diff options
Diffstat (limited to 'compiler')
| -rw-r--r-- | compiler/rustc_hir_analysis/src/collect/predicates_of.rs | 122 |
1 files changed, 47 insertions, 75 deletions
diff --git a/compiler/rustc_hir_analysis/src/collect/predicates_of.rs b/compiler/rustc_hir_analysis/src/collect/predicates_of.rs index db36aba7edf..606f1653767 100644 --- a/compiler/rustc_hir_analysis/src/collect/predicates_of.rs +++ b/compiler/rustc_hir_analysis/src/collect/predicates_of.rs @@ -461,83 +461,55 @@ pub(super) fn explicit_predicates_of<'tcx>( } } } else { - if matches!(def_kind, DefKind::AnonConst) && tcx.features().generic_const_exprs { - let hir_id = tcx.local_def_id_to_hir_id(def_id); - let parent_def_id = tcx.hir().get_parent_item(hir_id); - - if let Some(defaulted_param_def_id) = - tcx.hir().opt_const_param_default_param_def_id(hir_id) - { - // In `generics_of` we set the generics' parent to be our parent's parent which means that - // we lose out on the predicates of our actual parent if we dont return those predicates here. - // (See comment in `generics_of` for more information on why the parent shenanigans is necessary) - // - // struct Foo<T, const N: usize = { <T as Trait>::ASSOC }>(T) where T: Trait; - // ^^^ ^^^^^^^^^^^^^^^^^^^^^^^ the def id we are calling - // ^^^ explicit_predicates_of on - // parent item we dont have set as the - // parent of generics returned by `generics_of` - // - // In the above code we want the anon const to have predicates in its param env for `T: Trait` - // and we would be calling `explicit_predicates_of(Foo)` here - let parent_preds = tcx.explicit_predicates_of(parent_def_id); - - // If we dont filter out `ConstArgHasType` predicates then every single defaulted const parameter - // will ICE because of #106994. FIXME(generic_const_exprs): remove this when a more general solution - // to #106994 is implemented. - let filtered_predicates = parent_preds - .predicates - .into_iter() - .filter(|(pred, _)| { - if let ty::ClauseKind::ConstArgHasType(ct, _) = pred.kind().skip_binder() { - match ct.kind() { - ty::ConstKind::Param(param_const) => { - let defaulted_param_idx = tcx - .generics_of(parent_def_id) - .param_def_id_to_index[&defaulted_param_def_id.to_def_id()]; - param_const.index < defaulted_param_idx - } - _ => bug!( - "`ConstArgHasType` in `predicates_of`\ - that isn't a `Param` const" - ), + if matches!(def_kind, DefKind::AnonConst) + && tcx.features().generic_const_exprs + && let Some(defaulted_param_def_id) = + tcx.hir().opt_const_param_default_param_def_id(tcx.local_def_id_to_hir_id(def_id)) + { + // In `generics_of` we set the generics' parent to be our parent's parent which means that + // we lose out on the predicates of our actual parent if we dont return those predicates here. + // (See comment in `generics_of` for more information on why the parent shenanigans is necessary) + // + // struct Foo<T, const N: usize = { <T as Trait>::ASSOC }>(T) where T: Trait; + // ^^^ ^^^^^^^^^^^^^^^^^^^^^^^ the def id we are calling + // ^^^ explicit_predicates_of on + // parent item we dont have set as the + // parent of generics returned by `generics_of` + // + // In the above code we want the anon const to have predicates in its param env for `T: Trait` + // and we would be calling `explicit_predicates_of(Foo)` here + let parent_def_id = tcx.local_parent(def_id); + let parent_preds = tcx.explicit_predicates_of(parent_def_id); + + // If we dont filter out `ConstArgHasType` predicates then every single defaulted const parameter + // will ICE because of #106994. FIXME(generic_const_exprs): remove this when a more general solution + // to #106994 is implemented. + let filtered_predicates = parent_preds + .predicates + .into_iter() + .filter(|(pred, _)| { + if let ty::ClauseKind::ConstArgHasType(ct, _) = pred.kind().skip_binder() { + match ct.kind() { + ty::ConstKind::Param(param_const) => { + let defaulted_param_idx = tcx + .generics_of(parent_def_id) + .param_def_id_to_index[&defaulted_param_def_id.to_def_id()]; + param_const.index < defaulted_param_idx } - } else { - true + _ => bug!( + "`ConstArgHasType` in `predicates_of`\ + that isn't a `Param` const" + ), } - }) - .cloned(); - return GenericPredicates { - parent: parent_preds.parent, - predicates: { tcx.arena.alloc_from_iter(filtered_predicates) }, - }; - } - - let parent_def_kind = tcx.def_kind(parent_def_id); - if matches!(parent_def_kind, DefKind::OpaqueTy) { - // In `instantiate_identity` we inherit the predicates of our parent. - // However, opaque types do not have a parent (see `gather_explicit_predicates_of`), which means - // that we lose out on the predicates of our actual parent if we dont return those predicates here. - // - // - // fn foo<T: Trait>() -> impl Iterator<Output = Another<{ <T as Trait>::ASSOC }> > { todo!() } - // ^^^^^^^^^^^^^^^^^^^ the def id we are calling - // explicit_predicates_of on - // - // In the above code we want the anon const to have predicates in its param env for `T: Trait`. - // However, the anon const cannot inherit predicates from its parent since it's opaque. - // - // To fix this, we call `explicit_predicates_of` directly on `foo`, the parent's parent. - - // In the above example this is `foo::{opaque#0}` or `impl Iterator` - let parent_hir_id = tcx.local_def_id_to_hir_id(parent_def_id.def_id); - - // In the above example this is the function `foo` - let item_def_id = tcx.hir().get_parent_item(parent_hir_id); - - // In the above code example we would be calling `explicit_predicates_of(foo)` here - return tcx.explicit_predicates_of(item_def_id); - } + } else { + true + } + }) + .cloned(); + return GenericPredicates { + parent: parent_preds.parent, + predicates: { tcx.arena.alloc_from_iter(filtered_predicates) }, + }; } gather_explicit_predicates_of(tcx, def_id) } |