Format Function definitions (#4951)

crates/ruff_python_ast/src/function.rs

@@ -112,3 +112,22 @@ impl<'a> From<&'a StmtAsyncFunctionDef> for AnyFunctionDefinition<'a> {
         Self::AsyncFunctionDefinition(value)
     }
 }
+
+impl<'a> From<AnyFunctionDefinition<'a>> for AnyNodeRef<'a> {
+    fn from(value: AnyFunctionDefinition<'a>) -> Self {
+        match value {
+            AnyFunctionDefinition::FunctionDefinition(function_def) => {
+                AnyNodeRef::StmtFunctionDef(function_def)
+            }
+            AnyFunctionDefinition::AsyncFunctionDefinition(async_def) => {
+                AnyNodeRef::StmtAsyncFunctionDef(async_def)
+            }
+        }
+    }
+}
+
+impl<'a> From<&'a AnyFunctionDefinition<'a>> for AnyNodeRef<'a> {
+    fn from(value: &'a AnyFunctionDefinition<'a>) -> Self {
+        (*value).into()
+    }
+}

crates/ruff_python_formatter/generate.py

@@ -77,6 +77,11 @@ for group, group_nodes in nodes_grouped.items():
     # )
     # src.joinpath(groups[group]).joinpath("mod.rs").write_text(rustfmt(mod_section))
     for node in group_nodes:
+        node_path = src.joinpath(groups[group]).joinpath(f"{to_camel_case(node)}.rs")
+        # Don't override existing manual implementations
+        if node_path.exists():
+            continue
+
         code = f"""
             use crate::{{verbatim_text, FormatNodeRule, PyFormatter}};
             use ruff_formatter::{{write, Buffer, FormatResult}};
@@ -91,9 +96,8 @@ for group, group_nodes in nodes_grouped.items():
                 }}
             }}
             """.strip()  # noqa: E501
-        src.joinpath(groups[group]).joinpath(f"{to_camel_case(node)}.rs").write_text(
+
-            rustfmt(code)
+        node_path.write_text(rustfmt(code))
-        )
 
 # %%
 # Generate `FormatRule`, `AsFormat` and `IntoFormat`

crates/ruff_python_formatter/resources/test/fixtures/ruff/statement/function.py

@@ -0,0 +1,70 @@
+# Dangling comments
+def test(
+    # comment
+
+    # another
+
+): ...
+
+
+# Argument empty line spacing
+def test(
+    # comment
+    a,
+
+    # another
+
+    b,
+): ...
+
+
+### Different function argument wrappings
+
+def single_line(aaaaaaaaaaaaaaaaaaaaaaaaaaaaa, bbbbbbbbbbbbbbb, ccccccccccccccccc):
+    pass
+
+def arguments_on_their_own_line(aaaaaaaaaaaaaaaaaaaaaaaaaaaaa, bbbbbbbbbbbbbbb, ccccccccccc, ddddddddddddd, eeeeeee):
+    pass
+
+def argument_per_line(aaaaaaaaaaaaaaaaaaaaaaaaaaaaa, bbbbbbbbbbbbbbb, ccccccccccccccccc, ddddddddddddd, eeeeeeeeeeeeeeee, ffffffffffff):
+    pass
+
+def last_pos_only_trailing_comma(a, b, /,):
+    pass
+
+def last_pos_no_trailing_comma(a, b, /):
+    pass
+
+
+def varg_with_leading_comments(
+    a, b,
+    # comment
+    *args
+): ...
+
+def kwarg_with_leading_comments(
+    a, b,
+    # comment
+    **kwargs
+): ...
+
+def argument_with_long_default(
+    a,
+    b = ccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc + [
+        dddddddddddddddddddd, eeeeeeeeeeeeeeeeeeee, ffffffffffffffffffffffff
+    ],
+    h = []
+):  ...
+
+
+def argument_with_long_type_annotation(
+    a,
+    b: xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx | yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy | zzzzzzzzzzzzzzzzzzz = [0, 1, 2, 3],
+    h = []
+):  ...
+
+
+def test(): ...
+
+# Comment
+def with_leading_comment(): ...

crates/ruff_python_formatter/src/comments/format.rs

@@ -1,7 +1,7 @@
 use crate::comments::SourceComment;
 use crate::context::NodeLevel;
 use crate::prelude::*;
-use crate::trivia::{lines_after, lines_before};
+use crate::trivia::{lines_after, lines_before, skip_trailing_trivia};
 use ruff_formatter::{format_args, write, FormatError, SourceCode};
 use ruff_python_ast::node::AnyNodeRef;
 use ruff_python_ast::prelude::AstNode;
@@ -86,9 +86,10 @@ impl Format<PyFormatContext<'_>> for FormatLeadingAlternateBranchComments<'_> {
 
             write!(f, [leading_comments(self.comments)])?;
         } else if let Some(last_preceding) = self.last_node {
+            let full_end = skip_trailing_trivia(last_preceding.end(), f.context().contents());
             // The leading comments formatting ensures that it preserves the right amount of lines after
             // We need to take care of this ourselves, if there's no leading `else` comment.
-            if lines_after(last_preceding.end(), f.context().contents()) > 1 {
+            if lines_after(full_end, f.context().contents()) > 1 {
                 write!(f, [empty_line()])?;
             }
         }

crates/ruff_python_formatter/src/comments/mod.rs

@@ -103,7 +103,7 @@ use crate::comments::map::MultiMap;
 use crate::comments::node_key::NodeRefEqualityKey;
 use crate::comments::visitor::CommentsVisitor;
 pub(crate) use format::{
-    dangling_comments, dangling_node_comments, leading_alternate_branch_comments,
+    dangling_comments, dangling_node_comments, leading_alternate_branch_comments, leading_comments,
     leading_node_comments, trailing_comments, trailing_node_comments,
 };
 use ruff_formatter::{SourceCode, SourceCodeSlice};
@@ -295,6 +295,14 @@ impl<'a> Comments<'a> {
         !self.trailing_comments(node).is_empty()
     }
 
+    /// Returns `true` if the given `node` has any [trailing own line comments](self#trailing-comments).
+    #[inline]
+    pub(crate) fn has_trailing_own_line_comments(&self, node: AnyNodeRef) -> bool {
+        self.trailing_comments(node)
+            .iter()
+            .any(|comment| comment.position().is_own_line())
+    }
+
     /// Returns an iterator over the [leading](self#leading-comments) and [trailing comments](self#trailing-comments) of `node`.
     pub(crate) fn leading_trailing_comments(
         &self,

crates/ruff_python_formatter/src/comments/placement.rs

@@ -28,6 +28,7 @@ pub(super) fn place_comment<'a>(
         .or_else(|comment| {
             handle_trailing_binary_expression_left_or_operator_comment(comment, locator)
         })
+        .or_else(handle_leading_function_with_decorators_comment)
 }
 
 /// Handles leading comments in front of a match case or a trailing comment of the `match` statement.
@@ -103,9 +104,8 @@ fn handle_match_comment<'a>(
         }
     } else {
         // Comment after the last statement in a match case...
-        let match_stmt_indentation = whitespace::indentation(locator, match_stmt)
+        let match_stmt_indentation =
-            .unwrap_or_default()
+            whitespace::indentation(locator, match_stmt).map_or(usize::MAX, str::len);
-            .len();
 
         if comment_indentation <= match_case_indentation
             && comment_indentation > match_stmt_indentation
@@ -379,9 +379,8 @@ fn handle_trailing_body_comment<'a>(
     let mut grand_parent_body = None;
 
     loop {
-        let child_indentation = whitespace::indentation(locator, &current_child)
+        let child_indentation =
-            .map(str::len)
+            whitespace::indentation(locator, &current_child).map_or(usize::MAX, str::len);
-            .unwrap_or_default();
 
         match comment_indentation_len.cmp(&child_indentation) {
             Ordering::Less => {
@@ -511,6 +510,11 @@ fn handle_trailing_end_of_line_condition_comment<'a>(
         | AnyNodeRef::StmtAsyncWith(StmtAsyncWith { items, .. }) => {
             items.last().map(AnyNodeRef::from)
         }
+        AnyNodeRef::StmtFunctionDef(StmtFunctionDef { returns, args, .. })
+        | AnyNodeRef::StmtAsyncFunctionDef(StmtAsyncFunctionDef { returns, args, .. }) => returns
+            .as_deref()
+            .map(AnyNodeRef::from)
+            .or_else(|| Some(AnyNodeRef::from(args.as_ref()))),
         _ => None,
     };
 
@@ -820,6 +824,32 @@ fn find_pos_only_slash_offset(
     None
 }
 
+/// Handles own line comments between the last function decorator and the *header* of the function.
+/// It attaches these comments as dangling comments to the function instead of making them
+/// leading argument comments.
+///
+/// ```python
+/// @decorator
+/// # leading function comment
+/// def test():
+///      ...
+/// ```
+fn handle_leading_function_with_decorators_comment(comment: DecoratedComment) -> CommentPlacement {
+    let is_preceding_decorator = comment
+        .preceding_node()
+        .map_or(false, |node| node.is_decorator());
+
+    let is_following_arguments = comment
+        .following_node()
+        .map_or(false, |node| node.is_arguments());
+
+    if comment.text_position().is_own_line() && is_preceding_decorator && is_following_arguments {
+        CommentPlacement::dangling(comment.enclosing_node(), comment)
+    } else {
+        CommentPlacement::Default(comment)
+    }
+}
+
 /// Returns `true` if `right` is `Some` and `left` and `right` are referentially equal.
 fn are_same_optional<'a, T>(left: AnyNodeRef, right: Option<T>) -> bool
 where

crates/ruff_python_formatter/src/comments/snapshots/ruff_python_formatter__comments__tests__trailing_comment_after_single_statement_body.snap

@@ -4,18 +4,18 @@ expression: comments.debug(test_case.source_code)
 ---
 {
     Node {
-        kind: StmtPass,
+        kind: StmtExpr,
-        range: 12..16,
+        range: 29..42,
-        source: `pass`,
+        source: `print("test")`,
     }: {
-        "leading": [],
+        "leading": [
-        "dangling": [],
-        "trailing": [
             SourceComment {
                 text: "# Test",
                 position: OwnLine,
                 formatted: false,
             },
         ],
+        "dangling": [],
+        "trailing": [],
     },
 }

crates/ruff_python_formatter/src/comments/visitor.rs

@@ -165,6 +165,13 @@ impl<'ast> PreorderVisitor<'ast> for CommentsVisitor<'ast> {
         self.finish_node(expr);
     }
 
+    fn visit_decorator(&mut self, decorator: &'ast Decorator) {
+        if self.start_node(decorator).is_traverse() {
+            walk_decorator(self, decorator);
+        }
+        self.finish_node(decorator);
+    }
+
     fn visit_expr(&mut self, expr: &'ast Expr) {
         if self.start_node(expr).is_traverse() {
             walk_expr(self, expr);

crates/ruff_python_formatter/src/expression/expr_attribute.rs

@@ -1,3 +1,4 @@
+use crate::comments::Comments;
 use crate::expression::parentheses::{
     default_expression_needs_parentheses, NeedsParentheses, Parentheses, Parenthesize,
 };
@@ -39,7 +40,12 @@ impl FormatNodeRule<ExprAttribute> for FormatExprAttribute {
 }
 
 impl NeedsParentheses for ExprAttribute {
-    fn needs_parentheses(&self, parenthesize: Parenthesize, source: &str) -> Parentheses {
+    fn needs_parentheses(
-        default_expression_needs_parentheses(self.into(), parenthesize, source)
+        &self,
+        parenthesize: Parenthesize,
+        source: &str,
+        comments: &Comments,
+    ) -> Parentheses {
+        default_expression_needs_parentheses(self.into(), parenthesize, source, comments)
     }
 }

crates/ruff_python_formatter/src/expression/expr_await.rs

@@ -1,3 +1,4 @@
+use crate::comments::Comments;
 use crate::expression::parentheses::{
     default_expression_needs_parentheses, NeedsParentheses, Parentheses, Parenthesize,
 };
@@ -17,7 +18,12 @@ impl FormatNodeRule<ExprAwait> for FormatExprAwait {
 }
 
 impl NeedsParentheses for ExprAwait {
-    fn needs_parentheses(&self, parenthesize: Parenthesize, source: &str) -> Parentheses {
+    fn needs_parentheses(
-        default_expression_needs_parentheses(self.into(), parenthesize, source)
+        &self,
+        parenthesize: Parenthesize,
+        source: &str,
+        comments: &Comments,
+    ) -> Parentheses {
+        default_expression_needs_parentheses(self.into(), parenthesize, source, comments)
     }
 }

crates/ruff_python_formatter/src/expression/expr_bin_op.rs

@@ -1,4 +1,4 @@
-use crate::comments::trailing_comments;
+use crate::comments::{trailing_comments, Comments};
 use crate::expression::parentheses::{
     default_expression_needs_parentheses, NeedsParentheses, Parenthesize,
 };
@@ -171,8 +171,13 @@ impl FormatRule<Operator, PyFormatContext<'_>> for FormatOperator {
 }
 
 impl NeedsParentheses for ExprBinOp {
-    fn needs_parentheses(&self, parenthesize: Parenthesize, source: &str) -> Parentheses {
+    fn needs_parentheses(
-        match default_expression_needs_parentheses(self.into(), parenthesize, source) {
+        &self,
+        parenthesize: Parenthesize,
+        source: &str,
+        comments: &Comments,
+    ) -> Parentheses {
+        match default_expression_needs_parentheses(self.into(), parenthesize, source, comments) {
             Parentheses::Optional => {
                 if should_binary_break_right_side_first(self) {
                     Parentheses::Custom

crates/ruff_python_formatter/src/expression/expr_bool_op.rs

@@ -1,3 +1,4 @@
+use crate::comments::Comments;
 use crate::expression::parentheses::{
     default_expression_needs_parentheses, NeedsParentheses, Parentheses, Parenthesize,
 };
@@ -20,7 +21,12 @@ impl FormatNodeRule<ExprBoolOp> for FormatExprBoolOp {
 }
 
 impl NeedsParentheses for ExprBoolOp {
-    fn needs_parentheses(&self, parenthesize: Parenthesize, source: &str) -> Parentheses {
+    fn needs_parentheses(
-        default_expression_needs_parentheses(self.into(), parenthesize, source)
+        &self,
+        parenthesize: Parenthesize,
+        source: &str,
+        comments: &Comments,
+    ) -> Parentheses {
+        default_expression_needs_parentheses(self.into(), parenthesize, source, comments)
     }
 }

crates/ruff_python_formatter/src/expression/expr_call.rs

@@ -1,3 +1,4 @@
+use crate::comments::Comments;
 use crate::expression::parentheses::{
     default_expression_needs_parentheses, NeedsParentheses, Parentheses, Parenthesize,
 };
@@ -18,8 +19,13 @@ impl FormatNodeRule<ExprCall> for FormatExprCall {
 }
 
 impl NeedsParentheses for ExprCall {
-    fn needs_parentheses(&self, parenthesize: Parenthesize, source: &str) -> Parentheses {
+    fn needs_parentheses(
-        match default_expression_needs_parentheses(self.into(), parenthesize, source) {
+        &self,
+        parenthesize: Parenthesize,
+        source: &str,
+        comments: &Comments,
+    ) -> Parentheses {
+        match default_expression_needs_parentheses(self.into(), parenthesize, source, comments) {
             Parentheses::Optional => Parentheses::Never,
             parentheses => parentheses,
         }

crates/ruff_python_formatter/src/expression/expr_compare.rs

@@ -3,6 +3,7 @@ use crate::expression::parentheses::{
 };
 use crate::{not_yet_implemented_custom_text, FormatNodeRule, PyFormatter};
 
+use crate::comments::Comments;
 use ruff_formatter::{write, Buffer, FormatResult};
 use rustpython_parser::ast::ExprCompare;
 
@@ -21,7 +22,12 @@ impl FormatNodeRule<ExprCompare> for FormatExprCompare {
 }
 
 impl NeedsParentheses for ExprCompare {
-    fn needs_parentheses(&self, parenthesize: Parenthesize, source: &str) -> Parentheses {
+    fn needs_parentheses(
-        default_expression_needs_parentheses(self.into(), parenthesize, source)
+        &self,
+        parenthesize: Parenthesize,
+        source: &str,
+        comments: &Comments,
+    ) -> Parentheses {
+        default_expression_needs_parentheses(self.into(), parenthesize, source, comments)
     }
 }

crates/ruff_python_formatter/src/expression/expr_constant.rs

@@ -1,3 +1,4 @@
+use crate::comments::Comments;
 use crate::expression::parentheses::{
     default_expression_needs_parentheses, NeedsParentheses, Parentheses, Parenthesize,
 };
@@ -41,7 +42,15 @@ impl FormatNodeRule<ExprConstant> for FormatExprConstant {
 }
 
 impl NeedsParentheses for ExprConstant {
-    fn needs_parentheses(&self, parenthesize: Parenthesize, source: &str) -> Parentheses {
+    fn needs_parentheses(
-        default_expression_needs_parentheses(self.into(), parenthesize, source)
+        &self,
+        parenthesize: Parenthesize,
+        source: &str,
+        comments: &Comments,
+    ) -> Parentheses {
+        match default_expression_needs_parentheses(self.into(), parenthesize, source, comments) {
+            Parentheses::Optional => Parentheses::Never,
+            parentheses => parentheses,
+        }
     }
 }

crates/ruff_python_formatter/src/expression/expr_dict.rs

@@ -1,3 +1,4 @@
+use crate::comments::Comments;
 use crate::expression::parentheses::{
     default_expression_needs_parentheses, NeedsParentheses, Parentheses, Parenthesize,
 };
@@ -20,8 +21,13 @@ impl FormatNodeRule<ExprDict> for FormatExprDict {
 }
 
 impl NeedsParentheses for ExprDict {
-    fn needs_parentheses(&self, parenthesize: Parenthesize, source: &str) -> Parentheses {
+    fn needs_parentheses(
-        match default_expression_needs_parentheses(self.into(), parenthesize, source) {
+        &self,
+        parenthesize: Parenthesize,
+        source: &str,
+        comments: &Comments,
+    ) -> Parentheses {
+        match default_expression_needs_parentheses(self.into(), parenthesize, source, comments) {
             Parentheses::Optional => Parentheses::Never,
             parentheses => parentheses,
         }

crates/ruff_python_formatter/src/expression/expr_dict_comp.rs

@@ -1,3 +1,4 @@
+use crate::comments::Comments;
 use crate::expression::parentheses::{
     default_expression_needs_parentheses, NeedsParentheses, Parentheses, Parenthesize,
 };
@@ -20,8 +21,13 @@ impl FormatNodeRule<ExprDictComp> for FormatExprDictComp {
 }
 
 impl NeedsParentheses for ExprDictComp {
-    fn needs_parentheses(&self, parenthesize: Parenthesize, source: &str) -> Parentheses {
+    fn needs_parentheses(
-        match default_expression_needs_parentheses(self.into(), parenthesize, source) {
+        &self,
+        parenthesize: Parenthesize,
+        source: &str,
+        comments: &Comments,
+    ) -> Parentheses {
+        match default_expression_needs_parentheses(self.into(), parenthesize, source, comments) {
             Parentheses::Optional => Parentheses::Never,
             parentheses => parentheses,
         }

crates/ruff_python_formatter/src/expression/expr_formatted_value.rs

@@ -1,3 +1,4 @@
+use crate::comments::Comments;
 use crate::expression::parentheses::{
     default_expression_needs_parentheses, NeedsParentheses, Parentheses, Parenthesize,
 };
@@ -15,7 +16,12 @@ impl FormatNodeRule<ExprFormattedValue> for FormatExprFormattedValue {
 }
 
 impl NeedsParentheses for ExprFormattedValue {
-    fn needs_parentheses(&self, parenthesize: Parenthesize, source: &str) -> Parentheses {
+    fn needs_parentheses(
-        default_expression_needs_parentheses(self.into(), parenthesize, source)
+        &self,
+        parenthesize: Parenthesize,
+        source: &str,
+        comments: &Comments,
+    ) -> Parentheses {
+        default_expression_needs_parentheses(self.into(), parenthesize, source, comments)
     }
 }

crates/ruff_python_formatter/src/expression/expr_generator_exp.rs

@@ -1,3 +1,4 @@
+use crate::comments::Comments;
 use crate::expression::parentheses::{
     default_expression_needs_parentheses, NeedsParentheses, Parentheses, Parenthesize,
 };
@@ -15,8 +16,13 @@ impl FormatNodeRule<ExprGeneratorExp> for FormatExprGeneratorExp {
 }
 
 impl NeedsParentheses for ExprGeneratorExp {
-    fn needs_parentheses(&self, parenthesize: Parenthesize, source: &str) -> Parentheses {
+    fn needs_parentheses(
-        match default_expression_needs_parentheses(self.into(), parenthesize, source) {
+        &self,
+        parenthesize: Parenthesize,
+        source: &str,
+        comments: &Comments,
+    ) -> Parentheses {
+        match default_expression_needs_parentheses(self.into(), parenthesize, source, comments) {
             Parentheses::Optional => Parentheses::Never,
             parentheses => parentheses,
         }

crates/ruff_python_formatter/src/expression/expr_if_exp.rs

@@ -1,3 +1,4 @@
+use crate::comments::Comments;
 use crate::expression::parentheses::{
     default_expression_needs_parentheses, NeedsParentheses, Parentheses, Parenthesize,
 };
@@ -20,7 +21,12 @@ impl FormatNodeRule<ExprIfExp> for FormatExprIfExp {
 }
 
 impl NeedsParentheses for ExprIfExp {
-    fn needs_parentheses(&self, parenthesize: Parenthesize, source: &str) -> Parentheses {
+    fn needs_parentheses(
-        default_expression_needs_parentheses(self.into(), parenthesize, source)
+        &self,
+        parenthesize: Parenthesize,
+        source: &str,
+        comments: &Comments,
+    ) -> Parentheses {
+        default_expression_needs_parentheses(self.into(), parenthesize, source, comments)
     }
 }

crates/ruff_python_formatter/src/expression/expr_joined_str.rs

@@ -1,3 +1,4 @@
+use crate::comments::Comments;
 use crate::expression::parentheses::{
     default_expression_needs_parentheses, NeedsParentheses, Parentheses, Parenthesize,
 };
@@ -15,7 +16,12 @@ impl FormatNodeRule<ExprJoinedStr> for FormatExprJoinedStr {
 }
 
 impl NeedsParentheses for ExprJoinedStr {
-    fn needs_parentheses(&self, parenthesize: Parenthesize, source: &str) -> Parentheses {
+    fn needs_parentheses(
-        default_expression_needs_parentheses(self.into(), parenthesize, source)
+        &self,
+        parenthesize: Parenthesize,
+        source: &str,
+        comments: &Comments,
+    ) -> Parentheses {
+        default_expression_needs_parentheses(self.into(), parenthesize, source, comments)
     }
 }

crates/ruff_python_formatter/src/expression/expr_lambda.rs

@@ -1,3 +1,4 @@
+use crate::comments::Comments;
 use crate::expression::parentheses::{
     default_expression_needs_parentheses, NeedsParentheses, Parentheses, Parenthesize,
 };
@@ -15,7 +16,12 @@ impl FormatNodeRule<ExprLambda> for FormatExprLambda {
 }
 
 impl NeedsParentheses for ExprLambda {
-    fn needs_parentheses(&self, parenthesize: Parenthesize, source: &str) -> Parentheses {
+    fn needs_parentheses(
-        default_expression_needs_parentheses(self.into(), parenthesize, source)
+        &self,
+        parenthesize: Parenthesize,
+        source: &str,
+        comments: &Comments,
+    ) -> Parentheses {
+        default_expression_needs_parentheses(self.into(), parenthesize, source, comments)
     }
 }

crates/ruff_python_formatter/src/expression/expr_list.rs

@@ -1,4 +1,4 @@
-use crate::comments::dangling_comments;
+use crate::comments::{dangling_comments, Comments};
 use crate::expression::parentheses::{
     default_expression_needs_parentheses, NeedsParentheses, Parentheses, Parenthesize,
 };
@@ -57,8 +57,13 @@ impl FormatNodeRule<ExprList> for FormatExprList {
 }
 
 impl NeedsParentheses for ExprList {
-    fn needs_parentheses(&self, parenthesize: Parenthesize, source: &str) -> Parentheses {
+    fn needs_parentheses(
-        match default_expression_needs_parentheses(self.into(), parenthesize, source) {
+        &self,
+        parenthesize: Parenthesize,
+        source: &str,
+        comments: &Comments,
+    ) -> Parentheses {
+        match default_expression_needs_parentheses(self.into(), parenthesize, source, comments) {
             Parentheses::Optional => Parentheses::Never,
             parentheses => parentheses,
         }

crates/ruff_python_formatter/src/expression/expr_list_comp.rs

@@ -1,3 +1,4 @@
+use crate::comments::Comments;
 use crate::expression::parentheses::{
     default_expression_needs_parentheses, NeedsParentheses, Parentheses, Parenthesize,
 };
@@ -15,8 +16,13 @@ impl FormatNodeRule<ExprListComp> for FormatExprListComp {
 }
 
 impl NeedsParentheses for ExprListComp {
-    fn needs_parentheses(&self, parenthesize: Parenthesize, source: &str) -> Parentheses {
+    fn needs_parentheses(
-        match default_expression_needs_parentheses(self.into(), parenthesize, source) {
+        &self,
+        parenthesize: Parenthesize,
+        source: &str,
+        comments: &Comments,
+    ) -> Parentheses {
+        match default_expression_needs_parentheses(self.into(), parenthesize, source, comments) {
             Parentheses::Optional => Parentheses::Never,
             parentheses => parentheses,
         }

crates/ruff_python_formatter/src/expression/expr_name.rs

@@ -1,3 +1,4 @@
+use crate::comments::Comments;
 use crate::expression::parentheses::{
     default_expression_needs_parentheses, NeedsParentheses, Parentheses, Parenthesize,
 };
@@ -26,8 +27,13 @@ impl FormatNodeRule<ExprName> for FormatExprName {
 }
 
 impl NeedsParentheses for ExprName {
-    fn needs_parentheses(&self, parenthesize: Parenthesize, source: &str) -> Parentheses {
+    fn needs_parentheses(
-        default_expression_needs_parentheses(self.into(), parenthesize, source)
+        &self,
+        parenthesize: Parenthesize,
+        source: &str,
+        comments: &Comments,
+    ) -> Parentheses {
+        default_expression_needs_parentheses(self.into(), parenthesize, source, comments)
     }
 }
 

crates/ruff_python_formatter/src/expression/expr_named_expr.rs

@@ -1,3 +1,4 @@
+use crate::comments::Comments;
 use crate::expression::parentheses::{
     default_expression_needs_parentheses, NeedsParentheses, Parentheses, Parenthesize,
 };
@@ -15,7 +16,12 @@ impl FormatNodeRule<ExprNamedExpr> for FormatExprNamedExpr {
 }
 
 impl NeedsParentheses for ExprNamedExpr {
-    fn needs_parentheses(&self, parenthesize: Parenthesize, source: &str) -> Parentheses {
+    fn needs_parentheses(
-        default_expression_needs_parentheses(self.into(), parenthesize, source)
+        &self,
+        parenthesize: Parenthesize,
+        source: &str,
+        comments: &Comments,
+    ) -> Parentheses {
+        default_expression_needs_parentheses(self.into(), parenthesize, source, comments)
     }
 }

crates/ruff_python_formatter/src/expression/expr_set.rs

@@ -1,3 +1,4 @@
+use crate::comments::Comments;
 use crate::expression::parentheses::{
     default_expression_needs_parentheses, NeedsParentheses, Parentheses, Parenthesize,
 };
@@ -34,8 +35,13 @@ impl FormatNodeRule<ExprSet> for FormatExprSet {
 }
 
 impl NeedsParentheses for ExprSet {
-    fn needs_parentheses(&self, parenthesize: Parenthesize, source: &str) -> Parentheses {
+    fn needs_parentheses(
-        match default_expression_needs_parentheses(self.into(), parenthesize, source) {
+        &self,
+        parenthesize: Parenthesize,
+        source: &str,
+        comments: &Comments,
+    ) -> Parentheses {
+        match default_expression_needs_parentheses(self.into(), parenthesize, source, comments) {
             Parentheses::Optional => Parentheses::Never,
             parentheses => parentheses,
         }

crates/ruff_python_formatter/src/expression/expr_set_comp.rs

@@ -1,3 +1,4 @@
+use crate::comments::Comments;
 use crate::expression::parentheses::{
     default_expression_needs_parentheses, NeedsParentheses, Parentheses, Parenthesize,
 };
@@ -15,8 +16,13 @@ impl FormatNodeRule<ExprSetComp> for FormatExprSetComp {
 }
 
 impl NeedsParentheses for ExprSetComp {
-    fn needs_parentheses(&self, parenthesize: Parenthesize, source: &str) -> Parentheses {
+    fn needs_parentheses(
-        match default_expression_needs_parentheses(self.into(), parenthesize, source) {
+        &self,
+        parenthesize: Parenthesize,
+        source: &str,
+        comments: &Comments,
+    ) -> Parentheses {
+        match default_expression_needs_parentheses(self.into(), parenthesize, source, comments) {
             Parentheses::Optional => Parentheses::Never,
             parentheses => parentheses,
         }

crates/ruff_python_formatter/src/expression/expr_slice.rs

@@ -3,6 +3,7 @@ use crate::expression::parentheses::{
 };
 use crate::{not_yet_implemented_custom_text, FormatNodeRule, PyFormatter};
 
+use crate::comments::Comments;
 use ruff_formatter::{write, Buffer, FormatResult};
 use rustpython_parser::ast::ExprSlice;
 
@@ -21,7 +22,12 @@ impl FormatNodeRule<ExprSlice> for FormatExprSlice {
 }
 
 impl NeedsParentheses for ExprSlice {
-    fn needs_parentheses(&self, parenthesize: Parenthesize, source: &str) -> Parentheses {
+    fn needs_parentheses(
-        default_expression_needs_parentheses(self.into(), parenthesize, source)
+        &self,
+        parenthesize: Parenthesize,
+        source: &str,
+        comments: &Comments,
+    ) -> Parentheses {
+        default_expression_needs_parentheses(self.into(), parenthesize, source, comments)
     }
 }

crates/ruff_python_formatter/src/expression/expr_starred.rs

@@ -1,3 +1,4 @@
+use crate::comments::Comments;
 use crate::expression::parentheses::{
     default_expression_needs_parentheses, NeedsParentheses, Parentheses, Parenthesize,
 };
@@ -15,7 +16,12 @@ impl FormatNodeRule<ExprStarred> for FormatExprStarred {
 }
 
 impl NeedsParentheses for ExprStarred {
-    fn needs_parentheses(&self, parenthesize: Parenthesize, source: &str) -> Parentheses {
+    fn needs_parentheses(
-        default_expression_needs_parentheses(self.into(), parenthesize, source)
+        &self,
+        parenthesize: Parenthesize,
+        source: &str,
+        comments: &Comments,
+    ) -> Parentheses {
+        default_expression_needs_parentheses(self.into(), parenthesize, source, comments)
     }
 }

crates/ruff_python_formatter/src/expression/expr_subscript.rs

@@ -3,6 +3,7 @@ use crate::expression::parentheses::{
 };
 use crate::{not_yet_implemented_custom_text, FormatNodeRule, PyFormatter};
 
+use crate::comments::Comments;
 use ruff_formatter::{write, Buffer, FormatResult};
 use rustpython_parser::ast::ExprSubscript;
 
@@ -21,7 +22,12 @@ impl FormatNodeRule<ExprSubscript> for FormatExprSubscript {
 }
 
 impl NeedsParentheses for ExprSubscript {
-    fn needs_parentheses(&self, parenthesize: Parenthesize, source: &str) -> Parentheses {
+    fn needs_parentheses(
-        default_expression_needs_parentheses(self.into(), parenthesize, source)
+        &self,
+        parenthesize: Parenthesize,
+        source: &str,
+        comments: &Comments,
+    ) -> Parentheses {
+        default_expression_needs_parentheses(self.into(), parenthesize, source, comments)
     }
 }

crates/ruff_python_formatter/src/expression/expr_tuple.rs

@@ -1,3 +1,4 @@
+use crate::comments::Comments;
 use crate::expression::parentheses::{
     default_expression_needs_parentheses, NeedsParentheses, Parentheses, Parenthesize,
 };
@@ -15,8 +16,13 @@ impl FormatNodeRule<ExprTuple> for FormatExprTuple {
 }
 
 impl NeedsParentheses for ExprTuple {
-    fn needs_parentheses(&self, parenthesize: Parenthesize, source: &str) -> Parentheses {
+    fn needs_parentheses(
-        match default_expression_needs_parentheses(self.into(), parenthesize, source) {
+        &self,
+        parenthesize: Parenthesize,
+        source: &str,
+        comments: &Comments,
+    ) -> Parentheses {
+        match default_expression_needs_parentheses(self.into(), parenthesize, source, comments) {
             Parentheses::Optional => Parentheses::Never,
             parentheses => parentheses,
         }

crates/ruff_python_formatter/src/expression/expr_unary_op.rs

@@ -1,3 +1,4 @@
+use crate::comments::Comments;
 use crate::expression::parentheses::{
     default_expression_needs_parentheses, NeedsParentheses, Parentheses, Parenthesize,
 };
@@ -15,7 +16,12 @@ impl FormatNodeRule<ExprUnaryOp> for FormatExprUnaryOp {
 }
 
 impl NeedsParentheses for ExprUnaryOp {
-    fn needs_parentheses(&self, parenthesize: Parenthesize, source: &str) -> Parentheses {
+    fn needs_parentheses(
-        default_expression_needs_parentheses(self.into(), parenthesize, source)
+        &self,
+        parenthesize: Parenthesize,
+        source: &str,
+        comments: &Comments,
+    ) -> Parentheses {
+        default_expression_needs_parentheses(self.into(), parenthesize, source, comments)
     }
 }

crates/ruff_python_formatter/src/expression/expr_yield.rs

@@ -1,3 +1,4 @@
+use crate::comments::Comments;
 use crate::expression::parentheses::{
     default_expression_needs_parentheses, NeedsParentheses, Parentheses, Parenthesize,
 };
@@ -15,7 +16,12 @@ impl FormatNodeRule<ExprYield> for FormatExprYield {
 }
 
 impl NeedsParentheses for ExprYield {
-    fn needs_parentheses(&self, parenthesize: Parenthesize, source: &str) -> Parentheses {
+    fn needs_parentheses(
-        default_expression_needs_parentheses(self.into(), parenthesize, source)
+        &self,
+        parenthesize: Parenthesize,
+        source: &str,
+        comments: &Comments,
+    ) -> Parentheses {
+        default_expression_needs_parentheses(self.into(), parenthesize, source, comments)
     }
 }

crates/ruff_python_formatter/src/expression/expr_yield_from.rs

@@ -1,3 +1,4 @@
+use crate::comments::Comments;
 use crate::expression::parentheses::{
     default_expression_needs_parentheses, NeedsParentheses, Parentheses, Parenthesize,
 };
@@ -15,7 +16,12 @@ impl FormatNodeRule<ExprYieldFrom> for FormatExprYieldFrom {
 }
 
 impl NeedsParentheses for ExprYieldFrom {
-    fn needs_parentheses(&self, parenthesize: Parenthesize, source: &str) -> Parentheses {
+    fn needs_parentheses(
-        default_expression_needs_parentheses(self.into(), parenthesize, source)
+        &self,
+        parenthesize: Parenthesize,
+        source: &str,
+        comments: &Comments,
+    ) -> Parentheses {
+        default_expression_needs_parentheses(self.into(), parenthesize, source, comments)
     }
 }

crates/ruff_python_formatter/src/expression/mod.rs

@@ -1,3 +1,4 @@
+use crate::comments::Comments;
 use crate::context::NodeLevel;
 use crate::expression::parentheses::{NeedsParentheses, Parentheses, Parenthesize};
 use crate::prelude::*;
@@ -51,7 +52,11 @@ impl FormatRuleWithOptions<Expr, PyFormatContext<'_>> for FormatExpr {
 
 impl FormatRule<Expr, PyFormatContext<'_>> for FormatExpr {
     fn fmt(&self, item: &Expr, f: &mut PyFormatter) -> FormatResult<()> {
-        let parentheses = item.needs_parentheses(self.parenthesize, f.context().contents());
+        let parentheses = item.needs_parentheses(
+            self.parenthesize,
+            f.context().contents(),
+            f.context().comments(),
+        );
 
         let format_expr = format_with(|f| match item {
             Expr::BoolOp(expr) => expr.format().fmt(f),
@@ -118,35 +123,40 @@ impl FormatRule<Expr, PyFormatContext<'_>> for FormatExpr {
 }
 
 impl NeedsParentheses for Expr {
-    fn needs_parentheses(&self, parenthesize: Parenthesize, source: &str) -> Parentheses {
+    fn needs_parentheses(
+        &self,
+        parenthesize: Parenthesize,
+        source: &str,
+        comments: &Comments,
+    ) -> Parentheses {
         match self {
-            Expr::BoolOp(expr) => expr.needs_parentheses(parenthesize, source),
+            Expr::BoolOp(expr) => expr.needs_parentheses(parenthesize, source, comments),
-            Expr::NamedExpr(expr) => expr.needs_parentheses(parenthesize, source),
+            Expr::NamedExpr(expr) => expr.needs_parentheses(parenthesize, source, comments),
-            Expr::BinOp(expr) => expr.needs_parentheses(parenthesize, source),
+            Expr::BinOp(expr) => expr.needs_parentheses(parenthesize, source, comments),
-            Expr::UnaryOp(expr) => expr.needs_parentheses(parenthesize, source),
+            Expr::UnaryOp(expr) => expr.needs_parentheses(parenthesize, source, comments),
-            Expr::Lambda(expr) => expr.needs_parentheses(parenthesize, source),
+            Expr::Lambda(expr) => expr.needs_parentheses(parenthesize, source, comments),
-            Expr::IfExp(expr) => expr.needs_parentheses(parenthesize, source),
+            Expr::IfExp(expr) => expr.needs_parentheses(parenthesize, source, comments),
-            Expr::Dict(expr) => expr.needs_parentheses(parenthesize, source),
+            Expr::Dict(expr) => expr.needs_parentheses(parenthesize, source, comments),
-            Expr::Set(expr) => expr.needs_parentheses(parenthesize, source),
+            Expr::Set(expr) => expr.needs_parentheses(parenthesize, source, comments),
-            Expr::ListComp(expr) => expr.needs_parentheses(parenthesize, source),
+            Expr::ListComp(expr) => expr.needs_parentheses(parenthesize, source, comments),
-            Expr::SetComp(expr) => expr.needs_parentheses(parenthesize, source),
+            Expr::SetComp(expr) => expr.needs_parentheses(parenthesize, source, comments),
-            Expr::DictComp(expr) => expr.needs_parentheses(parenthesize, source),
+            Expr::DictComp(expr) => expr.needs_parentheses(parenthesize, source, comments),
-            Expr::GeneratorExp(expr) => expr.needs_parentheses(parenthesize, source),
+            Expr::GeneratorExp(expr) => expr.needs_parentheses(parenthesize, source, comments),
-            Expr::Await(expr) => expr.needs_parentheses(parenthesize, source),
+            Expr::Await(expr) => expr.needs_parentheses(parenthesize, source, comments),
-            Expr::Yield(expr) => expr.needs_parentheses(parenthesize, source),
+            Expr::Yield(expr) => expr.needs_parentheses(parenthesize, source, comments),
-            Expr::YieldFrom(expr) => expr.needs_parentheses(parenthesize, source),
+            Expr::YieldFrom(expr) => expr.needs_parentheses(parenthesize, source, comments),
-            Expr::Compare(expr) => expr.needs_parentheses(parenthesize, source),
+            Expr::Compare(expr) => expr.needs_parentheses(parenthesize, source, comments),
-            Expr::Call(expr) => expr.needs_parentheses(parenthesize, source),
+            Expr::Call(expr) => expr.needs_parentheses(parenthesize, source, comments),
-            Expr::FormattedValue(expr) => expr.needs_parentheses(parenthesize, source),
+            Expr::FormattedValue(expr) => expr.needs_parentheses(parenthesize, source, comments),
-            Expr::JoinedStr(expr) => expr.needs_parentheses(parenthesize, source),
+            Expr::JoinedStr(expr) => expr.needs_parentheses(parenthesize, source, comments),
-            Expr::Constant(expr) => expr.needs_parentheses(parenthesize, source),
+            Expr::Constant(expr) => expr.needs_parentheses(parenthesize, source, comments),
-            Expr::Attribute(expr) => expr.needs_parentheses(parenthesize, source),
+            Expr::Attribute(expr) => expr.needs_parentheses(parenthesize, source, comments),
-            Expr::Subscript(expr) => expr.needs_parentheses(parenthesize, source),
+            Expr::Subscript(expr) => expr.needs_parentheses(parenthesize, source, comments),
-            Expr::Starred(expr) => expr.needs_parentheses(parenthesize, source),
+            Expr::Starred(expr) => expr.needs_parentheses(parenthesize, source, comments),
-            Expr::Name(expr) => expr.needs_parentheses(parenthesize, source),
+            Expr::Name(expr) => expr.needs_parentheses(parenthesize, source, comments),
-            Expr::List(expr) => expr.needs_parentheses(parenthesize, source),
+            Expr::List(expr) => expr.needs_parentheses(parenthesize, source, comments),
-            Expr::Tuple(expr) => expr.needs_parentheses(parenthesize, source),
+            Expr::Tuple(expr) => expr.needs_parentheses(parenthesize, source, comments),
-            Expr::Slice(expr) => expr.needs_parentheses(parenthesize, source),
+            Expr::Slice(expr) => expr.needs_parentheses(parenthesize, source, comments),
         }
     }
 }

crates/ruff_python_formatter/src/expression/parentheses.rs

@@ -1,15 +1,22 @@
+use crate::comments::Comments;
 use crate::trivia::{first_non_trivia_token, first_non_trivia_token_rev, Token, TokenKind};
 use ruff_python_ast::node::AnyNodeRef;
 use rustpython_parser::ast::Ranged;
 
 pub(crate) trait NeedsParentheses {
-    fn needs_parentheses(&self, parenthesize: Parenthesize, source: &str) -> Parentheses;
+    fn needs_parentheses(
+        &self,
+        parenthesize: Parenthesize,
+        source: &str,
+        comments: &Comments,
+    ) -> Parentheses;
 }
 
 pub(super) fn default_expression_needs_parentheses(
     node: AnyNodeRef,
     parenthesize: Parenthesize,
     source: &str,
+    comments: &Comments,
 ) -> Parentheses {
     debug_assert!(
         node.is_expression(),
@@ -20,9 +27,14 @@ pub(super) fn default_expression_needs_parentheses(
     if !parenthesize.is_if_breaks() && is_expression_parenthesized(node, source) {
         Parentheses::Always
     }
-    // `Optional` or `IfBreaks`: Add parentheses if the expression doesn't fit on a line
+    // `Optional` or `IfBreaks`: Add parentheses if the expression doesn't fit on a line but enforce
+    // parentheses if the expression has leading comments
     else if !parenthesize.is_preserve() {
-        Parentheses::Optional
+        if comments.has_leading_comments(node) {
+            Parentheses::Always
+        } else {
+            Parentheses::Optional
+        }
     } else {
         //`Preserve` and expression has no parentheses in the source code
         Parentheses::Never

crates/ruff_python_formatter/src/generated.rs

@@ -2858,3 +2858,35 @@ impl<'ast> IntoFormat<PyFormatContext<'ast>> for ast::MatchCase {
         FormatOwnedWithRule::new(self, crate::other::match_case::FormatMatchCase::default())
     }
 }
+
+impl FormatRule<ast::Decorator, PyFormatContext<'_>> for crate::other::decorator::FormatDecorator {
+    #[inline]
+    fn fmt(
+        &self,
+        node: &ast::Decorator,
+        f: &mut Formatter<PyFormatContext<'_>>,
+    ) -> FormatResult<()> {
+        FormatNodeRule::<ast::Decorator>::fmt(self, node, f)
+    }
+}
+impl<'ast> AsFormat<PyFormatContext<'ast>> for ast::Decorator {
+    type Format<'a> = FormatRefWithRule<
+        'a,
+        ast::Decorator,
+        crate::other::decorator::FormatDecorator,
+        PyFormatContext<'ast>,
+    >;
+    fn format(&self) -> Self::Format<'_> {
+        FormatRefWithRule::new(self, crate::other::decorator::FormatDecorator::default())
+    }
+}
+impl<'ast> IntoFormat<PyFormatContext<'ast>> for ast::Decorator {
+    type Format = FormatOwnedWithRule<
+        ast::Decorator,
+        crate::other::decorator::FormatDecorator,
+        PyFormatContext<'ast>,
+    >;
+    fn into_format(self) -> Self::Format {
+        FormatOwnedWithRule::new(self, crate::other::decorator::FormatDecorator::default())
+    }
+}

crates/ruff_python_formatter/src/lib.rs

@@ -225,18 +225,16 @@ impl Format<PyFormatContext<'_>> for VerbatimText {
 
 #[cfg(test)]
 mod tests {
-    use std::fmt::{Formatter, Write};
-    use std::fs;
-    use std::path::Path;
-
     use anyhow::Result;
     use insta::assert_snapshot;
+    use ruff_python_ast::source_code::CommentRangesBuilder;
+    use ruff_testing_macros::fixture;
     use rustpython_parser::lexer::lex;
     use rustpython_parser::{parse_tokens, Mode};
     use similar::TextDiff;
-
+    use std::fmt::{Formatter, Write};
-    use ruff_python_ast::source_code::CommentRangesBuilder;
+    use std::fs;
-    use ruff_testing_macros::fixture;
+    use std::path::Path;
 
     use crate::{format_module, format_node};
 

crates/ruff_python_formatter/src/other/arg.rs

@@ -1,12 +1,66 @@
-use crate::{not_yet_implemented, FormatNodeRule, PyFormatter};
+use crate::comments::leading_node_comments;
-use ruff_formatter::{write, Buffer, FormatResult};
+use crate::prelude::*;
+use crate::FormatNodeRule;
+use ruff_formatter::{write, FormatRuleWithOptions};
+use ruff_text_size::{TextLen, TextRange};
 use rustpython_parser::ast::Arg;
 
 #[derive(Default)]
-pub struct FormatArg;
+pub struct FormatArg {
+    kind: ArgumentKind,
+}
+
+#[derive(Copy, Clone, Debug, Default)]
+pub enum ArgumentKind {
+    /// Positional only, regular argument, or a keyword only argument.
+    #[default]
+    Normal,
+    /// A `*args` arguments
+    Varg,
+    /// A `**kwargs` argument
+    Kwarg,
+}
 
 impl FormatNodeRule<Arg> for FormatArg {
     fn fmt_fields(&self, item: &Arg, f: &mut PyFormatter) -> FormatResult<()> {
-        write!(f, [not_yet_implemented(item)])
+        let Arg {
+            range,
+            arg,
+            annotation,
+            type_comment: _,
+        } = item;
+        write!(
+            f,
+            [
+                // The name of the argument
+                source_text_slice(
+                    TextRange::at(range.start(), arg.text_len()),
+                    ContainsNewlines::No
+                )
+            ]
+        )?;
+
+        if let Some(annotation) = annotation {
+            write!(f, [text(":"), space(), annotation.format()])?;
+        }
+
+        Ok(())
+    }
+
+    fn fmt_leading_comments(&self, node: &Arg, f: &mut PyFormatter) -> FormatResult<()> {
+        match self.kind {
+            ArgumentKind::Normal => leading_node_comments(node).fmt(f),
+            // Formatted as part of the `Arguments` to avoid emitting leading comments between the `*` and the argument.
+            ArgumentKind::Kwarg | ArgumentKind::Varg => Ok(()),
+        }
+    }
+}
+
+impl FormatRuleWithOptions<Arg, PyFormatContext<'_>> for FormatArg {
+    type Options = ArgumentKind;
+
+    fn with_options(mut self, options: Self::Options) -> Self {
+        self.kind = options;
+        self
     }
 }

crates/ruff_python_formatter/src/other/arguments.rs

@@ -1,12 +1,189 @@
-use crate::{not_yet_implemented, FormatNodeRule, PyFormatter};
+use crate::comments::{dangling_node_comments, leading_node_comments};
-use ruff_formatter::{write, Buffer, FormatResult};
+use crate::context::NodeLevel;
-use rustpython_parser::ast::Arguments;
+use crate::other::arg::ArgumentKind;
+use crate::prelude::*;
+use crate::trivia::{first_non_trivia_token, SimpleTokenizer, Token, TokenKind};
+use crate::FormatNodeRule;
+use ruff_formatter::{format_args, write, FormatError};
+use ruff_python_ast::node::{AnyNodeRef, AstNode};
+use rustpython_parser::ast::{Arg, Arguments, Expr, Ranged};
+use std::usize;
 
 #[derive(Default)]
 pub struct FormatArguments;
 
 impl FormatNodeRule<Arguments> for FormatArguments {
     fn fmt_fields(&self, item: &Arguments, f: &mut PyFormatter) -> FormatResult<()> {
-        write!(f, [not_yet_implemented(item)])
+        let Arguments {
+            range: _,
+            posonlyargs,
+            args,
+            defaults,
+            vararg,
+            kwonlyargs,
+            kw_defaults,
+            kwarg,
+        } = item;
+
+        let saved_level = f.context().node_level();
+        f.context_mut().set_node_level(NodeLevel::Expression);
+
+        let format_inner = format_with(|f: &mut PyFormatter| {
+            let separator = format_with(|f| write!(f, [text(","), soft_line_break_or_space()]));
+            let mut joiner = f.join_with(separator);
+            let mut last_node: Option<AnyNodeRef> = None;
+
+            let mut defaults = std::iter::repeat(None)
+                .take(posonlyargs.len() + args.len() - defaults.len())
+                .chain(defaults.iter().map(Some));
+
+            for positional in posonlyargs {
+                let default = defaults.next().ok_or(FormatError::SyntaxError)?;
+                joiner.entry(&ArgumentWithDefault {
+                    argument: positional,
+                    default,
+                });
+
+                last_node = Some(default.map_or_else(|| positional.into(), AnyNodeRef::from));
+            }
+
+            if !posonlyargs.is_empty() {
+                joiner.entry(&text("/"));
+            }
+
+            for argument in args {
+                let default = defaults.next().ok_or(FormatError::SyntaxError)?;
+
+                joiner.entry(&ArgumentWithDefault { argument, default });
+
+                last_node = Some(default.map_or_else(|| argument.into(), AnyNodeRef::from));
+            }
+
+            if let Some(vararg) = vararg {
+                joiner.entry(&format_args![
+                    leading_node_comments(vararg.as_ref()),
+                    text("*"),
+                    vararg.format().with_options(ArgumentKind::Varg)
+                ]);
+                last_node = Some(vararg.as_any_node_ref());
+            }
+
+            debug_assert!(defaults.next().is_none());
+
+            let mut defaults = std::iter::repeat(None)
+                .take(kwonlyargs.len() - kw_defaults.len())
+                .chain(kw_defaults.iter().map(Some));
+
+            for keyword_argument in kwonlyargs {
+                let default = defaults.next().ok_or(FormatError::SyntaxError)?;
+                joiner.entry(&ArgumentWithDefault {
+                    argument: keyword_argument,
+                    default,
+                });
+
+                last_node = Some(default.map_or_else(|| keyword_argument.into(), AnyNodeRef::from));
+            }
+
+            debug_assert!(defaults.next().is_none());
+
+            if let Some(kwarg) = kwarg {
+                joiner.entry(&format_args![
+                    leading_node_comments(kwarg.as_ref()),
+                    text("**"),
+                    kwarg.format().with_options(ArgumentKind::Kwarg)
+                ]);
+                last_node = Some(kwarg.as_any_node_ref());
+            }
+
+            joiner.finish()?;
+
+            write!(f, [if_group_breaks(&text(","))])?;
+
+            // Expand the group if the source has a trailing *magic* comma.
+            if let Some(last_node) = last_node {
+                let ends_with_pos_only_argument_separator = !posonlyargs.is_empty()
+                    && args.is_empty()
+                    && vararg.is_none()
+                    && kwonlyargs.is_empty()
+                    && kwarg.is_none();
+
+                let maybe_comma_token = if ends_with_pos_only_argument_separator {
+                    // `def a(b, c, /): ... `
+                    let mut tokens =
+                        SimpleTokenizer::starts_at(last_node.end(), f.context().contents())
+                            .skip_trivia();
+
+                    let comma = tokens.next();
+                    assert!(matches!(comma, Some(Token { kind: TokenKind::Comma, .. })), "The last positional only argument must be separated by a `,` from the positional only arguments separator `/` but found '{comma:?}'.");
+
+                    let slash = tokens.next();
+                    assert!(matches!(slash, Some(Token { kind: TokenKind::Slash, .. })), "The positional argument separator must be present for a function that has positional only arguments but found '{slash:?}'.");
+
+                    tokens.next()
+                } else {
+                    first_non_trivia_token(last_node.end(), f.context().contents())
+                };
+
+                if maybe_comma_token.map_or(false, |token| token.kind() == TokenKind::Comma) {
+                    write!(f, [hard_line_break()])?;
+                }
+            }
+
+            Ok(())
+        });
+
+        let num_arguments = posonlyargs.len()
+            + args.len()
+            + usize::from(vararg.is_some())
+            + kwonlyargs.len()
+            + usize::from(kwarg.is_some());
+
+        if num_arguments == 0 {
+            // No arguments, format any dangling comments between `()`
+            write!(
+                f,
+                [
+                    text("("),
+                    block_indent(&dangling_node_comments(item)),
+                    text(")")
+                ]
+            )?;
+        } else {
+            write!(
+                f,
+                [group(&format_args!(
+                    text("("),
+                    soft_block_indent(&group(&format_inner)),
+                    text(")")
+                ))]
+            )?;
+        }
+
+        f.context_mut().set_node_level(saved_level);
+
+        Ok(())
+    }
+
+    fn fmt_dangling_comments(&self, _node: &Arguments, _f: &mut PyFormatter) -> FormatResult<()> {
+        // Handled in `fmt_fields`
+        Ok(())
+    }
+}
+
+struct ArgumentWithDefault<'a> {
+    argument: &'a Arg,
+    default: Option<&'a Expr>,
+}
+
+impl Format<PyFormatContext<'_>> for ArgumentWithDefault<'_> {
+    fn fmt(&self, f: &mut Formatter<PyFormatContext<'_>>) -> FormatResult<()> {
+        write!(f, [self.argument.format()])?;
+
+        if let Some(default) = self.default {
+            let space = self.argument.annotation.is_some().then_some(space());
+            write!(f, [space, text("="), space, default.format()])?;
+        }
+
+        Ok(())
     }
 }

crates/ruff_python_formatter/src/other/decorator.rs

@@ -0,0 +1,25 @@
+use crate::expression::parentheses::Parenthesize;
+use crate::prelude::*;
+use crate::FormatNodeRule;
+use ruff_formatter::write;
+use rustpython_parser::ast::Decorator;
+
+#[derive(Default)]
+pub struct FormatDecorator;
+
+impl FormatNodeRule<Decorator> for FormatDecorator {
+    fn fmt_fields(&self, item: &Decorator, f: &mut PyFormatter) -> FormatResult<()> {
+        let Decorator {
+            expression,
+            range: _,
+        } = item;
+
+        write!(
+            f,
+            [
+                text("@"),
+                expression.format().with_options(Parenthesize::Optional)
+            ]
+        )
+    }
+}

crates/ruff_python_formatter/src/other/mod.rs

@@ -2,6 +2,7 @@ pub(crate) mod alias;
 pub(crate) mod arg;
 pub(crate) mod arguments;
 pub(crate) mod comprehension;
+pub(crate) mod decorator;
 pub(crate) mod excepthandler_except_handler;
 pub(crate) mod keyword;
 pub(crate) mod match_case;

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__class_blank_parentheses_py.snap

@@ -36,16 +36,16 @@ class NormalClass (
 ```diff
 --- Black
 +++ Ruff
-@@ -1,30 +1,16 @@
+@@ -1,18 +1,10 @@
 -class SimpleClassWithBlankParentheses:
 -    pass
--
 +NOT_YET_IMPLEMENTED_StmtClassDef
  
+ 
 -class ClassWithSpaceParentheses:
 -    first_test_data = 90
 -    second_test_data = 100
- 
+-
 -    def test_func(self):
 -        return None
 +NOT_YET_IMPLEMENTED_StmtClassDef
@@ -57,15 +57,14 @@ class NormalClass (
 +NOT_YET_IMPLEMENTED_StmtClassDef
  
  
--def public_func_with_blank_parentheses():
+ def public_func_with_blank_parentheses():
--    return None
+@@ -20,11 +12,7 @@
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
  
--def class_under_the_func_with_blank_parentheses():
+ def class_under_the_func_with_blank_parentheses():
 -    class InsideFunc:
 -        pass
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    NOT_YET_IMPLEMENTED_StmtClassDef
  
  
 -class NormalClass:
@@ -87,10 +86,12 @@ NOT_YET_IMPLEMENTED_StmtClassDef
 NOT_YET_IMPLEMENTED_StmtClassDef
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def public_func_with_blank_parentheses():
+    return None
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def class_under_the_func_with_blank_parentheses():
+    NOT_YET_IMPLEMENTED_StmtClassDef
 
 
 NOT_YET_IMPLEMENTED_StmtClassDef

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__comment_after_escaped_newline_py.snap

@@ -22,24 +22,30 @@ def bobtwo(): \
 ```diff
 --- Black
 +++ Ruff
-@@ -1,6 +1,4 @@
+@@ -1,6 +1,8 @@
 -def bob():  # pylint: disable=W9016
--    pass
++def bob():
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    # pylint: disable=W9016
+     pass
  
  
 -def bobtwo():  # some comment here
--    pass
++def bobtwo():
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    # some comment here
+     pass
 ```
 
 ## Ruff Output
 
 ```py
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def bob():
+    # pylint: disable=W9016
+    pass
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def bobtwo():
+    # some comment here
+    pass
 ```
 
 ## Black Output

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__comments2_py.snap

@@ -227,7 +227,7 @@ instruction()#comment with bad spacing
  ]
  
  not_shareables = [
-@@ -37,129 +33,28 @@
+@@ -37,51 +33,24 @@
      # builtin types and objects
      type,
      object,
@@ -258,7 +258,7 @@ instruction()#comment with bad spacing
  
  
  # Comment before function.
--def inline_comments_in_brackets_ruin_everything():
+ def inline_comments_in_brackets_ruin_everything():
 -    if typedargslist:
 -        parameters.children = [children[0], body, children[-1]]  # (1  # )1
 -        parameters.children = [
@@ -282,15 +282,15 @@ instruction()#comment with bad spacing
 -        and self._proc.poll() is None
 -    ):
 -        pass
--    # no newline before or after
++    NOT_YET_IMPLEMENTED_StmtIf
--    short = [
++    NOT_YET_IMPLEMENTED_StmtIf
--        # one
+     # no newline before or after
--        1,
+     short = [
--        # two
+         # one
--        2,
+@@ -91,75 +60,26 @@
--    ]
+     ]
--
+ 
--    # no newline after
+     # no newline after
 -    call(
 -        arg1,
 -        arg2,
@@ -299,9 +299,10 @@ instruction()#comment with bad spacing
 -""",
 -        arg3=True,
 -    )
--
++    NOT_IMPLEMENTED_call()
--    ############################################################################
+ 
--
+     ############################################################################
+ 
 -    call2(
 -        # short
 -        arg1,
@@ -333,19 +334,24 @@ instruction()#comment with bad spacing
 -        # right
 -        if element is not None
 -    ]
--    while True:
++    NOT_IMPLEMENTED_call()
++    lcomp = [i for i in []]
++    lcomp2 = [i for i in []]
++    lcomp3 = [i for i in []]
+     while True:
 -        if False:
 -            continue
 -
 -            # and round and round we go
--        # and round and round we go
++        NOT_YET_IMPLEMENTED_StmtIf
--
+         # and round and round we go
--    # let's return
+ 
+     # let's return
 -    return Node(
 -        syms.simple_stmt,
 -        [Node(statement, result), Leaf(token.NEWLINE, "\n")],  # FIXME: \r\n?
 -    )
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    return NOT_IMPLEMENTED_call()
  
  
 -CONFIG_FILES = (
@@ -366,7 +372,7 @@ instruction()#comment with bad spacing
  
  
  #######################
-@@ -167,7 +62,7 @@
+@@ -167,7 +87,7 @@
  #######################
  
  
@@ -430,7 +436,32 @@ NOT_YET_IMPLEMENTED_StmtIf
 
 
 # Comment before function.
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def inline_comments_in_brackets_ruin_everything():
+    NOT_YET_IMPLEMENTED_StmtIf
+    NOT_YET_IMPLEMENTED_StmtIf
+    # no newline before or after
+    short = [
+        # one
+        1,
+        # two
+        2,
+    ]
+
+    # no newline after
+    NOT_IMPLEMENTED_call()
+
+    ############################################################################
+
+    NOT_IMPLEMENTED_call()
+    lcomp = [i for i in []]
+    lcomp2 = [i for i in []]
+    lcomp3 = [i for i in []]
+    while True:
+        NOT_YET_IMPLEMENTED_StmtIf
+        # and round and round we go
+
+    # let's return
+    return NOT_IMPLEMENTED_call()
 
 
 CONFIG_FILES = [CONFIG_FILE] + SHARED_CONFIG_FILES + USER_CONFIG_FILES  # type: Final

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__comments3_py.snap

@@ -61,11 +61,10 @@ def func():
 ```diff
 --- Black
 +++ Ruff
-@@ -2,47 +2,7 @@
+@@ -3,46 +3,13 @@
- 
  
  # %%
--def func():
+ def func():
 -    x = """
 -    a really long string
 -    """
@@ -77,7 +76,9 @@ def func():
 -        # right
 -        if element is not None
 -    ]
--    # Capture each of the exceptions in the MultiError along with each of their causes and contexts
++    x = "NOT_YET_IMPLEMENTED_STRING"
++    lcomp3 = [i for i in []]
+     # Capture each of the exceptions in the MultiError along with each of their causes and contexts
 -    if isinstance(exc_value, MultiError):
 -        embedded = []
 -        for exc in exc_value.exceptions:
@@ -95,8 +96,9 @@ def func():
 -                    )
 -                    # This should be left alone (after)
 -                )
--
++    NOT_YET_IMPLEMENTED_StmtIf
--    # everything is fine if the expression isn't nested
+ 
+     # everything is fine if the expression isn't nested
 -    traceback.TracebackException.from_exception(
 -        exc,
 -        limit=limit,
@@ -106,7 +108,7 @@ def func():
 -        # shared between sub-exceptions are not omitted
 -        _seen=set(_seen),
 -    )
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    NOT_IMPLEMENTED_call()
  
  
  # %%
@@ -119,7 +121,14 @@ def func():
 
 
 # %%
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def func():
+    x = "NOT_YET_IMPLEMENTED_STRING"
+    lcomp3 = [i for i in []]
+    # Capture each of the exceptions in the MultiError along with each of their causes and contexts
+    NOT_YET_IMPLEMENTED_StmtIf
+
+    # everything is fine if the expression isn't nested
+    NOT_IMPLEMENTED_call()
 
 
 # %%

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__comments4_py.snap

@@ -107,7 +107,7 @@ def foo3(list_a, list_b):
 ```diff
 --- Black
 +++ Ruff
-@@ -1,94 +1,14 @@
+@@ -1,94 +1,22 @@
 -from com.my_lovely_company.my_lovely_team.my_lovely_project.my_lovely_component import (
 -    MyLovelyCompanyTeamProjectComponent,  # NOT DRY
 -)
@@ -169,7 +169,7 @@ def foo3(list_a, list_b):
 +NOT_YET_IMPLEMENTED_StmtClassDef
  
  
--def foo(list_a, list_b):
+ def foo(list_a, list_b):
 -    results = (
 -        User.query.filter(User.foo == "bar")
 -        .filter(  # Because foo.
@@ -182,12 +182,12 @@ def foo3(list_a, list_b):
 -        .with_for_update(key_share=True)
 -        .all()
 -    )
--    return results
++    results = NOT_IMPLEMENTED_call()
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
+     return results
  
  
--def foo2(list_a, list_b):
+ def foo2(list_a, list_b):
--    # Standalone comment reasonably placed.
+     # Standalone comment reasonably placed.
 -    return (
 -        User.query.filter(User.foo == "bar")
 -        .filter(
@@ -195,19 +195,19 @@ def foo3(list_a, list_b):
 -        )
 -        .filter(User.xyz.is_(None))
 -    )
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    return NOT_IMPLEMENTED_call()
  
  
--def foo3(list_a, list_b):
+ def foo3(list_a, list_b):
--    return (
+     return (
--        # Standalone comment but weirdly placed.
+         # Standalone comment but weirdly placed.
 -        User.query.filter(User.foo == "bar")
 -        .filter(
 -            db.or_(User.field_a.astext.in_(list_a), User.field_b.astext.in_(list_b))
 -        )
 -        .filter(User.xyz.is_(None))
--    )
++        NOT_IMPLEMENTED_call()
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
+     )
 ```
 
 ## Ruff Output
@@ -220,13 +220,21 @@ NOT_YET_IMPLEMENTED_StmtImportFrom
 NOT_YET_IMPLEMENTED_StmtClassDef
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def foo(list_a, list_b):
+    results = NOT_IMPLEMENTED_call()
+    return results
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def foo2(list_a, list_b):
+    # Standalone comment reasonably placed.
+    return NOT_IMPLEMENTED_call()
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def foo3(list_a, list_b):
+    return (
+        # Standalone comment but weirdly placed.
+        NOT_IMPLEMENTED_call()
+    )
 ```
 
 ## Black Output

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__comments5_py.snap

@@ -86,7 +86,7 @@ if __name__ == "__main__":
 ```diff
 --- Black
 +++ Ruff
-@@ -1,61 +1,33 @@
+@@ -1,33 +1,18 @@
  while True:
 -    if something.changed:
 -        do.stuff()  # trailing comment
@@ -97,72 +97,54 @@ if __name__ == "__main__":
      # Should this one, too?  I guess so.
  
  # This one is properly standalone now.
--
+ 
 -for i in range(100):
 -    # first we do this
 -    if i % 33 == 0:
 -        break
--
++NOT_YET_IMPLEMENTED_StmtFor
+ 
 -    # then we do this
 -    print(i)
 -    # and finally we loop around
++NOT_YET_IMPLEMENTED_StmtWith
  
 -with open(some_temp_file) as f:
 -    data = f.read()
-+NOT_YET_IMPLEMENTED_StmtFor
++NOT_YET_IMPLEMENTED_StmtTry
  
 -try:
 -    with open(some_other_file) as w:
 -        w.write(data)
-+NOT_YET_IMPLEMENTED_StmtWith
+-
- 
 -except OSError:
 -    print("problems")
-+NOT_YET_IMPLEMENTED_StmtTry
+-
- 
 -import sys
 +NOT_YET_IMPLEMENTED_StmtImport
  
  
  # leading function comment
--def wat():
+@@ -42,7 +27,7 @@
--    ...
--    # trailing function comment
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
- 
- 
- # SECTION COMMENT
- 
- 
  # leading 1
--@deco1
+ @deco1
--# leading 2
+ # leading 2
 -@deco2(with_args=True)
--# leading 3
++@NOT_IMPLEMENTED_call()
--@deco3
+ # leading 3
--def decorated1():
+ @deco3
--    ...
+ def decorated1():
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
+@@ -52,7 +37,7 @@
- 
- 
  # leading 1
--@deco1
+ @deco1
--# leading 2
+ # leading 2
 -@deco2(with_args=True)
--# leading function comment
++@NOT_IMPLEMENTED_call()
--def decorated1():
+ # leading function comment
--    ...
+ def decorated1():
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
+     ...
- 
+@@ -69,5 +54,4 @@
- 
+     ...
- # Note: this is fixed in
-@@ -65,9 +37,7 @@
- 
- 
- # This comment should be split from `some_instruction` by two lines but isn't.
--def g():
--    ...
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
  
 -if __name__ == "__main__":
@@ -191,18 +173,31 @@ NOT_YET_IMPLEMENTED_StmtImport
 
 
 # leading function comment
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def wat():
+    ...
+    # trailing function comment
 
 
 # SECTION COMMENT
 
 
 # leading 1
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+@deco1
+# leading 2
+@NOT_IMPLEMENTED_call()
+# leading 3
+@deco3
+def decorated1():
+    ...
 
 
 # leading 1
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+@deco1
+# leading 2
+@NOT_IMPLEMENTED_call()
+# leading function comment
+def decorated1():
+    ...
 
 
 # Note: this is fixed in
@@ -212,7 +207,8 @@ some_instruction
 
 
 # This comment should be split from `some_instruction` by two lines but isn't.
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def g():
+    ...
 
 
 NOT_YET_IMPLEMENTED_StmtIf

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__comments6_py.snap

@@ -131,103 +131,38 @@ aaaaaaaaaaaaa, bbbbbbbbb = map(list, map(itertools.chain.from_iterable, zip(*ite
 ```diff
 --- Black
 +++ Ruff
-@@ -1,118 +1,40 @@
+@@ -1,4 +1,4 @@
 -from typing import Any, Tuple
 +NOT_YET_IMPLEMENTED_StmtImportFrom
  
  
--def f(
+ def f(
--    a,  # type: int
+@@ -49,15 +49,10 @@
--):
+     element = 0  # type: int
--    pass
+     another_element = 1  # type: float
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
+     another_element_with_long_name = 2  # type: int
- 
- 
- # test type comments
--def f(a, b, c, d, e, f, g, h, i):
--    # type: (int, int, int, int, int, int, int, int, int) -> None
--    pass
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
- 
- 
--def f(
--    a,  # type: int
--    b,  # type: int
--    c,  # type: int
--    d,  # type: int
--    e,  # type: int
--    f,  # type: int
--    g,  # type: int
--    h,  # type: int
--    i,  # type: int
--):
--    # type: (...) -> None
--    pass
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
- 
- 
--def f(
--    arg,  # type: int
--    *args,  # type: *Any
--    default=False,  # type: bool
--    **kwargs,  # type: **Any
--):
--    # type: (...) -> None
--    pass
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
- 
- 
--def f(
--    a,  # type: int
--    b,  # type: int
--    c,  # type: int
--    d,  # type: int
--):
--    # type: (...) -> None
--
--    element = 0  # type: int
--    another_element = 1  # type: float
--    another_element_with_long_name = 2  # type: int
 -    another_really_really_long_element_with_a_unnecessarily_long_name_to_describe_what_it_does_enterprise_style = (
 -        3
 -    )  # type: int
 -    an_element_with_a_long_value = calls() or more_calls() and more()  # type: bool
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    another_really_really_long_element_with_a_unnecessarily_long_name_to_describe_what_it_does_enterprise_style = 3  # type: int
++    an_element_with_a_long_value = NOT_IMPLEMENTED_bool_op1 and NOT_IMPLEMENTED_bool_op2  # type: bool
  
 -    tup = (
 -        another_element,
 -        another_really_really_long_element_with_a_unnecessarily_long_name_to_describe_what_it_does_enterprise_style,
 -    )  # type: Tuple[int, int]
++    tup = (1, 2)  # type: Tuple[int, int]
  
--    a = (
+     a = (
--        element
+         element
--        + another_element
+@@ -84,35 +79,22 @@
--        + another_element_with_long_name
--        + element
--        + another_element
--        + another_element_with_long_name
--    )  # type: int
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
  
--def f(
+ def func(
--    x,  # not a type comment
--    y,  # type: int
--):
--    # type: (...) -> None
--    pass
--
--
--def f(
--    x,  # not a type comment
--):  # type: (int) -> None
--    pass
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
- 
- 
--def func(
 -    a=some_list[0],  # type: int
--):  # type: () -> int
++    a=NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key],  # type: int
+ ):  # type: () -> int
 -    c = call(
 -        0.0123,
 -        0.0456,
@@ -240,17 +175,20 @@ aaaaaaaaaaaaa, bbbbbbbbb = map(list, map(itertools.chain.from_iterable, zip(*ite
 -        0.0789,
 -        a[-1],  # type: ignore
 -    )
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    c = NOT_IMPLEMENTED_call()
  
 -    c = call(
 -        "aaaaaaaa", "aaaaaaaa", "aaaaaaaa", "aaaaaaaa", "aaaaaaaa", "aaaaaaaa", "aaaaaaaa"  # type: ignore
 -    )
++    c = NOT_IMPLEMENTED_call()
  
-+result = "NOT_YET_IMPLEMENTED_STRING"  # aaa
  
 -result = (  # aaa
 -    "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
 -)
++result = "NOT_YET_IMPLEMENTED_STRING"  # aaa
+ 
+-AAAAAAAAAAAAA = [AAAAAAAAAAAAA] + SHARED_AAAAAAAAAAAAA + USER_AAAAAAAAAAAAA + AAAAAAAAAAAAA  # type: ignore
 +AAAAAAAAAAAAA = (
 +    [AAAAAAAAAAAAA]
 +    + SHARED_AAAAAAAAAAAAA
@@ -258,14 +196,12 @@ aaaaaaaaaaaaa, bbbbbbbbb = map(list, map(itertools.chain.from_iterable, zip(*ite
 +    + AAAAAAAAAAAAA
 +)  # type: ignore
  
--AAAAAAAAAAAAA = [AAAAAAAAAAAAA] + SHARED_AAAAAAAAAAAAA + USER_AAAAAAAAAAAAA + AAAAAAAAAAAAA  # type: ignore
-+NOT_IMPLEMENTED_call()
- 
 -call_to_some_function_asdf(
 -    foo,
 -    [AAAAAAAAAAAAAAAAAAAAAAA, AAAAAAAAAAAAAAAAAAAAAAA, AAAAAAAAAAAAAAAAAAAAAAA, BBBBBBBBBBBB],  # type: ignore
 -)
--
++NOT_IMPLEMENTED_call()
+ 
 -aaaaaaaaaaaaa, bbbbbbbbb = map(list, map(itertools.chain.from_iterable, zip(*items)))  # type: ignore[arg-type]
 +(1, 2) = NOT_IMPLEMENTED_call()  # type: ignore[arg-type]
 ```
@@ -276,29 +212,89 @@ aaaaaaaaaaaaa, bbbbbbbbb = map(list, map(itertools.chain.from_iterable, zip(*ite
 NOT_YET_IMPLEMENTED_StmtImportFrom
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def f(
+    a,  # type: int
+):
+    pass
 
 
 # test type comments
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def f(a, b, c, d, e, f, g, h, i):
+    # type: (int, int, int, int, int, int, int, int, int) -> None
+    pass
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def f(
+    a,  # type: int
+    b,  # type: int
+    c,  # type: int
+    d,  # type: int
+    e,  # type: int
+    f,  # type: int
+    g,  # type: int
+    h,  # type: int
+    i,  # type: int
+):
+    # type: (...) -> None
+    pass
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def f(
+    arg,  # type: int
+    *args,  # type: *Any
+    default=False,  # type: bool
+    **kwargs,  # type: **Any
+):
+    # type: (...) -> None
+    pass
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def f(
+    a,  # type: int
+    b,  # type: int
+    c,  # type: int
+    d,  # type: int
+):
+    # type: (...) -> None
+
+    element = 0  # type: int
+    another_element = 1  # type: float
+    another_element_with_long_name = 2  # type: int
+    another_really_really_long_element_with_a_unnecessarily_long_name_to_describe_what_it_does_enterprise_style = 3  # type: int
+    an_element_with_a_long_value = NOT_IMPLEMENTED_bool_op1 and NOT_IMPLEMENTED_bool_op2  # type: bool
+
+    tup = (1, 2)  # type: Tuple[int, int]
+
+    a = (
+        element
+        + another_element
+        + another_element_with_long_name
+        + element
+        + another_element
+        + another_element_with_long_name
+    )  # type: int
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def f(
+    x,  # not a type comment
+    y,  # type: int
+):
+    # type: (...) -> None
+    pass
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def f(
+    x,  # not a type comment
+):  # type: (int) -> None
+    pass
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def func(
+    a=NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key],  # type: int
+):  # type: () -> int
+    c = NOT_IMPLEMENTED_call()
+
+    c = NOT_IMPLEMENTED_call()
 
 
 result = "NOT_YET_IMPLEMENTED_STRING"  # aaa

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__comments9_py.snap

@@ -152,35 +152,7 @@ def bar():
 ```diff
 --- Black
 +++ Ruff
-@@ -4,8 +4,7 @@
+@@ -30,8 +30,7 @@
- 
- 
- # This comment should be split from the statement above by two lines.
--def function():
--    pass
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
- 
- 
- some = statement
-@@ -14,24 +13,21 @@
- # This multiline comments section
- # should be split from the statement
- # above by two lines.
--def function():
--    pass
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
- 
- 
- some = statement
- 
- 
- # This comment should be split from the statement above by two lines.
--async def async_function():
--    pass
-+NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
- 
- 
- some = statement
  
  
  # This comment should be split from the statement above by two lines.
@@ -190,7 +162,7 @@ def bar():
  
  
  some = statement
-@@ -39,123 +35,55 @@
+@@ -39,17 +38,14 @@
  
  
  # This should be split from the above by two lines
@@ -211,54 +183,37 @@ def bar():
  
  
  some = statement
- 
+@@ -59,7 +55,7 @@
- 
+ @deco1
- # leading 1
+ # leading 2
--@deco1
+ # leading 2 extra
--# leading 2
--# leading 2 extra
 -@deco2(with_args=True)
--# leading 3
++@NOT_IMPLEMENTED_call()
--@deco3
+ # leading 3
--# leading 4
+ @deco3
--def decorated():
+ # leading 4
--    pass
+@@ -73,7 +69,7 @@
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
- 
- 
- some = statement
- 
- 
  # leading 1
--@deco1
+ @deco1
--# leading 2
+ # leading 2
 -@deco2(with_args=True)
--
++@NOT_IMPLEMENTED_call()
--# leading 3 that already has an empty line
--@deco3
--# leading 4
--def decorated_with_split_leading_comments():
--    pass
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
- 
- 
- some = statement
- 
  
+ # leading 3 that already has an empty line
+ @deco3
+@@ -88,7 +84,7 @@
  # leading 1
--@deco1
+ @deco1
--# leading 2
+ # leading 2
 -@deco2(with_args=True)
--# leading 3
++@NOT_IMPLEMENTED_call()
--@deco3
+ # leading 3
--
+ @deco3
--# leading 4 that already has an empty line
+ 
--def decorated_with_split_leading_comments():
+@@ -98,41 +94,13 @@
--    pass
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
  
--def main():
+ def main():
 -    if a:
 -        # Leading comment before inline function
 -        def inline():
@@ -267,19 +222,20 @@ def bar():
 -        # Another leading comment
 -        def another_inline():
 -            pass
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    NOT_YET_IMPLEMENTED_StmtIf
  
 -    else:
 -        # More leading comments
 -        def inline_after_else():
 -            pass
--
+ 
++NOT_YET_IMPLEMENTED_StmtIf
  
 -if a:
 -    # Leading comment before "top-level inline" function
 -    def top_level_quote_inline():
 -        pass
--
+ 
 -    # Another leading comment
 -    def another_top_level_quote_inline_inline():
 -        pass
@@ -288,9 +244,8 @@ def bar():
 -    # More leading comments
 -    def top_level_quote_inline_after_else():
 -        pass
-+NOT_YET_IMPLEMENTED_StmtIf
+-
- 
+-
- 
 -class MyClass:
 -    # First method has no empty lines between bare class def.
 -    # More comments.
@@ -300,33 +255,6 @@ def bar():
  
  
  # Regression test for https://github.com/psf/black/issues/3454.
--def foo():
--    pass
--    # Trailing comment that belongs to this function
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
- 
- 
--@decorator1
--@decorator2  # fmt: skip
--def bar():
--    pass
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
- 
- 
- # Regression test for https://github.com/psf/black/issues/3454.
--def foo():
--    pass
--    # Trailing comment that belongs to this function.
--    # NOTE this comment only has one empty line below, and the formatter
--    # should enforce two blank lines.
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
- 
- 
--@decorator1
--# A standalone comment
--def bar():
--    pass
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
 ```
 
 ## Ruff Output
@@ -338,7 +266,8 @@ some = statement
 
 
 # This comment should be split from the statement above by two lines.
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def function():
+    pass
 
 
 some = statement
@@ -347,14 +276,16 @@ some = statement
 # This multiline comments section
 # should be split from the statement
 # above by two lines.
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def function():
+    pass
 
 
 some = statement
 
 
 # This comment should be split from the statement above by two lines.
-NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
+async def async_function():
+    pass
 
 
 some = statement
@@ -383,24 +314,49 @@ some = statement
 
 
 # leading 1
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+@deco1
+# leading 2
+# leading 2 extra
+@NOT_IMPLEMENTED_call()
+# leading 3
+@deco3
+# leading 4
+def decorated():
+    pass
 
 
 some = statement
 
 
 # leading 1
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+@deco1
+# leading 2
+@NOT_IMPLEMENTED_call()
+
+# leading 3 that already has an empty line
+@deco3
+# leading 4
+def decorated_with_split_leading_comments():
+    pass
 
 
 some = statement
 
 
 # leading 1
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+@deco1
+# leading 2
+@NOT_IMPLEMENTED_call()
+# leading 3
+@deco3
+
+# leading 4 that already has an empty line
+def decorated_with_split_leading_comments():
+    pass
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def main():
+    NOT_YET_IMPLEMENTED_StmtIf
 
 
 NOT_YET_IMPLEMENTED_StmtIf
@@ -410,17 +366,29 @@ NOT_YET_IMPLEMENTED_StmtClassDef
 
 
 # Regression test for https://github.com/psf/black/issues/3454.
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def foo():
+    pass
+    # Trailing comment that belongs to this function
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+@decorator1
+@decorator2  # fmt: skip
+def bar():
+    pass
 
 
 # Regression test for https://github.com/psf/black/issues/3454.
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def foo():
+    pass
+    # Trailing comment that belongs to this function.
+    # NOTE this comment only has one empty line below, and the formatter
+    # should enforce two blank lines.
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+@decorator1
+# A standalone comment
+def bar():
+    pass
 ```
 
 ## Black Output

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__comments_non_breaking_space_py.snap

@@ -32,7 +32,7 @@ def function(a:int=42):
 ```diff
 --- Black
 +++ Ruff
-@@ -1,23 +1,11 @@
+@@ -1,23 +1,15 @@
 -from .config import (
 -    ConfigTypeAttributes,
 -    Int,
@@ -51,15 +51,15 @@ def function(a:int=42):
 +square = NOT_IMPLEMENTED_call()  #  type: Optional[Square]
  
  
--def function(a: int = 42):
+ def function(a: int = 42):
 -    """This docstring is already formatted
 -    a
 -    b
 -    """
--    #    There's a NBSP + 3 spaces before
++    "NOT_YET_IMPLEMENTED_STRING"
--    #    And 4 spaces on the next line
+     #    There's a NBSP + 3 spaces before
--    pass
+     #    And 4 spaces on the next line
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
+     pass
 ```
 
 ## Ruff Output
@@ -75,7 +75,11 @@ result = 1  # This comment is talking about type: ignore
 square = NOT_IMPLEMENTED_call()  #  type: Optional[Square]
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def function(a: int = 42):
+    "NOT_YET_IMPLEMENTED_STRING"
+    #    There's a NBSP + 3 spaces before
+    #    And 4 spaces on the next line
+    pass
 ```
 
 ## Black Output

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__comments_py.snap

@@ -109,7 +109,7 @@ async def wat():
 ```diff
 --- Black
 +++ Ruff
-@@ -4,93 +4,42 @@
+@@ -4,24 +4,15 @@
  #
  # Has many lines. Many, many lines.
  # Many, many, many lines.
@@ -117,50 +117,51 @@ async def wat():
 -
 -Possibly also many, many lines.
 -"""
--
++"NOT_YET_IMPLEMENTED_STRING"
+ 
 -import os.path
 -import sys
--
++NOT_YET_IMPLEMENTED_StmtImport
++NOT_YET_IMPLEMENTED_StmtImport
+ 
 -import a
 -from b.c import X  # some noqa comment
-+"NOT_YET_IMPLEMENTED_STRING"
++NOT_YET_IMPLEMENTED_StmtImport
++NOT_YET_IMPLEMENTED_StmtImportFrom  # some noqa comment
  
 -try:
 -    import fast
 -except ImportError:
 -    import slow as fast
-+NOT_YET_IMPLEMENTED_StmtImport
+-
-+NOT_YET_IMPLEMENTED_StmtImport
+-
- 
-+NOT_YET_IMPLEMENTED_StmtImport
-+NOT_YET_IMPLEMENTED_StmtImportFrom  # some noqa comment
- 
 -# Some comment before a function.
 +NOT_YET_IMPLEMENTED_StmtTry
  y = 1
  (
      # some strings
-     y  # type: ignore
+@@ -30,67 +21,39 @@
- )
+ 
--
+ 
--
+ def function(default=None):
--def function(default=None):
 -    """Docstring comes first.
 -
 -    Possibly many lines.
 -    """
--    # FIXME: Some comment about why this function is crap but still in production.
++    "NOT_YET_IMPLEMENTED_STRING"
+     # FIXME: Some comment about why this function is crap but still in production.
 -    import inner_imports
++    NOT_YET_IMPLEMENTED_StmtImport
  
 -    if inner_imports.are_evil():
 -        # Explains why we have this if.
 -        # In great detail indeed.
 -        x = X()
 -        return x.method1()  # type: ignore
++    NOT_YET_IMPLEMENTED_StmtIf
  
--    # This return is also commented for some reason.
+     # This return is also commented for some reason.
--    return default
+     return default
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
  
  # Explains why we use global state.
@@ -170,7 +171,7 @@ async def wat():
  
  # Another comment!
  # This time two lines.
- 
+-
  
 -class Foo:
 -    """Docstring for class Foo.  Example from Sphinx docs."""
@@ -178,7 +179,7 @@ async def wat():
 -    #: Doc comment for class attribute Foo.bar.
 -    #: It can have multiple lines.
 -    bar = 1
--
+ 
 -    flox = 1.5  #: Doc comment for Foo.flox. One line only.
 -
 -    baz = 2
@@ -187,27 +188,29 @@ async def wat():
 -    def __init__(self):
 -        #: Doc comment for instance attribute qux.
 -        self.qux = 3
-+NOT_YET_IMPLEMENTED_StmtClassDef
+-
- 
 -        self.spam = 4
 -        """Docstring for instance attribute spam."""
++NOT_YET_IMPLEMENTED_StmtClassDef
+ 
  
--
  #' <h1>This is pweave!</h1>
  
  
 -@fast(really=True)
--async def wat():
++@NOT_IMPLEMENTED_call()
--    # This comment, for some reason \
+ async def wat():
--    # contains a trailing backslash.
+     # This comment, for some reason \
+     # contains a trailing backslash.
 -    async with X.open_async() as x:  # Some more comments
 -        result = await x.method1()
--    # Comment after ending a block.
++    NOT_YET_IMPLEMENTED_StmtAsyncWith  # Some more comments
+     # Comment after ending a block.
 -    if result:
 -        print("A OK", file=sys.stdout)
 -        # Comment between things.
 -        print()
-+NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
++    NOT_YET_IMPLEMENTED_StmtIf
  
  
  # Some closing comments.
@@ -242,7 +245,15 @@ y = 1
 )
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def function(default=None):
+    "NOT_YET_IMPLEMENTED_STRING"
+    # FIXME: Some comment about why this function is crap but still in production.
+    NOT_YET_IMPLEMENTED_StmtImport
+
+    NOT_YET_IMPLEMENTED_StmtIf
+
+    # This return is also commented for some reason.
+    return default
 
 
 # Explains why we use global state.
@@ -259,7 +270,13 @@ NOT_YET_IMPLEMENTED_StmtClassDef
 #' <h1>This is pweave!</h1>
 
 
-NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
+@NOT_IMPLEMENTED_call()
+async def wat():
+    # This comment, for some reason \
+    # contains a trailing backslash.
+    NOT_YET_IMPLEMENTED_StmtAsyncWith  # Some more comments
+    # Comment after ending a block.
+    NOT_YET_IMPLEMENTED_StmtIf
 
 
 # Some closing comments.

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__docstring_preview_py.snap

@@ -63,98 +63,108 @@ def single_quote_docstring_over_line_limit2():
 ```diff
 --- Black
 +++ Ruff
-@@ -1,48 +1,28 @@
+@@ -1,48 +1,38 @@
--def docstring_almost_at_line_limit():
+ def docstring_almost_at_line_limit():
 -    """long docstring................................................................."""
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    "NOT_YET_IMPLEMENTED_STRING"
  
  
--def docstring_almost_at_line_limit_with_prefix():
+ def docstring_almost_at_line_limit_with_prefix():
 -    f"""long docstring................................................................"""
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    NOT_YET_IMPLEMENTED_ExprJoinedStr
  
  
--def mulitline_docstring_almost_at_line_limit():
+ def mulitline_docstring_almost_at_line_limit():
 -    """long docstring.................................................................
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
+-
- 
 -    ..................................................................................
 -    """
++    "NOT_YET_IMPLEMENTED_STRING"
  
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
--def mulitline_docstring_almost_at_line_limit_with_prefix():
+ def mulitline_docstring_almost_at_line_limit_with_prefix():
 -    f"""long docstring................................................................
- 
+-
 -    ..................................................................................
 -    """
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    NOT_YET_IMPLEMENTED_ExprJoinedStr
  
  
--def docstring_at_line_limit():
+ def docstring_at_line_limit():
 -    """long docstring................................................................"""
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    "NOT_YET_IMPLEMENTED_STRING"
  
  
--def docstring_at_line_limit_with_prefix():
+ def docstring_at_line_limit_with_prefix():
 -    f"""long docstring..............................................................."""
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    NOT_YET_IMPLEMENTED_ExprJoinedStr
  
  
--def multiline_docstring_at_line_limit():
+ def multiline_docstring_at_line_limit():
 -    """first line-----------------------------------------------------------------------
 -
 -    second line----------------------------------------------------------------------"""
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    "NOT_YET_IMPLEMENTED_STRING"
  
  
--def multiline_docstring_at_line_limit_with_prefix():
+ def multiline_docstring_at_line_limit_with_prefix():
 -    f"""first line----------------------------------------------------------------------
 -
 -    second line----------------------------------------------------------------------"""
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    NOT_YET_IMPLEMENTED_ExprJoinedStr
  
  
--def single_quote_docstring_over_line_limit():
+ def single_quote_docstring_over_line_limit():
 -    "We do not want to put the closing quote on a new line as that is invalid (see GH-3141)."
--
++    "NOT_YET_IMPLEMENTED_STRING"
--
+ 
--def single_quote_docstring_over_line_limit2():
+ 
+ def single_quote_docstring_over_line_limit2():
 -    "We do not want to put the closing quote on a new line as that is invalid (see GH-3141)."
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    "NOT_YET_IMPLEMENTED_STRING"
 ```
 
 ## Ruff Output
 
 ```py
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def docstring_almost_at_line_limit():
+    "NOT_YET_IMPLEMENTED_STRING"
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def docstring_almost_at_line_limit_with_prefix():
+    NOT_YET_IMPLEMENTED_ExprJoinedStr
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def mulitline_docstring_almost_at_line_limit():
+    "NOT_YET_IMPLEMENTED_STRING"
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def mulitline_docstring_almost_at_line_limit_with_prefix():
+    NOT_YET_IMPLEMENTED_ExprJoinedStr
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def docstring_at_line_limit():
+    "NOT_YET_IMPLEMENTED_STRING"
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def docstring_at_line_limit_with_prefix():
+    NOT_YET_IMPLEMENTED_ExprJoinedStr
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def multiline_docstring_at_line_limit():
+    "NOT_YET_IMPLEMENTED_STRING"
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def multiline_docstring_at_line_limit_with_prefix():
+    NOT_YET_IMPLEMENTED_ExprJoinedStr
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def single_quote_docstring_over_line_limit():
+    "NOT_YET_IMPLEMENTED_STRING"
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def single_quote_docstring_over_line_limit2():
+    "NOT_YET_IMPLEMENTED_STRING"
 ```
 
 ## Black Output

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__docstring_py.snap

@@ -234,65 +234,64 @@ def stable_quote_normalization_with_immediate_inner_single_quote(self):
 ```diff
 --- Black
 +++ Ruff
-@@ -1,219 +1,105 @@
+@@ -1,219 +1,149 @@
 -class MyClass:
 -    """Multiline
 -    class docstring
 -    """
-+NOT_YET_IMPLEMENTED_StmtClassDef
+-
- 
 -    def method(self):
 -        """Multiline
 -        method docstring
 -        """
 -        pass
++NOT_YET_IMPLEMENTED_StmtClassDef
  
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
--def foo():
+ def foo():
 -    """This is a docstring with
 -    some lines of text here
 -    """
--    return
++    "NOT_YET_IMPLEMENTED_STRING"
+     return
  
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
--def bar():
+ def bar():
 -    """This is another docstring
 -    with more lines of text
 -    """
--    return
++    "NOT_YET_IMPLEMENTED_STRING"
+     return
  
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
--def baz():
+ def baz():
 -    '''"This" is a string with some
 -    embedded "quotes"'''
--    return
++    "NOT_YET_IMPLEMENTED_STRING"
+     return
  
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
--def troz():
+ def troz():
 -    """Indentation with tabs
 -    is just as OK
 -    """
--    return
++    "NOT_YET_IMPLEMENTED_STRING"
+     return
  
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
--def zort():
+ def zort():
 -    """Another
 -    multiline
 -    docstring
 -    """
--    pass
++    "NOT_YET_IMPLEMENTED_STRING"
+     pass
  
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
--def poit():
+ def poit():
 -    """
 -    Lorem ipsum dolor sit amet.
- 
+-
 -    Consectetur adipiscing elit:
 -     - sed do eiusmod tempor incididunt ut labore
 -     - dolore magna aliqua
@@ -300,99 +299,99 @@ def stable_quote_normalization_with_immediate_inner_single_quote(self):
 -       - quis nostrud exercitation ullamco laboris nisi
 -     - aliquip ex ea commodo consequat
 -    """
--    pass
++    "NOT_YET_IMPLEMENTED_STRING"
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
+     pass
  
  
--def under_indent():
+ def under_indent():
 -    """
 -      These lines are indented in a way that does not
 -    make sense.
 -    """
--    pass
++    "NOT_YET_IMPLEMENTED_STRING"
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
+     pass
  
  
--def over_indent():
+ def over_indent():
 -    """
 -    This has a shallow indent
 -      - But some lines are deeper
 -      - And the closing quote is too deep
 -    """
--    pass
++    "NOT_YET_IMPLEMENTED_STRING"
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
+     pass
  
  
--def single_line():
+ def single_line():
 -    """But with a newline after it!"""
--    pass
++    "NOT_YET_IMPLEMENTED_STRING"
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
+     pass
  
  
--def this():
+ def this():
 -    r"""
 -    'hey ho'
 -    """
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    "NOT_YET_IMPLEMENTED_STRING"
  
  
--def that():
+ def that():
 -    """ "hey yah" """
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    "NOT_YET_IMPLEMENTED_STRING"
  
  
--def and_that():
+ def and_that():
 -    """
 -    "hey yah" """
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    "NOT_YET_IMPLEMENTED_STRING"
  
  
--def and_this():
+ def and_this():
 -    '''
 -    "hey yah"'''
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    "NOT_YET_IMPLEMENTED_STRING"
  
  
--def multiline_whitespace():
+ def multiline_whitespace():
 -    """ """
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    "NOT_YET_IMPLEMENTED_STRING"
  
  
--def oneline_whitespace():
+ def oneline_whitespace():
 -    """ """
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    "NOT_YET_IMPLEMENTED_STRING"
  
  
--def empty():
+ def empty():
 -    """"""
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    "NOT_YET_IMPLEMENTED_STRING"
  
  
--def single_quotes():
+ def single_quotes():
 -    "testing"
--
++    "NOT_YET_IMPLEMENTED_STRING"
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
--def believe_it_or_not_this_is_in_the_py_stdlib():
+ 
+ def believe_it_or_not_this_is_in_the_py_stdlib():
 -    '''
 -    "hey yah"'''
++    "NOT_YET_IMPLEMENTED_STRING"
  
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
--def ignored_docstring():
+ def ignored_docstring():
 -    """a => \
 -b"""
++    "NOT_YET_IMPLEMENTED_STRING"
  
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
--def single_line_docstring_with_whitespace():
+ def single_line_docstring_with_whitespace():
 -    """This should be stripped"""
++    "NOT_YET_IMPLEMENTED_STRING"
  
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
--def docstring_with_inline_tabs_and_space_indentation():
+ def docstring_with_inline_tabs_and_space_indentation():
 -    """hey
- 
+-
 -    tab	separated	value
 -        tab at start of line and then a tab	separated	value
 -                                multiple tabs at the beginning	and	inline
@@ -400,12 +399,12 @@ def stable_quote_normalization_with_immediate_inner_single_quote(self):
 -
 -    line ends with some tabs
 -    """
--
++    "NOT_YET_IMPLEMENTED_STRING"
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
--def docstring_with_inline_tabs_and_tab_indentation():
+ 
+ def docstring_with_inline_tabs_and_tab_indentation():
 -    """hey
- 
+-
 -    tab	separated	value
 -            tab at start of line and then a tab	separated	value
 -                                    multiple tabs at the beginning	and	inline
@@ -413,82 +412,83 @@ def stable_quote_normalization_with_immediate_inner_single_quote(self):
 -
 -    line ends with some tabs
 -    """
--    pass
++    "NOT_YET_IMPLEMENTED_STRING"
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
+     pass
  
  
--def backslash_space():
+ def backslash_space():
 -    """\ """
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    "NOT_YET_IMPLEMENTED_STRING"
  
  
--def multiline_backslash_1():
+ def multiline_backslash_1():
 -    """
 -  hey\there\
 -  \ """
--
++    "NOT_YET_IMPLEMENTED_STRING"
--
+ 
--def multiline_backslash_2():
+ 
+ def multiline_backslash_2():
 -    """
 -    hey there \ """
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    "NOT_YET_IMPLEMENTED_STRING"
  
  
  # Regression test for #3425
--def multiline_backslash_really_long_dont_crash():
+ def multiline_backslash_really_long_dont_crash():
 -    """
 -    hey there hello guten tag hi hoow are you ola zdravstvuyte ciao como estas ca va \ """
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    "NOT_YET_IMPLEMENTED_STRING"
  
  
--def multiline_backslash_3():
+ def multiline_backslash_3():
 -    """
 -    already escaped \\"""
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    "NOT_YET_IMPLEMENTED_STRING"
  
  
--def my_god_its_full_of_stars_1():
+ def my_god_its_full_of_stars_1():
 -    "I'm sorry Dave\u2001"
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    "NOT_YET_IMPLEMENTED_STRING"
  
  
  # the space below is actually a \u2001, removed in output
--def my_god_its_full_of_stars_2():
+ def my_god_its_full_of_stars_2():
 -    "I'm sorry Dave"
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    "NOT_YET_IMPLEMENTED_STRING"
  
  
--def docstring_almost_at_line_limit():
+ def docstring_almost_at_line_limit():
 -    """long docstring................................................................."""
--
++    "NOT_YET_IMPLEMENTED_STRING"
--
+ 
--def docstring_almost_at_line_limit2():
+ 
+ def docstring_almost_at_line_limit2():
 -    """long docstring.................................................................
 -
 -    ..................................................................................
 -    """
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    "NOT_YET_IMPLEMENTED_STRING"
  
  
--def docstring_at_line_limit():
+ def docstring_at_line_limit():
 -    """long docstring................................................................"""
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    "NOT_YET_IMPLEMENTED_STRING"
  
  
--def multiline_docstring_at_line_limit():
+ def multiline_docstring_at_line_limit():
 -    """first line-----------------------------------------------------------------------
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
+-
- 
 -    second line----------------------------------------------------------------------"""
++    "NOT_YET_IMPLEMENTED_STRING"
  
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
--def stable_quote_normalization_with_immediate_inner_single_quote(self):
+ def stable_quote_normalization_with_immediate_inner_single_quote(self):
 -    """'<text here>
- 
+-
 -    <text here, since without another non-empty line black is stable>
 -    """
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    "NOT_YET_IMPLEMENTED_STRING"
 ```
 
 ## Ruff Output
@@ -497,108 +497,152 @@ def stable_quote_normalization_with_immediate_inner_single_quote(self):
 NOT_YET_IMPLEMENTED_StmtClassDef
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def foo():
+    "NOT_YET_IMPLEMENTED_STRING"
+    return
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def bar():
+    "NOT_YET_IMPLEMENTED_STRING"
+    return
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def baz():
+    "NOT_YET_IMPLEMENTED_STRING"
+    return
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def troz():
+    "NOT_YET_IMPLEMENTED_STRING"
+    return
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def zort():
+    "NOT_YET_IMPLEMENTED_STRING"
+    pass
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def poit():
+    "NOT_YET_IMPLEMENTED_STRING"
+    pass
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def under_indent():
+    "NOT_YET_IMPLEMENTED_STRING"
+    pass
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def over_indent():
+    "NOT_YET_IMPLEMENTED_STRING"
+    pass
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def single_line():
+    "NOT_YET_IMPLEMENTED_STRING"
+    pass
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def this():
+    "NOT_YET_IMPLEMENTED_STRING"
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def that():
+    "NOT_YET_IMPLEMENTED_STRING"
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def and_that():
+    "NOT_YET_IMPLEMENTED_STRING"
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def and_this():
+    "NOT_YET_IMPLEMENTED_STRING"
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def multiline_whitespace():
+    "NOT_YET_IMPLEMENTED_STRING"
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def oneline_whitespace():
+    "NOT_YET_IMPLEMENTED_STRING"
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def empty():
+    "NOT_YET_IMPLEMENTED_STRING"
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def single_quotes():
+    "NOT_YET_IMPLEMENTED_STRING"
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def believe_it_or_not_this_is_in_the_py_stdlib():
+    "NOT_YET_IMPLEMENTED_STRING"
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def ignored_docstring():
+    "NOT_YET_IMPLEMENTED_STRING"
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def single_line_docstring_with_whitespace():
+    "NOT_YET_IMPLEMENTED_STRING"
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def docstring_with_inline_tabs_and_space_indentation():
+    "NOT_YET_IMPLEMENTED_STRING"
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def docstring_with_inline_tabs_and_tab_indentation():
+    "NOT_YET_IMPLEMENTED_STRING"
+    pass
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def backslash_space():
+    "NOT_YET_IMPLEMENTED_STRING"
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def multiline_backslash_1():
+    "NOT_YET_IMPLEMENTED_STRING"
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def multiline_backslash_2():
+    "NOT_YET_IMPLEMENTED_STRING"
 
 
 # Regression test for #3425
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def multiline_backslash_really_long_dont_crash():
+    "NOT_YET_IMPLEMENTED_STRING"
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def multiline_backslash_3():
+    "NOT_YET_IMPLEMENTED_STRING"
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def my_god_its_full_of_stars_1():
+    "NOT_YET_IMPLEMENTED_STRING"
 
 
 # the space below is actually a \u2001, removed in output
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def my_god_its_full_of_stars_2():
+    "NOT_YET_IMPLEMENTED_STRING"
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def docstring_almost_at_line_limit():
+    "NOT_YET_IMPLEMENTED_STRING"
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def docstring_almost_at_line_limit2():
+    "NOT_YET_IMPLEMENTED_STRING"
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def docstring_at_line_limit():
+    "NOT_YET_IMPLEMENTED_STRING"
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def multiline_docstring_at_line_limit():
+    "NOT_YET_IMPLEMENTED_STRING"
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def stable_quote_normalization_with_immediate_inner_single_quote(self):
+    "NOT_YET_IMPLEMENTED_STRING"
 ```
 
 ## Black Output

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__empty_lines_py.snap

@@ -105,13 +105,13 @@ def g():
 ```diff
 --- Black
 +++ Ruff
-@@ -1,89 +1,12 @@
+@@ -1,89 +1,45 @@
 -"""Docstring."""
 +"NOT_YET_IMPLEMENTED_STRING"
  
  
  # leading comment
--def f():
+ def f():
 -    NO = ""
 -    SPACE = " "
 -    DOUBLESPACE = "  "
@@ -124,15 +124,23 @@ def g():
 -        pass
 -    if t == token.COMMENT:  # another trailing comment
 -        return DOUBLESPACE
--
++    NO = "NOT_YET_IMPLEMENTED_STRING"
++    SPACE = "NOT_YET_IMPLEMENTED_STRING"
++    DOUBLESPACE = "NOT_YET_IMPLEMENTED_STRING"
+ 
 -    assert p is not None, f"INTERNAL ERROR: hand-made leaf without parent: {leaf!r}"
--
++    t = leaf.NOT_IMPLEMENTED_attr
++    p = leaf.NOT_IMPLEMENTED_attr  # trailing comment
++    v = leaf.NOT_IMPLEMENTED_attr
+ 
 -    prev = leaf.prev_sibling
 -    if not prev:
 -        prevp = preceding_leaf(p)
 -        if not prevp or prevp.type in OPENING_BRACKETS:
 -            return NO
--
++    NOT_YET_IMPLEMENTED_StmtIf
++    NOT_YET_IMPLEMENTED_StmtIf  # another trailing comment
+ 
 -        if prevp.type == token.EQUAL:
 -            if prevp.parent and prevp.parent.type in {
 -                syms.typedargslist,
@@ -142,7 +150,8 @@ def g():
 -                syms.argument,
 -            }:
 -                return NO
--
++    NOT_YET_IMPLEMENTED_StmtAssert
+ 
 -        elif prevp.type == token.DOUBLESTAR:
 -            if prevp.parent and prevp.parent.type in {
 -                syms.typedargslist,
@@ -152,7 +161,8 @@ def g():
 -                syms.dictsetmaker,
 -            }:
 -                return NO
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    prev = leaf.NOT_IMPLEMENTED_attr
++    NOT_YET_IMPLEMENTED_StmtIf
  
  
  ###############################################################################
@@ -160,29 +170,38 @@ def g():
  ###############################################################################
 -
  
--def g():
+ def g():
 -    NO = ""
 -    SPACE = " "
 -    DOUBLESPACE = "  "
--
++    NO = "NOT_YET_IMPLEMENTED_STRING"
++    SPACE = "NOT_YET_IMPLEMENTED_STRING"
++    DOUBLESPACE = "NOT_YET_IMPLEMENTED_STRING"
+ 
 -    t = leaf.type
 -    p = leaf.parent
 -    v = leaf.value
--
++    t = leaf.NOT_IMPLEMENTED_attr
--    # Comment because comments
++    p = leaf.NOT_IMPLEMENTED_attr
--
++    v = leaf.NOT_IMPLEMENTED_attr
+ 
+     # Comment because comments
+ 
 -    if t in ALWAYS_NO_SPACE:
 -        pass
 -    if t == token.COMMENT:
 -        return DOUBLESPACE
--
++    NOT_YET_IMPLEMENTED_StmtIf
--    # Another comment because more comments
++    NOT_YET_IMPLEMENTED_StmtIf
+ 
+     # Another comment because more comments
 -    assert p is not None, f"INTERNAL ERROR: hand-made leaf without parent: {leaf!r}"
 -
 -    prev = leaf.prev_sibling
 -    if not prev:
 -        prevp = preceding_leaf(p)
--
++    NOT_YET_IMPLEMENTED_StmtAssert
+ 
 -        if not prevp or prevp.type in OPENING_BRACKETS:
 -            # Start of the line or a bracketed expression.
 -            # More than one line for the comment.
@@ -197,7 +216,8 @@ def g():
 -                syms.argument,
 -            }:
 -                return NO
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    prev = leaf.NOT_IMPLEMENTED_attr
++    NOT_YET_IMPLEMENTED_StmtIf
 ```
 
 ## Ruff Output
@@ -207,14 +227,47 @@ def g():
 
 
 # leading comment
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def f():
+    NO = "NOT_YET_IMPLEMENTED_STRING"
+    SPACE = "NOT_YET_IMPLEMENTED_STRING"
+    DOUBLESPACE = "NOT_YET_IMPLEMENTED_STRING"
+
+    t = leaf.NOT_IMPLEMENTED_attr
+    p = leaf.NOT_IMPLEMENTED_attr  # trailing comment
+    v = leaf.NOT_IMPLEMENTED_attr
+
+    NOT_YET_IMPLEMENTED_StmtIf
+    NOT_YET_IMPLEMENTED_StmtIf  # another trailing comment
+
+    NOT_YET_IMPLEMENTED_StmtAssert
+
+    prev = leaf.NOT_IMPLEMENTED_attr
+    NOT_YET_IMPLEMENTED_StmtIf
 
 
 ###############################################################################
 # SECTION BECAUSE SECTIONS
 ###############################################################################
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def g():
+    NO = "NOT_YET_IMPLEMENTED_STRING"
+    SPACE = "NOT_YET_IMPLEMENTED_STRING"
+    DOUBLESPACE = "NOT_YET_IMPLEMENTED_STRING"
+
+    t = leaf.NOT_IMPLEMENTED_attr
+    p = leaf.NOT_IMPLEMENTED_attr
+    v = leaf.NOT_IMPLEMENTED_attr
+
+    # Comment because comments
+
+    NOT_YET_IMPLEMENTED_StmtIf
+    NOT_YET_IMPLEMENTED_StmtIf
+
+    # Another comment because more comments
+    NOT_YET_IMPLEMENTED_StmtAssert
+
+    prev = leaf.NOT_IMPLEMENTED_attr
+    NOT_YET_IMPLEMENTED_StmtIf
 ```
 
 ## Black Output

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__expression_py.snap

@@ -276,7 +276,7 @@ last_call()
  Name
  None
  True
-@@ -7,346 +8,240 @@
+@@ -7,346 +8,245 @@
  1
  1.0
  1j
@@ -541,6 +541,9 @@ last_call()
 -    int,
 -    float,
 -    dict[str, int],
+-]
+-very_long_variable_name_filters: t.List[
+-    t.Tuple[str, t.Union[str, t.List[t.Optional[str]]]],
 +[
 +    1,
 +    2,
@@ -555,9 +558,6 @@ last_call()
 +    NOT_IMPLEMENTED_bool_op1 and NOT_IMPLEMENTED_bool_op2,
 +    NOT_IMPLEMENTED_bool_op1 and NOT_IMPLEMENTED_bool_op2,
  ]
--very_long_variable_name_filters: t.List[
--    t.Tuple[str, t.Union[str, t.List[t.Optional[str]]]],
--]
 -xxxx_xxxxx_xxxx_xxx: Callable[..., List[SomeClass]] = classmethod(  # type: ignore
 -    sync(async_xxxx_xxx_xxxx_xxxxx_xxxx_xxx.__func__)
 -)
@@ -679,17 +679,20 @@ last_call()
 +mapping = {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value}
  
  
--def gen():
+ def gen():
 -    yield from outside_of_generator
 -    a = yield
 -    b = yield
 -    c = yield
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    NOT_YET_IMPLEMENTED_ExprYieldFrom
++    a = NOT_YET_IMPLEMENTED_ExprYield
++    b = NOT_YET_IMPLEMENTED_ExprYield
++    c = NOT_YET_IMPLEMENTED_ExprYield
  
  
--async def f():
+ async def f():
 -    await some.complicated[0].call(with_args=(True or (1 is not 1)))
-+NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
++    await NOT_IMPLEMENTED_call()
  
  
 -print(*[] or [1])
@@ -823,7 +826,7 @@ last_call()
  (
      aaaaaaaaaaaaaaaa
      + aaaaaaaaaaaaaaaa
-@@ -363,8 +258,9 @@
+@@ -363,8 +263,9 @@
  bbbb >> bbbb * bbbb
  (
      aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
@@ -1050,10 +1053,15 @@ NOT_IMPLEMENTED_call()
 mapping = {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value}
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def gen():
+    NOT_YET_IMPLEMENTED_ExprYieldFrom
+    a = NOT_YET_IMPLEMENTED_ExprYield
+    b = NOT_YET_IMPLEMENTED_ExprYield
+    c = NOT_YET_IMPLEMENTED_ExprYield
 
 
-NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
+async def f():
+    await NOT_IMPLEMENTED_call()
 
 
 NOT_IMPLEMENTED_call()

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__fmtonoff2_py.snap

@@ -53,7 +53,7 @@ def test_calculate_fades():
 ```diff
 --- Black
 +++ Ruff
-@@ -1,40 +1,26 @@
+@@ -1,40 +1,38 @@
 -import pytest
 +NOT_YET_IMPLEMENTED_StmtImport
  
@@ -67,40 +67,43 @@ def test_calculate_fades():
  #   Position, Volume, State, TmSt/TmEx/None, [call, [arg1...]]
  
 -@pytest.mark.parametrize('test', [
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
+-
-+
-+
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
- 
 -    # Test don't manage the volume
 -    [
 -        ('stuff', 'in')
 -    ],
 -])
--def test_fader(test):
++@NOT_IMPLEMENTED_call()
--    pass
+ def test_fader(test):
+     pass
  
--def check_fader(test):
++
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
+ def check_fader(test):
++    pass
  
 -    pass
  
--def verify_fader(test):
+ def verify_fader(test):
 -  # misaligned comment
--    pass
++    # misaligned comment
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
+     pass
  
--def verify_fader(test):
++
+ def verify_fader(test):
 -    """Hey, ho."""
 -    assert test.passed()
++    "NOT_YET_IMPLEMENTED_STRING"
++    NOT_YET_IMPLEMENTED_StmtAssert
++
  
--def test_calculate_fades():
+ def test_calculate_fades():
--    calcs = [
+     calcs = [
--        # one is zero/none
+         # one is zero/none
 -        (0, 4, 0, 0, 10,        0, 0, 6, 10),
 -        (None, 4, 0, 0, 10,     0, 0, 6, 10),
--    ]
++        (1, 2),
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++        (1, 2),
+     ]
  
  # fmt: on
 ```
@@ -119,19 +122,31 @@ TmEx = 2
 # Test data:
 #   Position, Volume, State, TmSt/TmEx/None, [call, [arg1...]]
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+@NOT_IMPLEMENTED_call()
+def test_fader(test):
+    pass
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def check_fader(test):
+    pass
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def verify_fader(test):
+    # misaligned comment
+    pass
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def verify_fader(test):
+    "NOT_YET_IMPLEMENTED_STRING"
+    NOT_YET_IMPLEMENTED_StmtAssert
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def test_calculate_fades():
+    calcs = [
+        # one is zero/none
+        (1, 2),
+        (1, 2),
+    ]
 
 # fmt: on
 ```

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__fmtonoff4_py.snap

@@ -26,16 +26,16 @@ def f(): pass
 ```diff
 --- Black
 +++ Ruff
-@@ -1,20 +1,5 @@
+@@ -1,20 +1,10 @@
  # fmt: off
 -@test([
 -    1, 2,
 -    3, 4,
 -])
--# fmt: on
++@NOT_IMPLEMENTED_call()
--def f():
+ # fmt: on
--    pass
+ def f():
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
+     pass
  
  
 -@test(
@@ -46,19 +46,24 @@ def f(): pass
 -        4,
 -    ]
 -)
--def f():
++@NOT_IMPLEMENTED_call()
--    pass
+ def f():
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
+     pass
 ```
 
 ## Ruff Output
 
 ```py
 # fmt: off
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+@NOT_IMPLEMENTED_call()
+# fmt: on
+def f():
+    pass
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+@NOT_IMPLEMENTED_call()
+def f():
+    pass
 ```
 
 ## Black Output

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__fmtonoff5_py.snap

@@ -97,7 +97,7 @@ elif   unformatted:
 ```diff
 --- Black
 +++ Ruff
-@@ -1,87 +1,29 @@
+@@ -1,87 +1,33 @@
  # Regression test for https://github.com/psf/black/issues/3129.
 -setup(
 -    entry_points={
@@ -127,18 +127,18 @@ elif   unformatted:
  
  
  # Regression test for https://github.com/psf/black/issues/3026.
--def test_func():
+ def test_func():
--    # yapf: disable
+     # yapf: disable
 -    if  unformatted(  args  ):
 -        return True
 -    # yapf: enable
 -    elif b:
 -        return True
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    NOT_YET_IMPLEMENTED_StmtIf
+ 
+     return False
  
--    return False
  
--
  # Regression test for https://github.com/psf/black/issues/2567.
 -if True:
 -    # fmt: off
@@ -161,14 +161,14 @@ elif   unformatted:
 -            )  :
 -                # fmt: on
 -                print ( "This won't be formatted" )
--
--            elif param[0:4] in ("ZZZZ",):
--                print ( "This won't be formatted either" )
--
--        print("This will be formatted")
 +NOT_YET_IMPLEMENTED_StmtClassDef
  
+-            elif param[0:4] in ("ZZZZ",):
+-                print ( "This won't be formatted either" )
  
+-        print("This will be formatted")
+-
+-
  # Regression test for https://github.com/psf/black/issues/2985.
 -class Named(t.Protocol):
 -    # fmt: off
@@ -180,10 +180,10 @@ elif   unformatted:
 -class Factory(t.Protocol):
 -    def this_will_be_formatted(self, **kwargs) -> Named:
 -        ...
+-
+-    # fmt: on
 +NOT_YET_IMPLEMENTED_StmtClassDef
  
--    # fmt: on
--
  
  # Regression test for https://github.com/psf/black/issues/3436.
 -if x:
@@ -207,7 +207,11 @@ NOT_IMPLEMENTED_call()
 
 
 # Regression test for https://github.com/psf/black/issues/3026.
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def test_func():
+    # yapf: disable
+    NOT_YET_IMPLEMENTED_StmtIf
+
+    return False
 
 
 # Regression test for https://github.com/psf/black/issues/2567.

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__fmtonoff_py.snap

@@ -199,7 +199,7 @@ d={'a':1,
 ```diff
 --- Black
 +++ Ruff
-@@ -1,224 +1,72 @@
+@@ -1,16 +1,14 @@
  #!/usr/bin/env python3
 -import asyncio
 -import sys
@@ -207,10 +207,10 @@ d={'a':1,
 +NOT_YET_IMPLEMENTED_StmtImport
  
 -from third_party import X, Y, Z
+-
+-from library import some_connection, some_decorator
 +NOT_YET_IMPLEMENTED_StmtImportFrom
  
--from library import some_connection, some_decorator
--
 +NOT_YET_IMPLEMENTED_StmtImportFrom
  # fmt: off
 -from third_party import (X,
@@ -222,10 +222,10 @@ d={'a':1,
  # Comment 1
  
  # Comment 2
- 
+@@ -18,109 +16,109 @@
  
  # fmt: off
--def func_no_args():
+ def func_no_args():
 -  a; b; c
 -  if True: raise RuntimeError
 -  if False: ...
@@ -234,7 +234,17 @@ d={'a':1,
 -    continue
 -  exec('new-style exec', {}, {})
 -  return None
--async def coroutine(arg, exec=False):
++    a
++    b
++    c
++    NOT_YET_IMPLEMENTED_StmtIf
++    NOT_YET_IMPLEMENTED_StmtIf
++    NOT_YET_IMPLEMENTED_StmtFor
++    NOT_IMPLEMENTED_call()
++    return None
++
++
+ async def coroutine(arg, exec=False):
 - 'Single-line docstring. Multiline is harder to reformat.'
 - async with some_connection() as conn:
 -     await conn.do_what_i_mean('SELECT bobby, tables FROM xkcd', timeout=2)
@@ -246,47 +256,75 @@ d={'a':1,
 -)
 -def function_signature_stress_test(number:int,no_annotation=None,text:str='default',* ,debug:bool=False,**kwargs) -> str:
 - return text[number:-1]
--# fmt: on
++    "NOT_YET_IMPLEMENTED_STRING"
++    NOT_YET_IMPLEMENTED_StmtAsyncWith
++    await NOT_IMPLEMENTED_call()
++
++
++@asyncio.NOT_IMPLEMENTED_attr
++@NOT_IMPLEMENTED_call()
++def function_signature_stress_test(
++    number: int,
++    no_annotation=None,
++    text: str = "NOT_YET_IMPLEMENTED_STRING",
++    debug: bool = False,
++    **kwargs,
++) -> str:
++    return NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key]
++
++
+ # fmt: on
 -def spaces(a=1, b=(), c=[], d={}, e=True, f=-1, g=1 if False else 2, h="", i=r""):
 -    offset = attr.ib(default=attr.Factory(lambda: _r.uniform(1, 2)))
 -    assert task._cancel_stack[: len(old_stack)] == old_stack
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++def spaces(
-+
++    a=1,
-+
++    b=(1, 2),
-+NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
++    c=[],
-+
++    d={NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value},
++    e=True,
++    f=NOT_YET_IMPLEMENTED_ExprUnaryOp,
++    g=NOT_IMPLEMENTED_true if NOT_IMPLEMENTED_cond else NOT_IMPLEMENTED_false,
++    h="NOT_YET_IMPLEMENTED_STRING",
++    i="NOT_YET_IMPLEMENTED_STRING",
++):
++    offset = NOT_IMPLEMENTED_call()
++    NOT_YET_IMPLEMENTED_StmtAssert
  
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
--def spaces_types(
+ def spaces_types(
--    a: int = 1,
+     a: int = 1,
 -    b: tuple = (),
--    c: list = [],
++    b: tuple = (1, 2),
+     c: list = [],
 -    d: dict = {},
--    e: bool = True,
++    d: dict = {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value},
+     e: bool = True,
 -    f: int = -1,
 -    g: int = 1 if False else 2,
 -    h: str = "",
 -    i: str = r"",
--):
++    f: int = NOT_YET_IMPLEMENTED_ExprUnaryOp,
--    ...
++    g: int = NOT_IMPLEMENTED_true if NOT_IMPLEMENTED_cond else NOT_IMPLEMENTED_false,
++    h: str = "NOT_YET_IMPLEMENTED_STRING",
++    i: str = "NOT_YET_IMPLEMENTED_STRING",
+ ):
+     ...
  
-+# fmt: on
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
 -def spaces2(result=_core.Value(None)):
--    ...
++def spaces2(result=NOT_IMPLEMENTED_call()):
+     ...
  
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
 -something = {
 -    # fmt: off
 -    key: 'value',
 -}
++something = {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value}
  
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
--def subscriptlist():
+ def subscriptlist():
 -    atom[
 -        # fmt: off
 -        'some big and',
@@ -295,81 +333,90 @@ d={'a':1,
 -        goes + here,
 -        andhere,
 -    ]
++    NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key]
  
-+something = {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value}
  
--def import_as_names():
+ def import_as_names():
--    # fmt: off
+     # fmt: off
 -    from hello import a,        b
 -    'unformatted'
--    # fmt: on
++    NOT_YET_IMPLEMENTED_StmtImportFrom
++    "NOT_YET_IMPLEMENTED_STRING"
+     # fmt: on
  
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
--def testlist_star_expr():
+ def testlist_star_expr():
--    # fmt: off
+     # fmt: off
 -    a , b = *hello
 -    'unformatted'
--    # fmt: on
++    (1, 2) = NOT_YET_IMPLEMENTED_ExprStarred
++    "NOT_YET_IMPLEMENTED_STRING"
+     # fmt: on
  
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
--def yield_expr():
+ def yield_expr():
--    # fmt: off
+     # fmt: off
 -    yield hello
 -    'unformatted'
--    # fmt: on
++    NOT_YET_IMPLEMENTED_ExprYield
++    "NOT_YET_IMPLEMENTED_STRING"
+     # fmt: on
 -    "formatted"
--    # fmt: off
++    "NOT_YET_IMPLEMENTED_STRING"
+     # fmt: off
 -    ( yield hello )
 -    'unformatted'
--    # fmt: on
++    (NOT_YET_IMPLEMENTED_ExprYield)
++    "NOT_YET_IMPLEMENTED_STRING"
+     # fmt: on
  
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
--def example(session):
+ def example(session):
--    # fmt: off
+     # fmt: off
 -    result = session\
 -        .query(models.Customer.id)\
 -        .filter(models.Customer.account_id == account_id,
 -                models.Customer.email == email_address)\
 -        .order_by(models.Customer.id.asc())\
 -        .all()
--    # fmt: on
++    result = NOT_IMPLEMENTED_call()
+     # fmt: on
  
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
--def off_and_on_without_data():
+ def off_and_on_without_data():
 -    """All comments here are technically on the same prefix.
- 
+-
 -    The comments between will be formatted. This is a known limitation.
 -    """
--    # fmt: off
++    "NOT_YET_IMPLEMENTED_STRING"
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
+     # fmt: off
  
--    # hey, that won't work
+     # hey, that won't work
- 
+@@ -130,13 +128,15 @@
--    # fmt: on
--    pass
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
  
--def on_and_off_broken():
+ def on_and_off_broken():
 -    """Another known limitation."""
--    # fmt: on
++    "NOT_YET_IMPLEMENTED_STRING"
--    # fmt: off
+     # fmt: on
+     # fmt: off
 -    this=should.not_be.formatted()
 -    and_=indeed . it  is  not  formatted
 -    because . the . handling . inside . generate_ignored_nodes()
 -    now . considers . multiple . fmt . directives . within . one . prefix
--    # fmt: on
++    this = NOT_IMPLEMENTED_call()
--    # fmt: off
++    and_ = NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right
--    # ...but comments still get reformatted even though they should not be
++    NOT_IMPLEMENTED_call()
--    # fmt: on
++    (
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++        now.NOT_IMPLEMENTED_attr.NOT_IMPLEMENTED_attr.NOT_IMPLEMENTED_attr.NOT_IMPLEMENTED_attr.NOT_IMPLEMENTED_attr.NOT_IMPLEMENTED_attr.NOT_IMPLEMENTED_attr
++    )
+     # fmt: on
+     # fmt: off
+     # ...but comments still get reformatted even though they should not be
+@@ -144,81 +144,18 @@
  
  
--def long_lines():
+ def long_lines():
 -    if True:
 -        typedargslist.extend(
 -            gen_annotated_params(
@@ -408,13 +455,15 @@ d={'a':1,
 -        re.MULTILINE|re.VERBOSE
 -        # fmt: on
 -    )
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    NOT_YET_IMPLEMENTED_StmtIf
++    _type_comment_re = NOT_IMPLEMENTED_call()
  
  
--def single_literal_yapf_disable():
+ def single_literal_yapf_disable():
 -    """Black does not support this."""
 -    BAZ = {(1, 2, 3, 4), (5, 6, 7, 8), (9, 10, 11, 12)}  # yapf: disable
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    "NOT_YET_IMPLEMENTED_STRING"
++    BAZ = {(1, 2), (1, 2), (1, 2)}  # yapf: disable
  
  
 -cfg.rule(
@@ -476,53 +525,142 @@ NOT_YET_IMPLEMENTED_ExprJoinedStr
 
 
 # fmt: off
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def func_no_args():
+    a
+    b
+    c
+    NOT_YET_IMPLEMENTED_StmtIf
+    NOT_YET_IMPLEMENTED_StmtIf
+    NOT_YET_IMPLEMENTED_StmtFor
+    NOT_IMPLEMENTED_call()
+    return None
 
 
-NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
+async def coroutine(arg, exec=False):
+    "NOT_YET_IMPLEMENTED_STRING"
+    NOT_YET_IMPLEMENTED_StmtAsyncWith
+    await NOT_IMPLEMENTED_call()
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+@asyncio.NOT_IMPLEMENTED_attr
+@NOT_IMPLEMENTED_call()
+def function_signature_stress_test(
+    number: int,
+    no_annotation=None,
+    text: str = "NOT_YET_IMPLEMENTED_STRING",
+    debug: bool = False,
+    **kwargs,
+) -> str:
+    return NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key]
 
 
 # fmt: on
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def spaces(
+    a=1,
+    b=(1, 2),
+    c=[],
+    d={NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value},
+    e=True,
+    f=NOT_YET_IMPLEMENTED_ExprUnaryOp,
+    g=NOT_IMPLEMENTED_true if NOT_IMPLEMENTED_cond else NOT_IMPLEMENTED_false,
+    h="NOT_YET_IMPLEMENTED_STRING",
+    i="NOT_YET_IMPLEMENTED_STRING",
+):
+    offset = NOT_IMPLEMENTED_call()
+    NOT_YET_IMPLEMENTED_StmtAssert
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def spaces_types(
+    a: int = 1,
+    b: tuple = (1, 2),
+    c: list = [],
+    d: dict = {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value},
+    e: bool = True,
+    f: int = NOT_YET_IMPLEMENTED_ExprUnaryOp,
+    g: int = NOT_IMPLEMENTED_true if NOT_IMPLEMENTED_cond else NOT_IMPLEMENTED_false,
+    h: str = "NOT_YET_IMPLEMENTED_STRING",
+    i: str = "NOT_YET_IMPLEMENTED_STRING",
+):
+    ...
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def spaces2(result=NOT_IMPLEMENTED_call()):
+    ...
 
 
 something = {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value}
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def subscriptlist():
+    NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key]
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def import_as_names():
+    # fmt: off
+    NOT_YET_IMPLEMENTED_StmtImportFrom
+    "NOT_YET_IMPLEMENTED_STRING"
+    # fmt: on
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def testlist_star_expr():
+    # fmt: off
+    (1, 2) = NOT_YET_IMPLEMENTED_ExprStarred
+    "NOT_YET_IMPLEMENTED_STRING"
+    # fmt: on
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def yield_expr():
+    # fmt: off
+    NOT_YET_IMPLEMENTED_ExprYield
+    "NOT_YET_IMPLEMENTED_STRING"
+    # fmt: on
+    "NOT_YET_IMPLEMENTED_STRING"
+    # fmt: off
+    (NOT_YET_IMPLEMENTED_ExprYield)
+    "NOT_YET_IMPLEMENTED_STRING"
+    # fmt: on
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def example(session):
+    # fmt: off
+    result = NOT_IMPLEMENTED_call()
+    # fmt: on
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def off_and_on_without_data():
+    "NOT_YET_IMPLEMENTED_STRING"
+    # fmt: off
+
+    # hey, that won't work
+
+    # fmt: on
+    pass
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def on_and_off_broken():
+    "NOT_YET_IMPLEMENTED_STRING"
+    # fmt: on
+    # fmt: off
+    this = NOT_IMPLEMENTED_call()
+    and_ = NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right
+    NOT_IMPLEMENTED_call()
+    (
+        now.NOT_IMPLEMENTED_attr.NOT_IMPLEMENTED_attr.NOT_IMPLEMENTED_attr.NOT_IMPLEMENTED_attr.NOT_IMPLEMENTED_attr.NOT_IMPLEMENTED_attr.NOT_IMPLEMENTED_attr
+    )
+    # fmt: on
+    # fmt: off
+    # ...but comments still get reformatted even though they should not be
+    # fmt: on
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def long_lines():
+    NOT_YET_IMPLEMENTED_StmtIf
+    _type_comment_re = NOT_IMPLEMENTED_call()
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def single_literal_yapf_disable():
+    "NOT_YET_IMPLEMENTED_STRING"
+    BAZ = {(1, 2), (1, 2), (1, 2)}  # yapf: disable
 
 
 NOT_IMPLEMENTED_call()

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__fmtskip8_py.snap

@@ -75,20 +75,23 @@ async def test_async_with():
 ```diff
 --- Black
 +++ Ruff
-@@ -1,62 +1,33 @@
+@@ -1,62 +1,40 @@
  # Make sure a leading comment is not removed.
 -def some_func(  unformatted,  args  ):  # fmt: skip
 -    print("I am some_func")
--    return 0
++def some_func(unformatted, args):  # fmt: skip
--    # Make sure this comment is not removed.
++    NOT_IMPLEMENTED_call()
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
+     return 0
+     # Make sure this comment is not removed.
  
  
  # Make sure a leading comment is not removed.
 -async def some_async_func(  unformatted,   args):  # fmt: skip
 -    print("I am some_async_func")
 -    await asyncio.sleep(1)
-+NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
++async def some_async_func(unformatted, args):  # fmt: skip
++    NOT_IMPLEMENTED_call()
++    await NOT_IMPLEMENTED_call()
  
  
  # Make sure a leading comment is not removed.
@@ -96,13 +99,13 @@ async def test_async_with():
 -    def some_method(  self,  unformatted,  args  ):  # fmt: skip
 -        print("I am some_method")
 -        return 0
-+NOT_YET_IMPLEMENTED_StmtClassDef
+-
- 
 -    async def some_async_method(  self,  unformatted,  args  ):  # fmt: skip
 -        print("I am some_async_method")
 -        await asyncio.sleep(1)
++NOT_YET_IMPLEMENTED_StmtClassDef
+ 
  
--
  # Make sure a leading comment is not removed.
 -if  unformatted_call(  args  ):  # fmt: skip
 -    print("First branch")
@@ -125,10 +128,10 @@ async def test_async_with():
 +NOT_YET_IMPLEMENTED_StmtFor  # fmt: skip
  
  
--async def test_async_for():
+ async def test_async_for():
 -    async  for  i  in  some_async_iter(  unformatted,  args  ):  # fmt: skip
 -        print("Do something")
-+NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
++    NOT_YET_IMPLEMENTED_StmtAsyncFor  # fmt: skip
  
  
 -try  :  # fmt: skip
@@ -145,21 +148,26 @@ async def test_async_with():
 +NOT_YET_IMPLEMENTED_StmtWith  # fmt: skip
  
  
--async def test_async_with():
+ async def test_async_with():
 -    async  with  give_me_async_context(  unformatted,  args  ):  # fmt: skip
 -        print("Do something")
-+NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
++    NOT_YET_IMPLEMENTED_StmtAsyncWith  # fmt: skip
 ```
 
 ## Ruff Output
 
 ```py
 # Make sure a leading comment is not removed.
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def some_func(unformatted, args):  # fmt: skip
+    NOT_IMPLEMENTED_call()
+    return 0
+    # Make sure this comment is not removed.
 
 
 # Make sure a leading comment is not removed.
-NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
+async def some_async_func(unformatted, args):  # fmt: skip
+    NOT_IMPLEMENTED_call()
+    await NOT_IMPLEMENTED_call()
 
 
 # Make sure a leading comment is not removed.
@@ -177,7 +185,8 @@ while NOT_IMPLEMENTED_call():  # fmt: skip
 NOT_YET_IMPLEMENTED_StmtFor  # fmt: skip
 
 
-NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
+async def test_async_for():
+    NOT_YET_IMPLEMENTED_StmtAsyncFor  # fmt: skip
 
 
 NOT_YET_IMPLEMENTED_StmtTry
@@ -186,7 +195,8 @@ NOT_YET_IMPLEMENTED_StmtTry
 NOT_YET_IMPLEMENTED_StmtWith  # fmt: skip
 
 
-NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
+async def test_async_with():
+    NOT_YET_IMPLEMENTED_StmtAsyncWith  # fmt: skip
 ```
 
 ## Black Output

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__function2_py.snap

@@ -66,11 +66,10 @@ with hmm_but_this_should_get_two_preceding_newlines():
 ```diff
 --- Black
 +++ Ruff
-@@ -1,65 +1,12 @@
+@@ -2,64 +2,27 @@
--def f(
+     a,
--    a,
+     **kwargs,
--    **kwargs,
+ ) -> A:
--) -> A:
 -    with cache_dir():
 -        if something:
 -            result = CliRunner().invoke(
@@ -82,19 +81,24 @@ with hmm_but_this_should_get_two_preceding_newlines():
 -        very_long_argument_name2=-very.long.value.for_the_argument,
 -        **kwargs,
 -    )
--
++    NOT_YET_IMPLEMENTED_StmtWith
--
++    NOT_IMPLEMENTED_call()  # negate top
--def g():
++    return NOT_IMPLEMENTED_call()
+ 
+ 
+ def g():
 -    "Docstring."
--
++    "NOT_YET_IMPLEMENTED_STRING"
--    def inner():
+ 
--        pass
+     def inner():
--
+         pass
+ 
 -    print("Inner defs should breathe a little.")
--
++    NOT_IMPLEMENTED_call()
--
+ 
--def h():
+ 
--    def inner():
+ def h():
+     def inner():
 -        pass
 -
 -    print("Inner defs should breathe a little.")
@@ -104,36 +108,34 @@ with hmm_but_this_should_get_two_preceding_newlines():
 -    import termios
 -
 -    def i_should_be_followed_by_only_one_newline():
--        pass
+         pass
--
+ 
 -elif os.name == "nt":
 -    try:
 -        import msvcrt
--
++    NOT_IMPLEMENTED_call()
+ 
 -        def i_should_be_followed_by_only_one_newline():
 -            pass
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
 -    except ImportError:
++NOT_YET_IMPLEMENTED_StmtIf
  
 -        def i_should_be_followed_by_only_one_newline():
 -            pass
 -
 -elif False:
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
+-
- 
 -    class IHopeYouAreHavingALovelyDay:
 -        def __call__(self):
 -            print("i_should_be_followed_by_only_one_newline")
- 
+-
 -else:
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
+-
- 
 -    def foo():
 -        pass
- 
+-
-+NOT_YET_IMPLEMENTED_StmtIf
+-
- 
 -with hmm_but_this_should_get_two_preceding_newlines():
 -    pass
 +NOT_YET_IMPLEMENTED_StmtWith
@@ -142,13 +144,29 @@ with hmm_but_this_should_get_two_preceding_newlines():
 ## Ruff Output
 
 ```py
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def f(
+    a,
+    **kwargs,
+) -> A:
+    NOT_YET_IMPLEMENTED_StmtWith
+    NOT_IMPLEMENTED_call()  # negate top
+    return NOT_IMPLEMENTED_call()
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def g():
+    "NOT_YET_IMPLEMENTED_STRING"
+
+    def inner():
+        pass
+
+    NOT_IMPLEMENTED_call()
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def h():
+    def inner():
+        pass
+
+    NOT_IMPLEMENTED_call()
 
 
 NOT_YET_IMPLEMENTED_StmtIf

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__function_py.snap

@@ -108,7 +108,7 @@ def __await__(): return (yield)
 ```diff
 --- Black
 +++ Ruff
-@@ -1,148 +1,41 @@
+@@ -1,148 +1,94 @@
  #!/usr/bin/env python3
 -import asyncio
 -import sys
@@ -125,10 +125,10 @@ def __await__(): return (yield)
 -f"trigger 3.6 mode"
 -
  
--def func_no_args():
+ def func_no_args():
--    a
+     a
--    b
+     b
--    c
+     c
 -    if True:
 -        raise RuntimeError
 -    if False:
@@ -137,59 +137,85 @@ def __await__(): return (yield)
 -        print(i)
 -        continue
 -    exec("new-style exec", {}, {})
--    return None
++    NOT_YET_IMPLEMENTED_StmtIf
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    NOT_YET_IMPLEMENTED_StmtIf
++    NOT_YET_IMPLEMENTED_StmtFor
++    NOT_IMPLEMENTED_call()
+     return None
  
  
--async def coroutine(arg, exec=False):
+ async def coroutine(arg, exec=False):
 -    "Single-line docstring. Multiline is harder to reformat."
 -    async with some_connection() as conn:
 -        await conn.do_what_i_mean("SELECT bobby, tables FROM xkcd", timeout=2)
 -    await asyncio.sleep(1)
-+NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
++    "NOT_YET_IMPLEMENTED_STRING"
++    NOT_YET_IMPLEMENTED_StmtAsyncWith
++    await NOT_IMPLEMENTED_call()
  
  
 -@asyncio.coroutine
 -@some_decorator(with_args=True, many_args=[1, 2, 3])
--def function_signature_stress_test(
++@asyncio.NOT_IMPLEMENTED_attr
--    number: int,
++@NOT_IMPLEMENTED_call()
--    no_annotation=None,
+ def function_signature_stress_test(
+     number: int,
+     no_annotation=None,
 -    text: str = "default",
 -    *,
--    debug: bool = False,
++    text: str = "NOT_YET_IMPLEMENTED_STRING",
--    **kwargs,
+     debug: bool = False,
--) -> str:
+     **kwargs,
+ ) -> str:
 -    return text[number:-1]
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    return NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key]
  
  
 -def spaces(a=1, b=(), c=[], d={}, e=True, f=-1, g=1 if False else 2, h="", i=r""):
 -    offset = attr.ib(default=attr.Factory(lambda: _r.uniform(10000, 200000)))
 -    assert task._cancel_stack[: len(old_stack)] == old_stack
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++def spaces(
++    a=1,
++    b=(1, 2),
++    c=[],
++    d={NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value},
++    e=True,
++    f=NOT_YET_IMPLEMENTED_ExprUnaryOp,
++    g=NOT_IMPLEMENTED_true if NOT_IMPLEMENTED_cond else NOT_IMPLEMENTED_false,
++    h="NOT_YET_IMPLEMENTED_STRING",
++    i="NOT_YET_IMPLEMENTED_STRING",
++):
++    offset = NOT_IMPLEMENTED_call()
++    NOT_YET_IMPLEMENTED_StmtAssert
  
  
--def spaces_types(
+ def spaces_types(
--    a: int = 1,
+     a: int = 1,
 -    b: tuple = (),
--    c: list = [],
++    b: tuple = (1, 2),
+     c: list = [],
 -    d: dict = {},
--    e: bool = True,
++    d: dict = {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value},
+     e: bool = True,
 -    f: int = -1,
 -    g: int = 1 if False else 2,
 -    h: str = "",
 -    i: str = r"",
--):
++    f: int = NOT_YET_IMPLEMENTED_ExprUnaryOp,
--    ...
++    g: int = NOT_IMPLEMENTED_true if NOT_IMPLEMENTED_cond else NOT_IMPLEMENTED_false,
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    h: str = "NOT_YET_IMPLEMENTED_STRING",
++    i: str = "NOT_YET_IMPLEMENTED_STRING",
+ ):
+     ...
  
  
 -def spaces2(result=_core.Value(None)):
 -    assert fut is self._read_fut, (fut, self._read_fut)
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++def spaces2(result=NOT_IMPLEMENTED_call()):
++    NOT_YET_IMPLEMENTED_StmtAssert
  
  
--def example(session):
+ def example(session):
 -    result = (
 -        session.query(models.Customer.id)
 -        .filter(
@@ -199,10 +225,10 @@ def __await__(): return (yield)
 -        .order_by(models.Customer.id.asc())
 -        .all()
 -    )
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    result = NOT_IMPLEMENTED_call()
  
  
--def long_lines():
+ def long_lines():
 -    if True:
 -        typedargslist.extend(
 -            gen_annotated_params(
@@ -243,23 +269,24 @@ def __await__(): return (yield)
 -        """,
 -        re.MULTILINE | re.VERBOSE,
 -    )
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    NOT_YET_IMPLEMENTED_StmtIf
++    _type_comment_re = NOT_IMPLEMENTED_call()
  
  
--def trailing_comma():
+ def trailing_comma():
 -    mapping = {
 -        A: 0.25 * (10.0 / 12),
 -        B: 0.1 * (10.0 / 12),
 -        C: 0.1 * (10.0 / 12),
 -        D: 0.1 * (10.0 / 12),
 -    }
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    mapping = {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value}
  
  
--def f(
+ def f(
--    a,
+     a,
--    **kwargs,
+     **kwargs,
--) -> A:
+ ) -> A:
 -    return (
 -        yield from A(
 -            very_long_argument_name1=very_long_value_for_the_argument,
@@ -267,12 +294,12 @@ def __await__(): return (yield)
 -            **kwargs,
 -        )
 -    )
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    return NOT_YET_IMPLEMENTED_ExprYieldFrom
  
  
--def __await__():
+ def __await__():
 -    return (yield)
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    return NOT_YET_IMPLEMENTED_ExprYield
 ```
 
 ## Ruff Output
@@ -288,37 +315,90 @@ NOT_YET_IMPLEMENTED_StmtImportFrom
 NOT_YET_IMPLEMENTED_ExprJoinedStr
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def func_no_args():
+    a
+    b
+    c
+    NOT_YET_IMPLEMENTED_StmtIf
+    NOT_YET_IMPLEMENTED_StmtIf
+    NOT_YET_IMPLEMENTED_StmtFor
+    NOT_IMPLEMENTED_call()
+    return None
 
 
-NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
+async def coroutine(arg, exec=False):
+    "NOT_YET_IMPLEMENTED_STRING"
+    NOT_YET_IMPLEMENTED_StmtAsyncWith
+    await NOT_IMPLEMENTED_call()
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+@asyncio.NOT_IMPLEMENTED_attr
+@NOT_IMPLEMENTED_call()
+def function_signature_stress_test(
+    number: int,
+    no_annotation=None,
+    text: str = "NOT_YET_IMPLEMENTED_STRING",
+    debug: bool = False,
+    **kwargs,
+) -> str:
+    return NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key]
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def spaces(
+    a=1,
+    b=(1, 2),
+    c=[],
+    d={NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value},
+    e=True,
+    f=NOT_YET_IMPLEMENTED_ExprUnaryOp,
+    g=NOT_IMPLEMENTED_true if NOT_IMPLEMENTED_cond else NOT_IMPLEMENTED_false,
+    h="NOT_YET_IMPLEMENTED_STRING",
+    i="NOT_YET_IMPLEMENTED_STRING",
+):
+    offset = NOT_IMPLEMENTED_call()
+    NOT_YET_IMPLEMENTED_StmtAssert
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def spaces_types(
+    a: int = 1,
+    b: tuple = (1, 2),
+    c: list = [],
+    d: dict = {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value},
+    e: bool = True,
+    f: int = NOT_YET_IMPLEMENTED_ExprUnaryOp,
+    g: int = NOT_IMPLEMENTED_true if NOT_IMPLEMENTED_cond else NOT_IMPLEMENTED_false,
+    h: str = "NOT_YET_IMPLEMENTED_STRING",
+    i: str = "NOT_YET_IMPLEMENTED_STRING",
+):
+    ...
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def spaces2(result=NOT_IMPLEMENTED_call()):
+    NOT_YET_IMPLEMENTED_StmtAssert
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def example(session):
+    result = NOT_IMPLEMENTED_call()
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def long_lines():
+    NOT_YET_IMPLEMENTED_StmtIf
+    _type_comment_re = NOT_IMPLEMENTED_call()
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def trailing_comma():
+    mapping = {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value}
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def f(
+    a,
+    **kwargs,
+) -> A:
+    return NOT_YET_IMPLEMENTED_ExprYieldFrom
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def __await__():
+    return NOT_YET_IMPLEMENTED_ExprYield
 ```
 
 ## Black Output

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__function_trailing_comma_py.snap

@@ -74,21 +74,22 @@ some_module.some_function(
 ```diff
 --- Black
 +++ Ruff
-@@ -1,114 +1,31 @@
+@@ -1,69 +1,29 @@
--def f(
+ def f(
--    a,
+     a,
--):
+ ):
 -    d = {
 -        "key": "value",
 -    }
 -    tup = (1,)
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    d = {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value}
++    tup = (1, 2)
  
  
--def f2(
+ def f2(
--    a,
+     a,
--    b,
+     b,
--):
+ ):
 -    d = {
 -        "key": "value",
 -        "key2": "value2",
@@ -97,12 +98,13 @@ some_module.some_function(
 -        1,
 -        2,
 -    )
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    d = {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value}
++    tup = (1, 2)
  
  
--def f(
+ def f(
--    a: int = 1,
+     a: int = 1,
--):
+ ):
 -    call(
 -        arg={
 -            "explode": "this",
@@ -129,7 +131,10 @@ some_module.some_function(
 -        }["a"]
 -    ):
 -        pass
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    NOT_IMPLEMENTED_call()
++    NOT_IMPLEMENTED_call()
++    x = NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key]
++    NOT_YET_IMPLEMENTED_StmtIf
  
  
 -def xxxxxxxxxxxxxxxxxxxxxxxxxxxx() -> (
@@ -144,23 +149,13 @@ some_module.some_function(
 -            }
 -        }
 -    }
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++def xxxxxxxxxxxxxxxxxxxxxxxxxxxx() -> NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key]:
++    json = {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value}
  
  
  # The type annotation shouldn't get a trailing comma since that would change its type.
- # Relevant bug report: https://github.com/psf/black/issues/2381.
+@@ -80,35 +40,16 @@
--def some_function_with_a_really_long_name() -> (
+     pass
--    returning_a_deeply_nested_import_of_a_type_i_suppose
--):
--    pass
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
- 
- 
--def some_method_with_a_really_long_name(
--    very_long_parameter_so_yeah: str, another_long_parameter: int
--) -> another_case_of_returning_a_deeply_nested_import_of_a_type_i_suppose_cause_why_not:
--    pass
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
  
 -def func() -> (
@@ -168,8 +163,8 @@ some_module.some_function(
 -        this_shouldn_t_get_a_trailing_comma_too
 -    )
 -):
--    pass
++def func() -> NOT_IMPLEMENTED_call():
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
+     pass
  
  
 -def func() -> (
@@ -177,8 +172,8 @@ some_module.some_function(
 -        this_shouldn_t_get_a_trailing_comma_too
 -    )
 -):
--    pass
++def func() -> NOT_IMPLEMENTED_call():
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
+     pass
  
  
  # Make sure inner one-element tuple won't explode
@@ -204,30 +199,54 @@ some_module.some_function(
 ## Ruff Output
 
 ```py
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def f(
+    a,
+):
+    d = {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value}
+    tup = (1, 2)
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def f2(
+    a,
+    b,
+):
+    d = {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value}
+    tup = (1, 2)
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def f(
+    a: int = 1,
+):
+    NOT_IMPLEMENTED_call()
+    NOT_IMPLEMENTED_call()
+    x = NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key]
+    NOT_YET_IMPLEMENTED_StmtIf
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def xxxxxxxxxxxxxxxxxxxxxxxxxxxx() -> NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key]:
+    json = {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value}
 
 
 # The type annotation shouldn't get a trailing comma since that would change its type.
 # Relevant bug report: https://github.com/psf/black/issues/2381.
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def some_function_with_a_really_long_name() -> (
+    returning_a_deeply_nested_import_of_a_type_i_suppose
+):
+    pass
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def some_method_with_a_really_long_name(
+    very_long_parameter_so_yeah: str, another_long_parameter: int
+) -> another_case_of_returning_a_deeply_nested_import_of_a_type_i_suppose_cause_why_not:
+    pass
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def func() -> NOT_IMPLEMENTED_call():
+    pass
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def func() -> NOT_IMPLEMENTED_call():
+    pass
 
 
 # Make sure inner one-element tuple won't explode

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__power_op_spacing_py.snap

@@ -76,21 +76,12 @@ return np.divide(
 ```diff
 --- Black
 +++ Ruff
-@@ -1,63 +1,51 @@
+@@ -8,56 +8,48 @@
--def function(**kwargs):
--    t = a**2 + b**3
--    return t**2
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
  
--def function_replace_spaces(**kwargs):
+ def function_dont_replace_spaces():
--    t = a**2 + b**3 + c**4
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
- 
- 
--def function_dont_replace_spaces():
 -    {**a, **b, **c}
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value}
  
  
 -a = 5**~4
@@ -184,13 +175,17 @@ return np.divide(
 ## Ruff Output
 
 ```py
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def function(**kwargs):
+    t = a**2 + b**3
+    return t**2
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def function_replace_spaces(**kwargs):
+    t = a**2 + b**3 + c**4
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def function_dont_replace_spaces():
+    {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value}
 
 
 a = 5**NOT_YET_IMPLEMENTED_ExprUnaryOp

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__remove_await_parens_py.snap

@@ -94,51 +94,58 @@ async def main():
 ```diff
 --- Black
 +++ Ruff
-@@ -1,93 +1,60 @@
+@@ -1,66 +1,57 @@
 -import asyncio
 +NOT_YET_IMPLEMENTED_StmtImport
  
  
  # Control example
--async def main():
+ async def main():
 -    await asyncio.sleep(1)
-+NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
++    await NOT_IMPLEMENTED_call()
  
  
  # Remove brackets for short coroutine/task
--async def main():
+ async def main():
 -    await asyncio.sleep(1)
-+NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
++    await (NOT_IMPLEMENTED_call())
  
  
--async def main():
+ async def main():
 -    await asyncio.sleep(1)
-+NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
++    await (NOT_IMPLEMENTED_call())
  
  
--async def main():
+ async def main():
 -    await asyncio.sleep(1)
-+NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
++    await (NOT_IMPLEMENTED_call())
  
  
  # Check comments
--async def main():
+ async def main():
 -    await asyncio.sleep(1)  # Hello
-+NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
++    (
++        await # Hello
++        NOT_IMPLEMENTED_call()
++    )
  
  
--async def main():
+ async def main():
 -    await asyncio.sleep(1)  # Hello
-+NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
++    (
++        await (
++            NOT_IMPLEMENTED_call()  # Hello
++        )
++    )
  
  
--async def main():
+ async def main():
 -    await asyncio.sleep(1)  # Hello
-+NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
++    await (NOT_IMPLEMENTED_call())  # Hello
  
  
  # Long lines
--async def main():
+ async def main():
 -    await asyncio.gather(
 -        asyncio.sleep(1),
 -        asyncio.sleep(1),
@@ -148,11 +155,11 @@ async def main():
 -        asyncio.sleep(1),
 -        asyncio.sleep(1),
 -    )
-+NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
++    await NOT_IMPLEMENTED_call()
  
  
  # Same as above but with magic trailing comma in function
--async def main():
+ async def main():
 -    await asyncio.gather(
 -        asyncio.sleep(1),
 -        asyncio.sleep(1),
@@ -162,50 +169,46 @@ async def main():
 -        asyncio.sleep(1),
 -        asyncio.sleep(1),
 -    )
-+NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
++    await NOT_IMPLEMENTED_call()
  
  
  # Cr@zY Br@ck3Tz
--async def main():
+ async def main():
 -    await black(1)
-+NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
++    await (NOT_IMPLEMENTED_call())
  
  
  # Keep brackets around non power operations and nested awaits
--async def main():
+@@ -69,7 +60,7 @@
--    await (set_of_tasks | other_set)
-+NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
  
  
--async def main():
+ async def main():
 -    await (await asyncio.sleep(1))
-+NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
++    await (await NOT_IMPLEMENTED_call())
  
  
  # It's awaits all the way down...
--async def main():
+@@ -78,16 +69,16 @@
--    await (await x)
-+NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
  
  
--async def main():
+ async def main():
 -    await (yield x)
-+NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
++    await (NOT_YET_IMPLEMENTED_ExprYield)
  
  
--async def main():
+ async def main():
 -    await (await asyncio.sleep(1))
-+NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
++    await (await (NOT_IMPLEMENTED_call()))
  
  
--async def main():
+ async def main():
 -    await (await (await (await (await asyncio.sleep(1)))))
-+NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
++    await (await (await (await (await (NOT_IMPLEMENTED_call())))))
  
  
--async def main():
+ async def main():
 -    await (yield)
-+NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
++    await (NOT_YET_IMPLEMENTED_ExprYield)
 ```
 
 ## Ruff Output
@@ -215,62 +218,86 @@ NOT_YET_IMPLEMENTED_StmtImport
 
 
 # Control example
-NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
+async def main():
+    await NOT_IMPLEMENTED_call()
 
 
 # Remove brackets for short coroutine/task
-NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
+async def main():
+    await (NOT_IMPLEMENTED_call())
 
 
-NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
+async def main():
+    await (NOT_IMPLEMENTED_call())
 
 
-NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
+async def main():
+    await (NOT_IMPLEMENTED_call())
 
 
 # Check comments
-NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
+async def main():
+    (
+        await # Hello
+        NOT_IMPLEMENTED_call()
+    )
 
 
-NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
+async def main():
+    (
+        await (
+            NOT_IMPLEMENTED_call()  # Hello
+        )
+    )
 
 
-NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
+async def main():
+    await (NOT_IMPLEMENTED_call())  # Hello
 
 
 # Long lines
-NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
+async def main():
+    await NOT_IMPLEMENTED_call()
 
 
 # Same as above but with magic trailing comma in function
-NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
+async def main():
+    await NOT_IMPLEMENTED_call()
 
 
 # Cr@zY Br@ck3Tz
-NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
+async def main():
+    await (NOT_IMPLEMENTED_call())
 
 
 # Keep brackets around non power operations and nested awaits
-NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
+async def main():
+    await (set_of_tasks | other_set)
 
 
-NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
+async def main():
+    await (await NOT_IMPLEMENTED_call())
 
 
 # It's awaits all the way down...
-NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
+async def main():
+    await (await x)
 
 
-NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
+async def main():
+    await (NOT_YET_IMPLEMENTED_ExprYield)
 
 
-NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
+async def main():
+    await (await (NOT_IMPLEMENTED_call()))
 
 
-NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
+async def main():
+    await (await (await (await (await (NOT_IMPLEMENTED_call())))))
 
 
-NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
+async def main():
+    await (NOT_YET_IMPLEMENTED_ExprYield)
 ```
 
 ## Black Output

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__remove_newline_after_code_block_open_py.snap

@@ -121,40 +121,40 @@ with open("/path/to/file.txt", mode="r") as read_file:
 ```diff
 --- Black
 +++ Ruff
-@@ -1,78 +1,56 @@
+@@ -1,78 +1,64 @@
 -import random
 +NOT_YET_IMPLEMENTED_StmtImport
  
  
--def foo1():
+ def foo1():
 -    print("The newline above me should be deleted!")
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    NOT_IMPLEMENTED_call()
  
  
--def foo2():
+ def foo2():
 -    print("All the newlines above me should be deleted!")
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    NOT_IMPLEMENTED_call()
  
  
--def foo3():
+ def foo3():
 -    print("No newline above me!")
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    NOT_IMPLEMENTED_call()
  
 -    print("There is a newline above me, and that's OK!")
++    NOT_IMPLEMENTED_call()
  
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
--def foo4():
+ def foo4():
--    # There is a comment here
+     # There is a comment here
  
 -    print("The newline above me should not be deleted!")
-+NOT_YET_IMPLEMENTED_StmtClassDef
++    NOT_IMPLEMENTED_call()
  
  
 -class Foo:
 -    def bar(self):
 -        print("The newline above me should be deleted!")
-+NOT_YET_IMPLEMENTED_StmtFor
++NOT_YET_IMPLEMENTED_StmtClassDef
  
  
 -for i in range(5):
@@ -170,8 +170,9 @@ with open("/path/to/file.txt", mode="r") as read_file:
 -for i in range(5):
 -    for j in range(7):
 -        print(f"{i}) The lines above me should be removed!")
--
++NOT_YET_IMPLEMENTED_StmtFor
--
+ 
+ 
 -if random.randint(0, 3) == 0:
 -    print("The new line above me is about to be removed!")
 +NOT_YET_IMPLEMENTED_StmtIf
@@ -226,16 +227,24 @@ with open("/path/to/file.txt", mode="r") as read_file:
 NOT_YET_IMPLEMENTED_StmtImport
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def foo1():
+    NOT_IMPLEMENTED_call()
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def foo2():
+    NOT_IMPLEMENTED_call()
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def foo3():
+    NOT_IMPLEMENTED_call()
+
+    NOT_IMPLEMENTED_call()
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def foo4():
+    # There is a comment here
+
+    NOT_IMPLEMENTED_call()
 
 
 NOT_YET_IMPLEMENTED_StmtClassDef

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__remove_parens_py.snap

@@ -68,7 +68,7 @@ def example8():
 ```diff
 --- Black
 +++ Ruff
-@@ -1,85 +1,37 @@
+@@ -1,24 +1,16 @@
  x = 1
  x = 1.2
  
@@ -78,8 +78,8 @@ def example8():
 +data = NOT_IMPLEMENTED_call()
  
  
--async def show_status():
+ async def show_status():
--    while True:
+     while True:
 -        try:
 -            if report_host:
 -                data = (
@@ -87,54 +87,47 @@ def example8():
 -                ).encode()
 -        except Exception as e:
 -            pass
-+NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
++        NOT_YET_IMPLEMENTED_StmtTry
  
  
--def example():
+ def example():
 -    return "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    return "NOT_YET_IMPLEMENTED_STRING"
  
  
--def example1():
+ def example1():
--    return 1111111111111111111111111111111111111111111111111111111111111111111111111111111111111
+@@ -30,15 +22,11 @@
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
  
--def example1point5():
+ def example2():
--    return 1111111111111111111111111111111111111111111111111111111111111111111111111111111111111
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
- 
- 
--def example2():
 -    return (
 -        "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
 -    )
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    return "NOT_YET_IMPLEMENTED_STRING"
  
  
--def example3():
+ def example3():
 -    return (
 -        1111111111111111111111111111111111111111111111111111111111111111111111111111111
 -    )
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    return 1111111111111111111111111111111111111111111111111111111111111111111111111111111
  
  
--def example4():
+ def example4():
--    return True
+@@ -46,39 +34,15 @@
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
  
--def example5():
+ def example5():
 -    return ()
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    return (1, 2)
  
  
--def example6():
+ def example6():
 -    return {a: a for a in [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17]}
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    return {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value for key, value in NOT_IMPLEMENTED_dict}
  
  
--def example7():
+ def example7():
 -    return {
 -        a: a
 -        for a in [
@@ -160,12 +153,10 @@ def example8():
 -            20000000000000000000,
 -        ]
 -    }
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    return {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value for key, value in NOT_IMPLEMENTED_dict}
  
  
--def example8():
+ def example8():
--    return None
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
 ```
 
 ## Ruff Output
@@ -177,37 +168,49 @@ x = 1.2
 data = NOT_IMPLEMENTED_call()
 
 
-NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
+async def show_status():
+    while True:
+        NOT_YET_IMPLEMENTED_StmtTry
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def example():
+    return "NOT_YET_IMPLEMENTED_STRING"
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def example1():
+    return 1111111111111111111111111111111111111111111111111111111111111111111111111111111111111
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def example1point5():
+    return 1111111111111111111111111111111111111111111111111111111111111111111111111111111111111
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def example2():
+    return "NOT_YET_IMPLEMENTED_STRING"
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def example3():
+    return 1111111111111111111111111111111111111111111111111111111111111111111111111111111
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def example4():
+    return True
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def example5():
+    return (1, 2)
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def example6():
+    return {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value for key, value in NOT_IMPLEMENTED_dict}
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def example7():
+    return {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value for key, value in NOT_IMPLEMENTED_dict}
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def example8():
+    return None
 ```
 
 ## Black Output

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__return_annotation_brackets_py.snap

@@ -101,123 +101,35 @@ def foo() -> tuple[int, int, int,]:
 ```diff
 --- Black
 +++ Ruff
-@@ -1,120 +1,65 @@
+@@ -26,7 +26,9 @@
- # Control
+     return 2 * a
--def double(a: int) -> int:
--    return 2 * a
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
- 
- 
- # Remove the brackets
--def double(a: int) -> int:
--    return 2 * a
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
- 
- 
- # Some newline variations
--def double(a: int) -> int:
--    return 2 * a
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
- 
- 
--def double(a: int) -> int:
--    return 2 * a
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
- 
- 
--def double(a: int) -> int:
--    return 2 * a
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
- 
- 
- # Don't lose the comments
--def double(a: int) -> int:  # Hello
--    return 2 * a
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
  
 -def double(a: int) -> int:  # Hello
--    return 2 * a
++def double(a: int) -> (
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    int  # Hello
++):
+     return 2 * a
  
  
- # Really long annotations
+@@ -54,7 +56,9 @@
--def foo() -> (
+     a: int,
--    intsdfsafafafdfdsasdfsfsdfasdfafdsafdfdsfasdskdsdsfdsafdsafsdfdasfffsfdsfdsafafhdskfhdsfjdslkfdlfsdkjhsdfjkdshfkljds
+     b: int,
--):
+     c: int,
--    return 2
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
- 
- 
--def foo() -> (
--    intsdfsafafafdfdsasdfsfsdfasdfafdsafdfdsfasdskdsdsfdsafdsafsdfdasfffsfdsfdsafafhdskfhdsfjdslkfdlfsdkjhsdfjkdshfkljds
--):
--    return 2
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
- 
- 
--def foo() -> (
--    intsdfsafafafdfdsasdfsfsdfasdfafdsafdfdsfasdskdsdsfdsafdsafsdfdasfffsfdsfdsafafhdskfhdsfjdslkfdlfsdkjhsdfjkdshfkljds
--    | intsdfsafafafdfdsasdfsfsdfasdfafdsafdfdsfasdskdsdsfdsafdsafsdfdasfffsfdsfdsafafhdskfhdsfjdslkfdlfsdkjhsdfjkdshfkljds
--):
--    return 2
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
- 
- 
--def foo(
--    a: int,
--    b: int,
--    c: int,
 -) -> intsdfsafafafdfdsasdfsfsdfasdfafdsafdfdsfasdskdsdsfdsafdsafsdfdasfffsfdsfdsafafhdskfhdsfjdslkfdlfsdkjhsdfjkdshfkljds:
--    return 2
++) -> (
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    intsdfsafafafdfdsasdfsfsdfasdfafdsafdfdsfasdskdsdsfdsafdsafsdfdasfffsfdsfdsafafhdskfhdsfjdslkfdlfsdkjhsdfjkdshfkljds
++):
+     return 2
  
  
--def foo(
+@@ -95,26 +99,14 @@
--    a: int,
--    b: int,
--    c: int,
--) -> (
--    intsdfsafafafdfdsasdfsfsdfasdfafdsafdfdsfasdskdsdsfdsafdsafsdfdasfffsfdsfdsafafhdskfhdsfjdslkfdlfsdkjhsdfjkdshfkljds
--    | intsdfsafafafdfdsasdfsfsdfasdfafdsafdfdsfasdskdsdsfdsafdsafsdfdasfffsfdsfdsafafhdskfhdsfjdslkfdlfsdkjhsdfjkdshfkljds
--):
--    return 2
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
- 
- 
- # Split args but no need to split return
--def foo(
--    a: int,
--    b: int,
--    c: int,
--) -> int:
--    return 2
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
- 
- 
- # Deeply nested brackets
- # with *interesting* spacing
--def double(a: int) -> int:
--    return 2 * a
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
- 
- 
--def double(a: int) -> int:
--    return 2 * a
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
- 
- 
--def foo() -> (
--    intsdfsafafafdfdsasdfsfsdfasdfafdsafdfdsfasdskdsdsfdsafdsafsdfdasfffsfdsfdsafafhdskfhdsfjdslkfdlfsdkjhsdfjkdshfkljds
--):
--    return 2
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
  
  
  # Return type with commas
 -def foo() -> tuple[int, int, int]:
--    return 2
++def foo() -> NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key]:
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
+     return 2
  
  
 -def foo() -> (
@@ -227,8 +139,8 @@ def foo() -> tuple[int, int, int,]:
 -        loooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooong,
 -    ]
 -):
--    return 2
++def foo() -> NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key]:
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
+     return 2
  
  
  # Magic trailing comma example
@@ -239,78 +151,125 @@ def foo() -> tuple[int, int, int,]:
 -        int,
 -    ]
 -):
--    return 2
++def foo() -> NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key]:
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
+     return 2
 ```
 
 ## Ruff Output
 
 ```py
 # Control
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def double(a: int) -> int:
+    return 2 * a
 
 
 # Remove the brackets
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def double(a: int) -> int:
+    return 2 * a
 
 
 # Some newline variations
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def double(a: int) -> int:
+    return 2 * a
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def double(a: int) -> int:
+    return 2 * a
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def double(a: int) -> int:
+    return 2 * a
 
 
 # Don't lose the comments
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def double(a: int) -> int:  # Hello
+    return 2 * a
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def double(a: int) -> (
+    int  # Hello
+):
+    return 2 * a
 
 
 # Really long annotations
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def foo() -> (
+    intsdfsafafafdfdsasdfsfsdfasdfafdsafdfdsfasdskdsdsfdsafdsafsdfdasfffsfdsfdsafafhdskfhdsfjdslkfdlfsdkjhsdfjkdshfkljds
+):
+    return 2
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def foo() -> (
+    intsdfsafafafdfdsasdfsfsdfasdfafdsafdfdsfasdskdsdsfdsafdsafsdfdasfffsfdsfdsafafhdskfhdsfjdslkfdlfsdkjhsdfjkdshfkljds
+):
+    return 2
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def foo() -> (
+    intsdfsafafafdfdsasdfsfsdfasdfafdsafdfdsfasdskdsdsfdsafdsafsdfdasfffsfdsfdsafafhdskfhdsfjdslkfdlfsdkjhsdfjkdshfkljds
+    | intsdfsafafafdfdsasdfsfsdfasdfafdsafdfdsfasdskdsdsfdsafdsafsdfdasfffsfdsfdsafafhdskfhdsfjdslkfdlfsdkjhsdfjkdshfkljds
+):
+    return 2
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def foo(
+    a: int,
+    b: int,
+    c: int,
+) -> (
+    intsdfsafafafdfdsasdfsfsdfasdfafdsafdfdsfasdskdsdsfdsafdsafsdfdasfffsfdsfdsafafhdskfhdsfjdslkfdlfsdkjhsdfjkdshfkljds
+):
+    return 2
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def foo(
+    a: int,
+    b: int,
+    c: int,
+) -> (
+    intsdfsafafafdfdsasdfsfsdfasdfafdsafdfdsfasdskdsdsfdsafdsafsdfdasfffsfdsfdsafafhdskfhdsfjdslkfdlfsdkjhsdfjkdshfkljds
+    | intsdfsafafafdfdsasdfsfsdfasdfafdsafdfdsfasdskdsdsfdsafdsafsdfdasfffsfdsfdsafafhdskfhdsfjdslkfdlfsdkjhsdfjkdshfkljds
+):
+    return 2
 
 
 # Split args but no need to split return
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def foo(
+    a: int,
+    b: int,
+    c: int,
+) -> int:
+    return 2
 
 
 # Deeply nested brackets
 # with *interesting* spacing
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def double(a: int) -> int:
+    return 2 * a
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def double(a: int) -> int:
+    return 2 * a
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def foo() -> (
+    intsdfsafafafdfdsasdfsfsdfasdfafdsafdfdsfasdskdsdsfdsafdsafsdfdasfffsfdsfdsafafhdskfhdsfjdslkfdlfsdkjhsdfjkdshfkljds
+):
+    return 2
 
 
 # Return type with commas
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def foo() -> NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key]:
+    return 2
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def foo() -> NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key]:
+    return 2
 
 
 # Magic trailing comma example
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def foo() -> NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key]:
+    return 2
 ```
 
 ## Black Output

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__slices_py.snap

@@ -76,7 +76,7 @@ x[
 ```diff
 --- Black
 +++ Ruff
-@@ -1,59 +1,37 @@
+@@ -1,59 +1,38 @@
 -slice[a.b : c.d]
 -slice[d :: d + 1]
 -slice[d + 1 :: d]
@@ -117,9 +117,9 @@ x[
 +NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key]
  
  
--async def f():
+ async def f():
 -    slice[await x : [i async for i in arange(42)] : 42]
-+NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
++    NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key]
  
  
  # These are from PEP-8:
@@ -191,7 +191,8 @@ NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key]
 NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key]
 
 
-NOT_YET_IMPLEMENTED_StmtAsyncFunctionDef
+async def f():
+    NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key]
 
 
 # These are from PEP-8:

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__string_prefixes_py.snap

@@ -33,7 +33,7 @@ def docstring_multiline():
 ```diff
 --- Black
 +++ Ruff
-@@ -1,20 +1,16 @@
+@@ -1,20 +1,18 @@
  #!/usr/bin/env python3
  
 -name = "Łukasz"
@@ -53,16 +53,16 @@ def docstring_multiline():
 +(1, 2)
  
  
--def docstring_singleline():
+ def docstring_singleline():
 -    R"""2020 was one hell of a year. The good news is that we were able to"""
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    "NOT_YET_IMPLEMENTED_STRING"
  
  
--def docstring_multiline():
+ def docstring_multiline():
 -    R"""
 -    clear out all of the issues opened in that time :p
 -    """
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    "NOT_YET_IMPLEMENTED_STRING"
 ```
 
 ## Ruff Output
@@ -80,10 +80,12 @@ name = "NOT_YET_IMPLEMENTED_STRING"
 (1, 2)
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def docstring_singleline():
+    "NOT_YET_IMPLEMENTED_STRING"
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def docstring_multiline():
+    "NOT_YET_IMPLEMENTED_STRING"
 ```
 
 ## Black Output

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__torture_py.snap

@@ -42,7 +42,7 @@ assert (
 ```diff
 --- Black
 +++ Ruff
-@@ -1,58 +1,21 @@
+@@ -1,58 +1,22 @@
  importA
  (
 -    ()
@@ -79,7 +79,7 @@ assert (
 +NOT_YET_IMPLEMENTED_StmtClassDef
  
  
--def test(self, othr):
+ def test(self, othr):
 -    return 1 == 2 and (
 -        name,
 -        description,
@@ -99,7 +99,7 @@ assert (
 -        othr.meta_data,
 -        othr.schedule,
 -    )
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    return NOT_IMPLEMENTED_bool_op1 and NOT_IMPLEMENTED_bool_op2
  
  
 -assert a_function(
@@ -129,7 +129,8 @@ importA
 NOT_YET_IMPLEMENTED_StmtClassDef
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def test(self, othr):
+    return NOT_IMPLEMENTED_bool_op1 and NOT_IMPLEMENTED_bool_op2
 
 
 NOT_YET_IMPLEMENTED_StmtAssert

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__trailing_commas_in_leading_parts_py.snap

@@ -46,7 +46,7 @@ assert xxxxxxxxx.xxxxxxxxx.xxxxxxxxx(
 ```diff
 --- Black
 +++ Ruff
-@@ -1,50 +1,20 @@
+@@ -1,50 +1,21 @@
 -zero(
 -    one,
 -).two(
@@ -79,14 +79,14 @@ assert xxxxxxxxx.xxxxxxxxx.xxxxxxxxx(
  
  
  # Example from https://github.com/psf/black/issues/3229
--def refresh_token(self, device_family, refresh_token, api_key):
+ def refresh_token(self, device_family, refresh_token, api_key):
 -    return self.orchestration.refresh_token(
 -        data={
 -            "refreshToken": refresh_token,
 -        },
 -        api_key=api_key,
 -    )["extensions"]["sdk"]["token"]
-+NOT_YET_IMPLEMENTED_StmtFunctionDef
++    return NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key]
  
  
  # Edge case where a bug in a working-in-progress version of
@@ -120,7 +120,8 @@ NOT_IMPLEMENTED_call()
 
 
 # Example from https://github.com/psf/black/issues/3229
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def refresh_token(self, device_family, refresh_token, api_key):
+    return NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key]
 
 
 # Edge case where a bug in a working-in-progress version of

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__ruff_test__statement__function_py.snap

@@ -0,0 +1,182 @@
+---
+source: crates/ruff_python_formatter/src/lib.rs
+expression: snapshot
+---
+## Input
+```py
+# Dangling comments
+def test(
+    # comment
+
+    # another
+
+): ...
+
+
+# Argument empty line spacing
+def test(
+    # comment
+    a,
+
+    # another
+
+    b,
+): ...
+
+
+### Different function argument wrappings
+
+def single_line(aaaaaaaaaaaaaaaaaaaaaaaaaaaaa, bbbbbbbbbbbbbbb, ccccccccccccccccc):
+    pass
+
+def arguments_on_their_own_line(aaaaaaaaaaaaaaaaaaaaaaaaaaaaa, bbbbbbbbbbbbbbb, ccccccccccc, ddddddddddddd, eeeeeee):
+    pass
+
+def argument_per_line(aaaaaaaaaaaaaaaaaaaaaaaaaaaaa, bbbbbbbbbbbbbbb, ccccccccccccccccc, ddddddddddddd, eeeeeeeeeeeeeeee, ffffffffffff):
+    pass
+
+def last_pos_only_trailing_comma(a, b, /,):
+    pass
+
+def last_pos_no_trailing_comma(a, b, /):
+    pass
+
+
+def varg_with_leading_comments(
+    a, b,
+    # comment
+    *args
+): ...
+
+def kwarg_with_leading_comments(
+    a, b,
+    # comment
+    **kwargs
+): ...
+
+def argument_with_long_default(
+    a,
+    b = ccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc + [
+        dddddddddddddddddddd, eeeeeeeeeeeeeeeeeeee, ffffffffffffffffffffffff
+    ],
+    h = []
+):  ...
+
+
+def argument_with_long_type_annotation(
+    a,
+    b: xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx | yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy | zzzzzzzzzzzzzzzzzzz = [0, 1, 2, 3],
+    h = []
+):  ...
+
+
+def test(): ...
+
+# Comment
+def with_leading_comment(): ...
+```
+
+
+
+## Output
+```py
+# Dangling comments
+def test(
+    # comment
+    # another
+):
+    ...
+
+
+# Argument empty line spacing
+def test(
+    # comment
+    a,
+    # another
+    b,
+):
+    ...
+
+
+### Different function argument wrappings
+
+def single_line(aaaaaaaaaaaaaaaaaaaaaaaaaaaaa, bbbbbbbbbbbbbbb, ccccccccccccccccc):
+    pass
+
+
+def arguments_on_their_own_line(
+    aaaaaaaaaaaaaaaaaaaaaaaaaaaaa, bbbbbbbbbbbbbbb, ccccccccccc, ddddddddddddd, eeeeeee
+):
+    pass
+
+
+def argument_per_line(
+    aaaaaaaaaaaaaaaaaaaaaaaaaaaaa,
+    bbbbbbbbbbbbbbb,
+    ccccccccccccccccc,
+    ddddddddddddd,
+    eeeeeeeeeeeeeeee,
+    ffffffffffff,
+):
+    pass
+
+
+def last_pos_only_trailing_comma(
+    a,
+    b,
+    /,
+):
+    pass
+
+
+def last_pos_no_trailing_comma(a, b, /):
+    pass
+
+
+def varg_with_leading_comments(
+    a,
+    b,
+    # comment
+    *args,
+):
+    ...
+
+
+def kwarg_with_leading_comments(
+    a,
+    b,
+    # comment
+    **kwargs,
+):
+    ...
+
+
+def argument_with_long_default(
+    a,
+    b=ccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc
+    + [dddddddddddddddddddd, eeeeeeeeeeeeeeeeeeee, ffffffffffffffffffffffff],
+    h=[],
+):
+    ...
+
+
+def argument_with_long_type_annotation(
+    a,
+    b: xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+    | yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy
+    | zzzzzzzzzzzzzzzzzzz = [0, 1, 2, 3],
+    h=[],
+):
+    ...
+
+
+def test():
+    ...
+
+
+# Comment
+def with_leading_comment():
+    ...
+```
+
+

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__ruff_test__statement__stmt_assign_py.snap

@@ -21,17 +21,13 @@ a = asdf = fjhalsdljfalflaflapamsakjsdhflakjdslfjhalsdljfalflaflapamsakjsdhflakj
 ## Output
 ```py
 # break left hand side
-a1akjdshflkjahdslkfjlasfdahjlfds = bakjdshflkjahdslkfjlasfdahjlfds = cakjdshflkjahdslkfjlasfdahjlfds = kjaödkjaföjfahlfdalfhaöfaöfhaöfha = fkjaödkjaföjfahlfdalfhaöfaöfhaöfha = g = (
+a1akjdshflkjahdslkfjlasfdahjlfds = bakjdshflkjahdslkfjlasfdahjlfds = cakjdshflkjahdslkfjlasfdahjlfds = kjaödkjaföjfahlfdalfhaöfaöfhaöfha = fkjaödkjaföjfahlfdalfhaöfaöfhaöfha = g = 3
-    3
-)
 
 # join left hand side
 a2 = (b2) = 2
 
 # Break the last element
-a = asdf = fjhalsdljfalflaflapamsakjsdhflakjdslfjhalsdljfalflaflapamsakjsdhflakjdslfjhalsdljfal = (
+a = asdf = fjhalsdljfalflaflapamsakjsdhflakjdslfjhalsdljfalflaflapamsakjsdhflakjdslfjhalsdljfal = 1
-    1
-)
 ```
 
 

crates/ruff_python_formatter/src/statement/stmt_async_function_def.rs

@@ -1,5 +1,6 @@
-use crate::{not_yet_implemented, FormatNodeRule, PyFormatter};
+use crate::prelude::*;
-use ruff_formatter::{write, Buffer, FormatResult};
+use crate::FormatNodeRule;
+use ruff_python_ast::function::AnyFunctionDefinition;
 use rustpython_parser::ast::StmtAsyncFunctionDef;
 
 #[derive(Default)]
@@ -7,6 +8,15 @@ pub struct FormatStmtAsyncFunctionDef;
 
 impl FormatNodeRule<StmtAsyncFunctionDef> for FormatStmtAsyncFunctionDef {
     fn fmt_fields(&self, item: &StmtAsyncFunctionDef, f: &mut PyFormatter) -> FormatResult<()> {
-        write!(f, [not_yet_implemented(item)])
+        AnyFunctionDefinition::from(item).format().fmt(f)
+    }
+
+    fn fmt_dangling_comments(
+        &self,
+        _node: &StmtAsyncFunctionDef,
+        _f: &mut PyFormatter,
+    ) -> FormatResult<()> {
+        // Handled by `AnyFunctionDef`
+        Ok(())
     }
 }

crates/ruff_python_formatter/src/statement/stmt_function_def.rs

@@ -1,12 +1,141 @@
-use crate::{not_yet_implemented, FormatNodeRule, PyFormatter};
+use crate::comments::{leading_comments, trailing_comments};
-use ruff_formatter::{write, Buffer, FormatResult};
+use crate::context::NodeLevel;
-use rustpython_parser::ast::StmtFunctionDef;
+use crate::expression::parentheses::Parenthesize;
+use crate::prelude::*;
+use crate::trivia::{lines_after, skip_trailing_trivia};
+use crate::FormatNodeRule;
+use ruff_formatter::{write, FormatOwnedWithRule, FormatRefWithRule};
+use ruff_python_ast::function::AnyFunctionDefinition;
+use rustpython_parser::ast::{Ranged, StmtFunctionDef};
 
 #[derive(Default)]
 pub struct FormatStmtFunctionDef;
 
 impl FormatNodeRule<StmtFunctionDef> for FormatStmtFunctionDef {
     fn fmt_fields(&self, item: &StmtFunctionDef, f: &mut PyFormatter) -> FormatResult<()> {
-        write!(f, [not_yet_implemented(item)])
+        AnyFunctionDefinition::from(item).format().fmt(f)
+    }
+
+    fn fmt_dangling_comments(
+        &self,
+        _node: &StmtFunctionDef,
+        _f: &mut PyFormatter,
+    ) -> FormatResult<()> {
+        // Handled by `AnyFunctionDef`
+        Ok(())
+    }
+}
+
+#[derive(Default)]
+pub struct FormatAnyFunctionDef;
+
+impl FormatRule<AnyFunctionDefinition<'_>, PyFormatContext<'_>> for FormatAnyFunctionDef {
+    fn fmt(
+        &self,
+        item: &AnyFunctionDefinition<'_>,
+        f: &mut Formatter<PyFormatContext<'_>>,
+    ) -> FormatResult<()> {
+        let comments = f.context().comments().clone();
+
+        let dangling_comments = comments.dangling_comments(item.into());
+        let trailing_definition_comments_start =
+            dangling_comments.partition_point(|comment| comment.position().is_own_line());
+
+        let (leading_function_definition_comments, trailing_definition_comments) =
+            dangling_comments.split_at(trailing_definition_comments_start);
+
+        if let Some(last_decorator) = item.decorators().last() {
+            f.join_nodes(NodeLevel::CompoundStatement)
+                .nodes(item.decorators())
+                .finish()?;
+
+            if leading_function_definition_comments.is_empty() {
+                write!(f, [hard_line_break()])?;
+            } else {
+                // Write any leading function comments (between last decorator and function header)
+                // while maintaining the right amount of empty lines between the comment
+                // and the last decorator.
+                let decorator_end =
+                    skip_trailing_trivia(last_decorator.end(), f.context().contents());
+
+                let leading_line = if lines_after(decorator_end, f.context().contents()) <= 1 {
+                    hard_line_break()
+                } else {
+                    empty_line()
+                };
+
+                write!(
+                    f,
+                    [
+                        leading_line,
+                        leading_comments(leading_function_definition_comments)
+                    ]
+                )?;
+            }
+        }
+
+        if item.is_async() {
+            write!(f, [text("async"), space()])?;
+        }
+
+        let name = item.name();
+
+        write!(
+            f,
+            [
+                text("def"),
+                space(),
+                dynamic_text(name.as_str(), None),
+                item.arguments().format(),
+            ]
+        )?;
+
+        if let Some(return_annotation) = item.returns() {
+            write!(
+                f,
+                [
+                    space(),
+                    text("->"),
+                    space(),
+                    return_annotation
+                        .format()
+                        .with_options(Parenthesize::IfBreaks)
+                ]
+            )?;
+        }
+
+        write!(
+            f,
+            [
+                text(":"),
+                trailing_comments(trailing_definition_comments),
+                block_indent(&item.body().format())
+            ]
+        )
+    }
+}
+
+impl<'def, 'ast> AsFormat<PyFormatContext<'ast>> for AnyFunctionDefinition<'def> {
+    type Format<'a> = FormatRefWithRule<
+        'a,
+        AnyFunctionDefinition<'def>,
+        FormatAnyFunctionDef,
+        PyFormatContext<'ast>,
+    > where Self: 'a;
+
+    fn format(&self) -> Self::Format<'_> {
+        FormatRefWithRule::new(self, FormatAnyFunctionDef::default())
+    }
+}
+
+impl<'def, 'ast> IntoFormat<PyFormatContext<'ast>> for AnyFunctionDefinition<'def> {
+    type Format = FormatOwnedWithRule<
+        AnyFunctionDefinition<'def>,
+        FormatAnyFunctionDef,
+        PyFormatContext<'ast>,
+    >;
+
+    fn into_format(self) -> Self::Format {
+        FormatOwnedWithRule::new(self, FormatAnyFunctionDef)
     }
 }

crates/ruff_python_formatter/src/statement/suite.rs

@@ -188,7 +188,7 @@ mod tests {
     use crate::comments::Comments;
     use crate::prelude::*;
     use crate::statement::suite::SuiteLevel;
-    use ruff_formatter::{format, SimpleFormatOptions};
+    use ruff_formatter::{format, IndentStyle, SimpleFormatOptions};
     use rustpython_parser::ast::Suite;
     use rustpython_parser::Parse;
 
@@ -216,8 +216,14 @@ def trailing_func():
 
         let statements = Suite::parse(source, "test.py").unwrap();
 
-        let context =
+        let context = PyFormatContext::new(
-            PyFormatContext::new(SimpleFormatOptions::default(), source, Comments::default());
+            SimpleFormatOptions {
+                indent_style: IndentStyle::Space(4),
+                ..SimpleFormatOptions::default()
+            },
+            source,
+            Comments::default(),
+        );
 
         let test_formatter =
             format_with(|f: &mut PyFormatter| statements.format().with_options(level).fmt(f));
@@ -252,10 +258,13 @@ NOT_YET_IMPLEMENTED_StmtClassDef
 trailing_statement = 1
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def func():
+    pass
 
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef"#
+def trailing_func():
+    pass
+"#
         );
     }
 
@@ -278,9 +287,12 @@ NOT_YET_IMPLEMENTED_StmtClassDef
 
 trailing_statement = 1
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef
+def func():
+    pass
 
-NOT_YET_IMPLEMENTED_StmtFunctionDef"#
+def trailing_func():
+    pass
+"#
         );
     }
 }