Since we don't care about its return value, don't use .map. We do have a

nice idiom for calling method like subs, so use that instead.

Author: gfldex

doc/Type/IO/Path.pod6

@@ -299,7 +299,7 @@ contents you will have to do something more complex.
 
     # When we have a directory first recurse, then remove it
     multi sub rm-all(IO::Path $path where :d) {
-        $path.dir.map({ rm-all($^p) });
+        .&rm-all for $path.dir;
         rmdir($path)
     }