diff options
| -rw-r--r-- | compiler/rustc_trait_selection/src/traits/select/mod.rs | 63 | ||||
| -rw-r--r-- | src/test/incremental/issue-92987-provisional-dep-node.rs | 24 |
2 files changed, 75 insertions, 12 deletions
diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs index 558ecd393b6..ab4fb9607ca 100644 --- a/compiler/rustc_trait_selection/src/traits/select/mod.rs +++ b/compiler/rustc_trait_selection/src/traits/select/mod.rs @@ -765,14 +765,38 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { debug!(?result, "CACHE MISS"); self.insert_evaluation_cache(param_env, fresh_trait_pred, dep_node, result); - stack.cache().on_completion(stack.dfn, |fresh_trait_pred, provisional_result| { - self.insert_evaluation_cache( - param_env, - fresh_trait_pred, - dep_node, - provisional_result.max(result), - ); - }); + stack.cache().on_completion( + stack.dfn, + |fresh_trait_pred, provisional_result, provisional_dep_node| { + // Create a new `DepNode` that has dependencies on: + // * The `DepNode` for the original evaluation that resulted in a provisional cache + // entry being crated + // * The `DepNode` for the *current* evaluation, which resulted in us completing + // provisional caches entries and inserting them into the evaluation cache + // + // This ensures that when a query reads this entry from the evaluation cache, + // it will end up (transitively) dependening on all of the incr-comp dependencies + // created during the evaluation of this trait. For example, evaluating a trait + // will usually require us to invoke `type_of(field_def_id)` to determine the + // constituent types, and we want any queries reading from this evaluation + // cache entry to end up with a transitive `type_of(field_def_id`)` dependency. + // + // By using `in_task`, we're also creating an edge from the *current* query + // to the newly-created `combined_dep_node`. This is probably redundant, + // but it's better to add too many dep graph edges than to add too few + // dep graph edges. + let ((), combined_dep_node) = self.in_task(|this| { + this.tcx().dep_graph.read_index(provisional_dep_node); + this.tcx().dep_graph.read_index(dep_node); + }); + self.insert_evaluation_cache( + param_env, + fresh_trait_pred, + combined_dep_node, + provisional_result.max(result), + ); + }, + ); } else { debug!(?result, "PROVISIONAL"); debug!( @@ -781,7 +805,13 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { fresh_trait_pred, stack.depth, reached_depth, ); - stack.cache().insert_provisional(stack.dfn, reached_depth, fresh_trait_pred, result); + stack.cache().insert_provisional( + stack.dfn, + reached_depth, + fresh_trait_pred, + result, + dep_node, + ); } Ok(result) @@ -2506,6 +2536,11 @@ struct ProvisionalEvaluation { from_dfn: usize, reached_depth: usize, result: EvaluationResult, + /// The `DepNodeIndex` created for the `evaluate_stack` call for this provisional + /// evaluation. When we create an entry in the evaluation cache using this provisional + /// cache entry (see `on_completion`), we use this `dep_node` to ensure that future reads from + /// the cache will have all of the necessary incr comp dependencies tracked. + dep_node: DepNodeIndex, } impl<'tcx> Default for ProvisionalEvaluationCache<'tcx> { @@ -2548,6 +2583,7 @@ impl<'tcx> ProvisionalEvaluationCache<'tcx> { reached_depth: usize, fresh_trait_pred: ty::PolyTraitPredicate<'tcx>, result: EvaluationResult, + dep_node: DepNodeIndex, ) { debug!(?from_dfn, ?fresh_trait_pred, ?result, "insert_provisional"); @@ -2573,7 +2609,10 @@ impl<'tcx> ProvisionalEvaluationCache<'tcx> { } } - map.insert(fresh_trait_pred, ProvisionalEvaluation { from_dfn, reached_depth, result }); + map.insert( + fresh_trait_pred, + ProvisionalEvaluation { from_dfn, reached_depth, result, dep_node }, + ); } /// Invoked when the node with dfn `dfn` does not get a successful @@ -2624,7 +2663,7 @@ impl<'tcx> ProvisionalEvaluationCache<'tcx> { fn on_completion( &self, dfn: usize, - mut op: impl FnMut(ty::PolyTraitPredicate<'tcx>, EvaluationResult), + mut op: impl FnMut(ty::PolyTraitPredicate<'tcx>, EvaluationResult, DepNodeIndex), ) { debug!(?dfn, "on_completion"); @@ -2633,7 +2672,7 @@ impl<'tcx> ProvisionalEvaluationCache<'tcx> { { debug!(?fresh_trait_pred, ?eval, "on_completion"); - op(fresh_trait_pred, eval.result); + op(fresh_trait_pred, eval.result, eval.dep_node); } } } diff --git a/src/test/incremental/issue-92987-provisional-dep-node.rs b/src/test/incremental/issue-92987-provisional-dep-node.rs new file mode 100644 index 00000000000..a48a8373c2b --- /dev/null +++ b/src/test/incremental/issue-92987-provisional-dep-node.rs @@ -0,0 +1,24 @@ +// revisions: rpass1 rpass2 + +// Regression test for issue #92987 +// Tests that we properly manage `DepNode`s during trait evaluation +// involing an auto-trait cycle. + +#[cfg(rpass1)] +struct CycleOne(Box<CycleTwo>); + +#[cfg(rpass2)] +enum CycleOne { + Variant(Box<CycleTwo>) +} + +struct CycleTwo(CycleOne); + +fn assert_send<T: Send>() {} + +fn bar() { + assert_send::<CycleOne>(); + assert_send::<CycleTwo>(); +} + +fn main() {} |