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The SCCs of the region graph are not a reliable heuristic to use for blaming an interesting constraint for diagnostics. For region errors, if the outlived region is `'static`, or the involved types are invariant in their lifetiems, there will be cycles in the constraint graph containing both the target region and the most interesting constraints to blame. To get better diagnostics in these cases, this commit removes that heuristic.
27 lines
1.3 KiB
Plaintext
27 lines
1.3 KiB
Plaintext
error[E0499]: cannot borrow `list[_].value` as mutable more than once at a time
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--> $DIR/issue-62007-assign-const-index.rs:23:21
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LL | fn to_refs<T>(mut list: [&mut List<T>; 2]) -> Vec<&mut T> {
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| - let's call the lifetime of this reference `'1`
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...
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LL | result.push(&mut list[0].value);
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| ^^^^^^^^^^^^^^^^^^ `list[_].value` was mutably borrowed here in the previous iteration of the loop
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...
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LL | return result;
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| ------ returning this value requires that `list[_].value` is borrowed for `'1`
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error[E0499]: cannot borrow `list[_].next` as mutable more than once at a time
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--> $DIR/issue-62007-assign-const-index.rs:24:26
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LL | fn to_refs<T>(mut list: [&mut List<T>; 2]) -> Vec<&mut T> {
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| - let's call the lifetime of this reference `'1`
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...
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LL | if let Some(n) = list[0].next.as_mut() {
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| ^^^^^^^^^^^^ `list[_].next` was mutably borrowed here in the previous iteration of the loop
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LL | list[0] = n;
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| ----------- assignment requires that `list[_].next` is borrowed for `'1`
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error: aborting due to 2 previous errors
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For more information about this error, try `rustc --explain E0499`.
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