perf(manual_is_power_of_two): perform the is_integer_literal check first (#16050)

y21 · web-flow · commit ee4390f07046 · 2025-11-08T12:11:30.000Z
.. as it's much cheaper than `count_ones_receiver`

changelog: none
diff --git a/clippy_lints/src/manual_is_power_of_two.rs b/clippy_lints/src/manual_is_power_of_two.rs
@@ -70,12 +70,12 @@ impl<'tcx> LateLintPass<'tcx> for ManualIsPowerOfTwo {
         if !expr.span.from_expansion()
             && let Some((lhs, rhs)) = unexpanded_binop_operands(expr, BinOpKind::Eq)
         {
-            if let Some(a) = count_ones_receiver(cx, lhs)
-                && is_integer_literal(rhs, 1)
+            if is_integer_literal(rhs, 1)
+                && let Some(a) = count_ones_receiver(cx, lhs)
             {
                 self.build_sugg(cx, expr, a);
-            } else if let Some(a) = count_ones_receiver(cx, rhs)
-                && is_integer_literal(lhs, 1)
+            } else if is_integer_literal(lhs, 1)
+                && let Some(a) = count_ones_receiver(cx, rhs)
             {
                 self.build_sugg(cx, expr, a);
             } else if is_integer_literal(rhs, 0)

Original file line number	Diff line number	Diff line change
`@@ -70,12 +70,12 @@ impl<'tcx> LateLintPass<'tcx> for ManualIsPowerOfTwo {`
`70`	`70`	`if !expr.span.from_expansion()`
`71`	`71`	`&& let Some((lhs, rhs)) = unexpanded_binop_operands(expr, BinOpKind::Eq)`
`72`	`72`	`{`
`73`		`- if let Some(a) = count_ones_receiver(cx, lhs)`
`74`		`- && is_integer_literal(rhs, 1)`
	`73`	`+ if is_integer_literal(rhs, 1)`
	`74`	`+ && let Some(a) = count_ones_receiver(cx, lhs)`
`75`	`75`	`{`
`76`	`76`	`self.build_sugg(cx, expr, a);`
`77`		`- } else if let Some(a) = count_ones_receiver(cx, rhs)`
`78`		`- && is_integer_literal(lhs, 1)`
	`77`	`+ } else if is_integer_literal(lhs, 1)`
	`78`	`+ && let Some(a) = count_ones_receiver(cx, rhs)`
`79`	`79`	`{`
`80`	`80`	`self.build_sugg(cx, expr, a);`
`81`	`81`	`} else if is_integer_literal(rhs, 0)`