diff --git a/crates/ruff/src/commands/format.rs b/crates/ruff/src/commands/format.rs
index 1f79e59339..0e245efa8c 100644
--- a/crates/ruff/src/commands/format.rs
+++ b/crates/ruff/src/commands/format.rs
@@ -370,7 +370,7 @@ pub(crate) fn format_source(
                 let line_index = LineIndex::from_source_text(unformatted);
                 let byte_range = range.to_text_range(unformatted, &line_index);
                 format_range(unformatted, byte_range, options).map(|formatted_range| {
-                    let mut formatted = unformatted.to_string();
+                    let mut formatted = unformatted.clone();
                     formatted.replace_range(
                         std::ops::Range::<usize>::from(formatted_range.source_range()),
                         formatted_range.as_code(),
diff --git a/crates/ruff_dev/src/generate_options.rs b/crates/ruff_dev/src/generate_options.rs
index 8b8579d730..49a898d6fe 100644
--- a/crates/ruff_dev/src/generate_options.rs
+++ b/crates/ruff_dev/src/generate_options.rs
@@ -62,7 +62,7 @@ fn generate_set(output: &mut String, set: Set, parents: &mut Vec<Set>) {
         generate_set(
             output,
             Set::Named {
-                name: set_name.to_string(),
+                name: set_name.clone(),
                 set: *sub_set,
             },
             parents,
diff --git a/crates/ruff_dev/src/generate_ty_options.rs b/crates/ruff_dev/src/generate_ty_options.rs
index af7794a0b2..4e4ab0a949 100644
--- a/crates/ruff_dev/src/generate_ty_options.rs
+++ b/crates/ruff_dev/src/generate_ty_options.rs
@@ -104,7 +104,7 @@ fn generate_set(output: &mut String, set: Set, parents: &mut Vec<Set>) {
         generate_set(
             output,
             Set::Named {
-                name: set_name.to_string(),
+                name: set_name.clone(),
                 set: *sub_set,
             },
             parents,
diff --git a/crates/ruff_formatter/src/builders.rs b/crates/ruff_formatter/src/builders.rs
index 14da643355..ab60103d99 100644
--- a/crates/ruff_formatter/src/builders.rs
+++ b/crates/ruff_formatter/src/builders.rs
@@ -1006,7 +1006,7 @@ impl<Context> std::fmt::Debug for Align<'_, Context> {
 /// Block indents indent a block of code, such as in a function body, and therefore insert a line
 /// break before and after the content.
 ///
-/// Doesn't create an indentation if the passed in content is [`FormatElement.is_empty`].
+/// Doesn't create an indentation if the passed in content is empty.
 ///
 /// # Examples
 ///
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 e0684056dc..6827e99b93 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
@@ -78,7 +78,7 @@ pub(crate) fn unconventional_import_alias(
     let mut diagnostic = checker.report_diagnostic(
         UnconventionalImportAlias {
             name: qualified_name,
-            asname: expected_alias.to_string(),
+            asname: expected_alias.clone(),
         },
         binding.range(),
     );
diff --git a/crates/ruff_linter/src/rules/flake8_pytest_style/types.rs b/crates/ruff_linter/src/rules/flake8_pytest_style/types.rs
index 0de6758635..bd57ad080c 100644
--- a/crates/ruff_linter/src/rules/flake8_pytest_style/types.rs
+++ b/crates/ruff_linter/src/rules/flake8_pytest_style/types.rs
@@ -6,21 +6,17 @@ use ruff_macros::CacheKey;
 
 #[derive(Clone, Copy, Debug, CacheKey, PartialEq, Eq, Serialize, Deserialize)]
 #[cfg_attr(feature = "schemars", derive(schemars::JsonSchema))]
+#[derive(Default)]
 pub enum ParametrizeNameType {
     #[serde(rename = "csv")]
     Csv,
     #[serde(rename = "tuple")]
+    #[default]
     Tuple,
     #[serde(rename = "list")]
     List,
 }
 
-impl Default for ParametrizeNameType {
-    fn default() -> Self {
-        Self::Tuple
-    }
-}
-
 impl Display for ParametrizeNameType {
     fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
         match self {
@@ -33,19 +29,15 @@ impl Display for ParametrizeNameType {
 
 #[derive(Clone, Copy, Debug, CacheKey, PartialEq, Eq, Serialize, Deserialize)]
 #[cfg_attr(feature = "schemars", derive(schemars::JsonSchema))]
+#[derive(Default)]
 pub enum ParametrizeValuesType {
     #[serde(rename = "tuple")]
     Tuple,
     #[serde(rename = "list")]
+    #[default]
     List,
 }
 
-impl Default for ParametrizeValuesType {
-    fn default() -> Self {
-        Self::List
-    }
-}
-
 impl Display for ParametrizeValuesType {
     fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
         match self {
@@ -57,19 +49,15 @@ impl Display for ParametrizeValuesType {
 
 #[derive(Clone, Copy, Debug, CacheKey, PartialEq, Eq, Serialize, Deserialize)]
 #[cfg_attr(feature = "schemars", derive(schemars::JsonSchema))]
+#[derive(Default)]
 pub enum ParametrizeValuesRowType {
     #[serde(rename = "tuple")]
+    #[default]
     Tuple,
     #[serde(rename = "list")]
     List,
 }
 
-impl Default for ParametrizeValuesRowType {
-    fn default() -> Self {
-        Self::Tuple
-    }
-}
-
 impl Display for ParametrizeValuesRowType {
     fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
         match self {
diff --git a/crates/ruff_linter/src/rules/flake8_quotes/settings.rs b/crates/ruff_linter/src/rules/flake8_quotes/settings.rs
index b241e70b49..fe5129d6e3 100644
--- a/crates/ruff_linter/src/rules/flake8_quotes/settings.rs
+++ b/crates/ruff_linter/src/rules/flake8_quotes/settings.rs
@@ -9,19 +9,15 @@ use ruff_macros::CacheKey;
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Serialize, Deserialize, CacheKey)]
 #[serde(deny_unknown_fields, rename_all = "kebab-case")]
 #[cfg_attr(feature = "schemars", derive(schemars::JsonSchema))]
+#[derive(Default)]
 pub enum Quote {
     /// Use double quotes.
+    #[default]
     Double,
     /// Use single quotes.
     Single,
 }
 
-impl Default for Quote {
-    fn default() -> Self {
-        Self::Double
-    }
-}
-
 impl From<ruff_python_ast::str::Quote> for Quote {
     fn from(value: ruff_python_ast::str::Quote) -> Self {
         match value {
diff --git a/crates/ruff_linter/src/rules/flake8_simplify/rules/reimplemented_builtin.rs b/crates/ruff_linter/src/rules/flake8_simplify/rules/reimplemented_builtin.rs
index 9c216311ed..4c858fb799 100644
--- a/crates/ruff_linter/src/rules/flake8_simplify/rules/reimplemented_builtin.rs
+++ b/crates/ruff_linter/src/rules/flake8_simplify/rules/reimplemented_builtin.rs
@@ -116,7 +116,7 @@ pub(crate) fn convert_for_loop_to_any_all(checker: &Checker, stmt: &Stmt) {
 
             let mut diagnostic = checker.report_diagnostic(
                 ReimplementedBuiltin {
-                    replacement: contents.to_string(),
+                    replacement: contents.clone(),
                 },
                 TextRange::new(stmt.start(), terminal.stmt.end()),
             );
@@ -212,7 +212,7 @@ pub(crate) fn convert_for_loop_to_any_all(checker: &Checker, stmt: &Stmt) {
 
             let mut diagnostic = checker.report_diagnostic(
                 ReimplementedBuiltin {
-                    replacement: contents.to_string(),
+                    replacement: contents.clone(),
                 },
                 TextRange::new(stmt.start(), terminal.stmt.end()),
             );
diff --git a/crates/ruff_linter/src/rules/flake8_tidy_imports/rules/banned_api.rs b/crates/ruff_linter/src/rules/flake8_tidy_imports/rules/banned_api.rs
index 6ada015222..6379304d5c 100644
--- a/crates/ruff_linter/src/rules/flake8_tidy_imports/rules/banned_api.rs
+++ b/crates/ruff_linter/src/rules/flake8_tidy_imports/rules/banned_api.rs
@@ -47,7 +47,7 @@ pub(crate) fn banned_api<T: Ranged>(checker: &Checker, policy: &NameMatchPolicy,
             checker.report_diagnostic(
                 BannedApi {
                     name: banned_module,
-                    message: reason.msg.to_string(),
+                    message: reason.msg.clone(),
                 },
                 node.range(),
             );
@@ -74,8 +74,8 @@ pub(crate) fn banned_attribute_access(checker: &Checker, expr: &Expr) {
     {
         checker.report_diagnostic(
             BannedApi {
-                name: banned_path.to_string(),
-                message: ban.msg.to_string(),
+                name: banned_path.clone(),
+                message: ban.msg.clone(),
             },
             expr.range(),
         );
diff --git a/crates/ruff_linter/src/rules/isort/settings.rs b/crates/ruff_linter/src/rules/isort/settings.rs
index 05a4dddf08..cab9ab35ed 100644
--- a/crates/ruff_linter/src/rules/isort/settings.rs
+++ b/crates/ruff_linter/src/rules/isort/settings.rs
@@ -20,21 +20,17 @@ use super::categorize::ImportSection;
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Serialize, Deserialize, CacheKey)]
 #[serde(deny_unknown_fields, rename_all = "kebab-case")]
 #[cfg_attr(feature = "schemars", derive(schemars::JsonSchema))]
+#[derive(Default)]
 pub enum RelativeImportsOrder {
     /// Place "closer" imports (fewer `.` characters, most local) before
     /// "further" imports (more `.` characters, least local).
     ClosestToFurthest,
     /// Place "further" imports (more `.` characters, least local) imports
     /// before "closer" imports (fewer `.` characters, most local).
+    #[default]
     FurthestToClosest,
 }
 
-impl Default for RelativeImportsOrder {
-    fn default() -> Self {
-        Self::FurthestToClosest
-    }
-}
-
 impl Display for RelativeImportsOrder {
     fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
         match self {
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 6ae6cea817..a68e492846 100644
--- a/crates/ruff_linter/src/rules/pycodestyle/rules/literal_comparisons.rs
+++ b/crates/ruff_linter/src/rules/pycodestyle/rules/literal_comparisons.rs
@@ -427,7 +427,7 @@ pub(crate) fn literal_comparisons(checker: &Checker, compare: &ast::ExprCompare)
 
         for diagnostic in &mut diagnostics {
             diagnostic.set_fix(Fix::unsafe_edit(Edit::range_replacement(
-                content.to_string(),
+                content.clone(),
                 compare.range(),
             )));
         }
diff --git a/crates/ruff_linter/src/rules/pydocstyle/rules/capitalized.rs b/crates/ruff_linter/src/rules/pydocstyle/rules/capitalized.rs
index 32cfa89406..23faabc2ec 100644
--- a/crates/ruff_linter/src/rules/pydocstyle/rules/capitalized.rs
+++ b/crates/ruff_linter/src/rules/pydocstyle/rules/capitalized.rs
@@ -94,7 +94,7 @@ pub(crate) fn capitalized(checker: &Checker, docstring: &Docstring) {
     let mut diagnostic = checker.report_diagnostic(
         FirstWordUncapitalized {
             first_word: first_word.to_string(),
-            capitalized_word: capitalized_word.to_string(),
+            capitalized_word: capitalized_word.clone(),
         },
         docstring.range(),
     );
diff --git a/crates/ruff_linter/src/rules/refurb/rules/bit_count.rs b/crates/ruff_linter/src/rules/refurb/rules/bit_count.rs
index b86c6e9d9e..0690ca5449 100644
--- a/crates/ruff_linter/src/rules/refurb/rules/bit_count.rs
+++ b/crates/ruff_linter/src/rules/refurb/rules/bit_count.rs
@@ -188,7 +188,7 @@ pub(crate) fn bit_count(checker: &Checker, call: &ExprCall) {
     let mut diagnostic = checker.report_diagnostic(
         BitCount {
             existing: SourceCodeSnippet::from_str(literal_text),
-            replacement: SourceCodeSnippet::new(replacement.to_string()),
+            replacement: SourceCodeSnippet::new(replacement.clone()),
         },
         call.range(),
     );
diff --git a/crates/ruff_python_formatter/src/lib.rs b/crates/ruff_python_formatter/src/lib.rs
index e6b2f9e7b8..bf68598e13 100644
--- a/crates/ruff_python_formatter/src/lib.rs
+++ b/crates/ruff_python_formatter/src/lib.rs
@@ -334,7 +334,7 @@ class A: ...
         let options = PyFormatOptions::from_source_type(source_type);
         let printed = format_range(&source, TextRange::new(start, end), options).unwrap();
 
-        let mut formatted = source.to_string();
+        let mut formatted = source.clone();
         formatted.replace_range(
             std::ops::Range::<usize>::from(printed.source_range()),
             printed.as_code(),
diff --git a/crates/ty_python_semantic/src/python_platform.rs b/crates/ty_python_semantic/src/python_platform.rs
index b21424ee33..04f7fa3598 100644
--- a/crates/ty_python_semantic/src/python_platform.rs
+++ b/crates/ty_python_semantic/src/python_platform.rs
@@ -24,7 +24,7 @@ impl From<String> for PythonPlatform {
     fn from(platform: String) -> Self {
         match platform.as_str() {
             "all" => PythonPlatform::All,
-            _ => PythonPlatform::Identifier(platform.to_string()),
+            _ => PythonPlatform::Identifier(platform.clone()),
         }
     }
 }
diff --git a/crates/ty_python_semantic/src/semantic_index/use_def.rs b/crates/ty_python_semantic/src/semantic_index/use_def.rs
index 39f3a1a8ec..dcca102b87 100644
--- a/crates/ty_python_semantic/src/semantic_index/use_def.rs
+++ b/crates/ty_python_semantic/src/semantic_index/use_def.rs
@@ -233,7 +233,7 @@
 //! have two live bindings of `x`: `x = 3` and `x = 4`.
 //!
 //! Another piece of information that the `UseDefMap` needs to provide are reachability constraints.
-//! See [`reachability_constraints.rs`] for more details, in particular how they apply to bindings.
+//! See `reachability_constraints.rs` for more details, in particular how they apply to bindings.
 //!
 //! The [`UseDefMapBuilder`] itself just exposes methods for taking a snapshot, resetting to a
 //! snapshot, and merging a snapshot into the current state. The logic using these methods lives in
diff --git a/rust-toolchain.toml b/rust-toolchain.toml
index 73328e053b..1a35d66439 100644
--- a/rust-toolchain.toml
+++ b/rust-toolchain.toml
@@ -1,2 +1,2 @@
 [toolchain]
-channel = "1.90"
+channel = "1.91"