diff options
Diffstat (limited to 'compiler/rustc_middle/src/traits/solve.rs')
| -rw-r--r-- | compiler/rustc_middle/src/traits/solve.rs | 30 |
1 files changed, 20 insertions, 10 deletions
diff --git a/compiler/rustc_middle/src/traits/solve.rs b/compiler/rustc_middle/src/traits/solve.rs index 048df367bd6..0dc65126011 100644 --- a/compiler/rustc_middle/src/traits/solve.rs +++ b/compiler/rustc_middle/src/traits/solve.rs @@ -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)] |