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Rewrite all_super_trait_refs as an iterator

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Doesn't fix the bug I was trying to fix, but now that I did it anyway it
seems fine to keep.
This commit is contained in:
Florian Diebold 2021-04-29 20:18:41 +02:00
parent b384cfcb81
commit 2d20ab7eaf
1 changed files with 35 additions and 19 deletions
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54
crates/hir_ty/src/utils.rs
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@ -1,6 +1,8 @@
//! 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::iter;
use chalk_ir::{fold::Shift, BoundVar, DebruijnIndex};
use hir_def::{
db::DefDatabase,
@ -14,8 +16,12 @@ use hir_def::{
AssocContainerId, GenericDefId, Lookup, TraitId, TypeAliasId, TypeParamId,
};
use hir_expand::name::{name, Name};
use rustc_hash::FxHashSet;
use crate::{db::HirDatabase, Interner, Substitution, TraitRef, TraitRefExt, TyKind, WhereClause};
use crate::{
db::HirDatabase, ChalkTraitId, Interner, Substitution, TraitRef, TraitRefExt, TyKind,
WhereClause,
};
fn direct_super_traits(db: &dyn DefDatabase, trait_: TraitId) -> Vec<TraitId> {
let resolver = trait_.resolver(db);
@ -102,25 +108,35 @@ pub fn all_super_traits(db: &dyn DefDatabase, trait_: TraitId) -> Vec<TraitId> {
/// `all_super_traits` is that we keep track of type parameters; for example if
/// we have `Self: Trait<u32, i32>` and `Trait<T, U>: OtherTrait<U>` we'll get
/// `Self: OtherTrait<i32>`.
pub(super) fn all_super_trait_refs(db: &dyn HirDatabase, trait_ref: TraitRef) -> Vec<TraitRef> {
// FIXME: replace by Chalk's `super_traits`, maybe make this a query
pub(super) fn all_super_trait_refs(db: &dyn HirDatabase, trait_ref: TraitRef) -> SuperTraits {
SuperTraits { db, seen: iter::once(trait_ref.trait_id).collect(), stack: vec![trait_ref] }
}
// 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_ref];
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_trait_refs(db, t) {
if !result.iter().any(|tr| tr.trait_id == tt.trait_id) {
result.push(tt);
}
}
i += 1;
pub(super) struct SuperTraits<'a> {
db: &'a dyn HirDatabase,
stack: Vec<TraitRef>,
seen: FxHashSet<ChalkTraitId>,
}
impl<'a> SuperTraits<'a> {
fn elaborate(&mut self, trait_ref: &TraitRef) {
let mut trait_refs = direct_super_trait_refs(self.db, trait_ref);
trait_refs.retain(|tr| !self.seen.contains(&tr.trait_id));
self.stack.extend(trait_refs);
}
}
impl<'a> Iterator for SuperTraits<'a> {
type Item = TraitRef;
fn next(&mut self) -> Option<Self::Item> {
if let Some(next) = self.stack.pop() {
self.elaborate(&next);
Some(next)
} else {
None
}
}
result
}
pub(super) fn associated_type_by_name_including_super_traits(
@ -128,7 +144,7 @@ pub(super) fn associated_type_by_name_including_super_traits(
trait_ref: TraitRef,
name: &Name,
) -> Option<(TraitRef, TypeAliasId)> {
all_super_trait_refs(db, trait_ref).into_iter().find_map(|t| {
all_super_trait_refs(db, trait_ref).find_map(|t| {
let assoc_type = db.trait_data(t.hir_trait_id()).associated_type_by_name(name)?;
Some((t, assoc_type))
})