Possible Visual Studio 2015 C++ Compiler and IntelliSense Bugs

Question

I encountered a compiler crash and intellisense false positives with Visual Studio 2015 using C++.

This crashes the compiler when written within a function block:

if();

This is the dialog that is shown when compiling (I am on a German version of Windows):

enter image description here

Even though the compiler crashes, I get error list output:

Error C2059 syntax error: ')'
Warning C4390 ';': empty controlled statement found; is this the intent?
Error C1903 unable to recover from previous error(s); stopping compilation

This produces squiggles and error annotations in the vertical scrollbar in map mode, but no actual intellisense errors:

#include <vector>

struct S { std::vector<S> Children; };

int main(int argc, char* argv[]) {
    S item;

    item.Children.push_back(S());
    //           ^
    // Error: no instance of overloaded function 
    // "std::vector<_Ty, _Alloc>::push_back [with _Ty=S, _Alloc=std::allocator<S>]" 
    // matches the argument list
    // argument types are: (S)
    // object type is: std::vector<S, std::allocator<S>>

    S& back = item.Children.back();
    //        ^^^^
    // Error: a reference of type "S &" (not const-qualified) cannot be
    // initialized with a value of type "S"

    return 0;
}

Are those bugs? Are they known? Can you reproduce them?

SO is not the place to file bug reports. I'm sure VS has its own bug tracker. — sashoalm, Jul 21 '15 at 07:15
That first one's not what I'd call a crash, either. More like a controlled exit after refusing to be stupid. Sure, compiler could optimize it out and carry on, but maaaan... — user4581301, Jul 21 '15 at 07:21
@sashoalm All related "possible compiler bugs" questions have a positive rating. How do you explain that? — Beta Carotin, Jul 21 '15 at 07:21
@BetaCarotin See http://meta.stackoverflow.com/questions/284708/what-can-we-do-with-questions-where-the-only-response-is-contact-the-vendor for reference. You're welcome to add your opinion to the discussion there about whether such questions should, or should not be asked here. — sashoalm, Jul 21 '15 at 07:28
@BetaCarotin A question should cover one single topic. Yours has two unrelated ones. Also the first is not even very clear: you state *This crashes the compiler* yet all you show is a normal compiler diagnostic. That is not a crash? — stijn, Jul 21 '15 at 07:31
@stijn They are both VS2015 problems. I don't consider those issues unrelated enough to open separate questions. Also, what do you want me to show? I assume you know what a program crash looks like. — Beta Carotin, Jul 21 '15 at 07:37
@user4581301 I don't expect the compiler to optimize out a syntax error. It crashes, it does not terminate gracefully. — Beta Carotin, Jul 21 '15 at 07:40
So you get something like a "cl.exe stopped working" dialog? — stijn, Jul 21 '15 at 07:53
@stijn Yes. _Microsoft (R) C/C++ Optimizing Compiler has stopped working_ in my case. — Beta Carotin, Jul 21 '15 at 07:56

score 1 · Accepted Answer · answered Jul 21 '15 at 08:10

For the first case: the compiler shouldn't crash but just issue the diagnostic you show. So yes, that's a bug. Which doesn't occur in VS2013 btw. Submit a report for it here

For the second case: it is the same in VS2013 and is due to nesting a vector of S inside S. This and other cases make the error squiggles appear incorrectly, it is actually not that uncommon. But ideally it should not happen so you can submit a bug report for it as well, though it might be something which is going to be labelled 'wontfix' as the compiler team usually focusses on more urgent cases.

Possible Visual Studio 2015 C++ Compiler and IntelliSense Bugs

1 Answers1