From 64d98f8ee037282c35007b64c2649055c56af1db Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 17 Apr 2024 14:19:03 +0200 Subject: Merging upstream version 1.68.2+dfsg1. Signed-off-by: Daniel Baumann --- tests/ui/nll/issue-62007-assign-const-index.rs | 32 ++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) create mode 100644 tests/ui/nll/issue-62007-assign-const-index.rs (limited to 'tests/ui/nll/issue-62007-assign-const-index.rs') diff --git a/tests/ui/nll/issue-62007-assign-const-index.rs b/tests/ui/nll/issue-62007-assign-const-index.rs new file mode 100644 index 000000000..3ea5d3a7a --- /dev/null +++ b/tests/ui/nll/issue-62007-assign-const-index.rs @@ -0,0 +1,32 @@ +// Issue #62007: assigning over a const-index projection of an array +// (in this case, `list[I] = n;`) should in theory be able to kill all borrows +// of `list[0]`, so that `list[0]` could be borrowed on the next +// iteration through the loop. +// +// Currently the compiler does not allow this. We may want to consider +// loosening that restriction in the future. (However, doing so would +// at *least* require T-lang team approval, and probably an RFC; e.g. +// such loosening might make complicate the user's mental mode; it +// also would make code more brittle in the face of refactorings that +// replace constants with variables. + +#![allow(dead_code)] + +struct List { + value: T, + next: Option>>, +} + +fn to_refs(mut list: [&mut List; 2]) -> Vec<&mut T> { + let mut result = vec![]; + loop { + result.push(&mut list[0].value); //~ ERROR cannot borrow `list[_].value` as mutable + if let Some(n) = list[0].next.as_mut() { //~ ERROR cannot borrow `list[_].next` as mutable + list[0] = n; + } else { + return result; + } + } +} + +fn main() {} -- cgit v1.2.3