bjoernager/rust
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Implement lint against coinductive impl overlap

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This commit is contained in:
Michael Goulet 2023-07-25 01:49:29 +00:00
parent 2ae4bedd85
commit 56f5704ff8
5 changed files with 183 additions and 6 deletions
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36
compiler/rustc_trait_selection/src/traits/select/mod.rs
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@ -118,6 +118,8 @@ pub struct SelectionContext<'cx, 'tcx> {
/// policy. In essence, canonicalized queries need their errors propagated
/// rather than immediately reported because we do not have accurate spans.
query_mode: TraitQueryMode,
treat_inductive_cycle: TreatInductiveCycleAs,
}
// A stack that walks back up the stack frame.
@ -198,6 +200,11 @@ enum BuiltinImplConditions<'tcx> {
Ambiguous,
}
enum TreatInductiveCycleAs {
Recur,
Ambig,
}
impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
pub fn new(infcx: &'cx InferCtxt<'tcx>) -> SelectionContext<'cx, 'tcx> {
SelectionContext {
@ -205,6 +212,20 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
freshener: infcx.freshener(),
intercrate_ambiguity_causes: None,
query_mode: TraitQueryMode::Standard,
treat_inductive_cycle: TreatInductiveCycleAs::Recur,
}
}
pub fn with_treat_inductive_cycle_as_ambiguous(
infcx: &'cx InferCtxt<'tcx>,
) -> SelectionContext<'cx, 'tcx> {
assert!(infcx.intercrate, "this doesn't do caching yet, so don't use it out of intercrate");
SelectionContext {
infcx,
freshener: infcx.freshener(),
intercrate_ambiguity_causes: None,
query_mode: TraitQueryMode::Standard,
treat_inductive_cycle: TreatInductiveCycleAs::Ambig,
}
}
@ -719,7 +740,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
stack.update_reached_depth(stack_arg.1);
return Ok(EvaluatedToOk);
} else {
return Ok(EvaluatedToRecur);
match self.treat_inductive_cycle {
TreatInductiveCycleAs::Ambig => return Ok(EvaluatedToAmbig),
TreatInductiveCycleAs::Recur => return Ok(EvaluatedToRecur),
}
}
}
return Ok(EvaluatedToOk);
@ -837,7 +861,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
}
}
ProjectAndUnifyResult::FailedNormalization => Ok(EvaluatedToAmbig),
ProjectAndUnifyResult::Recursive => Ok(EvaluatedToRecur),
ProjectAndUnifyResult::Recursive => match self.treat_inductive_cycle {
TreatInductiveCycleAs::Ambig => return Ok(EvaluatedToAmbig),
TreatInductiveCycleAs::Recur => return Ok(EvaluatedToRecur),
},
ProjectAndUnifyResult::MismatchedProjectionTypes(_) => Ok(EvaluatedToErr),
}
}
@ -1151,7 +1178,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
Some(EvaluatedToOk)
} else {
debug!("evaluate_stack --> recursive, inductive");
Some(EvaluatedToRecur)
match self.treat_inductive_cycle {
TreatInductiveCycleAs::Ambig => Some(EvaluatedToAmbig),
TreatInductiveCycleAs::Recur => Some(EvaluatedToRecur),
}
}
} else {
None