Overview

I notice a lot of things while reviewing code, not all of which I immediately address. I spent my Thanksgiving weekend draining some of my todo backlog (I still have ~160 lines).

As a general rule, we don't like "grab bag PRs" touching lots of code, because they increase risk and are more difficult to review. (We especially dislike mixing features/fixes with unrelated cleanups.) To mitigate this, I've separated out all of the changes with behavioral impact (#5921), higher risk and MSVC-internal impact (#5922), and complicated multi-step transformations (#5923). The commits here are low risk and cleanly organized for ease of reviewing. I believe that decomposing this further wouldn't be productive.

Commits

• xtime.cpp doesn't need awint.hpp, just Windows.h.
• validate.cpp doesn't use assert() anymore.
  • Followup to Add static_assert to is_sorted() for the lookup tables in validate.cpp #650 merged 2020-04-01.
• // namespace$ => // unnamed namespace
  • We had 11 occurrences of the former, now being added to 39 occurrences of the latter.
• Fuse _HAS_CXX20 regions.
• Guard _Supports_transparency for _HAS_CXX23.
  • Followup to Introduce _Is_transparent helper trait #3736 merged 2023-06-15.
• Exclude charconv tables and test cases from VSCode search.
  • They pollute search results when looking for numbers, and generally don't need to be searched. (There's a UI button to "Use Exclude Settings and Ignore Files", so this exclusion can be easily bypassed.)
• Drop unnecessary inline for function templates.
• _STATIC_LAMBDA => _STATIC_CALL_OPERATOR
  • Followup to Toolset update: VS 2022 17.14.5 Preview 1, WinSDK 26100 #5580 merged 2025-06-13.
• Add _STATIC_CALL_OPERATOR to more stateless lambdas.
• decltype(tzdb::leap_seconds) => vector<leap_second>
  • This was a relic of an early attempt to give tzdb::leap_seconds a fancy type.
• Drop unnecessary newlines in do-while loops.
• _CMPXCHG_MASK_OUT_PADDING_BITS implies _HAS_CXX20, so _INLINE_VAR => inline
• tests/utils/stl/util.py: Remove dead code, part 1.
• tests/utils/stl/util.py: Remove dead code, part 2.
  • We're never AIX.
  • psutil 2.0.0 was released on 2014-03-10. The current version is 7.1.3.
• Unwrap "strengthened" comments.
• _Vb_val::_Getal() is a direct member function; all other calls omit this->.
• Use is_null_pointer.
  • These locations are happy to ignore cv-quals.
• Add newlines to indicate that we don't like to interleave includes and conditionals.
• Avoid interleaving includes and conditionals.
• Include test support headers with angle brackets.
• int main() => void test() in test.compile.pass.cpp.
  • We don't like to have main() functions in compile-only tests, to make it extra-clear that they aren't running any code.
• Drop // COMPILE-ONLY in test.compile.pass.cpp.
  • These comments are redundant.
• Make VSO_0000000_type_traits compile-only.
  • test_all_function_types() is a non-template, so we don't need to call it.
  • Rename main() to test_VSO_707437() and move it up. It's testing overload resolution.
• Delete tests/tr1/env_single.lst.
  • Followup to Delete <cvt/meow> #4458 merged 2024-03-15.
• _USE_NAMED_IDL_NAMESPACE is unused.
  • IIRC this was intended for WCFB02 (the stranded vNext branch in Team Foundation Version Control).
• Consistently say "Unknown architecture".
  • And don't give string literals to #error.
• vector_algorithms.cpp: Use #ifdef _WIN64 when deciding between x64 and x86.
• Qualify a _STD _In_range call.
• <execution>: _In_range => _In_rng to avoid shadowing.
• Consistently reduce code duplication when checking intrinsic availability.
• stride_view ctor: Mark range_difference_t<_Vw> _Stride_ as const, to be consistent with others.
• <random>: Add parens when mixing left shifts with bitwise OR.
• _Zip_fn and _Zip_transform_fn should be class, not struct.
• Make ranges function objects structs when possible.
• steady_clock::now() should use _STL_INTERNAL_STATIC_ASSERT.
  • We fully control the inputs here, so users don't need these static_asserts.
• _STL_INTERNAL_STATIC_ASSERT(false) => static_assert(false) for C++17 and later.
  • These don't impose any costs, as they occur on "can't happen" branches and we've eliminated the _Always_false machinery. We should just leave them in for user code.
• _STL_INTERNAL_STATIC_ASSERT(false) => static_assert(false, "reason") in C++14 code.
• CMakeLists.txt: Avoid inconsistently quote-expanding VCLIBS_TARGET_ARCHITECTURE.
• iosptrs.cpp: Test _M_CEE_PURE instead of _M_CEE_MIXED.
  • We don't need to worry about /clr:safe. We don't need to provide a rationale.
• Move stdext macros to <exception> and limit their scope.
  • Followup to Remove non-Standard <hash_map> and <hash_set> #5764 merged 2025-10-10, <iterator>: Remove stdext::checked_array_iterator and stdext::unchecked_array_iterator #5817 merged 2025-11-05.
• xalloc.cpp: Include just <yvals.h>, we don't need <stdexcept>.
• yvals_core.h: Remove distinction between "directly controls" and "indirectly controls".
  • This was confusing for contributors to maintain, and didn't provide value.
• yvals_core.h: Omit "Other deprecation warnings".
  • Listing this isn't useful; the messages clearly explain what Standard deprecates stuff, and how to silence them.
• Avoid using is_constant_evaluated() to initialize const variables.
  • This is confusing and hazardous (witness the elements[0] hackaround - that's always 0). The squirrelliness happens because under certain circumstances, the compiler can perform constant initialization, making is_constant_evaluated() report that it was called at compile-time. For this reason, we should directly test it with if.
• Oops: xkeycheck.h doesn't have an "unnamed namespace".