Namespace resolution broken inside anonymous classes

[thekid]

HHVM Version

$ hhvm --version
HipHop VM 3.28.1 (rel)
Compiler: 1535652629_477638284
Repo schema: ff51ed686b7d3c44bf3f95bda084cb2afadcecb9

$ hh_client --version
hh--3.28.1 Thu Aug 30 20:13:18 2018

Operating System and Version

Debian Stretch

Standalone code, or other way to reproduce the problem

test.php:

<?php
use lang\{Value, IllegalStateException};

spl_autoload_register(function($class) {
  echo "Loading $class\n";
  include(strtr($class, '\\', DIRECTORY_SEPARATOR).'.php');
});

$v= new class() implements Value {
  public function toString() { throw new IllegalStateException('Cannot render string'); }
};

var_dump($v->toString());

lang/Value.php:

<?php namespace lang;

interface Value {
}

lang/IllegalStateException.php:

<?php namespace lang;

class IllegalStateException extends \Exception {
}

Actual result

$ hhvm test.php
Loading lang\Value
Loading IllegalStateException

Warning: include(IllegalStateException.php): File not found in /home/friebe/test.php on line 6

Fatal error: Uncaught Error: Class undefined: IllegalStateException in /home/friebe/test.php:10

The problem can be clearly seen in the second Loading output - it should include the namespace, but doesn't. This code works fine with older HHVM versions, e.g. 3.21.

Expected result

$ php7.0 test.php
Loading lang\Value
Loading lang\IllegalStateException
PHP Fatal error:  Uncaught lang\IllegalStateException: Cannot render string in /home/friebe/test.php:10

[thekid]

Might also be related to #7878

[thekid]

Oops, sorry, seems to be a duplicate of #8275; although a slightly different case: This is related to code inside the functions, while the other bug is about type hints.

Might be the same cause, close this at will.