Deprecated partially supported callables: should is_callable() throw a deprecation notice ?

L.s., I've just been looking in detail at the Partially Supported Callables deprecation RFC: https://wiki.php.net/rfc/deprecate_partially_supported_callables The RFC explicitly excludes the is_callable() function and the callable type from throwing deprecation notices.

The |is_callable()| function and |callable| type remain side-effect free and do not throw a deprecation warning. They will continue to accept these callables until support is removed entirely.

While I can fully support this for the callable type, I wonder if the decision to not throw a deprecation on use in is_callable() is the right one (though I understand the desire to keep it side-effect free). Consider these code samples: function foo(callable $callback) {} foo('static::method'); This function call not throwing a deprecation is not problematic as in PHP 9.0 the function will start throwing a TypeError. if (is_callable('static::method')) {

      static::method();

} The second code sample, however, is problematic, as in PHP 9.0, the behaviour of this code will be silently reversed for those callbacks which would previously result in is_callable() returning true, which makes this a potentially dangerous change without deprecation notice. Would anyone care to enlighten me as to whether this was given due consideration ? Smile, Juliette