[clang-tidy] Make copy-and-swap idiom more general for `bugprone-unhandled-self-assignment` (#147066)
This change enhances the `bugprone-unhandled-self-assignment` checker by
adding an additional matcher that generalizes the copy-and-swap idiom
pattern detection.
# What Changed
Added a new matcher that checks for:
- An instance of the current class being created in operator=
(regardless of constructor arguments)
- That instance being passed to a `swap` function call
# Problem Solved
This fix reduces false positives in PMR-like scenarios where "extended"
constructors are used (typically taking an additional allocator
argument). The checker now properly recognizes copy-and-swap
implementations that use extended copy/move constructors instead of
flagging them as unhandled self-assignment cases.
Fixes #146324
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Co-authored-by: Baranov Victor <bar.victor.2002@gmail.com>