Qt creator, CMake and c++17 code model.

mrFieldy

Hi, everybody. I write code in qt-creator 4.8.0 + cmake (on linux). When using the std::get and std::variant functions, if std::visit is called in the same translation unit, the IDE generates many errors.

class Foo {
   public:
    int a{1};
    int b{2};
    void set_a(const int new_a) { a = new_a; }
};
class Bat {
    int Arr[200]{};
};
int main() {
    int a;
    cin >> a;
    std::variant<Foo, Bat> var_1;
    if (a == 0)
        var_1 = Foo();
    else
        var_1 = Bat();
    std::variant<Foo, Bat> var_2;
    std::visit(
        [](auto& arg) {
        },
        var_2);
    std::get<Foo>(var_1).a = 444;
    std::get<Foo>(var_1).set_a(124);        // IDE throws an error (this argument to member function 'set_a' fas type 'const Foo', but function is not marked const)
    cout << std::get<Foo>(var_1).a << endl;
    return 0;
}

CMake script:

    cmake_minimum_required(VERSION 3.10)
    project(fast_test_2)
    set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
    set(CMAKE_CXX_STANDARD 17)
    add_executable(${PROJECT_NAME} "main.cpp")

Despite this, the code is compiled (GCC 7.3). I have a section of code where std::get is actively used, and after adding a call to std::visit, qt-creator has colored the 2к code lines in red. How can I fix this?

SGaist

Hi and welcome to devnet,

You may have unearthed a shortcoming from Qt Creator's current code model. You should check the bug report system to see if it's something known.

mrFieldy

@SGaist I didn't find my issue there. Should I write a bug report?

SGaist

One thing you can do is test the Qt Creator 4.9 Beta. If you still have the issue with it, then yes, please open a report.

aha_1980

That's QTCREATORBUG-21873 now.