From 0e9c3d95336efb6dd85f6b97235f58a7cf040bfc Mon Sep 17 00:00:00 2001 From: martha Date: Fri, 5 Jan 2024 03:34:21 +0100 Subject: [PATCH] Fix #119551: Rewrite Iterator::position default impl, storing the accumulating value outside of the fold in an attempt to improve code generation Squashed with: Add inheriting overflow checks back --- library/core/src/iter/traits/iterator.rs | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) diff --git a/library/core/src/iter/traits/iterator.rs b/library/core/src/iter/traits/iterator.rs index 8e2c887a161e0..d94a508b5b28a 100644 --- a/library/core/src/iter/traits/iterator.rs +++ b/library/core/src/iter/traits/iterator.rs @@ -3094,16 +3094,23 @@ pub trait Iterator { P: FnMut(Self::Item) -> bool, { #[inline] - fn check( - mut predicate: impl FnMut(T) -> bool, - ) -> impl FnMut(usize, T) -> ControlFlow { + fn check<'a, T>( + mut predicate: impl FnMut(T) -> bool + 'a, + acc: &'a mut usize, + ) -> impl FnMut((), T) -> ControlFlow + 'a { #[rustc_inherit_overflow_checks] - move |i, x| { - if predicate(x) { ControlFlow::Break(i) } else { ControlFlow::Continue(i + 1) } + move |_, x| { + if predicate(x) { + ControlFlow::Break(*acc) + } else { + *acc += 1; + ControlFlow::Continue(()) + } } } - self.try_fold(0, check(predicate)).break_value() + let mut acc = 0; + self.try_fold((), check(predicate, &mut acc)).break_value() } /// Searches for an element in an iterator from the right, returning its