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//! Helper functions for working with def, which don't need to be a separate
//! query, but can't be computed directly from `*Data` (ie, which need a `db`).
use std::sync::Arc;
use hir_def::generics::WherePredicateTarget;
use hir_def::{
adt::VariantData,
db::DefDatabase,
generics::{GenericParams, TypeParamData, TypeParamProvenance},
path::Path,
resolver::{HasResolver, TypeNs},
type_ref::TypeRef,
AssocContainerId, GenericDefId, Lookup, TraitId, TypeAliasId, TypeParamId, VariantId,
};
use hir_expand::name::{name, Name};
fn direct_super_traits(db: &impl DefDatabase, trait_: TraitId) -> Vec<TraitId> {
let resolver = trait_.resolver(db);
// returning the iterator directly doesn't easily work because of
// lifetime problems, but since there usually shouldn't be more than a
// few direct traits this should be fine (we could even use some kind of
// SmallVec if performance is a concern)
let generic_params = db.generic_params(trait_.into());
let trait_self = generic_params.find_trait_self_param();
generic_params
.where_predicates
.iter()
.filter_map(|pred| match &pred.target {
WherePredicateTarget::TypeRef(TypeRef::Path(p)) if p == &Path::from(name![Self]) => {
pred.bound.as_path()
}
WherePredicateTarget::TypeParam(local_id) if Some(*local_id) == trait_self => {
pred.bound.as_path()
}
_ => None,
})
.filter_map(|path| match resolver.resolve_path_in_type_ns_fully(db, path.mod_path()) {
Some(TypeNs::TraitId(t)) => Some(t),
_ => None,
})
.collect()
}
/// Returns an iterator over the whole super trait hierarchy (including the
/// trait itself).
pub(super) fn all_super_traits(db: &impl DefDatabase, trait_: TraitId) -> Vec<TraitId> {
// we need to take care a bit here to avoid infinite loops in case of cycles
// (i.e. if we have `trait A: B; trait B: A;`)
let mut result = vec![trait_];
let mut i = 0;
while i < result.len() {
let t = result[i];
// yeah this is quadratic, but trait hierarchies should be flat
// enough that this doesn't matter
for tt in direct_super_traits(db, t) {
if !result.contains(&tt) {
result.push(tt);
}
}
i += 1;
}
result
}
pub(super) fn associated_type_by_name_including_super_traits(
db: &impl DefDatabase,
trait_: TraitId,
name: &Name,
) -> Option<TypeAliasId> {
all_super_traits(db, trait_)
.into_iter()
.find_map(|t| db.trait_data(t).associated_type_by_name(name))
}
pub(super) fn variant_data(db: &impl DefDatabase, var: VariantId) -> Arc<VariantData> {
match var {
VariantId::StructId(it) => db.struct_data(it).variant_data.clone(),
VariantId::UnionId(it) => db.union_data(it).variant_data.clone(),
VariantId::EnumVariantId(it) => {
db.enum_data(it.parent).variants[it.local_id].variant_data.clone()
}
}
}
/// Helper for mutating `Arc<[T]>` (i.e. `Arc::make_mut` for Arc slices).
/// The underlying values are cloned if there are other strong references.
pub(crate) fn make_mut_slice<T: Clone>(a: &mut Arc<[T]>) -> &mut [T] {
if Arc::get_mut(a).is_none() {
*a = a.iter().cloned().collect();
}
Arc::get_mut(a).unwrap()
}
pub(crate) fn generics(db: &impl DefDatabase, def: GenericDefId) -> Generics {
let parent_generics = parent_generic_def(db, def).map(|def| Box::new(generics(db, def)));
Generics { def, params: db.generic_params(def), parent_generics }
}
pub(crate) struct Generics {
def: GenericDefId,
pub(crate) params: Arc<GenericParams>,
parent_generics: Option<Box<Generics>>,
}
impl Generics {
pub(crate) fn iter<'a>(
&'a self,
) -> impl Iterator<Item = (TypeParamId, &'a TypeParamData)> + 'a {
self.parent_generics
.as_ref()
.into_iter()
.flat_map(|it| {
it.params
.types
.iter()
.map(move |(local_id, p)| (TypeParamId { parent: it.def, local_id }, p))
})
.chain(
self.params
.types
.iter()
.map(move |(local_id, p)| (TypeParamId { parent: self.def, local_id }, p)),
)
}
pub(crate) fn iter_parent<'a>(
&'a self,
) -> impl Iterator<Item = (TypeParamId, &'a TypeParamData)> + 'a {
self.parent_generics.as_ref().into_iter().flat_map(|it| {
it.params
.types
.iter()
.map(move |(local_id, p)| (TypeParamId { parent: it.def, local_id }, p))
})
}
pub(crate) fn len(&self) -> usize {
self.len_split().0
}
/// (total, parents, child)
pub(crate) fn len_split(&self) -> (usize, usize, usize) {
let parent = self.parent_generics.as_ref().map_or(0, |p| p.len());
let child = self.params.types.len();
(parent + child, parent, child)
}
/// (parent total, self param, type param list, impl trait)
pub(crate) fn provenance_split(&self) -> (usize, usize, usize, usize) {
let parent = self.parent_generics.as_ref().map_or(0, |p| p.len());
let self_params = self
.params
.types
.iter()
.filter(|(_, p)| p.provenance == TypeParamProvenance::TraitSelf)
.count();
let list_params = self
.params
.types
.iter()
.filter(|(_, p)| p.provenance == TypeParamProvenance::TypeParamList)
.count();
let impl_trait_params = self
.params
.types
.iter()
.filter(|(_, p)| p.provenance == TypeParamProvenance::ArgumentImplTrait)
.count();
(parent, self_params, list_params, impl_trait_params)
}
pub(crate) fn param_idx(&self, param: TypeParamId) -> Option<u32> {
Some(self.find_param(param)?.0)
}
fn find_param(&self, param: TypeParamId) -> Option<(u32, &TypeParamData)> {
if param.parent == self.def {
let (idx, (_local_id, data)) = self
.params
.types
.iter()
.enumerate()
.find(|(_, (idx, _))| *idx == param.local_id)
.unwrap();
let (_total, parent_len, _child) = self.len_split();
Some(((parent_len + idx) as u32, data))
} else {
self.parent_generics.as_ref().and_then(|g| g.find_param(param))
}
}
}
fn parent_generic_def(db: &impl DefDatabase, def: GenericDefId) -> Option<GenericDefId> {
let container = match def {
GenericDefId::FunctionId(it) => it.lookup(db).container,
GenericDefId::TypeAliasId(it) => it.lookup(db).container,
GenericDefId::ConstId(it) => it.lookup(db).container,
GenericDefId::EnumVariantId(it) => return Some(it.parent.into()),
GenericDefId::AdtId(_) | GenericDefId::TraitId(_) | GenericDefId::ImplId(_) => return None,
};
match container {
AssocContainerId::ImplId(it) => Some(it.into()),
AssocContainerId::TraitId(it) => Some(it.into()),
AssocContainerId::ContainerId(_) => None,
}
}
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