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internal: Remove dead branches in `method_resolutiopn::is_valid_candi…
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…date`
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@Veykril
Veykril committed Feb 27, 2024
1 parent cc7fe32 commit 3a1b4c2
Showing 1 changed file with 109 additions and 136 deletions.
245 changes: 109 additions & 136 deletions crates/hir-ty/src/method_resolution.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1176,11 +1176,12 @@ fn iterate_trait_method_candidates(
for &(_, item) in data.items.iter() {
// Don't pass a `visible_from_module` down to `is_valid_candidate`,
// since only inherent methods should be included into visibility checking.
let visible = match is_valid_method_candidate(table, name, receiver_ty, item, self_ty) {
IsValidCandidate::Yes => true,
IsValidCandidate::NotVisible => false,
IsValidCandidate::No => continue,
};
let visible =
match is_valid_trait_method_candidate(table, t, name, receiver_ty, item, self_ty) {
IsValidCandidate::Yes => true,
IsValidCandidate::NotVisible => false,
IsValidCandidate::No => continue,
};
if !known_implemented {
let goal = generic_implements_goal(db, env.clone(), t, &canonical_self_ty);
if db.trait_solve(env.krate, env.block, goal.cast(Interner)).is_none() {
Expand Down Expand Up @@ -1302,12 +1303,18 @@ fn iterate_inherent_methods(
let data = db.trait_data(t);
for &(_, item) in data.items.iter() {
// We don't pass `visible_from_module` as all trait items should be visible.
let visible =
match is_valid_candidate(table, name, receiver_ty, item, self_ty, None) {
IsValidCandidate::Yes => true,
IsValidCandidate::NotVisible => false,
IsValidCandidate::No => continue,
};
let visible = match is_valid_trait_method_candidate(
table,
t,
name,
receiver_ty,
item,
self_ty,
) {
IsValidCandidate::Yes => true,
IsValidCandidate::NotVisible => false,
IsValidCandidate::No => continue,
};
callback(receiver_adjustments.clone().unwrap_or_default(), item, visible)?;
}
}
Expand All @@ -1325,17 +1332,16 @@ fn iterate_inherent_methods(
visible_from_module: Option<ModuleId>,
callback: &mut dyn FnMut(ReceiverAdjustments, AssocItemId, bool) -> ControlFlow<()>,
) -> ControlFlow<()> {
let db = table.db;
let impls_for_self_ty = impls.for_self_ty(self_ty);
for &impl_def in impls_for_self_ty {
for &item in &db.impl_data(impl_def).items {
let visible = match is_valid_candidate(
for &impl_id in impls.for_self_ty(self_ty) {
for &item in &table.db.impl_data(impl_id).items {
let visible = match is_valid_impl_method_candidate(
table,
name,
receiver_ty,
item,
self_ty,
receiver_ty,
visible_from_module,
name,
impl_id,
item,
) {
IsValidCandidate::Yes => true,
IsValidCandidate::NotVisible => false,
Expand Down Expand Up @@ -1378,21 +1384,34 @@ macro_rules! check_that {
};
}

enum IsValidCandidate {
Yes,
No,
NotVisible,
}

#[tracing::instrument(skip_all, fields(name))]
fn is_valid_candidate(
fn is_valid_impl_method_candidate(
table: &mut InferenceTable<'_>,
name: Option<&Name>,
receiver_ty: Option<&Ty>,
item: AssocItemId,
self_ty: &Ty,
receiver_ty: Option<&Ty>,
visible_from_module: Option<ModuleId>,
name: Option<&Name>,
impl_id: ImplId,
item: AssocItemId,
) -> IsValidCandidate {
let db = table.db;
match item {
AssocItemId::FunctionId(f) => {
is_valid_fn_candidate(table, f, name, receiver_ty, self_ty, visible_from_module)
}
AssocItemId::FunctionId(f) => is_valid_impl_fn_candidate(
table,
impl_id,
f,
name,
receiver_ty,
self_ty,
visible_from_module,
),
AssocItemId::ConstId(c) => {
let db = table.db;
check_that!(receiver_ty.is_none());
check_that!(name.map_or(true, |n| db.const_data(c).name.as_ref() == Some(n)));

Expand All @@ -1402,17 +1421,14 @@ fn is_valid_candidate(
return IsValidCandidate::NotVisible;
}
}
if let ItemContainerId::ImplId(impl_id) = c.lookup(db.upcast()).container {
let self_ty_matches = table.run_in_snapshot(|table| {
let expected_self_ty = TyBuilder::impl_self_ty(db, impl_id)
.fill_with_inference_vars(table)
.build();
table.unify(&expected_self_ty, self_ty)
});
if !self_ty_matches {
cov_mark::hit!(const_candidate_self_type_mismatch);
return IsValidCandidate::No;
}
let self_ty_matches = table.run_in_snapshot(|table| {
let expected_self_ty =
TyBuilder::impl_self_ty(db, impl_id).fill_with_inference_vars(table).build();
table.unify(&expected_self_ty, self_ty)
});
if !self_ty_matches {
cov_mark::hit!(const_candidate_self_type_mismatch);
return IsValidCandidate::No;
}
IsValidCandidate::Yes
}
Expand All @@ -1421,12 +1437,10 @@ fn is_valid_candidate(
}

/// Checks whether a given `AssocItemId` is applicable for `receiver_ty`.
///
/// This method should *only* be called by [`iterate_trait_method_candidates`],
/// as it is responsible for determining applicability in completions.
#[tracing::instrument(skip_all, fields(name))]
fn is_valid_method_candidate(
fn is_valid_trait_method_candidate(
table: &mut InferenceTable<'_>,
trait_id: TraitId,
name: Option<&Name>,
receiver_ty: Option<&Ty>,
item: AssocItemId,
Expand All @@ -1440,24 +1454,10 @@ fn is_valid_method_candidate(
check_that!(name.map_or(true, |n| n == &data.name));

table.run_in_snapshot(|table| {
let container = fn_id.lookup(db.upcast()).container;
let (impl_subst, expect_self_ty) = match container {
ItemContainerId::ImplId(it) => {
let subst = TyBuilder::subst_for_def(db, it, None)
.fill_with_inference_vars(table)
.build();
let self_ty = db.impl_self_ty(it).substitute(Interner, &subst);
(subst, self_ty)
}
ItemContainerId::TraitId(it) => {
let subst = TyBuilder::subst_for_def(db, it, None)
.fill_with_inference_vars(table)
.build();
let self_ty = subst.at(Interner, 0).assert_ty_ref(Interner).clone();
(subst, self_ty)
}
_ => unreachable!(),
};
let impl_subst = TyBuilder::subst_for_def(db, trait_id, None)
.fill_with_inference_vars(table)
.build();
let expect_self_ty = impl_subst.at(Interner, 0).assert_ty_ref(Interner).clone();

check_that!(table.unify(&expect_self_ty, self_ty));

Expand Down Expand Up @@ -1488,15 +1488,10 @@ fn is_valid_method_candidate(
}
}

enum IsValidCandidate {
Yes,
No,
NotVisible,
}

#[tracing::instrument(skip_all, fields(name))]
fn is_valid_fn_candidate(
fn is_valid_impl_fn_candidate(
table: &mut InferenceTable<'_>,
impl_id: ImplId,
fn_id: FunctionId,
name: Option<&Name>,
receiver_ty: Option<&Ty>,
Expand All @@ -1514,24 +1509,10 @@ fn is_valid_fn_candidate(
}
}
table.run_in_snapshot(|table| {
let container = fn_id.lookup(db.upcast()).container;

let _p = tracing::span!(tracing::Level::INFO, "subst_for_def").entered();
let (impl_subst, expect_self_ty) = match container {
ItemContainerId::ImplId(it) => {
let subst =
TyBuilder::subst_for_def(db, it, None).fill_with_inference_vars(table).build();
let self_ty = db.impl_self_ty(it).substitute(Interner, &subst);
(subst, self_ty)
}
ItemContainerId::TraitId(it) => {
let subst =
TyBuilder::subst_for_def(db, it, None).fill_with_inference_vars(table).build();
let self_ty = subst.at(Interner, 0).assert_ty_ref(Interner).clone();
(subst, self_ty)
}
_ => unreachable!(),
};
let impl_subst =
TyBuilder::subst_for_def(db, impl_id, None).fill_with_inference_vars(table).build();
let expect_self_ty = db.impl_self_ty(impl_id).substitute(Interner, &impl_subst);

check_that!(table.unify(&expect_self_ty, self_ty));

Expand All @@ -1550,63 +1531,55 @@ fn is_valid_fn_candidate(
check_that!(table.unify(receiver_ty, &expected_receiver));
}

if let ItemContainerId::ImplId(impl_id) = container {
let _p = tracing::span!(tracing::Level::INFO, "check_item_container").entered();
// We need to consider the bounds on the impl to distinguish functions of the same name
// for a type.
let predicates = db.generic_predicates(impl_id.into());
let goals = predicates.iter().map(|p| {
let (p, b) = p
.clone()
.substitute(Interner, &impl_subst)
// Skipping the inner binders is ok, as we don't handle quantified where
// clauses yet.
.into_value_and_skipped_binders();
stdx::always!(b.len(Interner) == 0);

p.cast::<Goal>(Interner)
});

for goal in goals.clone() {
let in_env = InEnvironment::new(&table.trait_env.env, goal);
let canonicalized = table.canonicalize(in_env);
let solution = table.db.trait_solve(
table.trait_env.krate,
table.trait_env.block,
canonicalized.value.clone(),
);

match solution {
Some(Solution::Unique(canonical_subst)) => {
canonicalized.apply_solution(
table,
Canonical {
binders: canonical_subst.binders,
value: canonical_subst.value.subst,
},
);
}
Some(Solution::Ambig(Guidance::Definite(substs))) => {
canonicalized.apply_solution(table, substs);
}
Some(_) => (),
None => return IsValidCandidate::No,
// We need to consider the bounds on the impl to distinguish functions of the same name
// for a type.
let predicates = db.generic_predicates(impl_id.into());
let goals = predicates.iter().map(|p| {
let (p, b) = p
.clone()
.substitute(Interner, &impl_subst)
// Skipping the inner binders is ok, as we don't handle quantified where
// clauses yet.
.into_value_and_skipped_binders();
stdx::always!(b.len(Interner) == 0);

p.cast::<Goal>(Interner)
});

for goal in goals.clone() {
let in_env = InEnvironment::new(&table.trait_env.env, goal);
let canonicalized = table.canonicalize(in_env);
let solution = table.db.trait_solve(
table.trait_env.krate,
table.trait_env.block,
canonicalized.value.clone(),
);

match solution {
Some(Solution::Unique(canonical_subst)) => {
canonicalized.apply_solution(
table,
Canonical {
binders: canonical_subst.binders,
value: canonical_subst.value.subst,
},
);
}
}

for goal in goals {
if table.try_obligation(goal).is_none() {
return IsValidCandidate::No;
Some(Solution::Ambig(Guidance::Definite(substs))) => {
canonicalized.apply_solution(table, substs);
}
Some(_) => (),
None => return IsValidCandidate::No,
}
}

IsValidCandidate::Yes
} else {
// For `ItemContainerId::TraitId`, we check if `self_ty` implements the trait in
// `iterate_trait_method_candidates()`.
// For others, this function shouldn't be called.
IsValidCandidate::Yes
for goal in goals {
if table.try_obligation(goal).is_none() {
return IsValidCandidate::No;
}
}

IsValidCandidate::Yes
})
}

Expand Down

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