Toolset update: MSVC Compiler 19.52.36405.1, Clang 22.1.3

[StephanTLavavej]

• Cycle locations.
• PowerShell 7.6.1.
• Python 3.14.5 (now required).
• CMake 4.3.1 (now required).
• MSVC Compiler 19.52.36405.1 (now required).
  • This is MSVC main as of 2026-05-06.
• Clang 22.1.3 (now required).
• Clang incorrectly rejects default construction of union with nontrivial member, part 2 llvm/llvm-project#81774 was fixed in Clang 22.
• [Clang] Unexpected results from __reference_{constructs,converts}_from_temporary llvm/llvm-project#114344 was fixed in Clang 21.
• [clang] __iso_volatile_load64/store64 not atomic on i386-windows llvm/llvm-project#126516 was fixed in Clang 22.
• [clang] Inconsistent __is_pointer_interconvertible_base_of results for direct vs. templated calls llvm/llvm-project#135273 was fixed in Clang 22.
• Coroutines on arm64ec-pc-windows-msvc emit error LNK2001: unresolved external symbol #__NoopCoro_ResumeDestroy (EC Symbol) llvm/llvm-project#158341 was fixed in Clang 22.
• [Clang] __builtin_is_implicit_lifetime isn't checking for trivial constructors llvm/llvm-project#160610 was fixed in Clang 22.
• Fix tagged_bool_like for Clang 22.
  • Thanks @frederick-vs-ja!
• Silence more -Wdeprecated-volatile.
• Unconditionally silence -Wcharacter-conversion, added in Clang 21.
• Add 'character-conversion-warnings' as a Clang feature.
  • For example, libcxx/test/std/algorithms/alg.nonmodifying/alg.equal/equal.pass.cpp has // ADDITIONAL_COMPILE_FLAGS(character-conversion-warnings): -Wno-character-conversion.
• "(anonymous class)" => "(lambda)" for Clang 22.
• Work around [Clang] reference_constructs_from_temporary mishandles cv-qualified arrays llvm/llvm-project#198580.
• Work around [Clang] Compiler regression affecting concept-constrained flat_map::at() llvm/llvm-project#198663.
• Work around [Clang] Clang incorrectly calculates constraints involving private members and multiple nested classes of the same name llvm/llvm-project#198716.
• Filed P2278R4_views_as_const: Clang 22 emits error: satisfaction of constraint '__is_constructible(_Ty, _ArgTys...)' depends on itself #6295 for followup.
  • Clang complains about concept depending on itself llvm/llvm-project#62096 was reportedly fixed in Clang 21, but I can't remove this workaround yet.
• clang-format, no manual changes.
  • All positive except for P0896R4_ranges_iterator_machinery adding a space in ranges::iter_move (&f)(42).
• Formatting: Remove manual wrapping that had literally no effect.
• Formatting: Remove manual wrapping that affected only indentation.
• Formatting: Remove manual wrapping, with reasonable reflow effects.
• Cleanup: Extract _Diff_max to avoid manual wrapping.
• Cleanup: Remove comment about warning C4127.
  • See Toolset update: MSVC Compiler 19.50 Preview 1, Clang 20 #5717, warning C4127 was removed by MSVC-PR-646313 on 2025-06-25. The name _Would_overflow still provides value, keep it.
• Cleanup: Extract _Effective_max for clarity.
• Cleanup: Extract _Invoker1<_Callable, _Ty1>::_Strategy for clarity.
• Cleanup: Extract _Valty to avoid manual wrapping.
• Cleanup: Remove unnecessary static_assert messages to avoid manual wrapping.
  • And split static_assert(X && Y).
• Cleanup: Avoid comments interfering with header sorting.
• Cleanup: Fix order-dependent/non-self-contained charconv test headers.
• Cleanup: Use lowercase 0x prefix.
• .clang-format: Update URL and defaults. No behavior changes.
• .clang-format: AlignAfterOpenBracket is now a bool.
  • We're still customizing it, no behavior change.
• .clang-format: Sort <benchmark/benchmark.h> as the first group.
• New pools.
• Mark robust_re_difference_type.compile.pass.cpp as SKIPPED.
  • This was unexpectedly passing for x86, but still failing for other architectures.

STL-ASan-CI passed; it had been failing for ARM64 since the previous toolset update #6260 and is now fixed by @zacklj89's MSVC-PR-731943 "[ARM64][ASan] Fix interception in jump tables" merged 2026-04-27.

[StephanTLavavej]

I'm mirroring this to the MSVC-internal repo. Please notify me if any further changes are pushed, otherwise no action is required.