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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.
18 lines
767 B
Plaintext
18 lines
767 B
Plaintext
error: lifetime may not live long enough
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--> $DIR/ex2d-push-inference-variable-2.rs:6:33
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LL | fn foo<'a, 'b, 'c>(x: &'a mut Vec<Ref<'b, i32>>, y: Ref<'c, i32>) {
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| -- -- lifetime `'c` defined here
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| lifetime `'b` defined here
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LL | let a: &mut Vec<Ref<i32>> = x;
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| ^ assignment requires that `'c` must outlive `'b`
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= help: consider adding the following bound: `'c: 'b`
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= note: requirement occurs because of a mutable reference to `Vec<Ref<'_, i32>>`
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= note: mutable references are invariant over their type parameter
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= help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
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error: aborting due to 1 previous error
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