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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-17 12:19:03 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-17 12:19:03 +0000
commit64d98f8ee037282c35007b64c2649055c56af1db (patch)
tree5492bcf97fce41ee1c0b1cc2add283f3e66cdab0 /tests/ui/nll/issue-62007-assign-const-index.rs
parentAdding debian version 1.67.1+dfsg1-1. (diff)
downloadrustc-64d98f8ee037282c35007b64c2649055c56af1db.tar.xz
rustc-64d98f8ee037282c35007b64c2649055c56af1db.zip
Merging upstream version 1.68.2+dfsg1.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'tests/ui/nll/issue-62007-assign-const-index.rs')
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diff --git a/tests/ui/nll/issue-62007-assign-const-index.rs b/tests/ui/nll/issue-62007-assign-const-index.rs
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+// 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<T> {
+ value: T,
+ next: Option<Box<List<T>>>,
+}
+
+fn to_refs<T>(mut list: [&mut List<T>; 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() {}