Derive block attributes from block item tree

crates/syntax/src/ast/node_ext.rs

@@ -61,6 +61,14 @@ impl ast::BlockExpr {
     pub fn tail_expr(&self) -> Option<ast::Expr> {
         self.stmt_list()?.tail_expr()
     }
+    /// Block expressions accept outer and inner attributes, but only when they are the outer
+    /// expression of an expression statement or the final expression of another block expression.
+    pub fn may_carry_attributes(&self) -> bool {
+        matches!(
+            self.syntax().parent().map(|it| it.kind()),
+            Some(SyntaxKind::BLOCK_EXPR | SyntaxKind::EXPR_STMT)
+        )
+    }
 }
 
 #[derive(Debug, PartialEq, Eq, Clone)]