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is_{some,ok}_and

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This commit is contained in:
Michael Goulet 2023-11-25 17:12:15 +00:00
parent fe3038f263
commit 079a2e865f
8 changed files with 21 additions and 13 deletions
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20
compiler/rustc_trait_selection/src/traits/coherence.rs
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@ -361,15 +361,23 @@ fn impl_intersection_has_impossible_obligation<'a, 'cx, 'tcx>(
let infcx = selcx.infcx;
obligations.iter().find(|obligation| {
if infcx.next_trait_solver() {
infcx.evaluate_obligation(obligation).map_or(false, |result| !result.may_apply())
let evaluation_result = if infcx.next_trait_solver() {
infcx.evaluate_obligation(obligation)
} else {
// We use `evaluate_root_obligation` to correctly track intercrate
// ambiguity clauses. We cannot use this in the new solver.
selcx.evaluate_root_obligation(obligation).map_or(
false, // Overflow has occurred, and treat the obligation as possibly holding.
|result| !result.may_apply(),
)
selcx.evaluate_root_obligation(obligation)
};
match evaluation_result {
Ok(result) => !result.may_apply(),
// If overflow occurs, we need to conservatively treat the goal as possibly holding,
// since there can be instantiations of this goal that don't overflow and result in
// success. This isn't much of a problem in the old solver, since we treat overflow
// fatally (this still can be encountered: <https://github.com/rust-lang/rust/issues/105231>),
// but in the new solver, this is very important for correctness, since overflow
// *must* be treated as ambiguity for completeness.
Err(_overflow) => false,
}
})
}