Various fixes for manual_is_power_of_two #14463
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rustbot added the S-waiting-on-review 
samueltardieu force-pushed the push-yqozmwtrqtqs branch 2 times, most recently from d0d7a23 to abde06c Compare | r? clippy |
This is a refactoring of the existing code to remove repetitive code.
Since the fixed expression is used as a receiver for `.is_power_of_two()`, it may require parentheses.
samueltardieu force-pushed the push-yqozmwtrqtqs branch from abde06c to 9659649 Compare 
blyxyas requested changes Apr 14, 2025
| ); | ||
| /// Return the unsigned integer receiver of `.count_ones()` | ||
| fn count_ones_receiver<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'tcx>) -> Option<&'tcx Expr<'tcx>> { | ||
| if let ExprKind::MethodCall(method_name, receiver, [], _) = expr.kind |
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This could also check for <int>::count_ones(x), it's a normal ExprKind::Call.
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Good catch. Done, and tested, in a new commit on top of the others.
| if let ExprKind::Binary(op, lhs, rhs) = smaller.kind | ||
| && !lhs.span.from_expansion() | ||
| && !rhs.span.from_expansion() | ||
| && op.node == BinOpKind::Sub |
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Could we move this op.node == BinOpKind::Sub to above the expansion checking?
Also, thinking about checking for expansion so many times, we could probably minimize some of these (as we check for expansions 3 times before linting)
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Right! All checks are necessary, but I've factored them in through a helper function. This makes code easier to read. The modified commit is Do not lint result from macro expansion.
If parts of the expression comes from macro expansion, it may match an expression equivalent to `is_power_of_two()` by chance only.
samueltardieu force-pushed the push-yqozmwtrqtqs branch from 9659649 to c43c87d Compare blyxyas approved these changes Apr 14, 2025
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Fix #14461:
constcontextCommits have been logically separated to facilitate review, and start with a refactoring (and simplification) of the existing code.
changelog: [
manual_is_power_of_two]: insert parentheses as required in suggestion, check MSRV before suggesting fix inconstcontext, do not lint macro expansion results