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Diffstat (limited to '')
-rw-r--r-- | src/tools/clippy/clippy_lints/src/operators/verbose_bit_mask.rs | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/src/tools/clippy/clippy_lints/src/operators/verbose_bit_mask.rs b/src/tools/clippy/clippy_lints/src/operators/verbose_bit_mask.rs new file mode 100644 index 000000000..ff85fd554 --- /dev/null +++ b/src/tools/clippy/clippy_lints/src/operators/verbose_bit_mask.rs @@ -0,0 +1,44 @@ +use clippy_utils::diagnostics::span_lint_and_then; +use clippy_utils::sugg::Sugg; +use rustc_ast::ast::LitKind; +use rustc_errors::Applicability; +use rustc_hir::{BinOpKind, Expr, ExprKind}; +use rustc_lint::LateContext; + +use super::VERBOSE_BIT_MASK; + +pub(super) fn check<'tcx>( + cx: &LateContext<'tcx>, + e: &'tcx Expr<'_>, + op: BinOpKind, + left: &'tcx Expr<'_>, + right: &'tcx Expr<'_>, + threshold: u64, +) { + if BinOpKind::Eq == op + && let ExprKind::Binary(op1, left1, right1) = &left.kind + && BinOpKind::BitAnd == op1.node + && let ExprKind::Lit(lit) = &right1.kind + && let LitKind::Int(n, _) = lit.node + && let ExprKind::Lit(lit1) = &right.kind + && let LitKind::Int(0, _) = lit1.node + && n.leading_zeros() == n.count_zeros() + && n > u128::from(threshold) + { + span_lint_and_then( + cx, + VERBOSE_BIT_MASK, + e.span, + "bit mask could be simplified with a call to `trailing_zeros`", + |diag| { + let sugg = Sugg::hir(cx, left1, "...").maybe_par(); + diag.span_suggestion( + e.span, + "try", + format!("{}.trailing_zeros() >= {}", sugg, n.count_ones()), + Applicability::MaybeIncorrect, + ); + }, + ); + } +} |