Format `class` definitions (#5289)

Cargo.lock

@@ -2105,7 +2105,7 @@ dependencies = [
 [[package]]
 name = "ruff_text_size"
 version = "0.0.0"
-source = "git+https://github.com/astral-sh/RustPython-Parser.git?rev=08ebbe40d7776cac6e3ba66277d435056f2b8dca#08ebbe40d7776cac6e3ba66277d435056f2b8dca"
+source = "git+https://github.com/astral-sh/RustPython-Parser.git?rev=f60e204b73b95bdb6ce87ccd0de34081b4a17c11#f60e204b73b95bdb6ce87ccd0de34081b4a17c11"
 dependencies = [
  "schemars",
  "serde",
@@ -2183,7 +2183,7 @@ dependencies = [
 [[package]]
 name = "rustpython-ast"
 version = "0.2.0"
-source = "git+https://github.com/astral-sh/RustPython-Parser.git?rev=08ebbe40d7776cac6e3ba66277d435056f2b8dca#08ebbe40d7776cac6e3ba66277d435056f2b8dca"
+source = "git+https://github.com/astral-sh/RustPython-Parser.git?rev=f60e204b73b95bdb6ce87ccd0de34081b4a17c11#f60e204b73b95bdb6ce87ccd0de34081b4a17c11"
 dependencies = [
  "is-macro",
  "num-bigint",
@@ -2194,7 +2194,7 @@ dependencies = [
 [[package]]
 name = "rustpython-format"
 version = "0.2.0"
-source = "git+https://github.com/astral-sh/RustPython-Parser.git?rev=08ebbe40d7776cac6e3ba66277d435056f2b8dca#08ebbe40d7776cac6e3ba66277d435056f2b8dca"
+source = "git+https://github.com/astral-sh/RustPython-Parser.git?rev=f60e204b73b95bdb6ce87ccd0de34081b4a17c11#f60e204b73b95bdb6ce87ccd0de34081b4a17c11"
 dependencies = [
  "bitflags 2.3.1",
  "itertools",
@@ -2206,7 +2206,7 @@ dependencies = [
 [[package]]
 name = "rustpython-literal"
 version = "0.2.0"
-source = "git+https://github.com/astral-sh/RustPython-Parser.git?rev=08ebbe40d7776cac6e3ba66277d435056f2b8dca#08ebbe40d7776cac6e3ba66277d435056f2b8dca"
+source = "git+https://github.com/astral-sh/RustPython-Parser.git?rev=f60e204b73b95bdb6ce87ccd0de34081b4a17c11#f60e204b73b95bdb6ce87ccd0de34081b4a17c11"
 dependencies = [
  "hexf-parse",
  "is-macro",
@@ -2218,7 +2218,7 @@ dependencies = [
 [[package]]
 name = "rustpython-parser"
 version = "0.2.0"
-source = "git+https://github.com/astral-sh/RustPython-Parser.git?rev=08ebbe40d7776cac6e3ba66277d435056f2b8dca#08ebbe40d7776cac6e3ba66277d435056f2b8dca"
+source = "git+https://github.com/astral-sh/RustPython-Parser.git?rev=f60e204b73b95bdb6ce87ccd0de34081b4a17c11#f60e204b73b95bdb6ce87ccd0de34081b4a17c11"
 dependencies = [
  "anyhow",
  "is-macro",
@@ -2241,7 +2241,7 @@ dependencies = [
 [[package]]
 name = "rustpython-parser-core"
 version = "0.2.0"
-source = "git+https://github.com/astral-sh/RustPython-Parser.git?rev=08ebbe40d7776cac6e3ba66277d435056f2b8dca#08ebbe40d7776cac6e3ba66277d435056f2b8dca"
+source = "git+https://github.com/astral-sh/RustPython-Parser.git?rev=f60e204b73b95bdb6ce87ccd0de34081b4a17c11#f60e204b73b95bdb6ce87ccd0de34081b4a17c11"
 dependencies = [
  "is-macro",
  "memchr",

Cargo.toml

@@ -50,15 +50,15 @@ toml = { version = "0.7.2" }
 # v0.0.1
 libcst = { git = "https://github.com/charliermarsh/LibCST", rev = "80e4c1399f95e5beb532fdd1e209ad2dbb470438" }
 # v0.0.3
-ruff_text_size = { git = "https://github.com/astral-sh/RustPython-Parser.git", rev = "08ebbe40d7776cac6e3ba66277d435056f2b8dca" }
+ruff_text_size = { git = "https://github.com/astral-sh/RustPython-Parser.git", rev = "f60e204b73b95bdb6ce87ccd0de34081b4a17c11" }
 # v0.0.3
-rustpython-ast = { git = "https://github.com/astral-sh/RustPython-Parser.git", rev = "08ebbe40d7776cac6e3ba66277d435056f2b8dca" , default-features = false, features = ["all-nodes-with-ranges", "num-bigint"]}
+rustpython-ast = { git = "https://github.com/astral-sh/RustPython-Parser.git", rev = "f60e204b73b95bdb6ce87ccd0de34081b4a17c11" , default-features = false, features = ["all-nodes-with-ranges", "num-bigint"]}
 # v0.0.3
-rustpython-format = { git = "https://github.com/astral-sh/RustPython-Parser.git", rev = "08ebbe40d7776cac6e3ba66277d435056f2b8dca", default-features = false, features = ["num-bigint"] }
+rustpython-format = { git = "https://github.com/astral-sh/RustPython-Parser.git", rev = "f60e204b73b95bdb6ce87ccd0de34081b4a17c11", default-features = false, features = ["num-bigint"] }
 # v0.0.3
-rustpython-literal = { git = "https://github.com/astral-sh/RustPython-Parser.git", rev = "08ebbe40d7776cac6e3ba66277d435056f2b8dca", default-features = false }
+rustpython-literal = { git = "https://github.com/astral-sh/RustPython-Parser.git", rev = "f60e204b73b95bdb6ce87ccd0de34081b4a17c11", default-features = false }
 # v0.0.3
-rustpython-parser = { git = "https://github.com/astral-sh/RustPython-Parser.git", rev = "08ebbe40d7776cac6e3ba66277d435056f2b8dca" , default-features = false, features = ["full-lexer", "all-nodes-with-ranges", "num-bigint"] }
+rustpython-parser = { git = "https://github.com/astral-sh/RustPython-Parser.git", rev = "f60e204b73b95bdb6ce87ccd0de34081b4a17c11" , default-features = false, features = ["full-lexer", "all-nodes-with-ranges", "num-bigint"] }
 
 [profile.release]
 lto = "fat"

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

@@ -0,0 +1,36 @@
+class Test(
+    Aaaaaaaaaaaaaaaaa,
+    Bbbbbbbbbbbbbbbb,
+    DDDDDDDDDDDDDDDD,
+    EEEEEEEEEEEEEE,
+    metaclass=meta,
+):
+    pass
+
+
+class Test((Aaaaaaaaaaaaaaaaa), Bbbbbbbbbbbbbbbb, metaclass=meta):
+    pass
+
+class Test( # trailing class comment
+    Aaaaaaaaaaaaaaaaa, # trailing comment
+
+    # in between comment
+
+    Bbbbbbbbbbbbbbbb,
+    # another leading comment
+    DDDDDDDDDDDDDDDD,
+    EEEEEEEEEEEEEE,
+    # meta comment
+    metaclass=meta, # trailing meta comment
+):
+    pass
+
+class Test((Aaaa)):
+    ...
+
+
+class Test(aaaaaaaaaaaaaaa + bbbbbbbbbbbbbbbbbbbbbb + cccccccccccccccccccccccc + dddddddddddddddddddddd + eeeeeeeee, ffffffffffffffffff, gggggggggggggggggg):
+    pass
+
+class Test(Aaaa): # trailing comment
+    pass

crates/ruff_python_formatter/src/comments/placement.rs

@@ -582,6 +582,12 @@ fn handle_trailing_end_of_line_condition_comment<'a>(
             .as_deref()
             .map(AnyNodeRef::from)
             .or_else(|| Some(AnyNodeRef::from(args.as_ref()))),
+        AnyNodeRef::StmtClassDef(StmtClassDef {
+            bases, keywords, ..
+        }) => keywords
+            .last()
+            .map(AnyNodeRef::from)
+            .or_else(|| bases.last().map(AnyNodeRef::from)),
         _ => None,
     };
 
@@ -622,8 +628,13 @@ fn handle_trailing_end_of_line_condition_comment<'a>(
                 TokenKind::RParen => {
                     // Skip over any closing parentheses
                 }
-                _ => {
+                TokenKind::Comma => {
-                    unreachable!("Only ')' or ':' should follow the condition")
+                    // Skip over any trailing comma
+                }
+                kind => {
+                    unreachable!(
+                        "Only ')' or ':' should follow the condition but encountered {kind:?}"
+                    )
                 }
             }
         }

crates/ruff_python_formatter/src/expression/parentheses.rs

@@ -26,6 +26,8 @@ pub(super) fn default_expression_needs_parentheses(
     #[allow(clippy::if_same_then_else)]
     if parenthesize.is_always() {
         Parentheses::Always
+    } else if parenthesize.is_never() {
+        Parentheses::Never
     }
     // `Optional` or `Preserve` and expression has parentheses in source code.
     else if !parenthesize.is_if_breaks() && is_expression_parenthesized(node, source) {
@@ -58,7 +60,11 @@ pub enum Parenthesize {
     /// Parenthesizes the expression only if it doesn't fit on a line.
     IfBreaks,
 
+    /// Always adds parentheses
     Always,
+
+    /// Never adds parentheses. Parentheses are handled by the caller.
+    Never,
 }
 
 impl Parenthesize {
@@ -66,6 +72,10 @@ impl Parenthesize {
         matches!(self, Parenthesize::Always)
     }
 
+    pub(crate) const fn is_never(self) -> bool {
+        matches!(self, Parenthesize::Never)
+    }
+
     pub(crate) const fn is_if_breaks(self) -> bool {
         matches!(self, Parenthesize::IfBreaks)
     }

crates/ruff_python_formatter/src/other/keyword.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_formatter::write;
 use rustpython_parser::ast::Keyword;
 
 #[derive(Default)]
@@ -7,6 +8,15 @@ pub struct FormatKeyword;
 
 impl FormatNodeRule<Keyword> for FormatKeyword {
     fn fmt_fields(&self, item: &Keyword, f: &mut PyFormatter) -> FormatResult<()> {
-        write!(f, [not_yet_implemented(item)])
+        let Keyword {
+            range: _,
+            arg,
+            value,
+        } = item;
+        if let Some(argument) = arg {
+            write!(f, [argument.format(), text("=")])?;
+        }
+
+        value.format().fmt(f)
     }
 }

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__class_blank_parentheses_py.snap

@@ -1,135 +0,0 @@
----
-source: crates/ruff_python_formatter/src/lib.rs
-expression: snapshot
-input_file: crates/ruff_python_formatter/resources/test/fixtures/black/simple_cases/class_blank_parentheses.py
----
-## Input
-
-```py
-class SimpleClassWithBlankParentheses():
-    pass
-class ClassWithSpaceParentheses ( ):
-    first_test_data = 90
-    second_test_data = 100
-    def test_func(self):
-        return None
-class ClassWithEmptyFunc(object):
-
-    def func_with_blank_parentheses():
-        return 5
-
-
-def public_func_with_blank_parentheses():
-    return None
-def class_under_the_func_with_blank_parentheses():
-    class InsideFunc():
-        pass
-class NormalClass (
-):
-    def func_for_testing(self, first, second):
-        sum = first + second
-        return sum
-```
-
-## Black Differences
-
-```diff
---- Black
-+++ Ruff
-@@ -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
- 
- 
--class ClassWithEmptyFunc(object):
--    def func_with_blank_parentheses():
--        return 5
-+NOT_YET_IMPLEMENTED_StmtClassDef
- 
- 
- def public_func_with_blank_parentheses():
-@@ -20,11 +12,7 @@
- 
- 
- def class_under_the_func_with_blank_parentheses():
--    class InsideFunc:
--        pass
-+    NOT_YET_IMPLEMENTED_StmtClassDef
- 
- 
--class NormalClass:
--    def func_for_testing(self, first, second):
--        sum = first + second
--        return sum
-+NOT_YET_IMPLEMENTED_StmtClassDef
-```
-
-## Ruff Output
-
-```py
-NOT_YET_IMPLEMENTED_StmtClassDef
-
-
-NOT_YET_IMPLEMENTED_StmtClassDef
-
-
-NOT_YET_IMPLEMENTED_StmtClassDef
-
-
-def public_func_with_blank_parentheses():
-    return None
-
-
-def class_under_the_func_with_blank_parentheses():
-    NOT_YET_IMPLEMENTED_StmtClassDef
-
-
-NOT_YET_IMPLEMENTED_StmtClassDef
-```
-
-## Black Output
-
-```py
-class SimpleClassWithBlankParentheses:
-    pass
-
-
-class ClassWithSpaceParentheses:
-    first_test_data = 90
-    second_test_data = 100
-
-    def test_func(self):
-        return None
-
-
-class ClassWithEmptyFunc(object):
-    def func_with_blank_parentheses():
-        return 5
-
-
-def public_func_with_blank_parentheses():
-    return None
-
-
-def class_under_the_func_with_blank_parentheses():
-    class InsideFunc:
-        pass
-
-
-class NormalClass:
-    def func_for_testing(self, first, second):
-        sum = first + second
-        return sum
-```
-
-

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__class_methods_new_line_py.snap

@@ -113,259 +113,257 @@ class ClassWithDecoInitAndVarsAndDocstringWithInner2:
 ```diff
 --- Black
 +++ Ruff
-@@ -1,165 +1,61 @@
+@@ -7,7 +7,7 @@
--class ClassSimplest:
--    pass
-+NOT_YET_IMPLEMENTED_StmtClassDef
  
  
--class ClassWithSingleField:
+ class ClassWithJustTheDocstring:
--    a = 1
-+NOT_YET_IMPLEMENTED_StmtClassDef
- 
- 
--class ClassWithJustTheDocstring:
 -    """Just a docstring."""
-+NOT_YET_IMPLEMENTED_StmtClassDef
++    "NOT_YET_IMPLEMENTED_STRING"
  
  
--class ClassWithInit:
+ class ClassWithInit:
--    def __init__(self):
+@@ -16,7 +16,7 @@
--        pass
-+NOT_YET_IMPLEMENTED_StmtClassDef
  
  
--class ClassWithTheDocstringAndInit:
+ class ClassWithTheDocstringAndInit:
 -    """Just a docstring."""
-+NOT_YET_IMPLEMENTED_StmtClassDef
++    "NOT_YET_IMPLEMENTED_STRING"
  
--    def __init__(self):
+     def __init__(self):
--        pass
+         pass
- 
+@@ -30,8 +30,7 @@
-+NOT_YET_IMPLEMENTED_StmtClassDef
- 
--class ClassWithInitAndVars:
--    cls_var = 100
- 
--    def __init__(self):
--        pass
-+NOT_YET_IMPLEMENTED_StmtClassDef
  
  
--class ClassWithInitAndVarsAndDocstring:
+ class ClassWithInitAndVarsAndDocstring:
 -    """Test class"""
-+NOT_YET_IMPLEMENTED_StmtClassDef
+-
++    "NOT_YET_IMPLEMENTED_STRING"
+     cls_var = 100
  
--    cls_var = 100
+     def __init__(self):
- 
+@@ -53,8 +52,7 @@
--    def __init__(self):
--        pass
-+NOT_YET_IMPLEMENTED_StmtClassDef
  
  
--class ClassWithDecoInit:
+ class ClassWithDecoInitAndVarsAndDocstring:
--    @deco
--    def __init__(self):
--        pass
-+NOT_YET_IMPLEMENTED_StmtClassDef
- 
- 
--class ClassWithDecoInitAndVars:
--    cls_var = 100
-+NOT_YET_IMPLEMENTED_StmtClassDef
- 
--    @deco
--    def __init__(self):
--        pass
- 
-+NOT_YET_IMPLEMENTED_StmtClassDef
- 
--class ClassWithDecoInitAndVarsAndDocstring:
 -    """Test class"""
+-
++    "NOT_YET_IMPLEMENTED_STRING"
+     cls_var = 100
  
--    cls_var = 100
+     @deco
-+NOT_YET_IMPLEMENTED_StmtClassDef
+@@ -69,7 +67,7 @@
  
--    @deco
+ class ClassSimplestWithInnerWithDocstring:
--    def __init__(self):
+     class Inner:
--        pass
- 
-+NOT_YET_IMPLEMENTED_StmtClassDef
- 
--class ClassSimplestWithInner:
--    class Inner:
--        pass
- 
-+NOT_YET_IMPLEMENTED_StmtClassDef
- 
--class ClassSimplestWithInnerWithDocstring:
--    class Inner:
 -        """Just a docstring."""
++        "NOT_YET_IMPLEMENTED_STRING"
  
--        def __init__(self):
+         def __init__(self):
--            pass
+             pass
-+NOT_YET_IMPLEMENTED_StmtClassDef
+@@ -83,7 +81,7 @@
  
  
--class ClassWithSingleFieldWithInner:
+ class ClassWithJustTheDocstringWithInner:
--    a = 1
-+NOT_YET_IMPLEMENTED_StmtClassDef
- 
--    class Inner:
--        pass
- 
-+NOT_YET_IMPLEMENTED_StmtClassDef
- 
--class ClassWithJustTheDocstringWithInner:
 -    """Just a docstring."""
++    "NOT_YET_IMPLEMENTED_STRING"
  
--    class Inner:
+     class Inner:
--        pass
+         pass
-+NOT_YET_IMPLEMENTED_StmtClassDef
+@@ -108,8 +106,7 @@
  
  
--class ClassWithInitWithInner:
+ class ClassWithInitAndVarsAndDocstringWithInner:
--    class Inner:
--        pass
--
--    def __init__(self):
--        pass
--
--
--class ClassWithInitAndVarsWithInner:
--    cls_var = 100
--
--    class Inner:
--        pass
--
--    def __init__(self):
--        pass
--
--
--class ClassWithInitAndVarsAndDocstringWithInner:
 -    """Test class"""
 -
--    cls_var = 100
++    "NOT_YET_IMPLEMENTED_STRING"
--
+     cls_var = 100
--    class Inner:
+ 
--        pass
+     class Inner:
--
+@@ -140,8 +137,7 @@
--    def __init__(self):
--        pass
--
--
--class ClassWithDecoInitWithInner:
--    class Inner:
--        pass
--
--    @deco
--    def __init__(self):
--        pass
-+NOT_YET_IMPLEMENTED_StmtClassDef
  
  
--class ClassWithDecoInitAndVarsWithInner:
+ class ClassWithDecoInitAndVarsAndDocstringWithInner:
--    cls_var = 100
--
--    class Inner:
--        pass
--
--    @deco
--    def __init__(self):
--        pass
--
--
--class ClassWithDecoInitAndVarsAndDocstringWithInner:
 -    """Test class"""
 -
--    cls_var = 100
++    "NOT_YET_IMPLEMENTED_STRING"
--
+     cls_var = 100
--    class Inner:
+ 
--        pass
+     class Inner:
--
+@@ -153,7 +149,7 @@
--    @deco
+ 
--    def __init__(self):
+ 
--        pass
+ class ClassWithDecoInitAndVarsAndDocstringWithInner2:
--
--
--class ClassWithDecoInitAndVarsAndDocstringWithInner2:
 -    """Test class"""
--
++    "NOT_YET_IMPLEMENTED_STRING"
--    class Inner:
+ 
--        pass
+     class Inner:
--
+         pass
--    cls_var = 100
--
--    @deco
--    def __init__(self):
--        pass
-+NOT_YET_IMPLEMENTED_StmtClassDef
 ```
 
 ## Ruff Output
 
 ```py
-NOT_YET_IMPLEMENTED_StmtClassDef
+class ClassSimplest:
+    pass
 
 
-NOT_YET_IMPLEMENTED_StmtClassDef
+class ClassWithSingleField:
+    a = 1
 
 
-NOT_YET_IMPLEMENTED_StmtClassDef
+class ClassWithJustTheDocstring:
+    "NOT_YET_IMPLEMENTED_STRING"
 
 
-NOT_YET_IMPLEMENTED_StmtClassDef
+class ClassWithInit:
+    def __init__(self):
+        pass
 
 
-NOT_YET_IMPLEMENTED_StmtClassDef
+class ClassWithTheDocstringAndInit:
+    "NOT_YET_IMPLEMENTED_STRING"
+
+    def __init__(self):
+        pass
 
 
-NOT_YET_IMPLEMENTED_StmtClassDef
+class ClassWithInitAndVars:
+    cls_var = 100
+
+    def __init__(self):
+        pass
 
 
-NOT_YET_IMPLEMENTED_StmtClassDef
+class ClassWithInitAndVarsAndDocstring:
+    "NOT_YET_IMPLEMENTED_STRING"
+    cls_var = 100
+
+    def __init__(self):
+        pass
 
 
-NOT_YET_IMPLEMENTED_StmtClassDef
+class ClassWithDecoInit:
+    @deco
+    def __init__(self):
+        pass
 
 
-NOT_YET_IMPLEMENTED_StmtClassDef
+class ClassWithDecoInitAndVars:
+    cls_var = 100
+
+    @deco
+    def __init__(self):
+        pass
 
 
-NOT_YET_IMPLEMENTED_StmtClassDef
+class ClassWithDecoInitAndVarsAndDocstring:
+    "NOT_YET_IMPLEMENTED_STRING"
+    cls_var = 100
+
+    @deco
+    def __init__(self):
+        pass
 
 
-NOT_YET_IMPLEMENTED_StmtClassDef
+class ClassSimplestWithInner:
+    class Inner:
+        pass
 
 
-NOT_YET_IMPLEMENTED_StmtClassDef
+class ClassSimplestWithInnerWithDocstring:
+    class Inner:
+        "NOT_YET_IMPLEMENTED_STRING"
+
+        def __init__(self):
+            pass
 
 
-NOT_YET_IMPLEMENTED_StmtClassDef
+class ClassWithSingleFieldWithInner:
+    a = 1
+
+    class Inner:
+        pass
 
 
-NOT_YET_IMPLEMENTED_StmtClassDef
+class ClassWithJustTheDocstringWithInner:
+    "NOT_YET_IMPLEMENTED_STRING"
+
+    class Inner:
+        pass
 
 
-NOT_YET_IMPLEMENTED_StmtClassDef
+class ClassWithInitWithInner:
+    class Inner:
+        pass
+
+    def __init__(self):
+        pass
 
 
-NOT_YET_IMPLEMENTED_StmtClassDef
+class ClassWithInitAndVarsWithInner:
+    cls_var = 100
+
+    class Inner:
+        pass
+
+    def __init__(self):
+        pass
 
 
-NOT_YET_IMPLEMENTED_StmtClassDef
+class ClassWithInitAndVarsAndDocstringWithInner:
+    "NOT_YET_IMPLEMENTED_STRING"
+    cls_var = 100
+
+    class Inner:
+        pass
+
+    def __init__(self):
+        pass
 
 
-NOT_YET_IMPLEMENTED_StmtClassDef
+class ClassWithDecoInitWithInner:
+    class Inner:
+        pass
+
+    @deco
+    def __init__(self):
+        pass
 
 
-NOT_YET_IMPLEMENTED_StmtClassDef
+class ClassWithDecoInitAndVarsWithInner:
+    cls_var = 100
+
+    class Inner:
+        pass
+
+    @deco
+    def __init__(self):
+        pass
 
 
-NOT_YET_IMPLEMENTED_StmtClassDef
+class ClassWithDecoInitAndVarsAndDocstringWithInner:
+    "NOT_YET_IMPLEMENTED_STRING"
+    cls_var = 100
+
+    class Inner:
+        pass
+
+    @deco
+    def __init__(self):
+        pass
 
 
-NOT_YET_IMPLEMENTED_StmtClassDef
+class ClassWithDecoInitAndVarsAndDocstringWithInner2:
+    "NOT_YET_IMPLEMENTED_STRING"
+
+    class Inner:
+        pass
+
+    cls_var = 100
+
+    @deco
+    def __init__(self):
+        pass
 ```
 
 ## Black Output

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__comments2_py.snap

@@ -349,7 +349,7 @@ instruction()#comment with bad spacing
      while True:
          if False:
              continue
-@@ -141,25 +111,13 @@
+@@ -141,24 +111,18 @@
          # and round and round we go
  
      # let's return
@@ -370,15 +370,17 @@ instruction()#comment with bad spacing
 +CONFIG_FILES = [CONFIG_FILE] + SHARED_CONFIG_FILES + USER_CONFIG_FILES  # type: Final
  
  
--class Test:
+ class Test:
--    def _init_host(self, parsed) -> None:
+     def _init_host(self, parsed) -> None:
 -        if parsed.hostname is None or not parsed.hostname.strip():  # type: ignore
--            pass
++        if (
-+NOT_YET_IMPLEMENTED_StmtClassDef
++            NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right  # type: ignore
++            or not NOT_IMPLEMENTED_call()
++        ):
+             pass
  
  
- #######################
+@@ -167,7 +131,7 @@
-@@ -167,7 +125,7 @@
  #######################
  
  
@@ -511,7 +513,13 @@ def inline_comments_in_brackets_ruin_everything():
 CONFIG_FILES = [CONFIG_FILE] + SHARED_CONFIG_FILES + USER_CONFIG_FILES  # type: Final
 
 
-NOT_YET_IMPLEMENTED_StmtClassDef
+class Test:
+    def _init_host(self, parsed) -> None:
+        if (
+            NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right  # type: ignore
+            or not NOT_IMPLEMENTED_call()
+        ):
+            pass
 
 
 #######################

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 +1,22 @@
+@@ -1,94 +1,28 @@
 -from com.my_lovely_company.my_lovely_team.my_lovely_project.my_lovely_component import (
 -    MyLovelyCompanyTeamProjectComponent,  # NOT DRY
 -)
@@ -118,7 +118,7 @@ def foo3(list_a, list_b):
 +NOT_YET_IMPLEMENTED_StmtImportFrom
  
  
--class C:
+ class C:
 -    @pytest.mark.parametrize(
 -        ("post_data", "message"),
 -        [
@@ -161,12 +161,14 @@ def foo3(list_a, list_b):
 -            ),
 -        ],
 -    )
--    def test_fails_invalid_post_data(
++    @NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)
--        self, pyramid_config, db_request, post_data, message
+     def test_fails_invalid_post_data(
--    ):
+         self, pyramid_config, db_request, post_data, message
+     ):
 -        pyramid_config.testing_securitypolicy(userid=1)
 -        db_request.POST = MultiDict(post_data)
-+NOT_YET_IMPLEMENTED_StmtClassDef
++        NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)
++        db_request.POST = NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)
  
  
  def foo(list_a, list_b):
@@ -217,7 +219,13 @@ NOT_YET_IMPLEMENTED_StmtImportFrom
 NOT_YET_IMPLEMENTED_StmtImportFrom
 
 
-NOT_YET_IMPLEMENTED_StmtClassDef
+class C:
+    @NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)
+    def test_fails_invalid_post_data(
+        self, pyramid_config, db_request, post_data, message
+    ):
+        NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)
+        db_request.POST = NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)
 
 
 def foo(list_a, list_b):

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__comments9_py.snap

@@ -152,38 +152,16 @@ def bar():
 ```diff
 --- Black
 +++ Ruff
-@@ -30,8 +30,7 @@
+@@ -44,7 +44,7 @@
  
  
- # This comment should be split from the statement above by two lines.
+ class ClassWithDocstring:
--class MyClass:
--    pass
-+NOT_YET_IMPLEMENTED_StmtClassDef
- 
- 
- some = statement
-@@ -39,17 +38,14 @@
- 
- 
- # This should be split from the above by two lines
--class MyClassWithComplexLeadingComments:
--    pass
-+NOT_YET_IMPLEMENTED_StmtClassDef
- 
- 
--class ClassWithDocstring:
 -    """A docstring."""
-+NOT_YET_IMPLEMENTED_StmtClassDef
++    "NOT_YET_IMPLEMENTED_STRING"
  
  
  # Leading comment after a class with just a docstring
--class MyClassAfterAnotherClassWithDocstring:
+@@ -59,7 +59,7 @@
--    pass
-+NOT_YET_IMPLEMENTED_StmtClassDef
- 
- 
- some = statement
-@@ -59,7 +55,7 @@
  @deco1
  # leading 2
  # leading 2 extra
@@ -192,7 +170,7 @@ def bar():
  # leading 3
  @deco3
  # leading 4
-@@ -73,7 +69,7 @@
+@@ -73,7 +73,7 @@
  # leading 1
  @deco1
  # leading 2
@@ -201,7 +179,7 @@ def bar():
  
  # leading 3 that already has an empty line
  @deco3
-@@ -88,7 +84,7 @@
+@@ -88,7 +88,7 @@
  # leading 1
  @deco1
  # leading 2
@@ -210,7 +188,7 @@ def bar():
  # leading 3
  @deco3
  
-@@ -106,7 +102,6 @@
+@@ -106,7 +106,6 @@
          # Another leading comment
          def another_inline():
              pass
@@ -218,7 +196,7 @@ def bar():
      else:
          # More leading comments
          def inline_after_else():
-@@ -121,18 +116,13 @@
+@@ -121,7 +120,6 @@
      # Another leading comment
      def another_top_level_quote_inline_inline():
          pass
@@ -226,18 +204,6 @@ def bar():
  else:
      # More leading comments
      def top_level_quote_inline_after_else():
-         pass
- 
- 
--class MyClass:
--    # First method has no empty lines between bare class def.
--    # More comments.
--    def first_method(self):
--        pass
-+NOT_YET_IMPLEMENTED_StmtClassDef
- 
- 
- # Regression test for https://github.com/psf/black/issues/3454.
 ```
 
 ## Ruff Output
@@ -275,7 +241,8 @@ some = statement
 
 
 # This comment should be split from the statement above by two lines.
-NOT_YET_IMPLEMENTED_StmtClassDef
+class MyClass:
+    pass
 
 
 some = statement
@@ -283,14 +250,17 @@ some = statement
 
 
 # This should be split from the above by two lines
-NOT_YET_IMPLEMENTED_StmtClassDef
+class MyClassWithComplexLeadingComments:
+    pass
 
 
-NOT_YET_IMPLEMENTED_StmtClassDef
+class ClassWithDocstring:
+    "NOT_YET_IMPLEMENTED_STRING"
 
 
 # Leading comment after a class with just a docstring
-NOT_YET_IMPLEMENTED_StmtClassDef
+class MyClassAfterAnotherClassWithDocstring:
+    pass
 
 
 some = statement
@@ -367,7 +337,11 @@ else:
         pass
 
 
-NOT_YET_IMPLEMENTED_StmtClassDef
+class MyClass:
+    # First method has no empty lines between bare class def.
+    # More comments.
+    def first_method(self):
+        pass
 
 
 # Regression test for https://github.com/psf/black/issues/3454.

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__comments_py.snap

@@ -114,16 +114,16 @@ async def wat():
  # Has many lines. Many, many lines.
  # Many, many, many lines.
 -"""Module docstring.
--
++"NOT_YET_IMPLEMENTED_STRING"
+ 
 -Possibly also many, many lines.
 -"""
-+"NOT_YET_IMPLEMENTED_STRING"
++NOT_YET_IMPLEMENTED_StmtImport
++NOT_YET_IMPLEMENTED_StmtImport
  
 -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_StmtImport
@@ -137,7 +137,7 @@ async def wat():
  
  
  # Some comment before a function.
-@@ -30,67 +24,50 @@
+@@ -30,25 +24,26 @@
  
  
  def function(default=None):
@@ -173,28 +173,29 @@ async def wat():
  
  
  # Another comment!
- # This time two lines.
+@@ -56,7 +51,7 @@
  
  
--class Foo:
+ class Foo:
 -    """Docstring for class Foo.  Example from Sphinx docs."""
--
++    "NOT_YET_IMPLEMENTED_STRING"
--    #: Doc comment for class attribute Foo.bar.
+ 
--    #: It can have multiple lines.
+     #: Doc comment for class attribute Foo.bar.
--    bar = 1
+     #: It can have multiple lines.
--
+@@ -65,32 +60,31 @@
--    flox = 1.5  #: Doc comment for Foo.flox. One line only.
+     flox = 1.5  #: Doc comment for Foo.flox. One line only.
--
+ 
--    baz = 2
+     baz = 2
 -    """Docstring for class attribute Foo.baz."""
--
++    "NOT_YET_IMPLEMENTED_STRING"
--    def __init__(self):
+ 
--        #: Doc comment for instance attribute qux.
+     def __init__(self):
--        self.qux = 3
+         #: Doc comment for instance attribute qux.
--
+         self.qux = 3
--        self.spam = 4
+ 
+         self.spam = 4
 -        """Docstring for instance attribute spam."""
-+NOT_YET_IMPLEMENTED_StmtClassDef
++        "NOT_YET_IMPLEMENTED_STRING"
  
  
  #' <h1>This is pweave!</h1>
@@ -279,7 +280,24 @@ GLOBAL_STATE = {
 # This time two lines.
 
 
-NOT_YET_IMPLEMENTED_StmtClassDef
+class Foo:
+    "NOT_YET_IMPLEMENTED_STRING"
+
+    #: 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
+    "NOT_YET_IMPLEMENTED_STRING"
+
+    def __init__(self):
+        #: Doc comment for instance attribute qux.
+        self.qux = 3
+
+        self.spam = 4
+        "NOT_YET_IMPLEMENTED_STRING"
 
 
 #' <h1>This is pweave!</h1>

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__composition_no_trailing_comma_py.snap

@@ -194,9 +194,9 @@ class C:
 ```diff
 --- Black
 +++ Ruff
-@@ -1,181 +1 @@
+@@ -1,181 +1,46 @@
--class C:
+ class C:
--    def test(self) -> None:
+     def test(self) -> None:
 -        with patch("black.out", print):
 -            self.assertEqual(
 -                unstyle(str(report)), "1 file reformatted, 1 file failed to reformat."
@@ -239,23 +239,38 @@ class C:
 -        return (
 -            'Utterly failed doctest test for %s\n   File "%s", line %s, in %s\n\n%s'
 -            % (test.name, test.filename, lineno, lname, err)
--        )
++        NOT_YET_IMPLEMENTED_StmtWith
--
++        xxxxxxxxxxxxxxxx = NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)
--    def omitting_trailers(self) -> None:
++        return "NOT_YET_IMPLEMENTED_STRING" % (
++            test.name,
++            test.filename,
++            lineno,
++            lname,
++            err,
+         )
+ 
+     def omitting_trailers(self) -> None:
 -        get_collection(
 -            hey_this_is_a_very_long_call, it_has_funny_attributes, really=True
 -        )[OneLevelIndex]
 -        get_collection(
 -            hey_this_is_a_very_long_call, it_has_funny_attributes, really=True
 -        )[OneLevelIndex][TwoLevelIndex][ThreeLevelIndex][FourLevelIndex]
--        d[0][1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][
++        NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)[OneLevelIndex]
--            22
++        NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)[OneLevelIndex][TwoLevelIndex][
--        ]
++            ThreeLevelIndex
++        ][
++            FourLevelIndex
++        ]
+         d[0][1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][
+             22
+         ]
 -        assignment = (
 -            some.rather.elaborate.rule() and another.rule.ending_with.index[123]
 -        )
--
++        assignment = NOT_IMPLEMENTED_call() and another.rule.ending_with.index[123]
--    def easy_asserts(self) -> None:
+ 
+     def easy_asserts(self) -> None:
 -        assert {
 -            key1: value1,
 -            key2: value2,
@@ -267,7 +282,8 @@ class C:
 -            key8: value8,
 -            key9: value9,
 -        } == expected, "Not what we expected"
--
++        NOT_YET_IMPLEMENTED_StmtAssert
+ 
 -        assert expected == {
 -            key1: value1,
 -            key2: value2,
@@ -279,7 +295,8 @@ class C:
 -            key8: value8,
 -            key9: value9,
 -        }, "Not what we expected"
--
++        NOT_YET_IMPLEMENTED_StmtAssert
+ 
 -        assert expected == {
 -            key1: value1,
 -            key2: value2,
@@ -291,8 +308,9 @@ class C:
 -            key8: value8,
 -            key9: value9,
 -        }
--
++        NOT_YET_IMPLEMENTED_StmtAssert
--    def tricky_asserts(self) -> None:
+ 
+     def tricky_asserts(self) -> None:
 -        assert {
 -            key1: value1,
 -            key2: value2,
@@ -306,7 +324,8 @@ class C:
 -        } == expected(
 -            value, is_going_to_be="too long to fit in a single line", srsly=True
 -        ), "Not what we expected"
--
++        NOT_YET_IMPLEMENTED_StmtAssert
+ 
 -        assert {
 -            key1: value1,
 -            key2: value2,
@@ -320,7 +339,8 @@ class C:
 -        } == expected, (
 -            "Not what we expected and the message is too long to fit in one line"
 -        )
--
++        NOT_YET_IMPLEMENTED_StmtAssert
+ 
 -        assert expected(
 -            value, is_going_to_be="too long to fit in a single line", srsly=True
 -        ) == {
@@ -334,7 +354,8 @@ class C:
 -            key8: value8,
 -            key9: value9,
 -        }, "Not what we expected"
--
++        NOT_YET_IMPLEMENTED_StmtAssert
+ 
 -        assert expected == {
 -            key1: value1,
 -            key2: value2,
@@ -349,7 +370,8 @@ class C:
 -            "Not what we expected and the message is too long to fit in one line"
 -            " because it's too long"
 -        )
--
++        NOT_YET_IMPLEMENTED_StmtAssert
+ 
 -        dis_c_instance_method = """\
 -        %3d           0 LOAD_FAST                1 (x)
 -                      2 LOAD_CONST               1 (1)
@@ -360,8 +382,11 @@ class C:
 -                     12 RETURN_VALUE
 -        """ % (
 -            _C.__init__.__code__.co_firstlineno + 1,
--        )
++        dis_c_instance_method = "NOT_YET_IMPLEMENTED_STRING" % (
--
++            _C.__init__.__code__.co_firstlineno
++            + 1,
+         )
+ 
 -        assert (
 -            expectedexpectedexpectedexpectedexpectedexpectedexpectedexpectedexpect
 -            == {
@@ -376,13 +401,58 @@ class C:
 -                key9: value9,
 -            }
 -        )
-+NOT_YET_IMPLEMENTED_StmtClassDef
++        NOT_YET_IMPLEMENTED_StmtAssert
 ```
 
 ## Ruff Output
 
 ```py
-NOT_YET_IMPLEMENTED_StmtClassDef
+class C:
+    def test(self) -> None:
+        NOT_YET_IMPLEMENTED_StmtWith
+        xxxxxxxxxxxxxxxx = NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)
+        return "NOT_YET_IMPLEMENTED_STRING" % (
+            test.name,
+            test.filename,
+            lineno,
+            lname,
+            err,
+        )
+
+    def omitting_trailers(self) -> None:
+        NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)[OneLevelIndex]
+        NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)[OneLevelIndex][TwoLevelIndex][
+            ThreeLevelIndex
+        ][
+            FourLevelIndex
+        ]
+        d[0][1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][
+            22
+        ]
+        assignment = NOT_IMPLEMENTED_call() and another.rule.ending_with.index[123]
+
+    def easy_asserts(self) -> None:
+        NOT_YET_IMPLEMENTED_StmtAssert
+
+        NOT_YET_IMPLEMENTED_StmtAssert
+
+        NOT_YET_IMPLEMENTED_StmtAssert
+
+    def tricky_asserts(self) -> None:
+        NOT_YET_IMPLEMENTED_StmtAssert
+
+        NOT_YET_IMPLEMENTED_StmtAssert
+
+        NOT_YET_IMPLEMENTED_StmtAssert
+
+        NOT_YET_IMPLEMENTED_StmtAssert
+
+        dis_c_instance_method = "NOT_YET_IMPLEMENTED_STRING" % (
+            _C.__init__.__code__.co_firstlineno
+            + 1,
+        )
+
+        NOT_YET_IMPLEMENTED_StmtAssert
 ```
 
 ## Black Output

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__composition_py.snap

@@ -194,9 +194,9 @@ class C:
 ```diff
 --- Black
 +++ Ruff
-@@ -1,181 +1 @@
+@@ -1,181 +1,46 @@
--class C:
+ class C:
--    def test(self) -> None:
+     def test(self) -> None:
 -        with patch("black.out", print):
 -            self.assertEqual(
 -                unstyle(str(report)), "1 file reformatted, 1 file failed to reformat."
@@ -239,23 +239,38 @@ class C:
 -        return (
 -            'Utterly failed doctest test for %s\n   File "%s", line %s, in %s\n\n%s'
 -            % (test.name, test.filename, lineno, lname, err)
--        )
++        NOT_YET_IMPLEMENTED_StmtWith
--
++        xxxxxxxxxxxxxxxx = NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)
--    def omitting_trailers(self) -> None:
++        return "NOT_YET_IMPLEMENTED_STRING" % (
++            test.name,
++            test.filename,
++            lineno,
++            lname,
++            err,
+         )
+ 
+     def omitting_trailers(self) -> None:
 -        get_collection(
 -            hey_this_is_a_very_long_call, it_has_funny_attributes, really=True
 -        )[OneLevelIndex]
 -        get_collection(
 -            hey_this_is_a_very_long_call, it_has_funny_attributes, really=True
 -        )[OneLevelIndex][TwoLevelIndex][ThreeLevelIndex][FourLevelIndex]
--        d[0][1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][
++        NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)[OneLevelIndex]
--            22
++        NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)[OneLevelIndex][TwoLevelIndex][
--        ]
++            ThreeLevelIndex
++        ][
++            FourLevelIndex
++        ]
+         d[0][1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][
+             22
+         ]
 -        assignment = (
 -            some.rather.elaborate.rule() and another.rule.ending_with.index[123]
 -        )
--
++        assignment = NOT_IMPLEMENTED_call() and another.rule.ending_with.index[123]
--    def easy_asserts(self) -> None:
+ 
+     def easy_asserts(self) -> None:
 -        assert {
 -            key1: value1,
 -            key2: value2,
@@ -267,7 +282,8 @@ class C:
 -            key8: value8,
 -            key9: value9,
 -        } == expected, "Not what we expected"
--
++        NOT_YET_IMPLEMENTED_StmtAssert
+ 
 -        assert expected == {
 -            key1: value1,
 -            key2: value2,
@@ -279,7 +295,8 @@ class C:
 -            key8: value8,
 -            key9: value9,
 -        }, "Not what we expected"
--
++        NOT_YET_IMPLEMENTED_StmtAssert
+ 
 -        assert expected == {
 -            key1: value1,
 -            key2: value2,
@@ -291,8 +308,9 @@ class C:
 -            key8: value8,
 -            key9: value9,
 -        }
--
++        NOT_YET_IMPLEMENTED_StmtAssert
--    def tricky_asserts(self) -> None:
+ 
+     def tricky_asserts(self) -> None:
 -        assert {
 -            key1: value1,
 -            key2: value2,
@@ -306,7 +324,8 @@ class C:
 -        } == expected(
 -            value, is_going_to_be="too long to fit in a single line", srsly=True
 -        ), "Not what we expected"
--
++        NOT_YET_IMPLEMENTED_StmtAssert
+ 
 -        assert {
 -            key1: value1,
 -            key2: value2,
@@ -320,7 +339,8 @@ class C:
 -        } == expected, (
 -            "Not what we expected and the message is too long to fit in one line"
 -        )
--
++        NOT_YET_IMPLEMENTED_StmtAssert
+ 
 -        assert expected(
 -            value, is_going_to_be="too long to fit in a single line", srsly=True
 -        ) == {
@@ -334,7 +354,8 @@ class C:
 -            key8: value8,
 -            key9: value9,
 -        }, "Not what we expected"
--
++        NOT_YET_IMPLEMENTED_StmtAssert
+ 
 -        assert expected == {
 -            key1: value1,
 -            key2: value2,
@@ -349,7 +370,8 @@ class C:
 -            "Not what we expected and the message is too long to fit in one line"
 -            " because it's too long"
 -        )
--
++        NOT_YET_IMPLEMENTED_StmtAssert
+ 
 -        dis_c_instance_method = """\
 -        %3d           0 LOAD_FAST                1 (x)
 -                      2 LOAD_CONST               1 (1)
@@ -360,8 +382,11 @@ class C:
 -                     12 RETURN_VALUE
 -        """ % (
 -            _C.__init__.__code__.co_firstlineno + 1,
--        )
++        dis_c_instance_method = "NOT_YET_IMPLEMENTED_STRING" % (
--
++            _C.__init__.__code__.co_firstlineno
++            + 1,
+         )
+ 
 -        assert (
 -            expectedexpectedexpectedexpectedexpectedexpectedexpectedexpectedexpect
 -            == {
@@ -376,13 +401,58 @@ class C:
 -                key9: value9,
 -            }
 -        )
-+NOT_YET_IMPLEMENTED_StmtClassDef
++        NOT_YET_IMPLEMENTED_StmtAssert
 ```
 
 ## Ruff Output
 
 ```py
-NOT_YET_IMPLEMENTED_StmtClassDef
+class C:
+    def test(self) -> None:
+        NOT_YET_IMPLEMENTED_StmtWith
+        xxxxxxxxxxxxxxxx = NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)
+        return "NOT_YET_IMPLEMENTED_STRING" % (
+            test.name,
+            test.filename,
+            lineno,
+            lname,
+            err,
+        )
+
+    def omitting_trailers(self) -> None:
+        NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)[OneLevelIndex]
+        NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)[OneLevelIndex][TwoLevelIndex][
+            ThreeLevelIndex
+        ][
+            FourLevelIndex
+        ]
+        d[0][1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][
+            22
+        ]
+        assignment = NOT_IMPLEMENTED_call() and another.rule.ending_with.index[123]
+
+    def easy_asserts(self) -> None:
+        NOT_YET_IMPLEMENTED_StmtAssert
+
+        NOT_YET_IMPLEMENTED_StmtAssert
+
+        NOT_YET_IMPLEMENTED_StmtAssert
+
+    def tricky_asserts(self) -> None:
+        NOT_YET_IMPLEMENTED_StmtAssert
+
+        NOT_YET_IMPLEMENTED_StmtAssert
+
+        NOT_YET_IMPLEMENTED_StmtAssert
+
+        NOT_YET_IMPLEMENTED_StmtAssert
+
+        dis_c_instance_method = "NOT_YET_IMPLEMENTED_STRING" % (
+            _C.__init__.__code__.co_firstlineno
+            + 1,
+        )
+
+        NOT_YET_IMPLEMENTED_StmtAssert
 ```
 
 ## Black Output

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__docstring_no_extra_empty_line_before_eof_py.snap

@@ -17,12 +17,12 @@ class ClassWithDocstring:
 ```diff
 --- Black
 +++ Ruff
-@@ -1,4 +1,3 @@
+@@ -1,4 +1,4 @@
  # Make sure when the file ends with class's docstring,
  # It doesn't add extra blank lines.
--class ClassWithDocstring:
+ class ClassWithDocstring:
 -    """A docstring."""
-+NOT_YET_IMPLEMENTED_StmtClassDef
++    "NOT_YET_IMPLEMENTED_STRING"
 ```
 
 ## Ruff Output
@@ -30,7 +30,8 @@ class ClassWithDocstring:
 ```py
 # Make sure when the file ends with class's docstring,
 # It doesn't add extra blank lines.
-NOT_YET_IMPLEMENTED_StmtClassDef
+class ClassWithDocstring:
+    "NOT_YET_IMPLEMENTED_STRING"
 ```
 
 ## Black Output

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__docstring_py.snap

@@ -234,18 +234,19 @@ def stable_quote_normalization_with_immediate_inner_single_quote(self):
 ```diff
 --- Black
 +++ Ruff
-@@ -1,219 +1,149 @@
+@@ -1,219 +1,154 @@
--class MyClass:
+ class MyClass:
 -    """Multiline
 -    class docstring
 -    """
--
++    "NOT_YET_IMPLEMENTED_STRING"
--    def method(self):
+ 
+     def method(self):
 -        """Multiline
 -        method docstring
 -        """
--        pass
++        "NOT_YET_IMPLEMENTED_STRING"
-+NOT_YET_IMPLEMENTED_StmtClassDef
+         pass
  
  
  def foo():
@@ -396,12 +397,12 @@ def stable_quote_normalization_with_immediate_inner_single_quote(self):
 -        tab at start of line and then a tab	separated	value
 -                                multiple tabs at the beginning	and	inline
 -                        mixed tabs and spaces at beginning. next line has mixed tabs and spaces only.
--
--    line ends with some tabs
--    """
 +    "NOT_YET_IMPLEMENTED_STRING"
  
+-    line ends with some tabs
+-    """
  
+-
  def docstring_with_inline_tabs_and_tab_indentation():
 -    """hey
 -
@@ -494,7 +495,12 @@ def stable_quote_normalization_with_immediate_inner_single_quote(self):
 ## Ruff Output
 
 ```py
-NOT_YET_IMPLEMENTED_StmtClassDef
+class MyClass:
+    "NOT_YET_IMPLEMENTED_STRING"
+
+    def method(self):
+        "NOT_YET_IMPLEMENTED_STRING"
+        pass
 
 
 def foo():

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__fmtonoff5_py.snap

@@ -134,7 +134,7 @@ elif   unformatted:
          return True
      # yapf: enable
      elif b:
-@@ -39,49 +21,29 @@
+@@ -39,12 +21,12 @@
  # Regression test for https://github.com/psf/black/issues/2567.
  if True:
      # fmt: off
@@ -152,40 +152,44 @@ elif   unformatted:
  
  
  # Regression test for https://github.com/psf/black/issues/3184.
--class A:
+@@ -52,29 +34,27 @@
--    async def call(param):
+     async def call(param):
--        if param:
+         if param:
--            # fmt: off
+             # fmt: off
 -            if param[0:4] in (
 -                "ABCD", "EFGH"
 -            )  :
--                # fmt: on
++            if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
+                 # fmt: on
 -                print ( "This won't be formatted" )
--
++                NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)
+ 
 -            elif param[0:4] in ("ZZZZ",):
 -                print ( "This won't be formatted either" )
--
++            elif NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
++                NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)
+ 
 -        print("This will be formatted")
-+NOT_YET_IMPLEMENTED_StmtClassDef
++        NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)
  
  
  # Regression test for https://github.com/psf/black/issues/2985.
--class Named(t.Protocol):
+ class Named(t.Protocol):
--    # fmt: off
+     # fmt: off
--    @property
+     @property
 -    def  this_wont_be_formatted ( self ) -> str: ...
-+NOT_YET_IMPLEMENTED_StmtClassDef
++    def this_wont_be_formatted(self) -> str:
++        ...
  
  
--class Factory(t.Protocol):
+ class Factory(t.Protocol):
--    def this_will_be_formatted(self, **kwargs) -> Named:
+     def this_will_be_formatted(self, **kwargs) -> Named:
--        ...
+         ...
 -
--    # fmt: on
+     # fmt: on
-+NOT_YET_IMPLEMENTED_StmtClassDef
  
  
- # Regression test for https://github.com/psf/black/issues/3436.
+@@ -82,6 +62,6 @@
  if x:
      return x
  # fmt: off
@@ -231,14 +235,32 @@ else:
 
 
 # Regression test for https://github.com/psf/black/issues/3184.
-NOT_YET_IMPLEMENTED_StmtClassDef
+class A:
+    async def call(param):
+        if param:
+            # fmt: off
+            if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
+                # fmt: on
+                NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)
+
+            elif NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
+                NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)
+
+        NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)
 
 
 # Regression test for https://github.com/psf/black/issues/2985.
-NOT_YET_IMPLEMENTED_StmtClassDef
+class Named(t.Protocol):
+    # fmt: off
+    @property
+    def this_wont_be_formatted(self) -> str:
+        ...
 
 
-NOT_YET_IMPLEMENTED_StmtClassDef
+class Factory(t.Protocol):
+    def this_will_be_formatted(self, **kwargs) -> Named:
+        ...
+    # fmt: on
 
 
 # Regression test for https://github.com/psf/black/issues/3436.

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__fmtskip6_py.snap

@@ -18,19 +18,23 @@ class A:
 ```diff
 --- Black
 +++ Ruff
-@@ -1,5 +1 @@
+@@ -1,5 +1,5 @@
--class A:
+ class A:
--    def f(self):
+     def f(self):
 -        for line in range(10):
--            if True:
++        for line in NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg):
--                pass  # fmt: skip
+             if True:
-+NOT_YET_IMPLEMENTED_StmtClassDef
+                 pass  # fmt: skip
 ```
 
 ## Ruff Output
 
 ```py
-NOT_YET_IMPLEMENTED_StmtClassDef
+class A:
+    def f(self):
+        for line in NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg):
+            if True:
+                pass  # fmt: skip
 ```
 
 ## Black Output

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__fmtskip8_py.snap

@@ -75,7 +75,7 @@ async def test_async_with():
 ```diff
 --- Black
 +++ Ruff
-@@ -1,62 +1,47 @@
+@@ -1,62 +1,54 @@
  # Make sure a leading comment is not removed.
 -def some_func(  unformatted,  args  ):  # fmt: skip
 -    print("I am some_func")
@@ -98,14 +98,19 @@ async def test_async_with():
 -class SomeClass(  Unformatted,  SuperClasses  ):  # fmt: skip
 -    def some_method(  self,  unformatted,  args  ):  # fmt: skip
 -        print("I am some_method")
--        return 0
++class SomeClass(Unformatted, SuperClasses):  # fmt: skip
-+NOT_YET_IMPLEMENTED_StmtClassDef
++    def some_method(self, unformatted, args):  # fmt: skip
++        NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)
+         return 0
  
 -    async def some_async_method(  self,  unformatted,  args  ):  # fmt: skip
 -        print("I am some_async_method")
 -        await asyncio.sleep(1)
++    async def some_async_method(self, unformatted, args):  # fmt: skip
++        NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)
++        await NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)
+ 
  
--
  # Make sure a leading comment is not removed.
 -if  unformatted_call(  args  ):  # fmt: skip
 -    print("First branch")
@@ -177,7 +182,14 @@ async def some_async_func(unformatted, args):  # fmt: skip
 
 
 # Make sure a leading comment is not removed.
-NOT_YET_IMPLEMENTED_StmtClassDef
+class SomeClass(Unformatted, SuperClasses):  # fmt: skip
+    def some_method(self, unformatted, args):  # fmt: skip
+        NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)
+        return 0
+
+    async def some_async_method(self, unformatted, args):  # fmt: skip
+        NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)
+        await NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)
 
 
 # Make sure a leading comment is not removed.

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__function2_py.snap

@@ -66,7 +66,7 @@ with hmm_but_this_should_get_two_preceding_newlines():
 ```diff
 --- Black
 +++ Ruff
-@@ -2,64 +2,39 @@
+@@ -2,64 +2,41 @@
      a,
      **kwargs,
  ) -> A:
@@ -129,17 +129,17 @@ with hmm_but_this_should_get_two_preceding_newlines():
  
  elif False:
 -
--    class IHopeYouAreHavingALovelyDay:
+     class IHopeYouAreHavingALovelyDay:
--        def __call__(self):
+         def __call__(self):
 -            print("i_should_be_followed_by_only_one_newline")
 -
-+    NOT_YET_IMPLEMENTED_StmtClassDef
++            NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)
  else:
 -
      def foo():
          pass
- 
 -
+ 
 -with hmm_but_this_should_get_two_preceding_newlines():
 -    pass
 +NOT_YET_IMPLEMENTED_StmtWith
@@ -182,7 +182,9 @@ elif NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
     NOT_YET_IMPLEMENTED_StmtTry
 
 elif False:
-    NOT_YET_IMPLEMENTED_StmtClassDef
+    class IHopeYouAreHavingALovelyDay:
+        def __call__(self):
+            NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)
 else:
     def foo():
         pass

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__remove_newline_after_code_block_open_py.snap

@@ -121,7 +121,7 @@ with open("/path/to/file.txt", mode="r") as read_file:
 ```diff
 --- Black
 +++ Ruff
-@@ -1,78 +1,72 @@
+@@ -1,78 +1,74 @@
 -import random
 +NOT_YET_IMPLEMENTED_StmtImport
  
@@ -151,10 +151,10 @@ with open("/path/to/file.txt", mode="r") as read_file:
 +    NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)
  
  
--class Foo:
+ class Foo:
--    def bar(self):
+     def bar(self):
 -        print("The newline above me should be deleted!")
-+NOT_YET_IMPLEMENTED_StmtClassDef
++        NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)
  
  
 -for i in range(5):
@@ -255,7 +255,9 @@ def foo4():
     NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)
 
 
-NOT_YET_IMPLEMENTED_StmtClassDef
+class Foo:
+    def bar(self):
+        NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)
 
 
 for i in NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg):

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__torture_py.snap

@@ -42,7 +42,7 @@ assert (
 ```diff
 --- Black
 +++ Ruff
-@@ -2,57 +2,24 @@
+@@ -2,20 +2,10 @@
  (
      ()
      << 0
@@ -65,16 +65,16 @@ assert (
  
  importA
  0
- 0 ^ 0  #
+@@ -24,35 +14,15 @@
  
- 
+ class A:
--class A:
+     def foo(self):
--    def foo(self):
 -        for _ in range(10):
 -            aaaaaaaaaaaaaaaaaaa = bbbbbbbbbbbbbbb.cccccccccc(
 -                xxxxxxxxxxxx
 -            )  # pylint: disable=no-member
-+NOT_YET_IMPLEMENTED_StmtClassDef
++        for _ in NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg):
++            aaaaaaaaaaaaaaaaaaa = NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)
  
  
  def test(self, othr):
@@ -126,7 +126,10 @@ importA
 0 ^ 0  #
 
 
-NOT_YET_IMPLEMENTED_StmtClassDef
+class A:
+    def foo(self):
+        for _ in NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg):
+            aaaaaaaaaaaaaaaaaaa = NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg)
 
 
 def test(self, othr):

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__trailing_comma_optional_parens1_py.snap

@@ -38,7 +38,7 @@ class A:
 ```diff
 --- Black
 +++ Ruff
-@@ -1,34 +1,15 @@
+@@ -1,34 +1,25 @@
 -if e1234123412341234.winerror not in (
 -    _winapi.ERROR_SEM_TIMEOUT,
 -    _winapi.ERROR_PIPE_BUSY,
@@ -61,25 +61,30 @@ class A:
 +        new_id = NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg) + 1
  
  
--class X:
+ class X:
--    def get_help_text(self):
+     def get_help_text(self):
 -        return ngettext(
 -            "Your password must contain at least %(min_length)d character.",
 -            "Your password must contain at least %(min_length)d characters.",
 -            self.min_length,
 -        ) % {"min_length": self.min_length}
-+NOT_YET_IMPLEMENTED_StmtClassDef
++        return NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg) % {
++            "NOT_YET_IMPLEMENTED_STRING": self.min_length,
++        }
  
  
--class A:
+ class A:
--    def b(self):
+     def b(self):
 -        if self.connection.mysql_is_mariadb and (
 -            10,
 -            4,
 -            3,
 -        ) < self.connection.mysql_version < (10, 5, 2):
--            pass
++        if (
-+NOT_YET_IMPLEMENTED_StmtClassDef
++            self.connection.mysql_is_mariadb
++            and NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right
++        ):
+             pass
 ```
 
 ## Ruff Output
@@ -96,10 +101,20 @@ if x:
         new_id = NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg) + 1
 
 
-NOT_YET_IMPLEMENTED_StmtClassDef
+class X:
+    def get_help_text(self):
+        return NOT_IMPLEMENTED_call(NOT_IMPLEMENTED_arg) % {
+            "NOT_YET_IMPLEMENTED_STRING": self.min_length,
+        }
 
 
-NOT_YET_IMPLEMENTED_StmtClassDef
+class A:
+    def b(self):
+        if (
+            self.connection.mysql_is_mariadb
+            and NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right
+        ):
+            pass
 ```
 
 ## Black Output

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__ruff_test__statement__class_definition_py.snap

@@ -0,0 +1,97 @@
+---
+source: crates/ruff_python_formatter/src/lib.rs
+expression: snapshot
+---
+## Input
+```py
+class Test(
+    Aaaaaaaaaaaaaaaaa,
+    Bbbbbbbbbbbbbbbb,
+    DDDDDDDDDDDDDDDD,
+    EEEEEEEEEEEEEE,
+    metaclass=meta,
+):
+    pass
+
+
+class Test((Aaaaaaaaaaaaaaaaa), Bbbbbbbbbbbbbbbb, metaclass=meta):
+    pass
+
+class Test( # trailing class comment
+    Aaaaaaaaaaaaaaaaa, # trailing comment
+
+    # in between comment
+
+    Bbbbbbbbbbbbbbbb,
+    # another leading comment
+    DDDDDDDDDDDDDDDD,
+    EEEEEEEEEEEEEE,
+    # meta comment
+    metaclass=meta, # trailing meta comment
+):
+    pass
+
+class Test((Aaaa)):
+    ...
+
+
+class Test(aaaaaaaaaaaaaaa + bbbbbbbbbbbbbbbbbbbbbb + cccccccccccccccccccccccc + dddddddddddddddddddddd + eeeeeeeee, ffffffffffffffffff, gggggggggggggggggg):
+    pass
+
+class Test(Aaaa): # trailing comment
+    pass
+```
+
+
+
+## Output
+```py
+class Test(
+    Aaaaaaaaaaaaaaaaa,
+    Bbbbbbbbbbbbbbbb,
+    DDDDDDDDDDDDDDDD,
+    EEEEEEEEEEEEEE,
+    metaclass=meta,
+):
+    pass
+
+
+class Test((Aaaaaaaaaaaaaaaaa), Bbbbbbbbbbbbbbbb, metaclass=meta):
+    pass
+
+
+class Test(
+    # trailing class comment
+    Aaaaaaaaaaaaaaaaa,  # trailing comment
+    # in between comment
+    Bbbbbbbbbbbbbbbb,
+    # another leading comment
+    DDDDDDDDDDDDDDDD,
+    EEEEEEEEEEEEEE,
+    # meta comment
+    metaclass=meta,  # trailing meta comment
+):
+    pass
+
+
+class Test((Aaaa)):
+    ...
+
+
+class Test(
+    aaaaaaaaaaaaaaa
+    + bbbbbbbbbbbbbbbbbbbbbb
+    + cccccccccccccccccccccccc
+    + dddddddddddddddddddddd
+    + eeeeeeeee,
+    ffffffffffffffffff,
+    gggggggggggggggggg,
+):
+    pass
+
+
+class Test(Aaaa):  # trailing comment
+    pass
+```
+
+

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__ruff_test__trivia_py.snap

@@ -52,7 +52,10 @@ b = 20
 
 
 # Adds two lines after `b`
-NOT_YET_IMPLEMENTED_StmtClassDef
+class Test:
+    def a(self):
+        pass
+        # trailing comment
 
 
 # two lines before, one line after

crates/ruff_python_formatter/src/statement/stmt_class_def.rs

@@ -1,12 +1,138 @@
-use crate::{not_yet_implemented, FormatNodeRule, PyFormatter};
+use crate::comments::trailing_comments;
-use ruff_formatter::{write, Buffer, FormatResult};
+use crate::expression::parentheses::Parenthesize;
-use rustpython_parser::ast::StmtClassDef;
+use crate::prelude::*;
+use crate::trivia::{first_non_trivia_token, SimpleTokenizer, Token, TokenKind};
+use crate::USE_MAGIC_TRAILING_COMMA;
+use ruff_formatter::{format_args, write};
+use ruff_text_size::TextRange;
+use rustpython_parser::ast::{Expr, Keyword, Ranged, StmtClassDef};
 
 #[derive(Default)]
 pub struct FormatStmtClassDef;
 
 impl FormatNodeRule<StmtClassDef> for FormatStmtClassDef {
     fn fmt_fields(&self, item: &StmtClassDef, f: &mut PyFormatter) -> FormatResult<()> {
-        write!(f, [not_yet_implemented(item)])
+        let StmtClassDef {
+            range: _,
+            name,
+            bases,
+            keywords,
+            body,
+            decorator_list,
+        } = item;
+
+        f.join_with(hard_line_break())
+            .entries(decorator_list.iter().formatted())
+            .finish()?;
+
+        if !decorator_list.is_empty() {
+            hard_line_break().fmt(f)?;
+        }
+
+        write!(f, [text("class"), space(), name.format()])?;
+
+        if !(bases.is_empty() && keywords.is_empty()) {
+            write!(
+                f,
+                [group(&format_args![
+                    text("("),
+                    soft_block_indent(&FormatInheritanceClause {
+                        class_definition: item
+                    }),
+                    text(")")
+                ])]
+            )?;
+        }
+
+        let comments = f.context().comments().clone();
+        let trailing_head_comments = comments.dangling_comments(item);
+
+        write!(
+            f,
+            [
+                text(":"),
+                trailing_comments(trailing_head_comments),
+                block_indent(&body.format())
+            ]
+        )
+    }
+
+    fn fmt_dangling_comments(
+        &self,
+        _node: &StmtClassDef,
+        _f: &mut PyFormatter,
+    ) -> FormatResult<()> {
+        // handled in fmt_fields
+        Ok(())
+    }
+}
+
+struct FormatInheritanceClause<'a> {
+    class_definition: &'a StmtClassDef,
+}
+
+impl Format<PyFormatContext<'_>> for FormatInheritanceClause<'_> {
+    fn fmt(&self, f: &mut Formatter<PyFormatContext<'_>>) -> FormatResult<()> {
+        let StmtClassDef {
+            bases,
+            keywords,
+            name,
+            ..
+        } = self.class_definition;
+
+        let separator = format_with(|f| write!(f, [text(","), soft_line_break_or_space()]));
+        let source = f.context().contents();
+
+        let mut joiner = f.join_with(&separator);
+
+        if let Some((first, rest)) = bases.split_first() {
+            // Manually handle parentheses for the first expression because the logic in `FormatExpr`
+            // doesn't know that it should disregard the parentheses of the inheritance clause.
+            // ```python
+            // class Test(A) # A is not parenthesized, the parentheses belong to the inheritance clause
+            // class Test((A)) # A is parenthesized
+            // ```
+            // parentheses from the inheritance clause belong to the expression.
+            let tokenizer = SimpleTokenizer::new(source, TextRange::new(name.end(), first.start()))
+                .skip_trivia();
+
+            let left_paren_count = tokenizer
+                .take_while(|token| token.kind() == TokenKind::LParen)
+                .count();
+
+            // Ignore the first parentheses count
+            let parenthesize = if left_paren_count > 1 {
+                Parenthesize::Always
+            } else {
+                Parenthesize::Never
+            };
+
+            joiner.entry(&first.format().with_options(parenthesize));
+            joiner.entries(rest.iter().formatted());
+        }
+
+        joiner.entries(keywords.iter().formatted()).finish()?;
+
+        if_group_breaks(&text(",")).fmt(f)?;
+
+        if USE_MAGIC_TRAILING_COMMA {
+            let last_end = keywords
+                .last()
+                .map(Keyword::end)
+                .or_else(|| bases.last().map(Expr::end))
+                .unwrap();
+
+            if matches!(
+                first_non_trivia_token(last_end, f.context().contents()),
+                Some(Token {
+                    kind: TokenKind::Comma,
+                    ..
+                })
+            ) {
+                hard_line_break().fmt(f)?;
+            }
+        }
+
+        Ok(())
     }
 }

crates/ruff_python_formatter/src/statement/suite.rs

@@ -252,7 +252,8 @@ one_leading_newline = 10
 no_leading_newline = 30
 
 
-NOT_YET_IMPLEMENTED_StmtClassDef
+class InTheMiddle:
+    pass
 
 
 trailing_statement = 1
@@ -283,7 +284,8 @@ two_leading_newlines = 20
 one_leading_newline = 10
 no_leading_newline = 30
 
-NOT_YET_IMPLEMENTED_StmtClassDef
+class InTheMiddle:
+    pass
 
 trailing_statement = 1