ReflectionParameter::isCallable Returns whether parameter MUST be callable &warn.deprecated.function-8-0-0; See the example below for an alternative way to derive this information. &reftitle.description; public boolReflectionParameter::isCallable &warn.undocumented.func; &reftitle.parameters; &no.function.parameters; &reftitle.returnvalues; Returns &true; if the parameter is callable, &false; if it is not or &null; on failure. &reftitle.examples; As of PHP 8.0.0, the following code will report if a type supports callables, including as part of a union. getType(); if (!$reflectionType) return false; $types = $reflectionType instanceof ReflectionUnionType ? $reflectionType->getTypes() : [$reflectionType]; return in_array('callable', array_map(fn(ReflectionNamedType $t) => $t->getName(), $types)); } ?> ]]>