averello/swift-mirror
1
0
Fork 0
mirror of https://github.com/apple/swift.git synced 2025-12-14 20:36:38 +01:00
Code Issues Packages Projects Releases Wiki Activity

Sema: Relax primary associated type matching in matchExistentialTypes()

Browse Source 
Recently I found a soundness hole here, where we would allow conversion
between `any P<T>` and `any Q<T>` even if P and Q have different primary
associated types.

However, the fix was too strict, because we still want to allow the
conversion when the associated types have the same name.

Fixes rdar://141968103.
This commit is contained in:
Slava Pestov
2025-01-10 15:32:42 -05:00
parent c17044381e
commit c257cdbc7c
2 changed files with 25 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
lib/Sema/CSSimplify.cpp
View File

@@ -4221,7 +4221,7 @@ ConstraintSystem::matchExistentialTypes(Type type1, Type type2,
// Finally, check parameterized protocol requirements.
if (!layout.getParameterizedProtocols().empty()) {
SmallVector<std::pair<AssociatedTypeDecl *, Type>, 4> fromReqs;
SmallVector<std::pair<Identifier, Type>, 4> fromReqs;
if (type1->isExistentialType()) {
auto fromLayout = type1->getExistentialLayout();
@@ -4232,8 +4232,7 @@ ConstraintSystem::matchExistentialTypes(Type type1, Type type2,
for (unsigned i : indices(argTypes)) {
auto argType = argTypes[i];
auto *assocType = assocTypes[i]->getAssociatedTypeAnchor();
fromReqs.push_back(std::make_pair(assocType, argType));
fromReqs.push_back(std::make_pair(assocTypes[i]->getName(), argType));
}
}
}
@@ -4248,10 +4247,9 @@ ConstraintSystem::matchExistentialTypes(Type type1, Type type2,
for (unsigned i : indices(argTypes)) {
auto argType = argTypes[i];
auto *assocType = assocTypes[i]->getAssociatedTypeAnchor();
bool found = false;
for (auto fromReq : fromReqs) {
if (fromReq.first == assocType) {
if (fromReq.first == assocTypes[i]->getName()) {
// FIXME: Extend the locator path to point to the argument
// inducing the requirement.
auto result = matchTypes(fromReq.second, argType,

23
test/Constraints/parameterized_existential_unrelated_args.swift
View File

@@ -31,4 +31,25 @@ var q: any Q<String> = p // expected-error {{cannot convert value of type 'any P
// Previously we accepted the above conversion, and then getB()
// would return something that was dynamically Array<String>
// and not String as expected.
print(q.getB())
// print(q.getB())
// However, this is OK -- the two A's have the same name, so by the
// semantics of the generics system they must be equivalent as type
// parameters.
protocol P1<A> {
associatedtype A
}
protocol P2<A> {
associatedtype A
}
protocol P3<A>: P1, P2 {
associatedtype A
}
func f<T>(_ value: any P3<T>) -> (any P1<T>, any P2<T>) {
return (value, value)
}