Remove remove_cv_t from standard integer type checks

[smundhra-git]

Fixes #5916, the issue where cv-qualified integer types (e.g., const int, volatile unsigned int) were incorrectly accepted as standard integer types. When the standard says "signed or unsigned integer type" or "standard integer type", only cv-unqualified versions are included.

Changes

• Removed remove_cv_t wrapper from _Is_standard_integer in stl/inc/utility (line 952)
• Removed remove_cv_t wrapper from _Is_standard_unsigned_integer in stl/inc/__msvc_bit_utils.hpp (line 312)

Impact

This fix ensures that:

• std::cmp_less<const int, const int> is correctly rejected
• std::extents<const int, 42> is correctly rejected
• Bit manipulation functions in <bit> correctly reject cv-qualified types

static_assert(std::cmp_less<const int, const int>(0, 1)); // should be rejected
static_assert(sizeof(std::extents<const int, 42>)); // should be rejected

Checklist

• Identifiers follow _Ugly naming convention (no changes needed - using existing identifiers)
• No ABI breaks introduced
• Changes are based on CWG-251 and the C++ Working Draft
• All affected code paths updated (utility and bit_utils)

[smundhra-git]

@microsoft-github-policy-service agree [company="Centren Health"]

[smundhra-git]

@microsoft-github-policy-service agree

[vmichal]

Also, @smundhra-git , write something like "fixes #5916" to make GitHub recognize that the given issue should be automatically closed when this PR is accepted. It also displays the issue differently in the list of issues.

[StephanTLavavej]

As @vmichal noted, I've gone ahead and edited your PR description to use GitHub's close/fix/resolve syntax, and removed the issue number from the PR title (as it doesn't turn into a link there, and isn't directly informative).

[StephanTLavavej]

I'm mirroring this to the MSVC-internal repo - please notify me if any further changes are pushed.

[StephanTLavavej]

Thanks for improving our conformance here, and congratulations on your first microsoft/STL commit! 😻

This will ship in the MSVC Build Tools 14.51, in a future update to VS 2026 18.x.

By the way, it looks like you might be creating commits with an email address that isn't associated with your GitHub account. You can easily link them up so that the commits appear to come from you either way. I do this myself, as my personal machine is configured to create commits with my personal email address, versus my work machine with work email. Click on your avatar in the upper-right of GitHub > Settings > Emails, then add a secondary email address.