Attempt to access run-time storage error

[pparuzel]

Bug type: Language Service

Describe the bug

• OS and Version: MacOS Monterey 12.1 (M1 processor)
• VS Code Version:
  • Version: 1.63.2
  • Commit: 899d46d82c4c95423fb7e10e68eba52050e30ba3
  • Date: 2021-12-15T09:38:17.605Z (1 mo ago)
  • Electron: 13.5.2
  • Chromium: 91.0.4472.164
  • Node.js: 14.16.0
  • V8: 9.1.269.39-electron.0
  • OS: Darwin arm64 21.2.0
• C/C++ Extension Version: v1.8.0-insiders2
• Other extensions you installed (and if the issue persists after disabling them):
  • CMake v0.0.17

Even though the program compiles fine on Apple Clang, Clang13, and GCC11 - IntelliSense reports an error in Problems Tab.

or if you change values[j] to values[i]:

Minimal example

Here's the most minimal example I could create to reproduce:

#include <array>

template <std::size_t N>
constexpr auto transform(const std::array<float, N>& arr)
{
    std::array<int, N> values;
    for (std::size_t i{0}; const auto& k : arr)
    {
        constexpr auto j = 0;
        values[j] = k;  // change this j to i and you get a different error as well
        ++i;
    }
    return values;
}

int main()
{
    constexpr auto values = transform(std::array{0.f});
}

Expected behavior

There should be no errors in Problems Tab as this C++20 code is perfectly valid.

[sean-mcmanus]

Thanks for reporting this. I've filed a bug on our shared VS parser at https://developercommunity.visualstudio.com/t/C-IntelliSense-gives-incorrect-error-/1637986 .

(Note to team: I didn't file an internal bug, because this issue seems more widely applicable to many VS users).