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rustdoc: render bounds of cross-crate GAT params

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León Orell Valerian Liehr 2022-10-18 15:34:41 +02:00
parent d7dd01fe8b
commit 2cc4a0aad7
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7 changed files with 41 additions and 22 deletions
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44
src/librustdoc/clean/mod.rs
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@ -1201,21 +1201,19 @@ pub(crate) fn clean_middle_assoc_item<'tcx>(
}
if let ty::TraitContainer = assoc_item.container {
// FIXME(fmease): `tcx.explicit_item_bounds` does not contain the bounds of GATs,
// e.g. the bounds `Copy`, `Display` & (implicitly) `Sized` in
// `type Assoc<T: Copy> where T: Display`. This also means that we
// later incorrectly render `where T: ?Sized`.
//
// The result of `tcx.explicit_predicates_of` *does* contain them but
// it does not contain the other bounds / predicates we need.
// Either merge those two interned lists somehow or refactor
// `clean_ty_generics` to call `explicit_item_bounds` by itself.
let bounds = tcx.explicit_item_bounds(assoc_item.def_id);
let predicates = ty::GenericPredicates { parent: None, predicates: bounds };
let mut generics =
clean_ty_generics(cx, tcx.generics_of(assoc_item.def_id), predicates);
// Filter out the bounds that are (likely?) directly attached to the associated type,
// as opposed to being located in the where clause.
let predicates = tcx.explicit_predicates_of(assoc_item.def_id).predicates;
let predicates =
tcx.arena.alloc_from_iter(bounds.into_iter().chain(predicates).copied());
let mut generics = clean_ty_generics(
cx,
tcx.generics_of(assoc_item.def_id),
ty::GenericPredicates { parent: None, predicates },
);
// Move bounds that are (likely) directly attached to the associated type
// from the where clause to the associated type.
// There is no guarantee that this is what the user actually wrote but we have
// no way of knowing.
let mut bounds = generics
.where_predicates
.drain_filter(|pred| match *pred {
@ -1273,6 +1271,24 @@ pub(crate) fn clean_middle_assoc_item<'tcx>(
}
None => bounds.push(GenericBound::maybe_sized(cx)),
}
// Move bounds that are (likely) directly attached to the parameters of the
// (generic) associated type from the where clause to the respective parameter.
// There is no guarantee that this is what the user actually wrote but we have
// no way of knowing.
let mut where_predicates = Vec::new();
for mut pred in generics.where_predicates {
if let WherePredicate::BoundPredicate { ty: Generic(arg), bounds, .. } = &mut pred
&& let Some(GenericParamDef {
kind: GenericParamDefKind::Type { bounds: param_bounds, .. },
..
}) = generics.params.iter_mut().find(|param| &param.name == arg)
{
param_bounds.extend(mem::take(bounds));
} else {
where_predicates.push(pred);
}
}
generics.where_predicates = where_predicates;
if tcx.impl_defaultness(assoc_item.def_id).has_value() {
AssocTypeItem(