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Rollup merge of #121497 - lcnr:coherence-suggest-increasing-recursion-limit, r=compiler-errors

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`-Znext-solver=coherence`: suggest increasing recursion limit

r? `@compiler-errors`
This commit is contained in:
Matthias Krüger 2024-03-01 22:38:47 +01:00 • committed by GitHub
commit 4d71fe7cc1
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29 changed files with 341 additions and 255 deletions
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30
compiler/rustc_middle/src/traits/solve.rs
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@ -60,7 +60,6 @@ pub enum Certainty {
impl Certainty {
pub const AMBIGUOUS: Certainty = Certainty::Maybe(MaybeCause::Ambiguity);
pub const OVERFLOW: Certainty = Certainty::Maybe(MaybeCause::Overflow);
/// Use this function to merge the certainty of multiple nested subgoals.
///
@ -79,16 +78,13 @@ impl Certainty {
(Certainty::Yes, Certainty::Yes) => Certainty::Yes,
(Certainty::Yes, Certainty::Maybe(_)) => other,
(Certainty::Maybe(_), Certainty::Yes) => self,
(Certainty::Maybe(MaybeCause::Ambiguity), Certainty::Maybe(MaybeCause::Ambiguity)) => {
Certainty::Maybe(MaybeCause::Ambiguity)
}
(Certainty::Maybe(MaybeCause::Ambiguity), Certainty::Maybe(MaybeCause::Overflow))
| (Certainty::Maybe(MaybeCause::Overflow), Certainty::Maybe(MaybeCause::Ambiguity))
| (Certainty::Maybe(MaybeCause::Overflow), Certainty::Maybe(MaybeCause::Overflow)) => {
Certainty::Maybe(MaybeCause::Overflow)
}
(Certainty::Maybe(a), Certainty::Maybe(b)) => Certainty::Maybe(a.unify_with(b)),
}
}
pub const fn overflow(suggest_increasing_limit: bool) -> Certainty {
Certainty::Maybe(MaybeCause::Overflow { suggest_increasing_limit })
}
}
/// Why we failed to evaluate a goal.
@ -99,7 +95,21 @@ pub enum MaybeCause {
/// or we hit a case where we just don't bother, e.g. `?x: Trait` goals.
Ambiguity,
/// We gave up due to an overflow, most often by hitting the recursion limit.
Overflow,
Overflow { suggest_increasing_limit: bool },
}
impl MaybeCause {
fn unify_with(self, other: MaybeCause) -> MaybeCause {
match (self, other) {
(MaybeCause::Ambiguity, MaybeCause::Ambiguity) => MaybeCause::Ambiguity,
(MaybeCause::Ambiguity, MaybeCause::Overflow { .. }) => other,
(MaybeCause::Overflow { .. }, MaybeCause::Ambiguity) => self,
(
MaybeCause::Overflow { suggest_increasing_limit: a },
MaybeCause::Overflow { suggest_increasing_limit: b },
) => MaybeCause::Overflow { suggest_increasing_limit: a || b },
}
}
}
#[derive(Debug, PartialEq, Eq, Clone, Copy, Hash, HashStable, TypeFoldable, TypeVisitable)]