ac922245f0
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.
22 lines
642 B
Rust
22 lines
642 B
Rust
// This test checks that the error messages you get for this example
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// at least mention `'a` and `'static`. The precise messages can drift
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// over time, but this test used to exhibit some pretty bogus messages
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// that were not remotely helpful.
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//@ error-pattern:requires that `'a` must outlive `'static`
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struct Invariant<'a>(Option<&'a mut &'a mut ()>);
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fn mk_static() -> Invariant<'static> { Invariant(None) }
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fn unify<'a>(x: Option<Invariant<'a>>, f: fn(Invariant<'a>)) {
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let bad = if x.is_some() {
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x.unwrap()
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} else {
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mk_static() //~ ERROR lifetime may not live long enough
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};
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f(bad);
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}
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fn main() {}
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