Removes @param mixed $x and @return mixed docblocks when a native type declaration is already present. A native type always overrules mixed (the widest type), so such tags add no information.

 final class SomeClass
 {
-    /**
-     * @param mixed $value
-     * @return mixed
-     */
     public function run(int $value): string
     {
     }
 }

Distinct from RemoveUselessParamTagRector, which only fires when the doc type equals the native type (e.g. @param string + string). This handles the mixed vs more-specific-native case (@param mixed + int).

Safety guards

• param must have a native type declaration; otherwise kept
• return must have a returnType; otherwise kept
• tags with a description are kept (description is the only useful info on a mixed tag)
• only pure mixed is matched (not mixed[], etc.)

Registered in DeadCodeLevel in the docblock group, right after RemoveDuplicatedReturnSelfDocblockRector.