Crash when parsing casted comparison

[danog]

Code:

<?php

$a = 0;
$b = 1;

var_dump((string) $a === (string) $b);

Result:

[daniil@daniil-arch jav]$ jppm start
-> linux
-> app:run 
-> install 
java.lang.VerifyError: Bad type on operand stack
Exception Details:
  Location:
    $php_module_m92fb06560cc04edabf397866fa04be32.__include(Lphp/runtime/env/Environment;[Lphp/runtime/Memory;Lphp/runtime/memory/ArrayMemory;)Lphp/runtime/Memory; @97: invokevirtual
  Reason:
    Type 'php/runtime/Memory' (current frame, stack[2]) is not assignable to 'java/lang/String'
  Current Frame:
    bci: @97
    flags: { }
    locals: { 'php/runtime/env/Environment', '[Lphp/runtime/Memory;', 'php/runtime/memory/ArrayMemory', 'php/runtime/memory/ArrayMemory', 'php/runtime/Memory', 'php/runtime/Memory' }
    stack: { 'php/runtime/env/Environment', 'java/lang/String', 'php/runtime/Memory' }
  Bytecode:
    0x0000000: 2cb8 002b 4e2d 122d b600 333a 042d 1235
    0x0000010: b600 333a 052a b200 3703 322d b600 3d2a
    0x0000020: b200 3704 322d b600 3d19 04b2 003f 0332
    0x0000030: b600 4357 2ab2 0037 0532 2db6 003d 1905
    0x0000040: b200 3f04 32b6 0043 572a b200 3706 322d
    0x0000050: b600 3d2a 1904 b600 4719 05b6 0047 b800
    0x0000060: 4cb6 0050 b800 5501 b800 5b57 b200 5fb0
    0x0000070:                                        

        at java.lang.Class.getDeclaredMethods0(Native Method)
        at java.lang.Class.privateGetDeclaredMethods(Class.java:2701)
        at java.lang.Class.getDeclaredMethod(Class.java:2128)
        at php.runtime.loader.RuntimeClassLoader.loadModule(RuntimeClassLoader.java:139)
        at php.runtime.env.CompileScope.loadModule(CompileScope.java:599)
        at php.runtime.env.CompileScope.loadModule(CompileScope.java:603)
        at php.runtime.env.Environment.importModule(Environment.java:1253)
        at php.runtime.env.ConcurrentEnvironment.importModule(ConcurrentEnvironment.java:175)
        at php.runtime.env.ModuleManager.fetchTemporaryModule(ModuleManager.java:71)
        at php.runtime.env.ModuleManager.fetchModule(ModuleManager.java:41)
        at php.runtime.env.ModuleManager.fetchModule(ModuleManager.java:27)
        at php.runtime.launcher.Launcher.loadFrom(Launcher.java:121)
        at php.runtime.launcher.Launcher.run(Launcher.java:308)
        at php.runtime.launcher.Launcher.run(Launcher.java:247)
        at php.runtime.launcher.Launcher.run(Launcher.java:243)
        at php.runtime.launcher.Launcher.main(Launcher.java:425)