Enable validateVariables(), fix fuzzing crash

[chrchr-github]

No description provided.

[firewave]

We need to adjust the fuzzer tests so they show the actual failure data (actually that applies to all Python tests - I want to clean that up in the future).

I think if the exitcode is negative we should show stderr instead of stdout (crashes, assert, abort, sanitizers, etc. generate negative exitcodes and our internal errors generate positive ones).

[chrchr-github]

So validateVariables() did not prevent the crash because we parse m t(=a[]); as a function declaration, and argument variables may not have a scope. What we need to verify is "Variables have a scope, or appear only in a function declaration".

[danmar]

isn't this executed before the symboldatabase? I wonder if the changes in symboldatabase+testgarbage is technically separated?

[chrchr-github]

Yes, those are separate changes. validateVariables() was (a) deactivated and (b) not doing sufficient checking to prevent the crash, so I added the syntaxError.

[chrchr-github]

What we need to verify is "Variables have a scope, or appear only in a function declaration".

This is not so easy because of declarations like auto f(T& x) -> decltype(x);.