Since phan got migrated to use Quibble, @Umherirrender reported:
It is possible that now the dev dependency are part of the vendor folder?
includes/RemoteSchema.php:9 PhanRedefinedInheritedInterface \RemoteSchema inherits abstract Interface \JsonSerializable declared at internal:0 which is also declared at ../../vendor/jakub-onderka/php-parallel-lint/src/JsonSerializable.php:4. This may lead to confusing errors.
That was not before, it was breaking Echo - I1cffc88a3f4ea4290892c0624a6f32e852cde1dd
Related to the migration of phan to Quibble and to use of composer instead of vendor