put dummy def check in a helper function.

crates/ruff_linter/src/rules/pycodestyle/rules/blank_lines.rs

@@ -642,6 +642,13 @@ enum Follows {
     Docstring,
 }
 
+impl Follows {
+    // Allow a function/method to follow a function/method with a dummy body.
+    const fn follows_def_with_dummy_body(self) -> bool {
+        matches!(self, Follows::DummyDef)
+    }
+}
+
 impl Follows {
     const fn is_any_def(self) -> bool {
         matches!(self, Follows::Def | Follows::DummyDef)
@@ -814,8 +821,7 @@ impl<'a> BlankLinesChecker<'a> {
             && matches!(line.kind,  LogicalLineKind::Function | LogicalLineKind::Decorator)
             // Allow groups of one-liners.
             && !(state.follows.is_any_def() && line.last_token != TokenKind::Colon)
-            // Allow a function/method to follow a function/method with a dummy body.
-            && !matches!(state.follows, Follows::DummyDef)
+            && !state.follows.follows_def_with_dummy_body()
             && matches!(state.class_status, Status::Inside(_))
             // The class/parent method's docstring can directly precede the def.
             // Allow following a decorator (if there is an error it will be triggered on the first decorator).
@@ -867,8 +873,7 @@ impl<'a> BlankLinesChecker<'a> {
             && !matches!(state.follows, Follows::Decorator)
             // Allow groups of one-liners.
             && !(state.follows.is_any_def() && line.last_token != TokenKind::Colon)
-            // Allow a function/method to follow a function/method with a dummy body.
-            && !matches!(state.follows, Follows::DummyDef)
+            && !state.follows.follows_def_with_dummy_body()
             // Only trigger on non-indented classes and functions (for example functions within an if are ignored)
             && line.indent_length == 0
             // Only apply to functions or classes.
@@ -1035,8 +1040,7 @@ impl<'a> BlankLinesChecker<'a> {
             && prev_indent_length.is_some_and(|prev_indent_length| prev_indent_length >= line.indent_length)
             // Allow groups of one-liners.
             && !(state.follows.is_any_def() && line.last_token != TokenKind::Colon)
-            // Allow a function/method to follow a function/method with a dummy body.
-            && !matches!(state.follows, Follows::DummyDef)
+            && !state.follows.follows_def_with_dummy_body()
             // Blank lines in stub files are only used for grouping. Don't enforce blank lines.
             && !self.source_type.is_stub()
         {