Merge `main` to `feature/flat_map`, update tests - #6033

Merged

Stephan T. Lavavej (StephanTLavavej) merged 11 commits into

microsoft:feature/flat_mapfrom

StephanTLavavej:no-mister-bond-i-expect-you-to-merge

Jan 21, 2026

Commits on Jan 20, 2026

`<functional>`: unwrap `move_only_function` with abominable and noexcept types (#5917)

Alex Guteniev (AlexGuteniev)
and
Stephan T. Lavavej (StephanTLavavej)
authored
f74acb0
Test that various Standard headers provide iterator range access functions (#5968)

Vojtěch Michal (vmichal)
and
Stephan T. Lavavej (StephanTLavavej)
authored
6f769cb
`<vector>`: Avoid off-by-default warning C4365 in `vector<bool>` copy algorithms with `/J` (#6013)
Stephan T. Lavavej (StephanTLavavej)
authored
f649288
`STL.natvis`: Add visualizers for `ranges::less` and other comparison objects. (#6016)
Vojtěch Michal (vmichal)
authored
e543428
`STL.natvis`: Improve iterator visualizations (#6019)
Vojtěch Michal (vmichal)
authored
855b004
Add Neon implementation of `is_sorted_until` (#6018)
Hari Limaye (hazzlim)
authored
d8e8e6f
`<cmath>`: Tolerate 80-bit `long double` (#6021)
statementreply
authored
2d6f26b
`<regex>`: Optimize matching of branchless loops (#6022)

Julian Müller (muellerj3)
and
Stephan T. Lavavej (StephanTLavavej)
authored
23b2324
`<regex>`: Skip initial NFA nodes that do nothing during matching (#6026)
Julian Müller (muellerj3)
authored
3f76681

Commits on Jan 21, 2026