Description:
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Trying to echo a COM object results in crash.

When zend_call_function() is called to lookup "__tostring" in a COM object, it calls into com_method_get().  In turn this calls ITypeComp_Bind to lookup the method.  If the method is not found the result is DESCKIND_NONE, but the switch(kind) statement isn't testing for this.  As a result com_method_get() returns a zend_internal_function with an invalid handler.  The handler is called and PHP crashes.

I came up with this possible code as the response to a DESCKIND_NONE:

case DESCKIND_NONE:
	ITypeComp_Release(comp);
	efree(olename);
	return NULL;

but I'm not too confident about it.  It does stop the crash in my test case, but there may be a better solution.

Reproduce code:
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$c = new COM("ADODB.Connection");
echo $c;


Expected result:
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Either error on trying to echo object with no __toString() method, or nothing.

Actual result:
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The instruction at "0x00e5c208" referenced memory at "0x0000000".  The memory could not be "written".