Is this a known bug in moc?

[piotr.dobrogost]

I'm just guessing, it's simply hard to believe the example from the docs doesn't work.

What I presented in my op is not the example from the docs but my code. I only copied and pasted signal declaration directly from the docs to show it's part of qt and not mine.

But moc has nothing to do with this...

In the most narrow sense moc is only a compiler but in a broader sense it's name of whole concept, system (name it as you like) which this compiler is only one part of. When using moc in the second sense QMetaObject::normalizedSignature() is vital part of moc.
On the other hand, if we agree moc is only a compiler than how should we call the whole system of meta information in qt?