diff options
3 files changed, 49 insertions, 8 deletions
diff --git a/compiler/rustc_hir_analysis/src/collect/predicates_of.rs b/compiler/rustc_hir_analysis/src/collect/predicates_of.rs index 351ac2eb770..f70bb8c4289 100644 --- a/compiler/rustc_hir_analysis/src/collect/predicates_of.rs +++ b/compiler/rustc_hir_analysis/src/collect/predicates_of.rs @@ -640,16 +640,30 @@ pub(super) fn implied_predicates_with_filter( // Now require that immediate supertraits are converted, which will, in // turn, reach indirect supertraits, so we detect cycles now instead of - // overflowing during elaboration. - if matches!(filter, PredicateFilter::SelfOnly) { - for &(pred, span) in implied_bounds { - debug!("superbound: {:?}", pred); - if let ty::ClauseKind::Trait(bound) = pred.kind().skip_binder() - && bound.polarity == ty::ImplPolarity::Positive - { - tcx.at(span).super_predicates_of(bound.def_id()); + // overflowing during elaboration. Same for implied predicates, which + // make sure we walk into associated type bounds. + match filter { + PredicateFilter::SelfOnly => { + for &(pred, span) in implied_bounds { + debug!("superbound: {:?}", pred); + if let ty::ClauseKind::Trait(bound) = pred.kind().skip_binder() + && bound.polarity == ty::ImplPolarity::Positive + { + tcx.at(span).super_predicates_of(bound.def_id()); + } + } + } + PredicateFilter::SelfAndAssociatedTypeBounds => { + for &(pred, span) in implied_bounds { + debug!("superbound: {:?}", pred); + if let ty::ClauseKind::Trait(bound) = pred.kind().skip_binder() + && bound.polarity == ty::ImplPolarity::Positive + { + tcx.at(span).implied_predicates_of(bound.def_id()); + } } } + _ => {} } ty::GenericPredicates { parent: None, predicates: implied_bounds } diff --git a/tests/ui/associated-type-bounds/implied-bounds-cycle.rs b/tests/ui/associated-type-bounds/implied-bounds-cycle.rs new file mode 100644 index 00000000000..785d47d4791 --- /dev/null +++ b/tests/ui/associated-type-bounds/implied-bounds-cycle.rs @@ -0,0 +1,10 @@ +#![feature(associated_type_bounds)] + +trait A { + type T; +} + +trait B: A<T: B> {} +//~^ ERROR cycle detected when computing the implied predicates of `B` + +fn main() {} diff --git a/tests/ui/associated-type-bounds/implied-bounds-cycle.stderr b/tests/ui/associated-type-bounds/implied-bounds-cycle.stderr new file mode 100644 index 00000000000..1c1c64ea5f5 --- /dev/null +++ b/tests/ui/associated-type-bounds/implied-bounds-cycle.stderr @@ -0,0 +1,17 @@ +error[E0391]: cycle detected when computing the implied predicates of `B` + --> $DIR/implied-bounds-cycle.rs:7:15 + | +LL | trait B: A<T: B> {} + | ^ + | + = note: ...which immediately requires computing the implied predicates of `B` again +note: cycle used when computing normalized predicates of `B` + --> $DIR/implied-bounds-cycle.rs:7:1 + | +LL | trait B: A<T: B> {} + | ^^^^^^^^^^^^^^^^ + = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information + +error: aborting due to 1 previous error + +For more information about this error, try `rustc --explain E0391`. |