(matched);
             Some((operation, fix))
         } else {
-            let indentation = indentation(self.locator, self.import_from_stmt);
+            let indentation = indentation(self.locator.contents(), self.import_from_stmt);
 
             // If we have matched _and_ unmatched names, but the import is not on its own
             // line, we can't add a statement after it. For example, if we have
diff --git a/crates/ruff_linter/src/rules/pyupgrade/rules/deprecated_mock_import.rs b/crates/ruff_linter/src/rules/pyupgrade/rules/deprecated_mock_import.rs
index bd7dbd3287..90ca89c957 100644
--- a/crates/ruff_linter/src/rules/pyupgrade/rules/deprecated_mock_import.rs
+++ b/crates/ruff_linter/src/rules/pyupgrade/rules/deprecated_mock_import.rs
@@ -282,7 +282,7 @@ pub(crate) fn deprecated_mock_import(checker: &mut Checker, stmt: &Stmt) {
                 .any(|name| &name.name == "mock" || &name.name == "mock.mock")
             {
                 // Generate the fix, if needed, which is shared between all `mock` imports.
-                let content = if let Some(indent) = indentation(checker.locator(), stmt) {
+                let content = if let Some(indent) = indentation(checker.source(), stmt) {
                     match format_import(stmt, indent, checker.locator(), checker.stylist()) {
                         Ok(content) => Some(content),
                         Err(e) => {
@@ -330,7 +330,7 @@ pub(crate) fn deprecated_mock_import(checker: &mut Checker, stmt: &Stmt) {
                     },
                     stmt.range(),
                 );
-                if let Some(indent) = indentation(checker.locator(), stmt) {
+                if let Some(indent) = indentation(checker.source(), stmt) {
                     diagnostic.try_set_fix(|| {
                         format_import_from(stmt, indent, checker.locator(), checker.stylist())
                             .map(|content| Edit::range_replacement(content, stmt.range()))
diff --git a/crates/ruff_linter/src/rules/pyupgrade/rules/outdated_version_block.rs b/crates/ruff_linter/src/rules/pyupgrade/rules/outdated_version_block.rs
index ca7faba02c..4de29d8ab8 100644
--- a/crates/ruff_linter/src/rules/pyupgrade/rules/outdated_version_block.rs
+++ b/crates/ruff_linter/src/rules/pyupgrade/rules/outdated_version_block.rs
@@ -299,7 +299,7 @@ fn fix_always_false_branch(
             }) => {
                 let start = body.first()?;
                 let end = body.last()?;
-                if indentation(checker.locator(), start).is_none() {
+                if indentation(checker.source(), start).is_none() {
                     // Inline `else` block (e.g., `else: x = 1`).
                     Some(Fix::unsafe_edit(Edit::range_replacement(
                         checker
@@ -309,7 +309,7 @@ fn fix_always_false_branch(
                         stmt_if.range(),
                     )))
                 } else {
-                    indentation(checker.locator(), stmt_if)
+                    indentation(checker.source(), stmt_if)
                         .and_then(|indentation| {
                             adjust_indentation(
                                 TextRange::new(
@@ -377,7 +377,7 @@ fn fix_always_true_branch(
             // the rest.
             let start = branch.body.first()?;
             let end = branch.body.last()?;
-            if indentation(checker.locator(), start).is_none() {
+            if indentation(checker.source(), start).is_none() {
                 // Inline `if` block (e.g., `if ...: x = 1`).
                 Some(Fix::unsafe_edit(Edit::range_replacement(
                     checker
@@ -387,7 +387,7 @@ fn fix_always_true_branch(
                     stmt_if.range,
                 )))
             } else {
-                indentation(checker.locator(), &stmt_if)
+                indentation(checker.source(), &stmt_if)
                     .and_then(|indentation| {
                         adjust_indentation(
                             TextRange::new(checker.locator().line_start(start.start()), end.end()),
diff --git a/crates/ruff_linter/src/rules/pyupgrade/rules/printf_string_formatting.rs b/crates/ruff_linter/src/rules/pyupgrade/rules/printf_string_formatting.rs
index 2c66fd26f1..b2b701eb01 100644
--- a/crates/ruff_linter/src/rules/pyupgrade/rules/printf_string_formatting.rs
+++ b/crates/ruff_linter/src/rules/pyupgrade/rules/printf_string_formatting.rs
@@ -251,7 +251,7 @@ fn clean_params_dictionary(right: &Expr, locator: &Locator, stylist: &Stylist) -
                     seen.push(key_string.to_str());
                     if is_multi_line {
                         if indent.is_none() {
-                            indent = indentation(locator, key);
+                            indent = indentation(locator.contents(), key);
                         }
                     }
 
diff --git a/crates/ruff_linter/src/rules/pyupgrade/rules/unnecessary_coding_comment.rs b/crates/ruff_linter/src/rules/pyupgrade/rules/unnecessary_coding_comment.rs
index f48c05a474..608984b829 100644
--- a/crates/ruff_linter/src/rules/pyupgrade/rules/unnecessary_coding_comment.rs
+++ b/crates/ruff_linter/src/rules/pyupgrade/rules/unnecessary_coding_comment.rs
@@ -75,7 +75,7 @@ pub(crate) fn unnecessary_coding_comment(
         // x = 2
         // ```
         if indexer
-            .preceded_by_continuations(line_range.start(), locator)
+            .preceded_by_continuations(line_range.start(), locator.contents())
             .is_some()
         {
             continue;
diff --git a/crates/ruff_linter/src/rules/refurb/rules/single_item_membership_test.rs b/crates/ruff_linter/src/rules/refurb/rules/single_item_membership_test.rs
index 85f7fe9ec5..4185cf3760 100644
--- a/crates/ruff_linter/src/rules/refurb/rules/single_item_membership_test.rs
+++ b/crates/ruff_linter/src/rules/refurb/rules/single_item_membership_test.rs
@@ -84,7 +84,7 @@ pub(crate) fn single_item_membership_test(
                 &[item.clone()],
                 expr.into(),
                 checker.comment_ranges(),
-                checker.locator(),
+                checker.source(),
             ),
             expr.range(),
             checker.locator(),
diff --git a/crates/ruff_linter/src/rules/ruff/rules/collection_literal_concatenation.rs b/crates/ruff_linter/src/rules/ruff/rules/collection_literal_concatenation.rs
index 1a69095473..0689a2957a 100644
--- a/crates/ruff_linter/src/rules/ruff/rules/collection_literal_concatenation.rs
+++ b/crates/ruff_linter/src/rules/ruff/rules/collection_literal_concatenation.rs
@@ -200,7 +200,7 @@ pub(crate) fn collection_literal_concatenation(checker: &mut Checker, expr: &Exp
     );
     if !checker
         .comment_ranges()
-        .has_comments(expr, checker.locator())
+        .has_comments(expr, checker.source())
     {
         // This suggestion could be unsafe if the non-literal expression in the
         // expression has overridden the `__add__` (or `__radd__`) magic methods.
diff --git a/crates/ruff_linter/src/rules/ruff/rules/invalid_formatter_suppression_comment.rs b/crates/ruff_linter/src/rules/ruff/rules/invalid_formatter_suppression_comment.rs
index 57201331c9..6a730801f5 100644
--- a/crates/ruff_linter/src/rules/ruff/rules/invalid_formatter_suppression_comment.rs
+++ b/crates/ruff_linter/src/rules/ruff/rules/invalid_formatter_suppression_comment.rs
@@ -166,11 +166,14 @@ impl<'src, 'loc> UselessSuppressionComments<'src, 'loc> {
             {
                 if following.is_first_statement_in_alternate_body(enclosing) {
                     // check indentation
-                    let comment_indentation =
-                        comment_indentation_after(preceding, comment.range, self.locator);
+                    let comment_indentation = comment_indentation_after(
+                        preceding,
+                        comment.range,
+                        self.locator.contents(),
+                    );
 
                     let preceding_indentation =
-                        indentation_at_offset(preceding.start(), self.locator)
+                        indentation_at_offset(preceding.start(), self.locator.contents())
                             .unwrap_or_default()
                             .text_len();
                     if comment_indentation != preceding_indentation {
diff --git a/crates/ruff_linter/src/rules/ruff/rules/post_init_default.rs b/crates/ruff_linter/src/rules/ruff/rules/post_init_default.rs
index a13949f167..2646aea31f 100644
--- a/crates/ruff_linter/src/rules/ruff/rules/post_init_default.rs
+++ b/crates/ruff_linter/src/rules/ruff/rules/post_init_default.rs
@@ -175,7 +175,7 @@ fn use_initvar(
         }
     };
 
-    let indentation = indentation_at_offset(post_init_def.start(), checker.locator())
+    let indentation = indentation_at_offset(post_init_def.start(), checker.source())
         .context("Failed to calculate leading indentation of `__post_init__` method")?;
     let content = textwrap::indent(&content, indentation);
 
diff --git a/crates/ruff_linter/src/rules/ruff/rules/suppression_comment_visitor.rs b/crates/ruff_linter/src/rules/ruff/rules/suppression_comment_visitor.rs
index 113f0a000f..5b300b1e9e 100644
--- a/crates/ruff_linter/src/rules/ruff/rules/suppression_comment_visitor.rs
+++ b/crates/ruff_linter/src/rules/ruff/rules/suppression_comment_visitor.rs
@@ -146,9 +146,11 @@ where
                 // We want `# fmt: on` to be considered a trailing comment of `func(x)` instead of a leading comment
                 // on `func2(y)`.
                 if line_position.is_own_line() {
-                    let comment_indent = comment_indentation_after(node, range, self.locator);
+                    let comment_indent =
+                        comment_indentation_after(node, range, self.locator.contents());
                     let node_indent = TextSize::of(
-                        indentation_at_offset(node.start(), self.locator).unwrap_or_default(),
+                        indentation_at_offset(node.start(), self.locator.contents())
+                            .unwrap_or_default(),
                     );
                     if node_indent >= comment_indent {
                         break;
diff --git a/crates/ruff_linter/src/rules/ruff/rules/test_rules.rs b/crates/ruff_linter/src/rules/ruff/rules/test_rules.rs
index a3f2548738..825ecb14d3 100644
--- a/crates/ruff_linter/src/rules/ruff/rules/test_rules.rs
+++ b/crates/ruff_linter/src/rules/ruff/rules/test_rules.rs
@@ -16,15 +16,15 @@
 use ruff_diagnostics::{Diagnostic, Edit, Fix, FixAvailability, Violation};
 use ruff_macros::{derive_message_formats, violation};
 use ruff_python_trivia::CommentRanges;
-use ruff_source_file::Locator;
+use ruff_source_file::Located;
 use ruff_text_size::TextSize;
 
 use crate::registry::Rule;
 
 /// Check if a comment exists anywhere in a given file
-fn comment_exists(text: &str, locator: &Locator, comment_ranges: &CommentRanges) -> bool {
+fn comment_exists(text: &str, source: &str, comment_ranges: &CommentRanges) -> bool {
     for range in comment_ranges {
-        let comment_text = locator.slice(range);
+        let comment_text = source.slice(range);
         if text.trim_end() == comment_text {
             return true;
         }
@@ -48,7 +48,7 @@ pub(crate) const TEST_RULES: &[Rule] = &[
 ];
 
 pub(crate) trait TestRule {
-    fn diagnostic(locator: &Locator, comment_ranges: &CommentRanges) -> Option<Diagnostic>;
+    fn diagnostic(source: &str, comment_ranges: &CommentRanges) -> Option<Diagnostic>;
 }
 
 /// ## What it does
@@ -79,7 +79,7 @@ impl Violation for StableTestRule {
 }
 
 impl TestRule for StableTestRule {
-    fn diagnostic(_locator: &Locator, _comment_ranges: &CommentRanges) -> Option<Diagnostic> {
+    fn diagnostic(_source: &str, _comment_ranges: &CommentRanges) -> Option<Diagnostic> {
         Some(Diagnostic::new(
             StableTestRule,
             ruff_text_size::TextRange::default(),
@@ -115,9 +115,9 @@ impl Violation for StableTestRuleSafeFix {
 }
 
 impl TestRule for StableTestRuleSafeFix {
-    fn diagnostic(locator: &Locator, comment_ranges: &CommentRanges) -> Option<Diagnostic> {
+    fn diagnostic(source: &str, comment_ranges: &CommentRanges) -> Option<Diagnostic> {
         let comment = format!("# fix from stable-test-rule-safe-fix\n");
-        if comment_exists(&comment, locator, comment_ranges) {
+        if comment_exists(&comment, source, comment_ranges) {
             None
         } else {
             Some(
@@ -156,9 +156,9 @@ impl Violation for StableTestRuleUnsafeFix {
 }
 
 impl TestRule for StableTestRuleUnsafeFix {
-    fn diagnostic(locator: &Locator, comment_ranges: &CommentRanges) -> Option<Diagnostic> {
+    fn diagnostic(source: &str, comment_ranges: &CommentRanges) -> Option<Diagnostic> {
         let comment = format!("# fix from stable-test-rule-unsafe-fix\n");
-        if comment_exists(&comment, locator, comment_ranges) {
+        if comment_exists(&comment, source, comment_ranges) {
             None
         } else {
             Some(
@@ -200,9 +200,9 @@ impl Violation for StableTestRuleDisplayOnlyFix {
 }
 
 impl TestRule for StableTestRuleDisplayOnlyFix {
-    fn diagnostic(locator: &Locator, comment_ranges: &CommentRanges) -> Option<Diagnostic> {
+    fn diagnostic(source: &str, comment_ranges: &CommentRanges) -> Option<Diagnostic> {
         let comment = format!("# fix from stable-test-rule-display-only-fix\n");
-        if comment_exists(&comment, locator, comment_ranges) {
+        if comment_exists(&comment, source, comment_ranges) {
             None
         } else {
             Some(
@@ -247,7 +247,7 @@ impl Violation for PreviewTestRule {
 }
 
 impl TestRule for PreviewTestRule {
-    fn diagnostic(_locator: &Locator, _comment_ranges: &CommentRanges) -> Option<Diagnostic> {
+    fn diagnostic(_source: &str, _comment_ranges: &CommentRanges) -> Option<Diagnostic> {
         Some(Diagnostic::new(
             PreviewTestRule,
             ruff_text_size::TextRange::default(),
@@ -283,7 +283,7 @@ impl Violation for DeprecatedTestRule {
 }
 
 impl TestRule for DeprecatedTestRule {
-    fn diagnostic(_locator: &Locator, _comment_ranges: &CommentRanges) -> Option<Diagnostic> {
+    fn diagnostic(_source: &str, _comment_ranges: &CommentRanges) -> Option<Diagnostic> {
         Some(Diagnostic::new(
             DeprecatedTestRule,
             ruff_text_size::TextRange::default(),
@@ -319,7 +319,7 @@ impl Violation for AnotherDeprecatedTestRule {
 }
 
 impl TestRule for AnotherDeprecatedTestRule {
-    fn diagnostic(_locator: &Locator, _comment_ranges: &CommentRanges) -> Option<Diagnostic> {
+    fn diagnostic(_source: &str, _comment_ranges: &CommentRanges) -> Option<Diagnostic> {
         Some(Diagnostic::new(
             AnotherDeprecatedTestRule,
             ruff_text_size::TextRange::default(),
@@ -355,7 +355,7 @@ impl Violation for RemovedTestRule {
 }
 
 impl TestRule for RemovedTestRule {
-    fn diagnostic(_locator: &Locator, _comment_ranges: &CommentRanges) -> Option<Diagnostic> {
+    fn diagnostic(_source: &str, _comment_ranges: &CommentRanges) -> Option<Diagnostic> {
         Some(Diagnostic::new(
             RemovedTestRule,
             ruff_text_size::TextRange::default(),
@@ -391,7 +391,7 @@ impl Violation for AnotherRemovedTestRule {
 }
 
 impl TestRule for AnotherRemovedTestRule {
-    fn diagnostic(_locator: &Locator, _comment_ranges: &CommentRanges) -> Option<Diagnostic> {
+    fn diagnostic(_source: &str, _comment_ranges: &CommentRanges) -> Option<Diagnostic> {
         Some(Diagnostic::new(
             AnotherRemovedTestRule,
             ruff_text_size::TextRange::default(),
@@ -427,7 +427,7 @@ impl Violation for RedirectedFromTestRule {
 }
 
 impl TestRule for RedirectedFromTestRule {
-    fn diagnostic(_locator: &Locator, _comment_ranges: &CommentRanges) -> Option<Diagnostic> {
+    fn diagnostic(_source: &str, _comment_ranges: &CommentRanges) -> Option<Diagnostic> {
         Some(Diagnostic::new(
             RedirectedFromTestRule,
             ruff_text_size::TextRange::default(),
@@ -463,7 +463,7 @@ impl Violation for RedirectedToTestRule {
 }
 
 impl TestRule for RedirectedToTestRule {
-    fn diagnostic(_locator: &Locator, _comment_ranges: &CommentRanges) -> Option<Diagnostic> {
+    fn diagnostic(_source: &str, _comment_ranges: &CommentRanges) -> Option<Diagnostic> {
         Some(Diagnostic::new(
             RedirectedToTestRule,
             ruff_text_size::TextRange::default(),
@@ -499,7 +499,7 @@ impl Violation for RedirectedFromPrefixTestRule {
 }
 
 impl TestRule for RedirectedFromPrefixTestRule {
-    fn diagnostic(_locator: &Locator, _comment_ranges: &CommentRanges) -> Option<Diagnostic> {
+    fn diagnostic(_source: &str, _comment_ranges: &CommentRanges) -> Option<Diagnostic> {
         Some(Diagnostic::new(
             RedirectedFromPrefixTestRule,
             ruff_text_size::TextRange::default(),
diff --git a/crates/ruff_linter/src/test.rs b/crates/ruff_linter/src/test.rs
index a4ac856499..1a28a05699 100644
--- a/crates/ruff_linter/src/test.rs
+++ b/crates/ruff_linter/src/test.rs
@@ -111,8 +111,8 @@ pub(crate) fn test_contents<'a>(
     let source_type = PySourceType::from(path);
     let parsed = ruff_python_parser::parse_unchecked_source(source_kind.source_code(), source_type);
     let locator = Locator::new(source_kind.source_code());
-    let stylist = Stylist::from_tokens(parsed.tokens(), &locator);
-    let indexer = Indexer::from_tokens(parsed.tokens(), &locator);
+    let stylist = Stylist::from_tokens(parsed.tokens(), source_kind.source_code());
+    let indexer = Indexer::from_tokens(parsed.tokens(), source_kind.source_code());
     let directives = directives::extract_directives(
         parsed.tokens(),
         directives::Flags::from_settings(settings),
@@ -174,8 +174,8 @@ pub(crate) fn test_contents<'a>(
             let parsed =
                 ruff_python_parser::parse_unchecked_source(transformed.source_code(), source_type);
             let locator = Locator::new(transformed.source_code());
-            let stylist = Stylist::from_tokens(parsed.tokens(), &locator);
-            let indexer = Indexer::from_tokens(parsed.tokens(), &locator);
+            let stylist = Stylist::from_tokens(parsed.tokens(), transformed.source_code());
+            let indexer = Indexer::from_tokens(parsed.tokens(), transformed.source_code());
             let directives = directives::extract_directives(
                 parsed.tokens(),
                 directives::Flags::from_settings(settings),
diff --git a/crates/ruff_python_ast/src/helpers.rs b/crates/ruff_python_ast/src/helpers.rs
index 565c67e585..2ea8650bd7 100644
--- a/crates/ruff_python_ast/src/helpers.rs
+++ b/crates/ruff_python_ast/src/helpers.rs
@@ -4,7 +4,7 @@ use std::path::Path;
 use rustc_hash::FxHashMap;
 
 use ruff_python_trivia::{indentation_at_offset, CommentRanges, SimpleTokenKind, SimpleTokenizer};
-use ruff_source_file::Locator;
+use ruff_source_file::Located;
 use ruff_text_size::{Ranged, TextLen, TextRange, TextSize};
 
 use crate::name::{Name, QualifiedName, QualifiedNameBuilder};
@@ -1333,19 +1333,16 @@ pub fn generate_comparison(
     comparators: &[Expr],
     parent: AnyNodeRef,
     comment_ranges: &CommentRanges,
-    locator: &Locator,
+    source: &str,
 ) -> String {
     let start = left.start();
     let end = comparators.last().map_or_else(|| left.end(), Ranged::end);
     let mut contents = String::with_capacity(usize::from(end - start));
 
     // Add the left side of the comparison.
-    contents.push_str(
-        locator.slice(
-            parenthesized_range(left.into(), parent, comment_ranges, locator.contents())
-                .unwrap_or(left.range()),
-        ),
-    );
+    contents.push_str(source.slice(
+        parenthesized_range(left.into(), parent, comment_ranges, source).unwrap_or(left.range()),
+    ));
 
     for (op, comparator) in ops.iter().zip(comparators) {
         // Add the operator.
@@ -1364,14 +1361,9 @@ pub fn generate_comparison(
 
         // Add the right side of the comparison.
         contents.push_str(
-            locator.slice(
-                parenthesized_range(
-                    comparator.into(),
-                    parent,
-                    comment_ranges,
-                    locator.contents(),
-                )
-                .unwrap_or(comparator.range()),
+            source.slice(
+                parenthesized_range(comparator.into(), parent, comment_ranges, source)
+                    .unwrap_or(comparator.range()),
             ),
         );
     }
@@ -1512,17 +1504,17 @@ pub fn typing_union(elts: &[Expr], binding: Name) -> Expr {
 pub fn comment_indentation_after(
     preceding: AnyNodeRef,
     comment_range: TextRange,
-    locator: &Locator,
+    source: &str,
 ) -> TextSize {
     let tokenizer = SimpleTokenizer::new(
-        locator.contents(),
-        TextRange::new(locator.full_line_end(preceding.end()), comment_range.end()),
+        source,
+        TextRange::new(source.full_line_end(preceding.end()), comment_range.end()),
     );
 
     tokenizer
         .filter_map(|token| {
             if token.kind() == SimpleTokenKind::Comment {
-                indentation_at_offset(token.start(), locator).map(TextLen::text_len)
+                indentation_at_offset(token.start(), source).map(TextLen::text_len)
             } else {
                 None
             }
diff --git a/crates/ruff_python_ast/src/whitespace.rs b/crates/ruff_python_ast/src/whitespace.rs
index 7a1ed847c3..c8d8949b31 100644
--- a/crates/ruff_python_ast/src/whitespace.rs
+++ b/crates/ruff_python_ast/src/whitespace.rs
@@ -1,35 +1,35 @@
 use ruff_python_trivia::{indentation_at_offset, is_python_whitespace, PythonWhitespace};
-use ruff_source_file::{Locator, UniversalNewlineIterator};
+use ruff_source_file::{Located, UniversalNewlineIterator};
 use ruff_text_size::{Ranged, TextRange, TextSize};
 
 use crate::Stmt;
 
 /// Extract the leading indentation from a line.
 #[inline]
-pub fn indentation<'a, T>(locator: &'a Locator, located: &T) -> Option<&'a str>
+pub fn indentation<'a, T>(source: &'a str, ranged: &T) -> Option<&'a str>
 where
     T: Ranged,
 {
-    indentation_at_offset(located.start(), locator)
+    indentation_at_offset(ranged.start(), source)
 }
 
 /// Return the end offset at which the empty lines following a statement.
-pub fn trailing_lines_end(stmt: &Stmt, locator: &Locator) -> TextSize {
-    let line_end = locator.full_line_end(stmt.end());
-    UniversalNewlineIterator::with_offset(locator.after(line_end), line_end)
+pub fn trailing_lines_end(stmt: &Stmt, source: &str) -> TextSize {
+    let line_end = source.full_line_end(stmt.end());
+    UniversalNewlineIterator::with_offset(source.after(line_end), line_end)
         .take_while(|line| line.trim_whitespace().is_empty())
         .last()
         .map_or(line_end, |line| line.full_end())
 }
 
 /// If a [`Ranged`] has a trailing comment, return the index of the hash.
-pub fn trailing_comment_start_offset<T>(located: &T, locator: &Locator) -> Option<TextSize>
+pub fn trailing_comment_start_offset<T>(located: &T, source: &str) -> Option<TextSize>
 where
     T: Ranged,
 {
-    let line_end = locator.line_end(located.end());
+    let line_end = source.line_end(located.end());
 
-    let trailing = locator.slice(TextRange::new(located.end(), line_end));
+    let trailing = source.slice(TextRange::new(located.end(), line_end));
 
     for (index, char) in trailing.char_indices() {
         if char == '#' {
diff --git a/crates/ruff_python_codegen/src/lib.rs b/crates/ruff_python_codegen/src/lib.rs
index 64a991edcd..6940b918ae 100644
--- a/crates/ruff_python_codegen/src/lib.rs
+++ b/crates/ruff_python_codegen/src/lib.rs
@@ -3,14 +3,12 @@ mod stylist;
 
 pub use generator::Generator;
 use ruff_python_parser::{parse_module, ParseError};
-use ruff_source_file::Locator;
 pub use stylist::Stylist;
 
 /// Run round-trip source code generation on a given Python code.
 pub fn round_trip(code: &str) -> Result<String, ParseError> {
-    let locator = Locator::new(code);
     let parsed = parse_module(code)?;
-    let stylist = Stylist::from_tokens(parsed.tokens(), &locator);
+    let stylist = Stylist::from_tokens(parsed.tokens(), code);
     let mut generator: Generator = (&stylist).into();
     generator.unparse_suite(parsed.suite());
     Ok(generator.generate())
diff --git a/crates/ruff_python_codegen/src/stylist.rs b/crates/ruff_python_codegen/src/stylist.rs
index b78417add2..990c20eac5 100644
--- a/crates/ruff_python_codegen/src/stylist.rs
+++ b/crates/ruff_python_codegen/src/stylist.rs
@@ -5,12 +5,12 @@ use std::ops::Deref;
 
 use ruff_python_ast::str::Quote;
 use ruff_python_parser::{Token, TokenKind, Tokens};
-use ruff_source_file::{find_newline, LineEnding, Locator};
+use ruff_source_file::{find_newline, LineEnding, Located};
 use ruff_text_size::Ranged;
 
 #[derive(Debug, Clone)]
 pub struct Stylist<'a> {
-    locator: &'a Locator<'a>,
+    source: &'a str,
     indentation: Indentation,
     quote: Quote,
     line_ending: OnceCell<LineEnding>,
@@ -27,18 +27,17 @@ impl<'a> Stylist<'a> {
 
     pub fn line_ending(&'a self) -> LineEnding {
         *self.line_ending.get_or_init(|| {
-            let contents = self.locator.contents();
-            find_newline(contents)
+            find_newline(self.source)
                 .map(|(_, ending)| ending)
                 .unwrap_or_default()
         })
     }
 
-    pub fn from_tokens(tokens: &Tokens, locator: &'a Locator<'a>) -> Self {
-        let indentation = detect_indentation(tokens, locator);
+    pub fn from_tokens(tokens: &Tokens, source: &'a str) -> Self {
+        let indentation = detect_indentation(tokens, source);
 
         Self {
-            locator,
+            source,
             indentation,
             quote: detect_quote(tokens),
             line_ending: OnceCell::default(),
@@ -59,7 +58,7 @@ fn detect_quote(tokens: &[Token]) -> Quote {
     Quote::default()
 }
 
-fn detect_indentation(tokens: &[Token], locator: &Locator) -> Indentation {
+fn detect_indentation(tokens: &[Token], source: &str) -> Indentation {
     let indent_range = tokens.iter().find_map(|token| {
         if matches!(token.kind(), TokenKind::Indent) {
             Some(token.range())
@@ -69,7 +68,7 @@ fn detect_indentation(tokens: &[Token], locator: &Locator) -> Indentation {
     });
 
     if let Some(indent_range) = indent_range {
-        let mut whitespace = locator.slice(indent_range);
+        let mut whitespace = source.slice(indent_range);
         // https://docs.python.org/3/reference/lexical_analysis.html#indentation
         // > A formfeed character may be present at the start of the line; it will be ignored for
         // > the indentation calculations above. Formfeed characters occurring elsewhere in the
@@ -98,7 +97,7 @@ fn detect_indentation(tokens: &[Token], locator: &Locator) -> Indentation {
         // ```
         for token in tokens {
             if token.kind() == TokenKind::NonLogicalNewline {
-                let line = locator.line(token.end());
+                let line = source.line_str(token.end());
                 let indent_index = line.find(|c: char| !c.is_whitespace());
                 if let Some(indent_index) = indent_index {
                     if indent_index > 0 {
@@ -154,41 +153,36 @@ mod tests {
     use ruff_source_file::{find_newline, LineEnding};
 
     use super::{Indentation, Quote, Stylist};
-    use ruff_source_file::Locator;
 
     #[test]
     fn indentation() {
         let contents = r"x = 1";
-        let locator = Locator::new(contents);
         let parsed = parse_module(contents).unwrap();
-        let stylist = Stylist::from_tokens(parsed.tokens(), &locator);
+        let stylist = Stylist::from_tokens(parsed.tokens(), contents);
         assert_eq!(stylist.indentation(), &Indentation::default());
 
         let contents = r"
 if True:
   pass
 ";
-        let locator = Locator::new(contents);
         let parsed = parse_module(contents).unwrap();
-        let stylist = Stylist::from_tokens(parsed.tokens(), &locator);
+        let stylist = Stylist::from_tokens(parsed.tokens(), contents);
         assert_eq!(stylist.indentation(), &Indentation("  ".to_string()));
 
         let contents = r"
 if True:
     pass
 ";
-        let locator = Locator::new(contents);
         let parsed = parse_module(contents).unwrap();
-        let stylist = Stylist::from_tokens(parsed.tokens(), &locator);
+        let stylist = Stylist::from_tokens(parsed.tokens(), contents);
         assert_eq!(stylist.indentation(), &Indentation("    ".to_string()));
 
         let contents = r"
 if True:
 	pass
 ";
-        let locator = Locator::new(contents);
         let parsed = parse_module(contents).unwrap();
-        let stylist = Stylist::from_tokens(parsed.tokens(), &locator);
+        let stylist = Stylist::from_tokens(parsed.tokens(), contents);
         assert_eq!(stylist.indentation(), &Indentation("\t".to_string()));
 
         let contents = r"
@@ -198,9 +192,8 @@ x = (
   3,
 )
 ";
-        let locator = Locator::new(contents);
         let parsed = parse_module(contents).unwrap();
-        let stylist = Stylist::from_tokens(parsed.tokens(), &locator);
+        let stylist = Stylist::from_tokens(parsed.tokens(), contents);
         assert_eq!(stylist.indentation(), &Indentation("  ".to_string()));
 
         // formfeed indent, see `detect_indentation` comment.
@@ -209,9 +202,8 @@ class FormFeedIndent:
    def __init__(self, a=[]):
         print(a)
 ";
-        let locator = Locator::new(contents);
         let parsed = parse_module(contents).unwrap();
-        let stylist = Stylist::from_tokens(parsed.tokens(), &locator);
+        let stylist = Stylist::from_tokens(parsed.tokens(), contents);
         assert_eq!(stylist.indentation(), &Indentation(" ".to_string()));
     }
 
@@ -224,10 +216,9 @@ x = (
  3,
 )
 ";
-        let locator = Locator::new(contents);
         let parsed = parse_unchecked(contents, Mode::Module);
         assert_eq!(
-            Stylist::from_tokens(parsed.tokens(), &locator).indentation(),
+            Stylist::from_tokens(parsed.tokens(), contents).indentation(),
             &Indentation(" ".to_string())
         );
     }
@@ -235,39 +226,33 @@ x = (
     #[test]
     fn quote() {
         let contents = r"x = 1";
-        let locator = Locator::new(contents);
         let parsed = parse_module(contents).unwrap();
-        let stylist = Stylist::from_tokens(parsed.tokens(), &locator);
+        let stylist = Stylist::from_tokens(parsed.tokens(), contents);
         assert_eq!(stylist.quote(), Quote::default());
 
         let contents = r"x = '1'";
-        let locator = Locator::new(contents);
         let parsed = parse_module(contents).unwrap();
-        let stylist = Stylist::from_tokens(parsed.tokens(), &locator);
+        let stylist = Stylist::from_tokens(parsed.tokens(), contents);
         assert_eq!(stylist.quote(), Quote::Single);
 
         let contents = r"x = f'1'";
-        let locator = Locator::new(contents);
         let parsed = parse_module(contents).unwrap();
-        let stylist = Stylist::from_tokens(parsed.tokens(), &locator);
+        let stylist = Stylist::from_tokens(parsed.tokens(), contents);
         assert_eq!(stylist.quote(), Quote::Single);
 
         let contents = r#"x = "1""#;
-        let locator = Locator::new(contents);
         let parsed = parse_module(contents).unwrap();
-        let stylist = Stylist::from_tokens(parsed.tokens(), &locator);
+        let stylist = Stylist::from_tokens(parsed.tokens(), contents);
         assert_eq!(stylist.quote(), Quote::Double);
 
         let contents = r#"x = f"1""#;
-        let locator = Locator::new(contents);
         let parsed = parse_module(contents).unwrap();
-        let stylist = Stylist::from_tokens(parsed.tokens(), &locator);
+        let stylist = Stylist::from_tokens(parsed.tokens(), contents);
         assert_eq!(stylist.quote(), Quote::Double);
 
         let contents = r#"s = "It's done.""#;
-        let locator = Locator::new(contents);
         let parsed = parse_module(contents).unwrap();
-        let stylist = Stylist::from_tokens(parsed.tokens(), &locator);
+        let stylist = Stylist::from_tokens(parsed.tokens(), contents);
         assert_eq!(stylist.quote(), Quote::Double);
 
         // No style if only double quoted docstring (will take default Double)
@@ -276,9 +261,8 @@ def f():
     """Docstring."""
     pass
 "#;
-        let locator = Locator::new(contents);
         let parsed = parse_module(contents).unwrap();
-        let stylist = Stylist::from_tokens(parsed.tokens(), &locator);
+        let stylist = Stylist::from_tokens(parsed.tokens(), contents);
         assert_eq!(stylist.quote(), Quote::default());
 
         // Detect from string literal appearing after docstring
@@ -287,9 +271,8 @@ def f():
 
 a = 'v'
 "#;
-        let locator = Locator::new(contents);
         let parsed = parse_module(contents).unwrap();
-        let stylist = Stylist::from_tokens(parsed.tokens(), &locator);
+        let stylist = Stylist::from_tokens(parsed.tokens(), contents);
         assert_eq!(stylist.quote(), Quote::Single);
 
         let contents = r#"
@@ -297,9 +280,8 @@ a = 'v'
 
 a = "v"
 "#;
-        let locator = Locator::new(contents);
         let parsed = parse_module(contents).unwrap();
-        let stylist = Stylist::from_tokens(parsed.tokens(), &locator);
+        let stylist = Stylist::from_tokens(parsed.tokens(), contents);
         assert_eq!(stylist.quote(), Quote::Double);
 
         // Detect from f-string appearing after docstring
@@ -308,9 +290,8 @@ a = "v"
 
 a = f'v'
 "#;
-        let locator = Locator::new(contents);
         let parsed = parse_module(contents).unwrap();
-        let stylist = Stylist::from_tokens(parsed.tokens(), &locator);
+        let stylist = Stylist::from_tokens(parsed.tokens(), contents);
         assert_eq!(stylist.quote(), Quote::Single);
 
         let contents = r#"
@@ -318,17 +299,15 @@ a = f'v'
 
 a = f"v"
 "#;
-        let locator = Locator::new(contents);
         let parsed = parse_module(contents).unwrap();
-        let stylist = Stylist::from_tokens(parsed.tokens(), &locator);
+        let stylist = Stylist::from_tokens(parsed.tokens(), contents);
         assert_eq!(stylist.quote(), Quote::Double);
 
         let contents = r"
 f'''Module docstring.'''
 ";
-        let locator = Locator::new(contents);
         let parsed = parse_module(contents).unwrap();
-        let stylist = Stylist::from_tokens(parsed.tokens(), &locator);
+        let stylist = Stylist::from_tokens(parsed.tokens(), contents);
         assert_eq!(stylist.quote(), Quote::Single);
     }
 
diff --git a/crates/ruff_python_formatter/src/comments/mod.rs b/crates/ruff_python_formatter/src/comments/mod.rs
index c2db89159b..40b7f47005 100644
--- a/crates/ruff_python_formatter/src/comments/mod.rs
+++ b/crates/ruff_python_formatter/src/comments/mod.rs
@@ -98,7 +98,6 @@ pub(crate) use format::{
 use ruff_formatter::{SourceCode, SourceCodeSlice};
 use ruff_python_ast::AnyNodeRef;
 use ruff_python_trivia::{CommentLinePosition, CommentRanges, SuppressionKind};
-use ruff_source_file::Locator;
 use ruff_text_size::{Ranged, TextRange};
 pub(crate) use visitor::collect_comments;
 
@@ -258,8 +257,7 @@ impl<'a> Comments<'a> {
             let map = if comment_ranges.is_empty() {
                 CommentsMap::new()
             } else {
-                let mut builder =
-                    CommentsMapBuilder::new(Locator::new(source_code.as_str()), comment_ranges);
+                let mut builder = CommentsMapBuilder::new(source_code.as_str(), comment_ranges);
                 CommentsVisitor::new(source_code, comment_ranges, &mut builder).visit(root);
                 builder.finish()
             };
diff --git a/crates/ruff_python_formatter/src/comments/placement.rs b/crates/ruff_python_formatter/src/comments/placement.rs
index badc8667ff..493b34192b 100644
--- a/crates/ruff_python_formatter/src/comments/placement.rs
+++ b/crates/ruff_python_formatter/src/comments/placement.rs
@@ -1,5 +1,9 @@
-use std::cmp::Ordering;
-
+use crate::comments::visitor::{CommentPlacement, DecoratedComment};
+use crate::expression::expr_slice::{assign_comment_in_slice, ExprSliceCommentSection};
+use crate::other::parameters::{
+    assign_argument_separator_comment_placement, find_parameter_separators,
+};
+use crate::pattern::pattern_match_sequence::SequenceType;
 use ast::helpers::comment_indentation_after;
 use ruff_python_ast::whitespace::indentation;
 use ruff_python_ast::{
@@ -9,26 +13,20 @@ use ruff_python_trivia::{
     find_only_token_in_range, first_non_trivia_token, indentation_at_offset, BackwardsTokenizer,
     CommentRanges, SimpleToken, SimpleTokenKind, SimpleTokenizer,
 };
-use ruff_source_file::Locator;
+use ruff_source_file::Located;
 use ruff_text_size::{Ranged, TextLen, TextRange};
-
-use crate::comments::visitor::{CommentPlacement, DecoratedComment};
-use crate::expression::expr_slice::{assign_comment_in_slice, ExprSliceCommentSection};
-use crate::other::parameters::{
-    assign_argument_separator_comment_placement, find_parameter_separators,
-};
-use crate::pattern::pattern_match_sequence::SequenceType;
+use std::cmp::Ordering;
 
 /// Manually attach comments to nodes that the default placement gets wrong.
 pub(super) fn place_comment<'a>(
     comment: DecoratedComment<'a>,
     comment_ranges: &CommentRanges,
-    locator: &Locator,
+    source: &'a str,
 ) -> CommentPlacement<'a> {
-    handle_parenthesized_comment(comment, locator)
-        .or_else(|comment| handle_end_of_line_comment_around_body(comment, locator))
-        .or_else(|comment| handle_own_line_comment_around_body(comment, locator))
-        .or_else(|comment| handle_enclosed_comment(comment, comment_ranges, locator))
+    handle_parenthesized_comment(comment, source)
+        .or_else(|comment| handle_end_of_line_comment_around_body(comment, source))
+        .or_else(|comment| handle_own_line_comment_around_body(comment, source))
+        .or_else(|comment| handle_enclosed_comment(comment, comment_ranges, source))
 }
 
 /// Handle parenthesized comments. A parenthesized comment is a comment that appears within a
@@ -71,7 +69,7 @@ pub(super) fn place_comment<'a>(
 /// comment is a leading comment of the following node.
 fn handle_parenthesized_comment<'a>(
     comment: DecoratedComment<'a>,
-    locator: &Locator,
+    source: &str,
 ) -> CommentPlacement<'a> {
     // As a special-case, ignore comments within f-strings, like:
     // ```python
@@ -133,7 +131,7 @@ fn handle_parenthesized_comment<'a>(
     // ]
     // ```
     let range = TextRange::new(preceding.end(), comment.start());
-    let tokenizer = SimpleTokenizer::new(locator.contents(), range);
+    let tokenizer = SimpleTokenizer::new(source, range);
     if tokenizer
         .skip_trivia()
         .take_while(|token| {
@@ -146,7 +144,7 @@ fn handle_parenthesized_comment<'a>(
             debug_assert!(
                 !matches!(token.kind, SimpleTokenKind::Bogus),
                 "Unexpected token between nodes: `{:?}`",
-                locator.slice(range)
+                source.slice(range)
             );
             token.kind() == SimpleTokenKind::LParen
         })
@@ -164,7 +162,7 @@ fn handle_parenthesized_comment<'a>(
     // ]
     // ```
     let range = TextRange::new(comment.end(), following.start());
-    let tokenizer = SimpleTokenizer::new(locator.contents(), range);
+    let tokenizer = SimpleTokenizer::new(source, range);
     if tokenizer
         .skip_trivia()
         .take_while(|token| {
@@ -177,7 +175,7 @@ fn handle_parenthesized_comment<'a>(
             debug_assert!(
                 !matches!(token.kind, SimpleTokenKind::Bogus),
                 "Unexpected token between nodes: `{:?}`",
-                locator.slice(range)
+                source.slice(range)
             );
             token.kind() == SimpleTokenKind::RParen
         })
@@ -192,61 +190,61 @@ fn handle_parenthesized_comment<'a>(
 fn handle_enclosed_comment<'a>(
     comment: DecoratedComment<'a>,
     comment_ranges: &CommentRanges,
-    locator: &Locator,
+    source: &str,
 ) -> CommentPlacement<'a> {
     match comment.enclosing_node() {
         AnyNodeRef::Parameters(parameters) => {
-            handle_parameters_separator_comment(comment, parameters, locator).or_else(|comment| {
-                if are_parameters_parenthesized(parameters, locator.contents()) {
-                    handle_bracketed_end_of_line_comment(comment, locator)
+            handle_parameters_separator_comment(comment, parameters, source).or_else(|comment| {
+                if are_parameters_parenthesized(parameters, source) {
+                    handle_bracketed_end_of_line_comment(comment, source)
                 } else {
                     CommentPlacement::Default(comment)
                 }
             })
         }
-        AnyNodeRef::Parameter(parameter) => handle_parameter_comment(comment, parameter, locator),
+        AnyNodeRef::Parameter(parameter) => handle_parameter_comment(comment, parameter, source),
         AnyNodeRef::Arguments(_) | AnyNodeRef::TypeParams(_) | AnyNodeRef::PatternArguments(_) => {
-            handle_bracketed_end_of_line_comment(comment, locator)
+            handle_bracketed_end_of_line_comment(comment, source)
         }
         AnyNodeRef::Comprehension(comprehension) => {
-            handle_comprehension_comment(comment, comprehension, locator)
+            handle_comprehension_comment(comment, comprehension, source)
         }
 
         AnyNodeRef::ExprAttribute(attribute) => {
-            handle_attribute_comment(comment, attribute, locator)
+            handle_attribute_comment(comment, attribute, source)
         }
         AnyNodeRef::ExprBinOp(binary_expression) => {
             handle_trailing_binary_expression_left_or_operator_comment(
                 comment,
                 binary_expression,
-                locator,
+                source,
             )
         }
         AnyNodeRef::ExprBoolOp(_) | AnyNodeRef::ExprCompare(_) => {
-            handle_trailing_binary_like_comment(comment, locator)
+            handle_trailing_binary_like_comment(comment, source)
         }
-        AnyNodeRef::Keyword(keyword) => handle_keyword_comment(comment, keyword, locator),
+        AnyNodeRef::Keyword(keyword) => handle_keyword_comment(comment, keyword, source),
         AnyNodeRef::PatternKeyword(pattern_keyword) => {
-            handle_pattern_keyword_comment(comment, pattern_keyword, locator)
+            handle_pattern_keyword_comment(comment, pattern_keyword, source)
         }
-        AnyNodeRef::ExprUnaryOp(unary_op) => handle_unary_op_comment(comment, unary_op, locator),
-        AnyNodeRef::ExprNamed(_) => handle_named_expr_comment(comment, locator),
-        AnyNodeRef::ExprLambda(lambda) => handle_lambda_comment(comment, lambda, locator),
-        AnyNodeRef::ExprDict(_) => handle_dict_unpacking_comment(comment, locator)
-            .or_else(|comment| handle_bracketed_end_of_line_comment(comment, locator))
-            .or_else(|comment| handle_key_value_comment(comment, locator)),
-        AnyNodeRef::ExprDictComp(_) => handle_key_value_comment(comment, locator)
-            .or_else(|comment| handle_bracketed_end_of_line_comment(comment, locator)),
-        AnyNodeRef::ExprIf(expr_if) => handle_expr_if_comment(comment, expr_if, locator),
+        AnyNodeRef::ExprUnaryOp(unary_op) => handle_unary_op_comment(comment, unary_op, source),
+        AnyNodeRef::ExprNamed(_) => handle_named_expr_comment(comment, source),
+        AnyNodeRef::ExprLambda(lambda) => handle_lambda_comment(comment, lambda, source),
+        AnyNodeRef::ExprDict(_) => handle_dict_unpacking_comment(comment, source)
+            .or_else(|comment| handle_bracketed_end_of_line_comment(comment, source))
+            .or_else(|comment| handle_key_value_comment(comment, source)),
+        AnyNodeRef::ExprDictComp(_) => handle_key_value_comment(comment, source)
+            .or_else(|comment| handle_bracketed_end_of_line_comment(comment, source)),
+        AnyNodeRef::ExprIf(expr_if) => handle_expr_if_comment(comment, expr_if, source),
         AnyNodeRef::ExprSlice(expr_slice) => {
-            handle_slice_comments(comment, expr_slice, comment_ranges, locator)
+            handle_slice_comments(comment, expr_slice, comment_ranges, source)
         }
         AnyNodeRef::ExprStarred(starred) => {
-            handle_trailing_expression_starred_star_end_of_line_comment(comment, starred, locator)
+            handle_trailing_expression_starred_star_end_of_line_comment(comment, starred, source)
         }
         AnyNodeRef::ExprSubscript(expr_subscript) => {
             if let Expr::Slice(expr_slice) = expr_subscript.slice.as_ref() {
-                return handle_slice_comments(comment, expr_slice, comment_ranges, locator);
+                return handle_slice_comments(comment, expr_slice, comment_ranges, source);
             }
 
             // Handle non-slice subscript end-of-line comments coming after the `[`
@@ -262,7 +260,7 @@ fn handle_enclosed_comment<'a>(
             {
                 // Ensure that there are no tokens between the open bracket and the comment.
                 let mut lexer = SimpleTokenizer::new(
-                    locator.contents(),
+                    source,
                     TextRange::new(expr_subscript.value.end(), comment.start()),
                 )
                 .skip_trivia();
@@ -288,26 +286,24 @@ fn handle_enclosed_comment<'a>(
         AnyNodeRef::ModModule(module) => {
             handle_trailing_module_comment(module, comment).or_else(|comment| {
                 handle_module_level_own_line_comment_before_class_or_function_comment(
-                    comment, locator,
+                    comment, source,
                 )
             })
         }
-        AnyNodeRef::WithItem(_) => handle_with_item_comment(comment, locator),
+        AnyNodeRef::WithItem(_) => handle_with_item_comment(comment, source),
         AnyNodeRef::PatternMatchSequence(pattern_match_sequence) => {
-            if SequenceType::from_pattern(pattern_match_sequence, locator.contents())
-                .is_parenthesized()
-            {
-                handle_bracketed_end_of_line_comment(comment, locator)
+            if SequenceType::from_pattern(pattern_match_sequence, source).is_parenthesized() {
+                handle_bracketed_end_of_line_comment(comment, source)
             } else {
                 CommentPlacement::Default(comment)
             }
         }
         AnyNodeRef::PatternMatchClass(class) => handle_pattern_match_class_comment(comment, class),
-        AnyNodeRef::PatternMatchAs(_) => handle_pattern_match_as_comment(comment, locator),
+        AnyNodeRef::PatternMatchAs(_) => handle_pattern_match_as_comment(comment, source),
         AnyNodeRef::PatternMatchStar(_) => handle_pattern_match_star_comment(comment),
         AnyNodeRef::PatternMatchMapping(pattern) => {
-            handle_bracketed_end_of_line_comment(comment, locator)
-                .or_else(|comment| handle_pattern_match_mapping_comment(comment, pattern, locator))
+            handle_bracketed_end_of_line_comment(comment, source)
+                .or_else(|comment| handle_pattern_match_mapping_comment(comment, pattern, source))
         }
         AnyNodeRef::StmtFunctionDef(_) => handle_leading_function_with_decorators_comment(comment),
         AnyNodeRef::StmtClassDef(class_def) => {
@@ -343,19 +339,19 @@ fn handle_enclosed_comment<'a>(
             ) {
                 CommentPlacement::trailing(comment.enclosing_node(), comment)
             } else {
-                handle_bracketed_end_of_line_comment(comment, locator)
+                handle_bracketed_end_of_line_comment(comment, source)
             }
         }
         AnyNodeRef::ExprList(_)
         | AnyNodeRef::ExprSet(_)
         | AnyNodeRef::ExprListComp(_)
-        | AnyNodeRef::ExprSetComp(_) => handle_bracketed_end_of_line_comment(comment, locator),
+        | AnyNodeRef::ExprSetComp(_) => handle_bracketed_end_of_line_comment(comment, source),
         AnyNodeRef::ExprTuple(ast::ExprTuple {
             parenthesized: true,
             ..
-        }) => handle_bracketed_end_of_line_comment(comment, locator),
+        }) => handle_bracketed_end_of_line_comment(comment, source),
         AnyNodeRef::ExprGenerator(generator) if generator.parenthesized => {
-            handle_bracketed_end_of_line_comment(comment, locator)
+            handle_bracketed_end_of_line_comment(comment, source)
         }
         _ => CommentPlacement::Default(comment),
     }
@@ -364,7 +360,7 @@ fn handle_enclosed_comment<'a>(
 /// Handle an end-of-line comment around a body.
 fn handle_end_of_line_comment_around_body<'a>(
     comment: DecoratedComment<'a>,
-    locator: &Locator,
+    source: &str,
 ) -> CommentPlacement<'a> {
     if comment.line_position().is_own_line() {
         return CommentPlacement::Default(comment);
@@ -379,13 +375,10 @@ fn handle_end_of_line_comment_around_body<'a>(
     // ```
     if let Some(following) = comment.following_node() {
         if following.is_first_statement_in_body(comment.enclosing_node())
-            && SimpleTokenizer::new(
-                locator.contents(),
-                TextRange::new(comment.end(), following.start()),
-            )
-            .skip_trivia()
-            .next()
-            .is_none()
+            && SimpleTokenizer::new(source, TextRange::new(comment.end(), following.start()))
+                .skip_trivia()
+                .next()
+                .is_none()
         {
             return CommentPlacement::dangling(comment.enclosing_node(), comment);
         }
@@ -436,7 +429,7 @@ fn handle_end_of_line_comment_around_body<'a>(
 /// ```
 fn handle_own_line_comment_around_body<'a>(
     comment: DecoratedComment<'a>,
-    locator: &Locator,
+    source: &str,
 ) -> CommentPlacement<'a> {
     if comment.line_position().is_end_of_line() {
         return CommentPlacement::Default(comment);
@@ -458,24 +451,22 @@ fn handle_own_line_comment_around_body<'a>(
     //     # default placement comment
     //     def inline_after_else(): ...
     // ```
-    let maybe_token = SimpleTokenizer::new(
-        locator.contents(),
-        TextRange::new(preceding.end(), comment.start()),
-    )
-    .skip_trivia()
-    .next();
+    let maybe_token =
+        SimpleTokenizer::new(source, TextRange::new(preceding.end(), comment.start()))
+            .skip_trivia()
+            .next();
     if maybe_token.is_some() {
         return CommentPlacement::Default(comment);
     }
 
     // Check if we're between bodies and should attach to the following body.
-    handle_own_line_comment_between_branches(comment, preceding, locator)
+    handle_own_line_comment_between_branches(comment, preceding, source)
         .or_else(|comment| {
             // Otherwise, there's no following branch or the indentation is too deep, so attach to the
             // recursively last statement in the preceding body with the matching indentation.
-            handle_own_line_comment_after_branch(comment, preceding, locator)
+            handle_own_line_comment_after_branch(comment, preceding, source)
         })
-        .or_else(|comment| handle_own_line_comment_between_statements(comment, locator))
+        .or_else(|comment| handle_own_line_comment_between_statements(comment, source))
 }
 
 /// Handles own-line comments between statements. If an own-line comment is between two statements,
@@ -500,7 +491,7 @@ fn handle_own_line_comment_around_body<'a>(
 /// ```
 fn handle_own_line_comment_between_statements<'a>(
     comment: DecoratedComment<'a>,
-    locator: &Locator,
+    source: &str,
 ) -> CommentPlacement<'a> {
     let Some(preceding) = comment.preceding_node() else {
         return CommentPlacement::Default(comment);
@@ -540,7 +531,7 @@ fn handle_own_line_comment_between_statements<'a>(
     //
     // y = 2
     // ```
-    if max_empty_lines(locator.slice(TextRange::new(comment.end(), following.start()))) == 0 {
+    if max_empty_lines(source.slice(TextRange::new(comment.end(), following.start()))) == 0 {
         CommentPlacement::leading(following, comment)
     } else {
         CommentPlacement::trailing(preceding, comment)
@@ -559,7 +550,7 @@ fn handle_own_line_comment_between_statements<'a>(
 fn handle_own_line_comment_between_branches<'a>(
     comment: DecoratedComment<'a>,
     preceding: AnyNodeRef<'a>,
-    locator: &Locator,
+    source: &str,
 ) -> CommentPlacement<'a> {
     // The following statement must be the first statement in an alternate body, otherwise check
     // if it's a comment after the final body and handle that case
@@ -572,9 +563,9 @@ fn handle_own_line_comment_between_branches<'a>(
 
     // It depends on the indentation level of the comment if it is a leading comment for the
     // following branch or if it a trailing comment of the previous body's last statement.
-    let comment_indentation = comment_indentation_after(preceding, comment.range(), locator);
+    let comment_indentation = comment_indentation_after(preceding, comment.range(), source);
 
-    let preceding_indentation = indentation(locator, &preceding)
+    let preceding_indentation = indentation(source, &preceding)
         .unwrap_or_default()
         .text_len();
 
@@ -648,7 +639,7 @@ fn handle_own_line_comment_between_branches<'a>(
 fn handle_own_line_comment_after_branch<'a>(
     comment: DecoratedComment<'a>,
     preceding: AnyNodeRef<'a>,
-    locator: &Locator,
+    source: &str,
 ) -> CommentPlacement<'a> {
     let Some(last_child) = preceding.last_child_in_body() else {
         return CommentPlacement::Default(comment);
@@ -656,7 +647,7 @@ fn handle_own_line_comment_after_branch<'a>(
 
     // We only care about the length because indentations with mixed spaces and tabs are only valid if
     // the indent-level doesn't depend on the tab width (the indent level must be the same if the tab width is 1 or 8).
-    let comment_indentation = comment_indentation_after(preceding, comment.range(), locator);
+    let comment_indentation = comment_indentation_after(preceding, comment.range(), source);
 
     // Keep the comment on the entire statement in case it's a trailing comment
     // ```python
@@ -667,7 +658,7 @@ fn handle_own_line_comment_after_branch<'a>(
     // # Trailing if comment
     // ```
     // Here we keep the comment a trailing comment of the `if`
-    let preceding_indentation = indentation_at_offset(preceding.start(), locator)
+    let preceding_indentation = indentation_at_offset(preceding.start(), source)
         .unwrap_or_default()
         .text_len();
     if comment_indentation == preceding_indentation {
@@ -678,7 +669,7 @@ fn handle_own_line_comment_after_branch<'a>(
     let mut last_child_in_parent = last_child;
 
     loop {
-        let child_indentation = indentation(locator, &last_child_in_parent)
+        let child_indentation = indentation(source, &last_child_in_parent)
             .unwrap_or_default()
             .text_len();
 
@@ -739,9 +730,9 @@ fn handle_own_line_comment_after_branch<'a>(
 fn handle_parameters_separator_comment<'a>(
     comment: DecoratedComment<'a>,
     parameters: &Parameters,
-    locator: &Locator,
+    source: &str,
 ) -> CommentPlacement<'a> {
-    let (slash, star) = find_parameter_separators(locator.contents(), parameters);
+    let (slash, star) = find_parameter_separators(source, parameters);
     let placement = assign_argument_separator_comment_placement(
         slash.as_ref(),
         star.as_ref(),
@@ -768,10 +759,10 @@ fn handle_parameters_separator_comment<'a>(
 fn handle_parameter_comment<'a>(
     comment: DecoratedComment<'a>,
     parameter: &'a Parameter,
-    locator: &Locator,
+    source: &str,
 ) -> CommentPlacement<'a> {
     if parameter.annotation.as_deref().is_some() {
-        let colon = first_non_trivia_token(parameter.name.end(), locator.contents()).expect(
+        let colon = first_non_trivia_token(parameter.name.end(), source).expect(
             "A annotated parameter should have a colon following its name when it is valid syntax.",
         );
 
@@ -804,7 +795,7 @@ fn handle_parameter_comment<'a>(
 fn handle_trailing_binary_expression_left_or_operator_comment<'a>(
     comment: DecoratedComment<'a>,
     binary_expression: &'a ast::ExprBinOp,
-    locator: &Locator,
+    source: &str,
 ) -> CommentPlacement<'a> {
     // Only if there's a preceding node (in which case, the preceding node is `left`).
     if comment.preceding_node().is_none() || comment.following_node().is_none() {
@@ -816,7 +807,7 @@ fn handle_trailing_binary_expression_left_or_operator_comment<'a>(
         binary_expression.right.start(),
     );
 
-    let mut tokens = SimpleTokenizer::new(locator.contents(), between_operands_range)
+    let mut tokens = SimpleTokenizer::new(source, between_operands_range)
         .skip_trivia()
         .skip_while(|token| token.kind == SimpleTokenKind::RParen);
     let operator_offset = tokens
@@ -836,10 +827,10 @@ fn handle_trailing_binary_expression_left_or_operator_comment<'a>(
         CommentPlacement::trailing(binary_expression.left.as_ref(), comment)
     } else if comment.line_position().is_end_of_line() {
         // Is the operator on its own line.
-        if locator.contains_line_break(TextRange::new(
+        if source.contains_line_break(TextRange::new(
             binary_expression.left.end(),
             operator_offset,
-        )) && locator.contains_line_break(TextRange::new(
+        )) && source.contains_line_break(TextRange::new(
             operator_offset,
             binary_expression.right.start(),
         )) {
@@ -893,7 +884,7 @@ fn handle_trailing_binary_expression_left_or_operator_comment<'a>(
 /// ```
 fn handle_trailing_binary_like_comment<'a>(
     comment: DecoratedComment<'a>,
-    locator: &Locator,
+    source: &str,
 ) -> CommentPlacement<'a> {
     debug_assert!(
         comment.enclosing_node().is_expr_bool_op() || comment.enclosing_node().is_expr_compare()
@@ -908,7 +899,7 @@ fn handle_trailing_binary_like_comment<'a>(
 
     let between_operands_range = TextRange::new(left_operand.end(), right_operand.start());
 
-    let mut tokens = SimpleTokenizer::new(locator.contents(), between_operands_range)
+    let mut tokens = SimpleTokenizer::new(source, between_operands_range)
         .skip_trivia()
         .skip_while(|token| token.kind == SimpleTokenKind::RParen);
     let operator_offset = tokens
@@ -990,7 +981,7 @@ fn handle_trailing_module_comment<'a>(
 /// a trailing comment of the previous statement.
 fn handle_module_level_own_line_comment_before_class_or_function_comment<'a>(
     comment: DecoratedComment<'a>,
-    locator: &Locator,
+    source: &str,
 ) -> CommentPlacement<'a> {
     debug_assert!(comment.enclosing_node().is_module());
     // Only applies for own line comments on the module level...
@@ -1013,7 +1004,7 @@ fn handle_module_level_own_line_comment_before_class_or_function_comment<'a>(
     }
 
     // Make the comment a leading comment if there's no empty line between the comment and the function / class header
-    if max_empty_lines(locator.slice(TextRange::new(comment.end(), following.start()))) == 0 {
+    if max_empty_lines(source.slice(TextRange::new(comment.end(), following.start()))) == 0 {
         CommentPlacement::leading(following, comment)
     } else {
         // Otherwise attach the comment as trailing comment to the previous statement
@@ -1034,7 +1025,7 @@ fn handle_slice_comments<'a>(
     comment: DecoratedComment<'a>,
     expr_slice: &'a ast::ExprSlice,
     comment_ranges: &CommentRanges,
-    locator: &Locator,
+    source: &str,
 ) -> CommentPlacement<'a> {
     let ast::ExprSlice {
         range: _,
@@ -1045,7 +1036,7 @@ fn handle_slice_comments<'a>(
 
     // Check for `foo[ # comment`, but only if they are on the same line
     let after_lbracket = matches!(
-        BackwardsTokenizer::up_to(comment.start(), locator.contents(), comment_ranges)
+        BackwardsTokenizer::up_to(comment.start(), source, comment_ranges)
             .skip_trivia()
             .next(),
         Some(SimpleToken {
@@ -1069,7 +1060,7 @@ fn handle_slice_comments<'a>(
         return CommentPlacement::dangling(comment.enclosing_node(), comment);
     }
 
-    let assignment = assign_comment_in_slice(comment.range(), locator.contents(), expr_slice);
+    let assignment = assign_comment_in_slice(comment.range(), source, expr_slice);
     let node = match assignment {
         ExprSliceCommentSection::Lower => lower,
         ExprSliceCommentSection::Upper => upper,
@@ -1155,7 +1146,7 @@ fn handle_leading_class_with_decorators_comment<'a>(
 fn handle_keyword_comment<'a>(
     comment: DecoratedComment<'a>,
     keyword: &'a ast::Keyword,
-    locator: &Locator,
+    source: &str,
 ) -> CommentPlacement<'a> {
     let start = keyword.arg.as_ref().map_or(keyword.start(), Ranged::end);
 
@@ -1167,8 +1158,7 @@ fn handle_keyword_comment<'a>(
     //     )
     // )
     // ```
-    let mut tokenizer =
-        SimpleTokenizer::new(locator.contents(), TextRange::new(start, comment.start()));
+    let mut tokenizer = SimpleTokenizer::new(source, TextRange::new(start, comment.start()));
     if tokenizer.any(|token| token.kind == SimpleTokenKind::LParen) {
         return CommentPlacement::Default(comment);
     }
@@ -1188,7 +1178,7 @@ fn handle_keyword_comment<'a>(
 fn handle_pattern_keyword_comment<'a>(
     comment: DecoratedComment<'a>,
     pattern_keyword: &'a ast::PatternKeyword,
-    locator: &Locator,
+    source: &str,
 ) -> CommentPlacement<'a> {
     // If the comment is parenthesized, it should be attached to the value:
     // ```python
@@ -1199,7 +1189,7 @@ fn handle_pattern_keyword_comment<'a>(
     // )
     // ```
     let mut tokenizer = SimpleTokenizer::new(
-        locator.contents(),
+        source,
         TextRange::new(pattern_keyword.attr.end(), comment.start()),
     );
     if tokenizer.any(|token| token.kind == SimpleTokenKind::LParen) {
@@ -1221,7 +1211,7 @@ fn handle_pattern_keyword_comment<'a>(
 /// ```
 fn handle_dict_unpacking_comment<'a>(
     comment: DecoratedComment<'a>,
-    locator: &Locator,
+    source: &str,
 ) -> CommentPlacement<'a> {
     debug_assert!(matches!(comment.enclosing_node(), AnyNodeRef::ExprDict(_)));
 
@@ -1236,12 +1226,9 @@ fn handle_dict_unpacking_comment<'a>(
         Some(preceding) => preceding.end(),
         None => comment.enclosing_node().start(),
     };
-    let mut tokens = SimpleTokenizer::new(
-        locator.contents(),
-        TextRange::new(preceding_end, comment.start()),
-    )
-    .skip_trivia()
-    .skip_while(|token| token.kind == SimpleTokenKind::RParen);
+    let mut tokens = SimpleTokenizer::new(source, TextRange::new(preceding_end, comment.start()))
+        .skip_trivia()
+        .skip_while(|token| token.kind == SimpleTokenKind::RParen);
 
     // if the remaining tokens from the previous node are exactly `**`,
     // re-assign the comment to the one that follows the stars.
@@ -1264,7 +1251,7 @@ fn handle_dict_unpacking_comment<'a>(
 /// ```
 fn handle_key_value_comment<'a>(
     comment: DecoratedComment<'a>,
-    locator: &Locator,
+    source: &str,
 ) -> CommentPlacement<'a> {
     debug_assert!(matches!(
         comment.enclosing_node(),
@@ -1284,10 +1271,7 @@ fn handle_key_value_comment<'a>(
     // }
     // ```
     // This prevents against detecting comments on starred expressions as key-value comments.
-    let tokens = SimpleTokenizer::new(
-        locator.contents(),
-        TextRange::new(preceding.end(), following.start()),
-    );
+    let tokens = SimpleTokenizer::new(source, TextRange::new(preceding.end(), following.start()));
     if tokens
         .skip_trivia()
         .any(|token| token.kind == SimpleTokenKind::Colon)
@@ -1334,7 +1318,7 @@ fn handle_call_comment(comment: DecoratedComment) -> CommentPlacement {
 fn handle_attribute_comment<'a>(
     comment: DecoratedComment<'a>,
     attribute: &'a ast::ExprAttribute,
-    locator: &Locator,
+    source: &str,
 ) -> CommentPlacement<'a> {
     if comment.preceding_node().is_none() {
         // ```text
@@ -1365,7 +1349,7 @@ fn handle_attribute_comment<'a>(
     //     .attribute
     // )
     // ```
-    if let Some(right_paren) = SimpleTokenizer::starts_at(attribute.value.end(), locator.contents())
+    if let Some(right_paren) = SimpleTokenizer::starts_at(attribute.value.end(), source)
         .skip_trivia()
         .take_while(|token| token.kind == SimpleTokenKind::RParen)
         .last()
@@ -1398,7 +1382,7 @@ fn handle_attribute_comment<'a>(
         let dot_token = find_only_token_in_range(
             TextRange::new(attribute.value.end(), attribute.attr.start()),
             SimpleTokenKind::Dot,
-            locator.contents(),
+            source,
         );
         if comment.end() < dot_token.start() {
             return CommentPlacement::trailing(attribute.value.as_ref(), comment);
@@ -1426,7 +1410,7 @@ fn handle_attribute_comment<'a>(
 fn handle_expr_if_comment<'a>(
     comment: DecoratedComment<'a>,
     expr_if: &'a ast::ExprIf,
-    locator: &Locator,
+    source: &str,
 ) -> CommentPlacement<'a> {
     let ast::ExprIf {
         range: _,
@@ -1442,7 +1426,7 @@ fn handle_expr_if_comment<'a>(
     let if_token = find_only_token_in_range(
         TextRange::new(body.end(), test.start()),
         SimpleTokenKind::If,
-        locator.contents(),
+        source,
     );
     // Between `if` and `test`
     if if_token.start() < comment.start() && comment.start() < test.start() {
@@ -1452,7 +1436,7 @@ fn handle_expr_if_comment<'a>(
     let else_token = find_only_token_in_range(
         TextRange::new(test.end(), orelse.start()),
         SimpleTokenKind::Else,
-        locator.contents(),
+        source,
     );
     // Between `else` and `orelse`
     if else_token.start() < comment.start() && comment.start() < orelse.start() {
@@ -1477,13 +1461,11 @@ fn handle_expr_if_comment<'a>(
 fn handle_trailing_expression_starred_star_end_of_line_comment<'a>(
     comment: DecoratedComment<'a>,
     starred: &'a ast::ExprStarred,
-    locator: &Locator,
+    source: &str,
 ) -> CommentPlacement<'a> {
     if comment.following_node().is_some() {
-        let tokenizer = SimpleTokenizer::new(
-            locator.contents(),
-            TextRange::new(starred.start(), comment.start()),
-        );
+        let tokenizer =
+            SimpleTokenizer::new(source, TextRange::new(starred.start(), comment.start()));
         if !tokenizer
             .skip_trivia()
             .any(|token| token.kind() == SimpleTokenKind::LParen)
@@ -1508,7 +1490,7 @@ fn handle_trailing_expression_starred_star_end_of_line_comment<'a>(
 /// ```
 fn handle_with_item_comment<'a>(
     comment: DecoratedComment<'a>,
-    locator: &Locator,
+    source: &str,
 ) -> CommentPlacement<'a> {
     debug_assert!(comment.enclosing_node().is_with_item());
 
@@ -1522,7 +1504,7 @@ fn handle_with_item_comment<'a>(
     let as_token = find_only_token_in_range(
         TextRange::new(context_expr.end(), optional_vars.start()),
         SimpleTokenKind::As,
-        locator.contents(),
+        source,
     );
 
     if comment.end() < as_token.start() {
@@ -1567,7 +1549,7 @@ fn handle_pattern_match_class_comment<'a>(
 /// ```
 fn handle_pattern_match_as_comment<'a>(
     comment: DecoratedComment<'a>,
-    locator: &Locator,
+    source: &str,
 ) -> CommentPlacement<'a> {
     debug_assert!(comment.enclosing_node().is_pattern_match_as());
 
@@ -1575,7 +1557,7 @@ fn handle_pattern_match_as_comment<'a>(
         return CommentPlacement::Default(comment);
     };
 
-    let mut tokens = SimpleTokenizer::starts_at(pattern.end(), locator.contents())
+    let mut tokens = SimpleTokenizer::starts_at(pattern.end(), source)
         .skip_trivia()
         .skip_while(|token| token.kind == SimpleTokenKind::RParen);
 
@@ -1625,7 +1607,7 @@ fn handle_pattern_match_star_comment(comment: DecoratedComment) -> CommentPlacem
 fn handle_pattern_match_mapping_comment<'a>(
     comment: DecoratedComment<'a>,
     pattern: &'a ast::PatternMatchMapping,
-    locator: &Locator,
+    source: &str,
 ) -> CommentPlacement<'a> {
     // The `**` has to come at the end, so there can't be another node after it. (The identifier,
     // like `rest` above, isn't a node.)
@@ -1649,11 +1631,8 @@ fn handle_pattern_match_mapping_comment<'a>(
         Some(preceding) => preceding.end(),
         None => comment.enclosing_node().start(),
     };
-    let mut tokens = SimpleTokenizer::new(
-        locator.contents(),
-        TextRange::new(preceding_end, comment.start()),
-    )
-    .skip_trivia();
+    let mut tokens =
+        SimpleTokenizer::new(source, TextRange::new(preceding_end, comment.start())).skip_trivia();
 
     // If the remaining tokens from the previous node include `**`, mark as a dangling comment.
     if tokens.any(|token| token.kind == SimpleTokenKind::DoubleStar) {
@@ -1682,7 +1661,7 @@ fn handle_pattern_match_mapping_comment<'a>(
 /// ```
 fn handle_named_expr_comment<'a>(
     comment: DecoratedComment<'a>,
-    locator: &Locator,
+    source: &str,
 ) -> CommentPlacement<'a> {
     debug_assert!(comment.enclosing_node().is_expr_named());
 
@@ -1693,7 +1672,7 @@ fn handle_named_expr_comment<'a>(
     let colon_equal = find_only_token_in_range(
         TextRange::new(target.end(), value.start()),
         SimpleTokenKind::ColonEqual,
-        locator.contents(),
+        source,
     );
 
     if comment.end() < colon_equal.start() {
@@ -1738,7 +1717,7 @@ fn handle_named_expr_comment<'a>(
 fn handle_lambda_comment<'a>(
     comment: DecoratedComment<'a>,
     lambda: &'a ast::ExprLambda,
-    locator: &Locator,
+    source: &str,
 ) -> CommentPlacement<'a> {
     if let Some(parameters) = lambda.parameters.as_deref() {
         // Comments between the `lambda` and the parameters are dangling on the lambda:
@@ -1770,10 +1749,8 @@ fn handle_lambda_comment<'a>(
             //     )
             // )
             // ```
-            let tokenizer = SimpleTokenizer::new(
-                locator.contents(),
-                TextRange::new(parameters.end(), comment.start()),
-            );
+            let tokenizer =
+                SimpleTokenizer::new(source, TextRange::new(parameters.end(), comment.start()));
             if tokenizer
                 .skip_trivia()
                 .any(|token| token.kind == SimpleTokenKind::LParen)
@@ -1801,10 +1778,8 @@ fn handle_lambda_comment<'a>(
             //     )
             // )
             // ```
-            let tokenizer = SimpleTokenizer::new(
-                locator.contents(),
-                TextRange::new(lambda.start(), comment.start()),
-            );
+            let tokenizer =
+                SimpleTokenizer::new(source, TextRange::new(lambda.start(), comment.start()));
             if tokenizer
                 .skip_trivia()
                 .any(|token| token.kind == SimpleTokenKind::LParen)
@@ -1834,10 +1809,10 @@ fn handle_lambda_comment<'a>(
 fn handle_unary_op_comment<'a>(
     comment: DecoratedComment<'a>,
     unary_op: &'a ast::ExprUnaryOp,
-    locator: &Locator,
+    source: &str,
 ) -> CommentPlacement<'a> {
     let mut tokenizer = SimpleTokenizer::new(
-        locator.contents(),
+        source,
         TextRange::new(unary_op.start(), unary_op.operand.start()),
     )
     .skip_trivia();
@@ -1883,12 +1858,12 @@ fn handle_unary_op_comment<'a>(
 /// that it remains on the same line as open bracket.
 fn handle_bracketed_end_of_line_comment<'a>(
     comment: DecoratedComment<'a>,
-    locator: &Locator,
+    source: &str,
 ) -> CommentPlacement<'a> {
     if comment.line_position().is_end_of_line() {
         // Ensure that there are no tokens between the open bracket and the comment.
         let mut lexer = SimpleTokenizer::new(
-            locator.contents(),
+            source,
             TextRange::new(comment.enclosing_node().start(), comment.start()),
         )
         .skip_trivia();
@@ -2006,7 +1981,7 @@ fn handle_with_comment<'a>(
 fn handle_comprehension_comment<'a>(
     comment: DecoratedComment<'a>,
     comprehension: &'a Comprehension,
-    locator: &Locator,
+    source: &str,
 ) -> CommentPlacement<'a> {
     let is_own_line = comment.line_position().is_own_line();
 
@@ -2031,7 +2006,7 @@ fn handle_comprehension_comment<'a>(
     let in_token = find_only_token_in_range(
         TextRange::new(comprehension.target.end(), comprehension.iter.start()),
         SimpleTokenKind::In,
-        locator.contents(),
+        source,
     );
 
     // Comments between the target and the `in`
@@ -2094,7 +2069,7 @@ fn handle_comprehension_comment<'a>(
         let if_token = find_only_token_in_range(
             TextRange::new(last_end, if_node.start()),
             SimpleTokenKind::If,
-            locator.contents(),
+            source,
         );
         if is_own_line {
             if last_end < comment.start() && comment.start() < if_token.start() {
diff --git a/crates/ruff_python_formatter/src/comments/visitor.rs b/crates/ruff_python_formatter/src/comments/visitor.rs
index 6ba2879eab..52bd5d2009 100644
--- a/crates/ruff_python_formatter/src/comments/visitor.rs
+++ b/crates/ruff_python_formatter/src/comments/visitor.rs
@@ -9,7 +9,6 @@ use ruff_python_ast::{Mod, Stmt};
 #[allow(clippy::wildcard_imports)]
 use ruff_python_ast::visitor::source_order::*;
 use ruff_python_trivia::{CommentLinePosition, CommentRanges};
-use ruff_source_file::Locator;
 use ruff_text_size::{Ranged, TextRange, TextSize};
 
 use crate::comments::node_key::NodeRefEqualityKey;
@@ -531,12 +530,12 @@ pub(super) struct CommentsMapBuilder<'a> {
     comments: CommentsMap<'a>,
     /// We need those for backwards lexing
     comment_ranges: &'a CommentRanges,
-    locator: Locator<'a>,
+    source: &'a str,
 }
 
 impl<'a> PushComment<'a> for CommentsMapBuilder<'a> {
     fn push_comment(&mut self, placement: DecoratedComment<'a>) {
-        let placement = place_comment(placement, self.comment_ranges, &self.locator);
+        let placement = place_comment(placement, self.comment_ranges, self.source);
         match placement {
             CommentPlacement::Leading { node, comment } => {
                 self.push_leading_comment(node, comment);
@@ -598,11 +597,11 @@ impl<'a> PushComment<'a> for CommentsMapBuilder<'a> {
 }
 
 impl<'a> CommentsMapBuilder<'a> {
-    pub(crate) fn new(locator: Locator<'a>, comment_ranges: &'a CommentRanges) -> Self {
+    pub(crate) fn new(source: &'a str, comment_ranges: &'a CommentRanges) -> Self {
         Self {
             comments: CommentsMap::default(),
             comment_ranges,
-            locator,
+            source,
         }
     }
 
diff --git a/crates/ruff_python_formatter/src/context.rs b/crates/ruff_python_formatter/src/context.rs
index b449b95eca..cebeda1799 100644
--- a/crates/ruff_python_formatter/src/context.rs
+++ b/crates/ruff_python_formatter/src/context.rs
@@ -4,7 +4,6 @@ use crate::PyFormatOptions;
 use ruff_formatter::{Buffer, FormatContext, GroupId, IndentWidth, SourceCode};
 use ruff_python_ast::str::Quote;
 use ruff_python_parser::Tokens;
-use ruff_source_file::Locator;
 use std::fmt::{Debug, Formatter};
 use std::ops::{Deref, DerefMut};
 
@@ -51,10 +50,6 @@ impl<'a> PyFormatContext<'a> {
         self.contents
     }
 
-    pub(crate) fn locator(&self) -> Locator<'a> {
-        Locator::new(self.contents)
-    }
-
     pub(crate) fn set_node_level(&mut self, level: NodeLevel) {
         self.node_level = level;
     }
diff --git a/crates/ruff_python_formatter/src/expression/expr_f_string.rs b/crates/ruff_python_formatter/src/expression/expr_f_string.rs
index a4b0325d79..7e034cfef8 100644
--- a/crates/ruff_python_formatter/src/expression/expr_f_string.rs
+++ b/crates/ruff_python_formatter/src/expression/expr_f_string.rs
@@ -1,6 +1,5 @@
 use ruff_python_ast::{AnyNodeRef, ExprFString, StringLike};
-use ruff_source_file::Locator;
-use ruff_text_size::Ranged;
+use ruff_source_file::Located;
 
 use crate::expression::parentheses::{
     in_parentheses_only_group, NeedsParentheses, OptionalParentheses,
@@ -18,11 +17,8 @@ impl FormatNodeRule<ExprFString> for FormatExprFString {
         let ExprFString { value, .. } = item;
 
         if let [f_string_part] = value.as_slice() {
-            FormatFStringPart::new(
-                f_string_part,
-                f_string_quoting(item, &f.context().locator()),
-            )
-            .fmt(f)
+            FormatFStringPart::new(f_string_part, f_string_quoting(item, f.context().source()))
+                .fmt(f)
         } else {
             // Always join fstrings that aren't parenthesized and thus, are always on a single line.
             if !f.context().node_level().is_parenthesized() {
@@ -73,9 +69,9 @@ impl NeedsParentheses for ExprFString {
     }
 }
 
-pub(crate) fn f_string_quoting(f_string: &ExprFString, locator: &Locator) -> Quoting {
-    let unprefixed = locator
-        .slice(f_string.range())
+pub(crate) fn f_string_quoting(f_string: &ExprFString, source: &str) -> Quoting {
+    let unprefixed = source
+        .slice(f_string)
         .trim_start_matches(|c| c != '"' && c != '\'');
     let triple_quoted = unprefixed.starts_with(r#"""""#) || unprefixed.starts_with(r"'''");
 
@@ -84,7 +80,7 @@ pub(crate) fn f_string_quoting(f_string: &ExprFString, locator: &Locator) -> Quo
         .elements()
         .filter_map(|element| element.as_expression())
         .any(|expression| {
-            let string_content = locator.slice(expression.range());
+            let string_content = source.slice(expression);
             if triple_quoted {
                 string_content.contains(r#"""""#) || string_content.contains("'''")
             } else {
diff --git a/crates/ruff_python_formatter/src/expression/expr_number_literal.rs b/crates/ruff_python_formatter/src/expression/expr_number_literal.rs
index ab46ab3f0b..98929d149c 100644
--- a/crates/ruff_python_formatter/src/expression/expr_number_literal.rs
+++ b/crates/ruff_python_formatter/src/expression/expr_number_literal.rs
@@ -2,6 +2,7 @@ use std::borrow::Cow;
 
 use ruff_python_ast::AnyNodeRef;
 use ruff_python_ast::{ExprNumberLiteral, Number};
+use ruff_source_file::Located;
 use ruff_text_size::{Ranged, TextSize};
 
 use crate::expression::parentheses::{NeedsParentheses, OptionalParentheses};
@@ -15,7 +16,7 @@ impl FormatNodeRule<ExprNumberLiteral> for FormatExprNumberLiteral {
         match item.value {
             Number::Int(_) => {
                 let range = item.range();
-                let content = f.context().locator().slice(range);
+                let content = f.context().source().slice(range);
                 let normalized = normalize_integer(content);
 
                 match normalized {
@@ -25,7 +26,7 @@ impl FormatNodeRule<ExprNumberLiteral> for FormatExprNumberLiteral {
             }
             Number::Float(_) => {
                 let range = item.range();
-                let content = f.context().locator().slice(range);
+                let content = f.context().source().slice(range);
                 let normalized = normalize_floating_number(content);
 
                 match normalized {
@@ -35,7 +36,7 @@ impl FormatNodeRule<ExprNumberLiteral> for FormatExprNumberLiteral {
             }
             Number::Complex { .. } => {
                 let range = item.range();
-                let content = f.context().locator().slice(range);
+                let content = f.context().source().slice(range);
                 let normalized = normalize_floating_number(content.trim_end_matches(['j', 'J']));
 
                 match normalized {
diff --git a/crates/ruff_python_formatter/src/lib.rs b/crates/ruff_python_formatter/src/lib.rs
index fcb512c63c..c80f91eeba 100644
--- a/crates/ruff_python_formatter/src/lib.rs
+++ b/crates/ruff_python_formatter/src/lib.rs
@@ -1,15 +1,6 @@
 use thiserror::Error;
 use tracing::Level;
 
-pub use range::format_range;
-use ruff_formatter::prelude::*;
-use ruff_formatter::{format, write, FormatError, Formatted, PrintError, Printed, SourceCode};
-use ruff_python_ast::AstNode;
-use ruff_python_ast::Mod;
-use ruff_python_parser::{parse, AsMode, ParseError, Parsed};
-use ruff_python_trivia::CommentRanges;
-use ruff_source_file::Locator;
-
 use crate::comments::{
     has_skip_comment, leading_comments, trailing_comments, Comments, SourceComment,
 };
@@ -21,6 +12,14 @@ pub use crate::options::{
 use crate::range::is_logical_line;
 pub use crate::shared_traits::{AsFormat, FormattedIter, FormattedIterExt, IntoFormat};
 use crate::verbatim::suppressed_node;
+pub use range::format_range;
+use ruff_formatter::prelude::*;
+use ruff_formatter::{format, write, FormatError, Formatted, PrintError, Printed, SourceCode};
+use ruff_python_ast::AstNode;
+use ruff_python_ast::Mod;
+use ruff_python_parser::{parse, AsMode, ParseError, Parsed};
+use ruff_python_trivia::CommentRanges;
+use ruff_source_file::Located;
 
 pub(crate) mod builders;
 pub mod cli;
@@ -127,10 +126,9 @@ pub fn format_module_ast<'a>(
 ) -> FormatResult<Formatted<PyFormatContext<'a>>> {
     let source_code = SourceCode::new(source);
     let comments = Comments::from_ast(parsed.syntax(), source_code, comment_ranges);
-    let locator = Locator::new(source);
 
     let formatted = format!(
-        PyFormatContext::new(options, locator.contents(), comments, parsed.tokens()),
+        PyFormatContext::new(options, source.as_str(), comments, parsed.tokens()),
         [parsed.syntax().format()]
     )?;
     formatted
diff --git a/crates/ruff_python_formatter/src/other/f_string.rs b/crates/ruff_python_formatter/src/other/f_string.rs
index a8e7926432..81dada8c4c 100644
--- a/crates/ruff_python_formatter/src/other/f_string.rs
+++ b/crates/ruff_python_formatter/src/other/f_string.rs
@@ -1,6 +1,6 @@
 use ruff_formatter::write;
 use ruff_python_ast::{AnyStringFlags, FString, StringFlags};
-use ruff_source_file::Locator;
+use ruff_source_file::Located;
 
 use crate::prelude::*;
 use crate::preview::is_f_string_formatting_enabled;
@@ -27,8 +27,6 @@ impl<'a> FormatFString<'a> {
 
 impl Format<PyFormatContext<'_>> for FormatFString<'_> {
     fn fmt(&self, f: &mut PyFormatter) -> FormatResult<()> {
-        let locator = f.context().locator();
-
         // If the preview style is enabled, make the decision on what quotes to use locally for each
         // f-string instead of globally for the entire f-string expression.
         let quoting = if is_f_string_formatting_enabled(f.context()) {
@@ -66,7 +64,7 @@ impl Format<PyFormatContext<'_>> for FormatFString<'_> {
 
         let context = FStringContext::new(
             string_kind,
-            FStringLayout::from_f_string(self.value, &locator),
+            FStringLayout::from_f_string(self.value, f.context().source()),
         );
 
         // Starting prefix and quote
@@ -117,7 +115,7 @@ pub(crate) enum FStringLayout {
 }
 
 impl FStringLayout {
-    pub(crate) fn from_f_string(f_string: &FString, locator: &Locator) -> Self {
+    pub(crate) fn from_f_string(f_string: &FString, source: &str) -> Self {
         // Heuristic: Allow breaking the f-string expressions across multiple lines
         // only if there already is at least one multiline expression. This puts the
         // control in the hands of the user to decide if they want to break the
@@ -133,7 +131,7 @@ impl FStringLayout {
         if f_string
             .elements
             .expressions()
-            .any(|expr| memchr::memchr2(b'\n', b'\r', locator.slice(expr).as_bytes()).is_some())
+            .any(|expr| memchr::memchr2(b'\n', b'\r', source.slice(expr).as_bytes()).is_some())
         {
             Self::Multiline
         } else {
diff --git a/crates/ruff_python_formatter/src/other/f_string_element.rs b/crates/ruff_python_formatter/src/other/f_string_element.rs
index 77daaca0d2..3e50ec7376 100644
--- a/crates/ruff_python_formatter/src/other/f_string_element.rs
+++ b/crates/ruff_python_formatter/src/other/f_string_element.rs
@@ -5,6 +5,7 @@ use ruff_python_ast::{
     AnyStringFlags, ConversionFlag, Expr, FStringElement, FStringExpressionElement,
     FStringLiteralElement, StringFlags,
 };
+use ruff_source_file::Located;
 use ruff_text_size::Ranged;
 
 use crate::comments::{dangling_open_parenthesis_comments, trailing_comments};
@@ -60,7 +61,7 @@ impl<'a> FormatFStringLiteralElement<'a> {
 
 impl Format<PyFormatContext<'_>> for FormatFStringLiteralElement<'_> {
     fn fmt(&self, f: &mut PyFormatter) -> FormatResult<()> {
-        let literal_content = f.context().locator().slice(self.element.range());
+        let literal_content = f.context().source().slice(self.element);
         let normalized =
             normalize_string(literal_content, 0, self.fstring_flags, false, false, true);
         match &normalized {
diff --git a/crates/ruff_python_formatter/src/range.rs b/crates/ruff_python_formatter/src/range.rs
index 33f7d2a1d2..c0f5cfa0c3 100644
--- a/crates/ruff_python_formatter/src/range.rs
+++ b/crates/ruff_python_formatter/src/range.rs
@@ -10,7 +10,6 @@ use ruff_python_parser::{parse, AsMode};
 use ruff_python_trivia::{
     indentation_at_offset, BackwardsTokenizer, CommentRanges, SimpleToken, SimpleTokenKind,
 };
-use ruff_source_file::Locator;
 use ruff_text_size::{Ranged, TextLen, TextRange, TextSize};
 
 use crate::comments::Comments;
@@ -300,8 +299,7 @@ fn narrow_range(
     enclosing_node: AnyNodeRef,
     context: &PyFormatContext,
 ) -> TextRange {
-    let locator = context.locator();
-    let enclosing_indent = indentation_at_offset(enclosing_node.start(), &locator)
+    let enclosing_indent = indentation_at_offset(enclosing_node.start(), context.source())
         .expect("Expected enclosing to never be a same line body statement.");
 
     let mut visitor = NarrowRange {
@@ -513,7 +511,7 @@ impl NarrowRange<'_> {
             // dedent the second line to 0 spaces and the `indent` then adds a 2 space indentation to match the indentation in the source.
             // This is incorrect because the leading whitespace is the content of the string and not indentation, resulting in changed string content.
             if let Some(indentation) =
-                indentation_at_offset(first_child.start(), &self.context.locator())
+                indentation_at_offset(first_child.start(), self.context.source())
             {
                 let relative_indent = indentation.strip_prefix(self.enclosing_indent).unwrap();
                 let expected_indents = self.level;
@@ -718,8 +716,7 @@ impl Format<PyFormatContext<'_>> for FormatEnclosingNode<'_> {
 /// # Panics
 /// If `offset` is outside of `source`.
 fn indent_level(offset: TextSize, source: &str, options: &PyFormatOptions) -> Option<u16> {
-    let locator = Locator::new(source);
-    let indentation = indentation_at_offset(offset, &locator)?;
+    let indentation = indentation_at_offset(offset, source)?;
 
     let level = match options.indent_style() {
         IndentStyle::Tab => {
diff --git a/crates/ruff_python_formatter/src/string/docstring.rs b/crates/ruff_python_formatter/src/string/docstring.rs
index 3279d40106..c5bc185ffe 100644
--- a/crates/ruff_python_formatter/src/string/docstring.rs
+++ b/crates/ruff_python_formatter/src/string/docstring.rs
@@ -14,7 +14,6 @@ use ruff_python_trivia::CommentRanges;
 use {
     ruff_formatter::{write, FormatOptions, IndentStyle, LineWidth, Printed},
     ruff_python_trivia::{is_python_whitespace, PythonWhitespace},
-    ruff_source_file::Locator,
     ruff_text_size::{Ranged, TextLen, TextRange, TextSize},
 };
 
@@ -1592,9 +1591,8 @@ fn docstring_format_source(
     let comment_ranges = CommentRanges::from(parsed.tokens());
     let source_code = ruff_formatter::SourceCode::new(source);
     let comments = crate::Comments::from_ast(parsed.syntax(), source_code, &comment_ranges);
-    let locator = Locator::new(source);
 
-    let ctx = PyFormatContext::new(options, locator.contents(), comments, parsed.tokens())
+    let ctx = PyFormatContext::new(options, source, comments, parsed.tokens())
         .in_docstring(docstring_quote_style);
     let formatted = crate::format!(ctx, [parsed.syntax().format()])?;
     formatted
diff --git a/crates/ruff_python_formatter/src/string/implicit.rs b/crates/ruff_python_formatter/src/string/implicit.rs
index 0ef4aae5af..d6c7fb4d80 100644
--- a/crates/ruff_python_formatter/src/string/implicit.rs
+++ b/crates/ruff_python_formatter/src/string/implicit.rs
@@ -6,6 +6,7 @@ use ruff_python_ast::str_prefix::{
     AnyStringPrefix, ByteStringPrefix, FStringPrefix, StringLiteralPrefix,
 };
 use ruff_python_ast::{AnyStringFlags, FStringElement, StringFlags, StringLike, StringLikePart};
+use ruff_source_file::Located;
 use ruff_text_size::{Ranged, TextRange};
 
 use crate::comments::{leading_comments, trailing_comments};
@@ -72,7 +73,7 @@ impl<'a> FormatImplicitConcatenatedStringExpanded<'a> {
 impl Format<PyFormatContext<'_>> for FormatImplicitConcatenatedStringExpanded<'_> {
     fn fmt(&self, f: &mut Formatter<PyFormatContext<'_>>) -> FormatResult<()> {
         let comments = f.context().comments().clone();
-        let quoting = self.string.quoting(&f.context().locator());
+        let quoting = self.string.quoting(f.context().source());
 
         let join_implicit_concatenated_string_enabled =
             is_join_implicit_concatenated_string_enabled(f.context());
@@ -158,10 +159,9 @@ impl<'a> FormatImplicitConcatenatedStringFlat<'a> {
                 if let StringLikePart::FString(fstring) = part {
                     if fstring.elements.iter().any(|element| match element {
                         // Same as for other literals. Multiline literals can't fit on a single line.
-                        FStringElement::Literal(literal) => context
-                            .locator()
-                            .slice(literal.range())
-                            .contains(['\n', '\r']),
+                        FStringElement::Literal(literal) => {
+                            context.source().slice(literal).contains(['\n', '\r'])
+                        }
                         FStringElement::Expression(expression) => {
                             if is_f_string_formatting_enabled(context) {
                                 // Expressions containing comments can't be joined.
@@ -169,7 +169,7 @@ impl<'a> FormatImplicitConcatenatedStringFlat<'a> {
                             } else {
                                 // Multiline f-string expressions can't be joined if the f-string formatting is disabled because
                                 // the string gets inserted in verbatim preserving the newlines.
-                                context.locator().slice(expression).contains(['\n', '\r'])
+                                context.source().slice(expression).contains(['\n', '\r'])
                             }
                         }
                     }) {
@@ -270,7 +270,7 @@ impl Format<PyFormatContext<'_>> for FormatImplicitConcatenatedStringFlat<'_> {
                 assert!(part.is_string_literal());
 
                 if f.context()
-                    .locator()
+                    .source()
                     .slice(part.content_range())
                     .trim()
                     .is_empty()
@@ -300,7 +300,7 @@ impl Format<PyFormatContext<'_>> for FormatImplicitConcatenatedStringFlat<'_> {
                     if first_non_empty {
                         first_non_empty = f
                             .context()
-                            .locator()
+                            .source()
                             .slice(part.content_range())
                             .trim_start()
                             .is_empty();
@@ -328,7 +328,7 @@ impl Format<PyFormatContext<'_>> for FormatImplicitConcatenatedStringFlat<'_> {
                                         self.flags,
                                         FStringLayout::from_f_string(
                                             f_string,
-                                            &f.context().locator(),
+                                            f.context().source(),
                                         ),
                                     );
 
@@ -365,7 +365,7 @@ struct FormatLiteralContent {
 
 impl Format<PyFormatContext<'_>> for FormatLiteralContent {
     fn fmt(&self, f: &mut PyFormatter) -> FormatResult<()> {
-        let content = f.context().locator().slice(self.range);
+        let content = f.context().source().slice(self.range);
         let mut normalized = normalize_string(
             content,
             0,
diff --git a/crates/ruff_python_formatter/src/string/mod.rs b/crates/ruff_python_formatter/src/string/mod.rs
index dba9adc555..a803014256 100644
--- a/crates/ruff_python_formatter/src/string/mod.rs
+++ b/crates/ruff_python_formatter/src/string/mod.rs
@@ -7,7 +7,6 @@ use ruff_python_ast::{
     str_prefix::{AnyStringPrefix, StringLiteralPrefix},
     AnyStringFlags, StringFlags,
 };
-use ruff_source_file::Locator;
 use ruff_text_size::Ranged;
 
 use crate::expression::expr_f_string::f_string_quoting;
@@ -89,16 +88,16 @@ impl From<Quote> for QuoteStyle {
 
 // Extension trait that adds formatter specific helper methods to `StringLike`.
 pub(crate) trait StringLikeExtensions {
-    fn quoting(&self, locator: &Locator<'_>) -> Quoting;
+    fn quoting(&self, locator: &str) -> Quoting;
 
     fn is_multiline(&self, source: &str) -> bool;
 }
 
 impl StringLikeExtensions for ast::StringLike<'_> {
-    fn quoting(&self, locator: &Locator<'_>) -> Quoting {
+    fn quoting(&self, source: &str) -> Quoting {
         match self {
             Self::String(_) | Self::Bytes(_) => Quoting::CanChange,
-            Self::FString(f_string) => f_string_quoting(f_string, locator),
+            Self::FString(f_string) => f_string_quoting(f_string, source),
         }
     }
 
diff --git a/crates/ruff_python_formatter/src/string/normalize.rs b/crates/ruff_python_formatter/src/string/normalize.rs
index 3defefb75f..2df64843bf 100644
--- a/crates/ruff_python_formatter/src/string/normalize.rs
+++ b/crates/ruff_python_formatter/src/string/normalize.rs
@@ -7,6 +7,7 @@ use ruff_python_ast::visitor::source_order::SourceOrderVisitor;
 use ruff_python_ast::{
     str::Quote, AnyStringFlags, BytesLiteral, FString, StringFlags, StringLikePart, StringLiteral,
 };
+use ruff_source_file::Located;
 use ruff_text_size::{Ranged, TextRange};
 
 use crate::context::FStringState;
@@ -152,7 +153,7 @@ impl<'a, 'src> StringNormalizer<'a, 'src> {
 
     /// Computes the strings preferred quotes.
     pub(crate) fn choose_quotes(&self, string: StringLikePart) -> QuoteSelection {
-        let raw_content = self.context.locator().slice(string.content_range());
+        let raw_content = self.context.source().slice(string.content_range());
         let first_quote_or_normalized_char_offset = raw_content
             .bytes()
             .position(|b| matches!(b, b'\\' | b'"' | b'\'' | b'\r' | b'{'));
@@ -196,7 +197,7 @@ impl<'a, 'src> StringNormalizer<'a, 'src> {
 
     /// Computes the strings preferred quotes and normalizes its content.
     pub(crate) fn normalize(&self, string: StringLikePart) -> NormalizedString<'src> {
-        let raw_content = self.context.locator().slice(string.content_range());
+        let raw_content = self.context.source().slice(string.content_range());
         let quote_selection = self.choose_quotes(string);
 
         let normalized = if let Some(first_quote_or_escape_offset) =
@@ -256,7 +257,7 @@ impl QuoteMetadata {
     ) -> Self {
         match part {
             StringLikePart::String(_) | StringLikePart::Bytes(_) => {
-                let text = context.locator().slice(part.content_range());
+                let text = context.source().slice(part.content_range());
 
                 Self::from_str(text, part.flags(), preferred_quote)
             }
@@ -277,7 +278,7 @@ impl QuoteMetadata {
                     };
 
                     let mut metadata = QuoteMetadata::from_str(
-                        context.locator().slice(first.range()),
+                        context.source().slice(first),
                         fstring.flags.into(),
                         preferred_quote,
                     );
@@ -285,7 +286,7 @@ impl QuoteMetadata {
                     for literal in literals {
                         metadata = metadata
                             .merge(&QuoteMetadata::from_str(
-                                context.locator().slice(literal.range()),
+                                context.source().slice(literal),
                                 fstring.flags.into(),
                                 preferred_quote,
                             ))
@@ -294,7 +295,7 @@ impl QuoteMetadata {
 
                     metadata
                 } else {
-                    let text = context.locator().slice(part.content_range());
+                    let text = context.source().slice(part.content_range());
 
                     Self::from_str(text, part.flags(), preferred_quote)
                 }
@@ -893,7 +894,7 @@ pub(super) fn is_fstring_with_quoted_debug_expression(
 ) -> bool {
     if fstring.elements.expressions().any(|expression| {
         if expression.debug_text.is_some() {
-            let content = context.locator().slice(expression.range());
+            let content = context.source().slice(expression);
             match fstring.flags.quote_style() {
                 Quote::Single => {
                     if fstring.flags.is_triple_quoted() {
@@ -970,7 +971,7 @@ pub(super) fn is_fstring_with_triple_quoted_literal_expression_containing_quotes
 
         fn contains_quote(&self, range: TextRange, flags: AnyStringFlags) -> bool {
             self.context
-                .locator()
+                .source()
                 .slice(range)
                 .contains(flags.quote_style().as_char())
         }
diff --git a/crates/ruff_python_formatter/src/verbatim.rs b/crates/ruff_python_formatter/src/verbatim.rs
index df70e6e298..b693a8bb0e 100644
--- a/crates/ruff_python_formatter/src/verbatim.rs
+++ b/crates/ruff_python_formatter/src/verbatim.rs
@@ -7,7 +7,7 @@ use ruff_python_ast::AnyNodeRef;
 use ruff_python_ast::Stmt;
 use ruff_python_parser::{self as parser, TokenKind};
 use ruff_python_trivia::lines_before;
-use ruff_source_file::Locator;
+use ruff_source_file::Located;
 use ruff_text_size::{Ranged, TextRange, TextSize};
 
 use crate::comments::format::{empty_lines, format_comment};
@@ -647,7 +647,7 @@ struct Indentation(u32);
 
 impl Indentation {
     fn from_stmt(stmt: &Stmt, source: &str) -> Indentation {
-        let line_start = Locator::new(source).line_start(stmt.start());
+        let line_start = source.line_start(stmt.start());
 
         let mut indentation = 0u32;
         for c in source[TextRange::new(line_start, stmt.start())].chars() {
@@ -878,7 +878,7 @@ impl Format<PyFormatContext<'_>> for VerbatimText {
             },
         )));
 
-        match normalize_newlines(f.context().locator().slice(self.verbatim_range), ['\r']) {
+        match normalize_newlines(f.context().source().slice(self.verbatim_range), ['\r']) {
             Cow::Borrowed(_) => {
                 write!(f, [source_text_slice(self.verbatim_range)])?;
             }
diff --git a/crates/ruff_python_index/src/indexer.rs b/crates/ruff_python_index/src/indexer.rs
index 596aa812b8..b2a49ba5fe 100644
--- a/crates/ruff_python_index/src/indexer.rs
+++ b/crates/ruff_python_index/src/indexer.rs
@@ -6,7 +6,7 @@ use ruff_python_parser::{TokenKind, Tokens};
 use ruff_python_trivia::{
     has_leading_content, has_trailing_content, is_python_whitespace, CommentRanges,
 };
-use ruff_source_file::Locator;
+use ruff_source_file::Located;
 use ruff_text_size::{Ranged, TextRange, TextSize};
 
 use crate::fstring_ranges::{FStringRanges, FStringRangesBuilder};
@@ -27,8 +27,8 @@ pub struct Indexer {
 }
 
 impl Indexer {
-    pub fn from_tokens(tokens: &Tokens, locator: &Locator<'_>) -> Self {
-        assert!(TextSize::try_from(locator.contents().len()).is_ok());
+    pub fn from_tokens(tokens: &Tokens, source: &str) -> Self {
+        assert!(TextSize::try_from(source.len()).is_ok());
 
         let mut fstring_ranges_builder = FStringRangesBuilder::default();
         let mut multiline_ranges_builder = MultilineRangesBuilder::default();
@@ -40,7 +40,7 @@ impl Indexer {
         let mut line_start = TextSize::default();
 
         for token in tokens {
-            let trivia = locator.slice(TextRange::new(prev_end, token.start()));
+            let trivia = source.slice(TextRange::new(prev_end, token.start()));
 
             // Get the trivia between the previous and the current token and detect any newlines.
             // This is necessary because `RustPython` doesn't emit `[Tok::Newline]` tokens
@@ -69,7 +69,7 @@ impl Indexer {
                 TokenKind::String => {
                     // If the previous token was a string, find the start of the line that contains
                     // the closing delimiter, since the token itself can span multiple lines.
-                    line_start = locator.line_start(token.end());
+                    line_start = source.line_start(token.end());
                 }
                 TokenKind::Comment => {
                     comment_ranges.push(token.range());
@@ -109,25 +109,20 @@ impl Indexer {
     }
 
     /// Returns `true` if the given offset is part of a continuation line.
-    pub fn is_continuation(&self, offset: TextSize, locator: &Locator) -> bool {
-        let line_start = locator.line_start(offset);
+    pub fn is_continuation(&self, offset: TextSize, source: &str) -> bool {
+        let line_start = source.line_start(offset);
         self.continuation_lines.binary_search(&line_start).is_ok()
     }
 
     /// Given an offset at the end of a line (including newlines), return the offset of the
     /// continuation at the end of that line.
-    fn find_continuation(&self, offset: TextSize, locator: &Locator) -> Option<TextSize> {
+    fn find_continuation(&self, offset: TextSize, source: &str) -> Option<TextSize> {
         let newline_pos = usize::from(offset).saturating_sub(1);
 
         // Skip the newline.
-        let newline_len = match locator.contents().as_bytes()[newline_pos] {
+        let newline_len = match source.as_bytes()[newline_pos] {
             b'\n' => {
-                if locator
-                    .contents()
-                    .as_bytes()
-                    .get(newline_pos.saturating_sub(1))
-                    == Some(&b'\r')
-                {
+                if source.as_bytes().get(newline_pos.saturating_sub(1)) == Some(&b'\r') {
                     2
                 } else {
                     1
@@ -138,7 +133,7 @@ impl Indexer {
             _ => return None,
         };
 
-        self.is_continuation(offset - TextSize::from(newline_len), locator)
+        self.is_continuation(offset - TextSize::from(newline_len), source)
             .then(|| offset - TextSize::from(newline_len) - TextSize::from(1))
     }
 
@@ -164,15 +159,11 @@ impl Indexer {
     ///
     /// When passed the offset of `y`, this function will again return the offset of the backslash at
     /// the end of the first line.
-    pub fn preceded_by_continuations(
-        &self,
-        offset: TextSize,
-        locator: &Locator,
-    ) -> Option<TextSize> {
+    pub fn preceded_by_continuations(&self, offset: TextSize, source: &str) -> Option<TextSize> {
         // Find the first preceding continuation. If the offset isn't the first non-whitespace
         // character on the line, then we can't have a continuation.
-        let previous_line_end = locator.line_start(offset);
-        if !locator
+        let previous_line_end = source.line_start(offset);
+        if !source
             .slice(TextRange::new(previous_line_end, offset))
             .chars()
             .all(is_python_whitespace)
@@ -180,19 +171,18 @@ impl Indexer {
             return None;
         }
 
-        let mut continuation = self.find_continuation(previous_line_end, locator)?;
+        let mut continuation = self.find_continuation(previous_line_end, source)?;
 
         // Continue searching for continuations, in the unlikely event that we have multiple
         // continuations in a row.
         loop {
-            let previous_line_end = locator.line_start(continuation);
-            if locator
+            let previous_line_end = source.line_start(continuation);
+            if source
                 .slice(TextRange::new(previous_line_end, continuation))
                 .chars()
                 .all(is_python_whitespace)
             {
-                if let Some(next_continuation) = self.find_continuation(previous_line_end, locator)
-                {
+                if let Some(next_continuation) = self.find_continuation(previous_line_end, source) {
                     continuation = next_continuation;
                     continue;
                 }
@@ -205,38 +195,37 @@ impl Indexer {
 
     /// Return `true` if a [`Stmt`] appears to be preceded by other statements in a multi-statement
     /// line.
-    pub fn preceded_by_multi_statement_line(&self, stmt: &Stmt, locator: &Locator) -> bool {
-        has_leading_content(stmt.start(), locator)
+    pub fn preceded_by_multi_statement_line(&self, stmt: &Stmt, source: &str) -> bool {
+        has_leading_content(stmt.start(), source)
             || self
-                .preceded_by_continuations(stmt.start(), locator)
+                .preceded_by_continuations(stmt.start(), source)
                 .is_some()
     }
 
     /// Return `true` if a [`Stmt`] appears to be followed by other statements in a multi-statement
     /// line.
-    pub fn followed_by_multi_statement_line(&self, stmt: &Stmt, locator: &Locator) -> bool {
-        has_trailing_content(stmt.end(), locator)
+    pub fn followed_by_multi_statement_line(&self, stmt: &Stmt, source: &str) -> bool {
+        has_trailing_content(stmt.end(), source)
     }
 
     /// Return `true` if a [`Stmt`] appears to be part of a multi-statement line.
-    pub fn in_multi_statement_line(&self, stmt: &Stmt, locator: &Locator) -> bool {
-        self.followed_by_multi_statement_line(stmt, locator)
-            || self.preceded_by_multi_statement_line(stmt, locator)
+    pub fn in_multi_statement_line(&self, stmt: &Stmt, source: &str) -> bool {
+        self.followed_by_multi_statement_line(stmt, source)
+            || self.preceded_by_multi_statement_line(stmt, source)
     }
 }
 
 #[cfg(test)]
 mod tests {
     use ruff_python_parser::parse_module;
-    use ruff_source_file::Locator;
+
     use ruff_text_size::{TextRange, TextSize};
 
     use crate::Indexer;
 
     fn new_indexer(contents: &str) -> Indexer {
         let parsed = parse_module(contents).unwrap();
-        let locator = Locator::new(contents);
-        Indexer::from_tokens(parsed.tokens(), &locator)
+        Indexer::from_tokens(parsed.tokens(), contents)
     }
 
     #[test]
diff --git a/crates/ruff_python_semantic/src/binding.rs b/crates/ruff_python_semantic/src/binding.rs
index 9b9c74aa81..8fcea2f57f 100644
--- a/crates/ruff_python_semantic/src/binding.rs
+++ b/crates/ruff_python_semantic/src/binding.rs
@@ -8,7 +8,7 @@ use ruff_index::{newtype_index, IndexSlice, IndexVec};
 use ruff_python_ast::helpers::extract_handled_exceptions;
 use ruff_python_ast::name::QualifiedName;
 use ruff_python_ast::{self as ast, Stmt};
-use ruff_source_file::Locator;
+use ruff_source_file::Located;
 use ruff_text_size::{Ranged, TextRange};
 
 use crate::context::ExecutionContext;
@@ -228,8 +228,8 @@ impl<'a> Binding<'a> {
     }
 
     /// Returns the name of the binding (e.g., `x` in `x = 1`).
-    pub fn name<'b>(&self, locator: &Locator<'b>) -> &'b str {
-        locator.slice(self.range)
+    pub fn name<'b>(&self, source: &'b str) -> &'b str {
+        source.slice(self.range)
     }
 
     /// Returns the statement in which the binding was defined.
diff --git a/crates/ruff_python_semantic/src/reference.rs b/crates/ruff_python_semantic/src/reference.rs
index 1b79347684..d1c0e4f35e 100644
--- a/crates/ruff_python_semantic/src/reference.rs
+++ b/crates/ruff_python_semantic/src/reference.rs
@@ -4,7 +4,7 @@ use bitflags::bitflags;
 
 use ruff_index::{newtype_index, IndexSlice, IndexVec};
 use ruff_python_ast::ExprContext;
-use ruff_source_file::Locator;
+use ruff_source_file::Located;
 use ruff_text_size::{Ranged, TextRange};
 
 use crate::scope::ScopeId;
@@ -157,8 +157,8 @@ pub struct UnresolvedReference {
 
 impl UnresolvedReference {
     /// Returns the name of the reference.
-    pub fn name<'a>(&self, locator: &Locator<'a>) -> &'a str {
-        locator.slice(self.range)
+    pub fn name<'a>(&self, source: &'a str) -> &'a str {
+        source.slice(self.range)
     }
 
     /// The range of the reference in the source code.
diff --git a/crates/ruff_python_trivia/src/comment_ranges.rs b/crates/ruff_python_trivia/src/comment_ranges.rs
index 673a4aefd6..e0b66a85a6 100644
--- a/crates/ruff_python_trivia/src/comment_ranges.rs
+++ b/crates/ruff_python_trivia/src/comment_ranges.rs
@@ -2,7 +2,7 @@ use std::fmt::{Debug, Formatter};
 use std::ops::Deref;
 
 use itertools::Itertools;
-use ruff_source_file::Locator;
+use ruff_source_file::Located;
 
 use ruff_text_size::{Ranged, TextRange, TextSize};
 
@@ -50,19 +50,19 @@ impl CommentRanges {
     }
 
     /// Returns `true` if a statement or expression includes at least one comment.
-    pub fn has_comments<T>(&self, node: &T, locator: &Locator) -> bool
+    pub fn has_comments<T>(&self, node: &T, source: &str) -> bool
     where
         T: Ranged,
     {
-        let start = if has_leading_content(node.start(), locator) {
+        let start = if has_leading_content(node.start(), source) {
             node.start()
         } else {
-            locator.line_start(node.start())
+            source.line_start(node.start())
         };
-        let end = if has_trailing_content(node.end(), locator) {
+        let end = if has_trailing_content(node.end(), source) {
             node.end()
         } else {
-            locator.line_end(node.end())
+            source.line_end(node.end())
         };
 
         self.intersects(TextRange::new(start, end))
@@ -98,7 +98,7 @@ impl CommentRanges {
     /// # contained within a multi-line string/comment
     /// """
     /// ```
-    pub fn block_comments(&self, locator: &Locator) -> Vec<TextSize> {
+    pub fn block_comments(&self, source: &str) -> Vec<TextSize> {
         let mut block_comments: Vec<TextSize> = Vec::new();
 
         let mut current_block: Vec<TextSize> = Vec::new();
@@ -109,12 +109,12 @@ impl CommentRanges {
 
         for comment_range in &self.raw {
             let offset = comment_range.start();
-            let line_start = locator.line_start(offset);
-            let line_end = locator.full_line_end(offset);
+            let line_start = source.line_start(offset);
+            let line_end = source.full_line_end(offset);
             let column = offset - line_start;
 
             // If this is an end-of-line comment, reset the current block.
-            if !Self::is_own_line(offset, locator) {
+            if !Self::is_own_line(offset, source) {
                 // Push the current block, and reset.
                 if current_block.len() > 1 && current_block_non_empty {
                     block_comments.extend(current_block);
@@ -129,7 +129,7 @@ impl CommentRanges {
             // If there's a blank line between this comment and the previous
             // comment, reset the current block.
             if prev_line_end.is_some_and(|prev_line_end| {
-                locator.contains_line_break(TextRange::new(prev_line_end, line_start))
+                source.contains_line_break(TextRange::new(prev_line_end, line_start))
             }) {
                 // Push the current block.
                 if current_block.len() > 1 && current_block_non_empty {
@@ -139,7 +139,7 @@ impl CommentRanges {
                 // Reset the block state.
                 current_block = vec![offset];
                 current_block_column = Some(column);
-                current_block_non_empty = !Self::is_empty(*comment_range, locator);
+                current_block_non_empty = !Self::is_empty(*comment_range, source);
                 prev_line_end = Some(line_end);
                 continue;
             }
@@ -148,7 +148,7 @@ impl CommentRanges {
                 if column == current_column {
                     // Add the comment to the current block.
                     current_block.push(offset);
-                    current_block_non_empty |= !Self::is_empty(*comment_range, locator);
+                    current_block_non_empty |= !Self::is_empty(*comment_range, source);
                     prev_line_end = Some(line_end);
                 } else {
                     // Push the current block.
@@ -159,7 +159,7 @@ impl CommentRanges {
                     // Reset the block state.
                     current_block = vec![offset];
                     current_block_column = Some(column);
-                    current_block_non_empty = !Self::is_empty(*comment_range, locator);
+                    current_block_non_empty = !Self::is_empty(*comment_range, source);
                     prev_line_end = Some(line_end);
                 }
             } else {
@@ -171,7 +171,7 @@ impl CommentRanges {
                 // Reset the block state.
                 current_block = vec![offset];
                 current_block_column = Some(column);
-                current_block_non_empty = !Self::is_empty(*comment_range, locator);
+                current_block_non_empty = !Self::is_empty(*comment_range, source);
                 prev_line_end = Some(line_end);
             }
         }
@@ -185,8 +185,8 @@ impl CommentRanges {
     }
 
     /// Returns `true` if the given range is an empty comment.
-    fn is_empty(range: TextRange, locator: &Locator) -> bool {
-        locator
+    fn is_empty(range: TextRange, source: &str) -> bool {
+        source
             .slice(range)
             .chars()
             .skip(1)
@@ -194,9 +194,9 @@ impl CommentRanges {
     }
 
     /// Returns `true` if a comment is an own-line comment (as opposed to an end-of-line comment).
-    pub fn is_own_line(offset: TextSize, locator: &Locator) -> bool {
-        let range = TextRange::new(locator.line_start(offset), offset);
-        locator.slice(range).chars().all(is_python_whitespace)
+    pub fn is_own_line(offset: TextSize, source: &str) -> bool {
+        let range = TextRange::new(source.line_start(offset), offset);
+        source.slice(range).chars().all(is_python_whitespace)
     }
 }
 
diff --git a/crates/ruff_python_trivia/src/whitespace.rs b/crates/ruff_python_trivia/src/whitespace.rs
index 7b8b5e90ea..ce388e3fd1 100644
--- a/crates/ruff_python_trivia/src/whitespace.rs
+++ b/crates/ruff_python_trivia/src/whitespace.rs
@@ -1,29 +1,28 @@
-use ruff_source_file::Locator;
+use ruff_source_file::Located;
 use ruff_text_size::{TextRange, TextSize};
 
 /// Extract the leading indentation from a line.
-pub fn indentation_at_offset<'a>(offset: TextSize, locator: &'a Locator) -> Option<&'a str> {
-    let line_start = locator.line_start(offset);
-    let indentation = locator.slice(TextRange::new(line_start, offset));
+pub fn indentation_at_offset(offset: TextSize, source: &str) -> Option<&str> {
+    let line_start = source.line_start(offset);
+    let indentation = source.slice(TextRange::new(line_start, offset));
 
-    if indentation.chars().all(is_python_whitespace) {
-        Some(indentation)
-    } else {
-        None
-    }
+    indentation
+        .chars()
+        .all(is_python_whitespace)
+        .then_some(indentation)
 }
 
 /// Return `true` if the node starting the given [`TextSize`] has leading content.
-pub fn has_leading_content(offset: TextSize, locator: &Locator) -> bool {
-    let line_start = locator.line_start(offset);
-    let leading = locator.slice(TextRange::new(line_start, offset));
+pub fn has_leading_content(offset: TextSize, source: &str) -> bool {
+    let line_start = source.line_start(offset);
+    let leading = source.slice(TextRange::new(line_start, offset));
     leading.chars().any(|char| !is_python_whitespace(char))
 }
 
 /// Return `true` if the node ending at the given [`TextSize`] has trailing content.
-pub fn has_trailing_content(offset: TextSize, locator: &Locator) -> bool {
-    let line_end = locator.line_end(offset);
-    let trailing = locator.slice(TextRange::new(offset, line_end));
+pub fn has_trailing_content(offset: TextSize, source: &str) -> bool {
+    let line_end = source.line_end(offset);
+    let trailing = source.slice(TextRange::new(offset, line_end));
 
     for char in trailing.chars() {
         if char == '#' {
diff --git a/crates/ruff_python_trivia_integration_tests/tests/block_comments.rs b/crates/ruff_python_trivia_integration_tests/tests/block_comments.rs
index d93abf4ca4..13bec0bc43 100644
--- a/crates/ruff_python_trivia_integration_tests/tests/block_comments.rs
+++ b/crates/ruff_python_trivia_integration_tests/tests/block_comments.rs
@@ -1,6 +1,5 @@
 use ruff_python_parser::{parse_unchecked, Mode};
 use ruff_python_trivia::CommentRanges;
-use ruff_source_file::Locator;
 use ruff_text_size::TextSize;
 
 #[test]
@@ -8,11 +7,10 @@ fn block_comments_two_line_block_at_start() {
     // arrange
     let source = "# line 1\n# line 2\n";
     let parsed = parse_unchecked(source, Mode::Module);
-    let locator = Locator::new(source);
     let comment_ranges = CommentRanges::from(parsed.tokens());
 
     // act
-    let block_comments = comment_ranges.block_comments(&locator);
+    let block_comments = comment_ranges.block_comments(source);
 
     // assert
     assert_eq!(block_comments, vec![TextSize::new(0), TextSize::new(9)]);
@@ -23,11 +21,10 @@ fn block_comments_indented_block() {
     // arrange
     let source = "    # line 1\n    # line 2\n";
     let parsed = parse_unchecked(source, Mode::Module);
-    let locator = Locator::new(source);
     let comment_ranges = CommentRanges::from(parsed.tokens());
 
     // act
-    let block_comments = comment_ranges.block_comments(&locator);
+    let block_comments = comment_ranges.block_comments(source);
 
     // assert
     assert_eq!(block_comments, vec![TextSize::new(4), TextSize::new(17)]);
@@ -38,11 +35,10 @@ fn block_comments_single_line_is_not_a_block() {
     // arrange
     let source = "\n";
     let parsed = parse_unchecked(source, Mode::Module);
-    let locator = Locator::new(source);
     let comment_ranges = CommentRanges::from(parsed.tokens());
 
     // act
-    let block_comments = comment_ranges.block_comments(&locator);
+    let block_comments = comment_ranges.block_comments(source);
 
     // assert
     assert_eq!(block_comments, Vec::<TextSize>::new());
@@ -53,11 +49,10 @@ fn block_comments_lines_with_code_not_a_block() {
     // arrange
     let source = "x = 1  # line 1\ny = 2  # line 2\n";
     let parsed = parse_unchecked(source, Mode::Module);
-    let locator = Locator::new(source);
     let comment_ranges = CommentRanges::from(parsed.tokens());
 
     // act
-    let block_comments = comment_ranges.block_comments(&locator);
+    let block_comments = comment_ranges.block_comments(source);
 
     // assert
     assert_eq!(block_comments, Vec::<TextSize>::new());
@@ -68,11 +63,10 @@ fn block_comments_sequential_lines_not_in_block() {
     // arrange
     let source = "    # line 1\n        # line 2\n";
     let parsed = parse_unchecked(source, Mode::Module);
-    let locator = Locator::new(source);
     let comment_ranges = CommentRanges::from(parsed.tokens());
 
     // act
-    let block_comments = comment_ranges.block_comments(&locator);
+    let block_comments = comment_ranges.block_comments(source);
 
     // assert
     assert_eq!(block_comments, Vec::<TextSize>::new());
@@ -88,11 +82,10 @@ fn block_comments_lines_in_triple_quotes_not_a_block() {
         """
         "#;
     let parsed = parse_unchecked(source, Mode::Module);
-    let locator = Locator::new(source);
     let comment_ranges = CommentRanges::from(parsed.tokens());
 
     // act
-    let block_comments = comment_ranges.block_comments(&locator);
+    let block_comments = comment_ranges.block_comments(source);
 
     // assert
     assert_eq!(block_comments, Vec::<TextSize>::new());
@@ -125,11 +118,10 @@ y = 2  # do not form a block comment
 """
         "#;
     let parsed = parse_unchecked(source, Mode::Module);
-    let locator = Locator::new(source);
     let comment_ranges = CommentRanges::from(parsed.tokens());
 
     // act
-    let block_comments = comment_ranges.block_comments(&locator);
+    let block_comments = comment_ranges.block_comments(source);
 
     // assert
     assert_eq!(
diff --git a/crates/ruff_python_trivia_integration_tests/tests/whitespace.rs b/crates/ruff_python_trivia_integration_tests/tests/whitespace.rs
index d73e2052b3..feb2268615 100644
--- a/crates/ruff_python_trivia_integration_tests/tests/whitespace.rs
+++ b/crates/ruff_python_trivia_integration_tests/tests/whitespace.rs
@@ -1,6 +1,5 @@
 use ruff_python_parser::{parse_module, ParseError};
 use ruff_python_trivia::has_trailing_content;
-use ruff_source_file::Locator;
 use ruff_text_size::Ranged;
 
 #[test]
@@ -8,26 +7,22 @@ fn trailing_content() -> Result<(), ParseError> {
     let contents = "x = 1";
     let suite = parse_module(contents)?.into_suite();
     let stmt = suite.first().unwrap();
-    let locator = Locator::new(contents);
-    assert!(!has_trailing_content(stmt.end(), &locator));
+    assert!(!has_trailing_content(stmt.end(), contents));
 
     let contents = "x = 1; y = 2";
     let suite = parse_module(contents)?.into_suite();
     let stmt = suite.first().unwrap();
-    let locator = Locator::new(contents);
-    assert!(has_trailing_content(stmt.end(), &locator));
+    assert!(has_trailing_content(stmt.end(), contents));
 
     let contents = "x = 1  ";
     let suite = parse_module(contents)?.into_suite();
     let stmt = suite.first().unwrap();
-    let locator = Locator::new(contents);
-    assert!(!has_trailing_content(stmt.end(), &locator));
+    assert!(!has_trailing_content(stmt.end(), contents));
 
     let contents = "x = 1  # Comment";
     let suite = parse_module(contents)?.into_suite();
     let stmt = suite.first().unwrap();
-    let locator = Locator::new(contents);
-    assert!(!has_trailing_content(stmt.end(), &locator));
+    assert!(!has_trailing_content(stmt.end(), contents));
 
     let contents = r"
 x = 1
@@ -36,8 +31,7 @@ y = 2
     .trim();
     let suite = parse_module(contents)?.into_suite();
     let stmt = suite.first().unwrap();
-    let locator = Locator::new(contents);
-    assert!(!has_trailing_content(stmt.end(), &locator));
+    assert!(!has_trailing_content(stmt.end(), contents));
 
     Ok(())
 }
diff --git a/crates/ruff_server/src/lint.rs b/crates/ruff_server/src/lint.rs
index f5c967aeea..1c6f6686d7 100644
--- a/crates/ruff_server/src/lint.rs
+++ b/crates/ruff_server/src/lint.rs
@@ -103,10 +103,10 @@ pub(crate) fn check(
     let locator = Locator::with_index(source_kind.source_code(), index.clone());
 
     // Detect the current code style (lazily).
-    let stylist = Stylist::from_tokens(parsed.tokens(), &locator);
+    let stylist = Stylist::from_tokens(parsed.tokens(), source_kind.source_code());
 
     // Extra indices from the code.
-    let indexer = Indexer::from_tokens(parsed.tokens(), &locator);
+    let indexer = Indexer::from_tokens(parsed.tokens(), source_kind.source_code());
 
     // Extract the `# noqa` and `# isort: skip` directives from the source.
     let directives = extract_directives(parsed.tokens(), Flags::all(), &locator, &indexer);
diff --git a/crates/ruff_source_file/src/lib.rs b/crates/ruff_source_file/src/lib.rs
index a0de92b1c1..f6f736fce6 100644
--- a/crates/ruff_source_file/src/lib.rs
+++ b/crates/ruff_source_file/src/lib.rs
@@ -8,6 +8,7 @@ use serde::{Deserialize, Serialize};
 use ruff_text_size::{Ranged, TextRange, TextSize};
 
 pub use crate::line_index::{LineIndex, OneIndexed};
+pub use crate::located::Located;
 pub use crate::locator::Locator;
 pub use crate::newlines::{
     find_newline, Line, LineEnding, NewlineWithTrailingNewline, UniversalNewlineIterator,
@@ -15,6 +16,7 @@ pub use crate::newlines::{
 };
 
 mod line_index;
+mod located;
 mod locator;
 mod newlines;
 
diff --git a/crates/ruff_source_file/src/located.rs b/crates/ruff_source_file/src/located.rs
new file mode 100644
index 0000000000..2ddd648597
--- /dev/null
+++ b/crates/ruff_source_file/src/located.rs
@@ -0,0 +1,422 @@
+//! Struct used to efficiently slice source code at (row, column) Locations.
+
+use memchr::{memchr2, memrchr2};
+use ruff_text_size::{Ranged, TextLen, TextRange, TextSize};
+
+use std::ops::Add;
+
+use crate::newlines::find_newline;
+
+pub trait Located {
+    fn as_str(&self) -> &str;
+
+    /// Computes the start position of the line of `offset`.
+    ///
+    /// ## Examples
+    ///
+    /// ```
+    /// # use ruff_text_size::TextSize;
+    /// # use ruff_source_file::Located;
+    ///
+    /// let located = "First line\nsecond line\rthird line";
+    ///
+    /// assert_eq!(located.line_start(TextSize::from(0)), TextSize::from(0));
+    /// assert_eq!(located.line_start(TextSize::from(4)), TextSize::from(0));
+    ///
+    /// assert_eq!(located.line_start(TextSize::from(14)), TextSize::from(11));
+    /// assert_eq!(located.line_start(TextSize::from(28)), TextSize::from(23));
+    /// ```
+    ///
+    /// ## Panics
+    /// If `offset` is out of bounds.
+    fn line_start(&self, offset: TextSize) -> TextSize {
+        let bytes = self.as_str()[TextRange::up_to(offset)].as_bytes();
+        if let Some(index) = memrchr2(b'\n', b'\r', bytes) {
+            // SAFETY: Safe because `index < offset`
+            TextSize::try_from(index).unwrap().add(TextSize::from(1))
+        } else {
+            self.contents_start()
+        }
+    }
+
+    /// Computes the start position of the file contents: either the first byte, or the byte after
+    /// the BOM.
+    fn contents_start(&self) -> TextSize {
+        if self.as_str().starts_with('\u{feff}') {
+            // Skip the BOM.
+            '\u{feff}'.text_len()
+        } else {
+            // Start of file.
+            TextSize::default()
+        }
+    }
+
+    /// Returns `true` if `offset` is at the start of a line.
+    fn is_at_start_of_line(&self, offset: TextSize) -> bool {
+        self.line_start(offset) == offset
+    }
+
+    /// Computes the offset that is right after the newline character that ends `offset`'s line.
+    ///
+    /// ## Examples
+    ///
+    /// ```
+    /// # use ruff_text_size::{Ranged, TextRange, TextSize};
+    /// # use ruff_source_file::Located;
+    ///
+    /// let located = "First line\nsecond line\r\nthird line";
+    ///
+    /// assert_eq!(located.full_line_end(TextSize::from(3)), TextSize::from(11));
+    /// assert_eq!(located.full_line_end(TextSize::from(14)), TextSize::from(24));
+    /// assert_eq!(located.full_line_end(TextSize::from(28)), TextSize::from(34));
+    /// ```
+    ///
+    /// ## Panics
+    ///
+    /// If `offset` is passed the end of the content.
+    fn full_line_end(&self, offset: TextSize) -> TextSize {
+        let slice = &self.as_str()[usize::from(offset)..];
+        if let Some((index, line_ending)) = find_newline(slice) {
+            offset + TextSize::try_from(index).unwrap() + line_ending.text_len()
+        } else {
+            self.as_str().text_len()
+        }
+    }
+
+    /// Computes the offset that is right before the newline character that ends `offset`'s line.
+    ///
+    /// ## Examples
+    ///
+    /// ```
+    /// # use ruff_text_size::{Ranged, TextRange, TextSize};
+    /// # use ruff_source_file::Located;
+    ///
+    /// let located = "First line\nsecond line\r\nthird line";
+    ///
+    /// assert_eq!(located.line_end(TextSize::from(3)), TextSize::from(10));
+    /// assert_eq!(located.line_end(TextSize::from(14)), TextSize::from(22));
+    /// assert_eq!(located.line_end(TextSize::from(28)), TextSize::from(34));
+    /// ```
+    ///
+    /// ## Panics
+    ///
+    /// If `offset` is passed the end of the content.
+    fn line_end(&self, offset: TextSize) -> TextSize {
+        let slice = &self.as_str()[usize::from(offset)..];
+        if let Some(index) = memchr2(b'\n', b'\r', slice.as_bytes()) {
+            offset + TextSize::try_from(index).unwrap()
+        } else {
+            self.as_str().text_len()
+        }
+    }
+
+    /// Computes the range of this `offset`s line.
+    ///
+    /// The range starts at the beginning of the line and goes up to, and including, the new line character
+    /// at the end of the line.
+    ///
+    /// ## Examples
+    ///
+    /// ```
+    /// # use ruff_text_size::{Ranged, TextRange, TextSize};
+    /// # use ruff_source_file::Located;
+    ///
+    /// let located = "First line\nsecond line\r\nthird line";
+    ///
+    /// assert_eq!(located.full_line_range(TextSize::from(3)), TextRange::new(TextSize::from(0), TextSize::from(11)));
+    /// assert_eq!(located.full_line_range(TextSize::from(14)), TextRange::new(TextSize::from(11), TextSize::from(24)));
+    /// assert_eq!(located.full_line_range(TextSize::from(28)), TextRange::new(TextSize::from(24), TextSize::from(34)));
+    /// ```
+    ///
+    /// ## Panics
+    /// If `offset` is out of bounds.
+    fn full_line_range(&self, offset: TextSize) -> TextRange {
+        TextRange::new(self.line_start(offset), self.full_line_end(offset))
+    }
+
+    /// Computes the range of this `offset`s line ending before the newline character.
+    ///
+    /// The range starts at the beginning of the line and goes up to, but excluding, the new line character
+    /// at the end of the line.
+    ///
+    /// ## Examples
+    ///
+    /// ```
+    /// # use ruff_text_size::{Ranged, TextRange, TextSize};
+    /// # use ruff_source_file::Located;
+    ///
+    /// let located = "First line\nsecond line\r\nthird line";
+    ///
+    /// assert_eq!(located.line_range(TextSize::from(3)), TextRange::new(TextSize::from(0), TextSize::from(10)));
+    /// assert_eq!(located.line_range(TextSize::from(14)), TextRange::new(TextSize::from(11), TextSize::from(22)));
+    /// assert_eq!(located.line_range(TextSize::from(28)), TextRange::new(TextSize::from(24), TextSize::from(34)));
+    /// ```
+    ///
+    /// ## Panics
+    /// If `offset` is out of bounds.
+    fn line_range(&self, offset: TextSize) -> TextRange {
+        TextRange::new(self.line_start(offset), self.line_end(offset))
+    }
+
+    /// Returns the text of the `offset`'s line.
+    ///
+    /// The line includes the newline characters at the end of the line.
+    ///
+    /// ## Examples
+    ///
+    /// ```
+    /// # use ruff_text_size::{Ranged, TextRange, TextSize};
+    /// # use ruff_source_file::Locator;
+    /// # use ruff_source_file::Located;
+    ///
+    /// let located = "First line\nsecond line\r\nthird line";
+    ///
+    /// assert_eq!(located.full_line_str(TextSize::from(3)), "First line\n");
+    /// assert_eq!(located.full_line_str(TextSize::from(14)), "second line\r\n");
+    /// assert_eq!(located.full_line_str(TextSize::from(28)), "third line");
+    /// ```
+    ///
+    /// ## Panics
+    /// If `offset` is out of bounds.
+    fn full_line_str(&self, offset: TextSize) -> &str {
+        &self.as_str()[self.full_line_range(offset)]
+    }
+
+    /// Returns the text of the `offset`'s line.
+    ///
+    /// Excludes the newline characters at the end of the line.
+    ///
+    /// ## Examples
+    ///
+    /// ```
+    /// # use ruff_text_size::{Ranged, TextRange, TextSize};
+    /// # use ruff_source_file::Located;
+    ///
+    /// let located = "First line\nsecond line\r\nthird line";
+    ///
+    /// assert_eq!(located.line_str(TextSize::from(3)), "First line");
+    /// assert_eq!(located.line_str(TextSize::from(14)), "second line");
+    /// assert_eq!(located.line_str(TextSize::from(28)), "third line");
+    /// ```
+    ///
+    /// ## Panics
+    /// If `offset` is out of bounds.
+    fn line_str(&self, offset: TextSize) -> &str {
+        &self.as_str()[self.line_range(offset)]
+    }
+
+    /// Computes the range of all lines that this `range` covers.
+    ///
+    /// The range starts at the beginning of the line at `range.start()` and goes up to, and including, the new line character
+    /// at the end of `range.ends()`'s line.
+    ///
+    /// ## Examples
+    ///
+    /// ```
+    /// # use ruff_text_size::{Ranged, TextRange, TextSize};
+    /// # use ruff_source_file::Located;
+    ///
+    /// let located = "First line\nsecond line\r\nthird line";
+    ///
+    /// assert_eq!(
+    ///     located.full_lines_range(TextRange::new(TextSize::from(3), TextSize::from(5))),
+    ///     TextRange::new(TextSize::from(0), TextSize::from(11))
+    /// );
+    /// assert_eq!(
+    ///     located.full_lines_range(TextRange::new(TextSize::from(3), TextSize::from(14))),
+    ///     TextRange::new(TextSize::from(0), TextSize::from(24))
+    /// );
+    /// ```
+    ///
+    /// ## Panics
+    /// If the start or end of `range` is out of bounds.
+    fn full_lines_range(&self, range: TextRange) -> TextRange {
+        TextRange::new(
+            self.line_start(range.start()),
+            self.full_line_end(range.end()),
+        )
+    }
+
+    /// Computes the range of all lines that this `range` covers.
+    ///
+    /// The range starts at the beginning of the line at `range.start()` and goes up to, but excluding, the new line character
+    /// at the end of `range.end()`'s line.
+    ///
+    /// ## Examples
+    ///
+    /// ```
+    /// # use ruff_text_size::{Ranged, TextRange, TextSize};
+    /// # use ruff_source_file::Located;
+    ///
+    /// let located = "First line\nsecond line\r\nthird line";
+    ///
+    /// assert_eq!(
+    ///     located.lines_range(TextRange::new(TextSize::from(3), TextSize::from(5))),
+    ///     TextRange::new(TextSize::from(0), TextSize::from(10))
+    /// );
+    /// assert_eq!(
+    ///     located.lines_range(TextRange::new(TextSize::from(3), TextSize::from(14))),
+    ///     TextRange::new(TextSize::from(0), TextSize::from(22))
+    /// );
+    /// ```
+    ///
+    /// ## Panics
+    /// If the start or end of `range` is out of bounds.
+    fn lines_range(&self, range: TextRange) -> TextRange {
+        TextRange::new(self.line_start(range.start()), self.line_end(range.end()))
+    }
+
+    /// Returns true if the text of `range` contains any line break.
+    ///
+    /// ```
+    /// # use ruff_text_size::{Ranged, TextRange, TextSize};
+    /// # use ruff_source_file::Located;
+    ///
+    /// let located = "First line\nsecond line\r\nthird line";
+    ///
+    /// assert!(
+    ///     !located.contains_line_break(TextRange::new(TextSize::from(3), TextSize::from(5))),
+    /// );
+    /// assert!(
+    ///     located.contains_line_break(TextRange::new(TextSize::from(3), TextSize::from(14))),
+    /// );
+    /// ```
+    ///
+    /// ## Panics
+    /// If the `range` is out of bounds.
+    fn contains_line_break(&self, range: TextRange) -> bool {
+        let text = &self.as_str()[range];
+        text.contains(['\n', '\r'])
+    }
+
+    /// Returns the text of all lines that include `range`.
+    ///
+    /// ## Examples
+    ///
+    /// ```
+    /// # use ruff_text_size::{Ranged, TextRange, TextSize};
+    /// # use ruff_source_file::Located;
+    ///
+    /// let located = "First line\nsecond line\r\nthird line";
+    ///
+    /// assert_eq!(
+    ///     located.lines_str(TextRange::new(TextSize::from(3), TextSize::from(5))),
+    ///     "First line"
+    /// );
+    /// assert_eq!(
+    ///     located.lines_str(TextRange::new(TextSize::from(3), TextSize::from(14))),
+    ///     "First line\nsecond line"
+    /// );
+    /// ```
+    ///
+    /// ## Panics
+    /// If the start or end of `range` is out of bounds.
+    fn lines_str(&self, range: TextRange) -> &str {
+        &self.as_str()[self.lines_range(range)]
+    }
+
+    /// Returns the text of all lines that include `range`.
+    ///
+    /// Includes the newline characters of the last line.
+    ///
+    /// ## Examples
+    ///
+    /// ```
+    /// # use ruff_text_size::{Ranged, TextRange, TextSize};
+    /// # use ruff_source_file::Located;
+    ///
+    /// let located = "First line\nsecond line\r\nthird line";
+    ///
+    /// assert_eq!(
+    ///     located.full_lines_str(TextRange::new(TextSize::from(3), TextSize::from(5))),
+    ///     "First line\n"
+    /// );
+    /// assert_eq!(
+    ///     located.full_lines_str(TextRange::new(TextSize::from(3), TextSize::from(14))),
+    ///     "First line\nsecond line\r\n"
+    /// );
+    /// ```
+    ///
+    /// ## Panics
+    /// If the start or end of `range` is out of bounds.
+    fn full_lines_str(&self, range: TextRange) -> &str {
+        &self.as_str()[self.full_lines_range(range)]
+    }
+
+    /// Take the source code up to the given [`TextSize`].
+    #[inline]
+    fn up_to(&self, offset: TextSize) -> &str {
+        &self.as_str()[TextRange::up_to(offset)]
+    }
+
+    /// Take the source code after the given [`TextSize`].
+    #[inline]
+    fn after(&self, offset: TextSize) -> &str {
+        &self.as_str()[usize::from(offset)..]
+    }
+
+    /// Finds the closest [`TextSize`] not exceeding the offset for which `is_char_boundary` is
+    /// `true`.
+    ///
+    /// Can be replaced with `str::floor_char_boundary` once it's stable.
+    ///
+    /// ## Examples
+    ///
+    /// ```
+    /// # use ruff_text_size::{Ranged, TextRange, TextSize};
+    /// # use ruff_source_file::Located;
+    ///
+    /// let located = "Hello";
+    ///
+    /// assert_eq!(
+    ///     Located::floor_char_boundary(located, TextSize::from(0)),
+    ///     TextSize::from(0)
+    /// );
+    ///
+    /// assert_eq!(
+    ///     Located::floor_char_boundary(located, TextSize::from(5)),
+    ///     TextSize::from(5)
+    /// );
+    ///
+    /// let located = "α";
+    ///
+    /// assert_eq!(
+    ///     Located::floor_char_boundary(located, TextSize::from(0)),
+    ///     TextSize::from(0)
+    /// );
+    ///
+    /// assert_eq!(
+    ///     Located::floor_char_boundary(located, TextSize::from(1)),
+    ///     TextSize::from(0)
+    /// );
+    ///
+    /// assert_eq!(
+    ///     Located::floor_char_boundary(located, TextSize::from(2)),
+    ///     TextSize::from(2)
+    /// );
+    /// ```
+    fn floor_char_boundary(&self, offset: TextSize) -> TextSize {
+        if offset >= self.as_str().text_len() {
+            self.as_str().text_len()
+        } else {
+            // We know that the character boundary is within four bytes.
+            (0u32..=3u32)
+                .map(TextSize::from)
+                .filter_map(|index| offset.checked_sub(index))
+                .find(|offset| self.as_str().is_char_boundary(offset.to_usize()))
+                .unwrap_or_default()
+        }
+    }
+
+    /// Take the source code between the given [`TextRange`].
+    #[inline]
+    fn slice<T: Ranged>(&self, ranged: T) -> &str {
+        &self.as_str()[ranged.range()]
+    }
+}
+
+impl Located for str {
+    fn as_str(&self) -> &str {
+        self
+    }
+}
diff --git a/crates/ruff_source_file/src/locator.rs b/crates/ruff_source_file/src/locator.rs
index f133377a9e..5a86ea3f1f 100644
--- a/crates/ruff_source_file/src/locator.rs
+++ b/crates/ruff_source_file/src/locator.rs
@@ -1,12 +1,11 @@
 //! Struct used to efficiently slice source code at (row, column) Locations.
 
-use memchr::{memchr2, memrchr2};
+use memchr::memrchr2;
 use ruff_text_size::{Ranged, TextLen, TextRange, TextSize};
 use std::cell::OnceCell;
 use std::ops::Add;
 
-use crate::newlines::find_newline;
-use crate::{LineIndex, OneIndexed, SourceCode, SourceLocation};
+use crate::{LineIndex, Located, OneIndexed, SourceCode, SourceLocation};
 
 #[derive(Debug)]
 pub struct Locator<'a> {
@@ -91,18 +90,12 @@ impl<'a> Locator<'a> {
     /// Computes the start position of the file contents: either the first byte, or the byte after
     /// the BOM.
     pub fn contents_start(&self) -> TextSize {
-        if self.contents.starts_with('\u{feff}') {
-            // Skip the BOM.
-            '\u{feff}'.text_len()
-        } else {
-            // Start of file.
-            TextSize::default()
-        }
+        self.contents.contents_start()
     }
 
     /// Returns `true` if `offset` is at the start of a line.
     pub fn is_at_start_of_line(&self, offset: TextSize) -> bool {
-        self.line_start(offset) == offset
+        self.contents.is_at_start_of_line(offset)
     }
 
     /// Computes the offset that is right after the newline character that ends `offset`'s line.
@@ -124,12 +117,7 @@ impl<'a> Locator<'a> {
     ///
     /// If `offset` is passed the end of the content.
     pub fn full_line_end(&self, offset: TextSize) -> TextSize {
-        let slice = &self.contents[usize::from(offset)..];
-        if let Some((index, line_ending)) = find_newline(slice) {
-            offset + TextSize::try_from(index).unwrap() + line_ending.text_len()
-        } else {
-            self.contents.text_len()
-        }
+        self.contents.full_line_end(offset)
     }
 
     /// Computes the offset that is right before the newline character that ends `offset`'s line.
@@ -151,12 +139,7 @@ impl<'a> Locator<'a> {
     ///
     /// If `offset` is passed the end of the content.
     pub fn line_end(&self, offset: TextSize) -> TextSize {
-        let slice = &self.contents[usize::from(offset)..];
-        if let Some(index) = memchr2(b'\n', b'\r', slice.as_bytes()) {
-            offset + TextSize::try_from(index).unwrap()
-        } else {
-            self.contents.text_len()
-        }
+        self.contents.line_end(offset)
     }
 
     /// Computes the range of this `offset`s line.
@@ -180,7 +163,7 @@ impl<'a> Locator<'a> {
     /// ## Panics
     /// If `offset` is out of bounds.
     pub fn full_line_range(&self, offset: TextSize) -> TextRange {
-        TextRange::new(self.line_start(offset), self.full_line_end(offset))
+        self.contents.full_line_range(offset)
     }
 
     /// Computes the range of this `offset`s line ending before the newline character.
@@ -204,7 +187,7 @@ impl<'a> Locator<'a> {
     /// ## Panics
     /// If `offset` is out of bounds.
     pub fn line_range(&self, offset: TextSize) -> TextRange {
-        TextRange::new(self.line_start(offset), self.line_end(offset))
+        self.contents.line_range(offset)
     }
 
     /// Returns the text of the `offset`'s line.
@@ -227,7 +210,7 @@ impl<'a> Locator<'a> {
     /// ## Panics
     /// If `offset` is out of bounds.
     pub fn full_line(&self, offset: TextSize) -> &'a str {
-        &self.contents[self.full_line_range(offset)]
+        self.contents.full_line_str(offset)
     }
 
     /// Returns the text of the `offset`'s line.
@@ -250,7 +233,7 @@ impl<'a> Locator<'a> {
     /// ## Panics
     /// If `offset` is out of bounds.
     pub fn line(&self, offset: TextSize) -> &'a str {
-        &self.contents[self.line_range(offset)]
+        self.contents.line_str(offset)
     }
 
     /// Computes the range of all lines that this `range` covers.
@@ -279,10 +262,7 @@ impl<'a> Locator<'a> {
     /// ## Panics
     /// If the start or end of `range` is out of bounds.
     pub fn full_lines_range(&self, range: TextRange) -> TextRange {
-        TextRange::new(
-            self.line_start(range.start()),
-            self.full_line_end(range.end()),
-        )
+        self.contents.full_lines_range(range)
     }
 
     /// Computes the range of all lines that this `range` covers.
@@ -311,7 +291,7 @@ impl<'a> Locator<'a> {
     /// ## Panics
     /// If the start or end of `range` is out of bounds.
     pub fn lines_range(&self, range: TextRange) -> TextRange {
-        TextRange::new(self.line_start(range.start()), self.line_end(range.end()))
+        self.contents.lines_range(range)
     }
 
     /// Returns true if the text of `range` contains any line break.
@@ -333,8 +313,7 @@ impl<'a> Locator<'a> {
     /// ## Panics
     /// If the `range` is out of bounds.
     pub fn contains_line_break(&self, range: TextRange) -> bool {
-        let text = &self.contents[range];
-        text.contains(['\n', '\r'])
+        self.contents.contains_line_break(range)
     }
 
     /// Returns the text of all lines that include `range`.
@@ -360,6 +339,7 @@ impl<'a> Locator<'a> {
     /// ## Panics
     /// If the start or end of `range` is out of bounds.
     pub fn lines(&self, range: TextRange) -> &'a str {
+        // FIXME: `lines` collides with str.lines method
         &self.contents[self.lines_range(range)]
     }
 
@@ -388,19 +368,19 @@ impl<'a> Locator<'a> {
     /// ## Panics
     /// If the start or end of `range` is out of bounds.
     pub fn full_lines(&self, range: TextRange) -> &'a str {
-        &self.contents[self.full_lines_range(range)]
+        self.contents.full_lines_str(range)
     }
 
     /// Take the source code up to the given [`TextSize`].
     #[inline]
     pub fn up_to(&self, offset: TextSize) -> &'a str {
-        &self.contents[TextRange::up_to(offset)]
+        self.contents.up_to(offset)
     }
 
     /// Take the source code after the given [`TextSize`].
     #[inline]
     pub fn after(&self, offset: TextSize) -> &'a str {
-        &self.contents[usize::from(offset)..]
+        self.contents.after(offset)
     }
 
     /// Finds the closest [`TextSize`] not exceeding the offset for which `is_char_boundary` is
@@ -444,6 +424,7 @@ impl<'a> Locator<'a> {
     /// );
     /// ```
     pub fn floor_char_boundary(&self, offset: TextSize) -> TextSize {
+        // FIXME: Method collides with std method
         if offset >= self.text_len() {
             self.text_len()
         } else {
@@ -459,11 +440,11 @@ impl<'a> Locator<'a> {
     /// Take the source code between the given [`TextRange`].
     #[inline]
     pub fn slice<T: Ranged>(&self, ranged: T) -> &'a str {
-        &self.contents[ranged.range()]
+        self.contents.slice(ranged)
     }
 
     /// Return the underlying source code.
-    pub fn contents(&self) -> &'a str {
+    pub const fn contents(&self) -> &'a str {
         self.contents
     }
 
diff --git a/crates/ruff_wasm/src/lib.rs b/crates/ruff_wasm/src/lib.rs
index 121f3d81ff..e84e0ecc98 100644
--- a/crates/ruff_wasm/src/lib.rs
+++ b/crates/ruff_wasm/src/lib.rs
@@ -167,10 +167,10 @@ impl Workspace {
         let locator = Locator::new(contents);
 
         // Detect the current code style (lazily).
-        let stylist = Stylist::from_tokens(parsed.tokens(), &locator);
+        let stylist = Stylist::from_tokens(parsed.tokens(), contents);
 
         // Extra indices from the code.
-        let indexer = Indexer::from_tokens(parsed.tokens(), &locator);
+        let indexer = Indexer::from_tokens(parsed.tokens(), contents);
 
         // Extract the `# noqa` and `# isort: skip` directives from the source.
         let directives = directives::extract_directives(