Respect self as positional-only argument in annotation rules (#2927)

crates/ruff/resources/test/fixtures/flake8_annotations/annotation_presence.py

@@ -103,3 +103,7 @@ class Foo:
     @classmethod
     def foo(cls, a: int, b: int) -> int:
         pass
+
+    # ANN101
+    def foo(self, /, a: int, b: int) -> int:
+        pass

crates/ruff/src/rules/flake8_annotations/rules.rs

@@ -475,9 +475,9 @@ pub fn definition(
 
         // ANN001, ANN401
         for arg in args
-            .args
+            .posonlyargs
             .iter()
-            .chain(args.posonlyargs.iter())
+            .chain(args.args.iter())
             .chain(args.kwonlyargs.iter())
             .skip(
                 // If this is a non-static method, skip `cls` or `self`.
@@ -581,7 +581,7 @@ pub fn definition(
 
         // ANN101, ANN102
         if is_method && !visibility::is_staticmethod(checker, cast::decorator_list(stmt)) {
-            if let Some(arg) = args.args.first() {
+            if let Some(arg) = args.posonlyargs.first().or_else(|| args.args.first()) {
                 if arg.node.annotation.is_none() {
                     if visibility::is_classmethod(checker, cast::decorator_list(stmt)) {
                         if checker.settings.rules.enabled(&Rule::MissingTypeCls) {

crates/ruff/src/rules/flake8_annotations/snapshots/ruff__rules__flake8_annotations__tests__defaults.snap

@@ -244,4 +244,15 @@ expression: diagnostics
     column: 15
   fix: ~
   parent: ~
+- kind:
+    MissingTypeSelf:
+      name: self
+  location:
+    row: 108
+    column: 12
+  end_location:
+    row: 108
+    column: 16
+  fix: ~
+  parent: ~
 

crates/ruff_python_formatter/src/trivia.rs

@@ -225,7 +225,6 @@ fn sorted_child_nodes_inner<'a>(node: &Node<'a>, result: &mut Vec<Node<'a>>) {
                 for decorator in decorator_list {
                     result.push(Node::Expr(decorator));
                 }
-                // TODO(charlie): Retain order.
                 for arg in &args.posonlyargs {
                     if let Some(expr) = &arg.node.annotation {
                         result.push(Node::Expr(expr));