Review PHP 7.1 feature: nullable types

[asgrim]

https://wiki.php.net/rfc/nullable_types

Nullable types are coming in PHP 7.1 - we need to check we deal with these correctly in BR.

[asgrim]

PHP-Parser does not support this syntax at any version, issue reported at nikic/PHP-Parser#286

[asgrim]

Also tracking other PHP 7.1 additions: nikic/PHP-Parser#260

[asgrim]

Need to fix FindTypeFromAst before release - NullableType is introduced in PHP Parser 3.0, which we currently ignore in #217. Therefore FindTypeFromAst must be updated before release.

        // @todo Nullable types are effectively ignored - to be fixed
        /* @see https://github.com/Roave/BetterReflection/issues/202 */
        if ($astType instanceof NullableType) {
            $astType = $astType->type;
        }

Not sure how PhpDocumentor's TypeResolver library handles ?nullable types (if at all) which could be a blocker for us.

[asgrim]

Needs to be added upstream in phpDocumentor/TypeResolver - I'll patch it but I've queried Mike about how he'd prefer to see it implemented (ref: https://twitter.com/asgrim/status/853588473646919680 )

[asgrim]

Created an issue, in retrospect, Twitter probably not the best place for conversation regarding this :) phpDocumentor/TypeResolver#31