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[ConstraintSystem] Don't introduce implicit keypath choice for keypath dynamic member lookup

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This commit is contained in:
Pavel Yaskevich
2019-03-27 01:07:50 -07:00
parent 7032095b53
commit 41f6eb9a15
2 changed files with 25 additions and 15 deletions
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37
lib/Sema/CSSimplify.cpp
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@@ -3537,6 +3537,10 @@ static bool hasDynamicMemberLookupAttribute(Type type,
return result; return result;
} }
static bool isKeyPathDynamicMemberLookup(ConstraintLocator *locator) {
auto path = locator ? locator->getPath() : None;
return !path.empty() && path.back().isKeyPathDynamicMember();
}
/// Given a ValueMember, UnresolvedValueMember, or TypeMember constraint, /// Given a ValueMember, UnresolvedValueMember, or TypeMember constraint,
/// perform a lookup into the specified base type to find a candidate list. /// perform a lookup into the specified base type to find a candidate list.
@@ -3568,10 +3572,15 @@ performMemberLookup(ConstraintKind constraintKind, DeclName memberName,
// Okay, start building up the result list. // Okay, start building up the result list.
MemberLookupResult result; MemberLookupResult result;
result.OverallResult = MemberLookupResult::HasResults; result.OverallResult = MemberLookupResult::HasResults;
// If we're looking for a subscript, consider key path operations. // If we're looking for a subscript, consider key path operations.
//
// TODO: This logic needs to be refactored to make sure that implicit
// keypath result is only introduced when it makes sense e.g. if there
// is a single argument with `keypath:` label or `\.` syntax is used.
if (memberName.isSimpleName() && if (memberName.isSimpleName() &&
memberName.getBaseName().getKind() == DeclBaseName::Kind::Subscript) { memberName.getBaseName().getKind() == DeclBaseName::Kind::Subscript &&
!isKeyPathDynamicMemberLookup(memberLocator)) {
result.ViableCandidates.push_back( result.ViableCandidates.push_back(
OverloadChoice(baseTy, OverloadChoiceKind::KeyPathApplication)); OverloadChoice(baseTy, OverloadChoiceKind::KeyPathApplication));
} }
@@ -3831,20 +3840,18 @@ performMemberLookup(ConstraintKind constraintKind, DeclName memberName,
// based dynamic member lookup. Since it's unknown upfront // based dynamic member lookup. Since it's unknown upfront
// what kind of declaration lookup is going to find, let's // what kind of declaration lookup is going to find, let's
// double check here that given keypath is appropriate for it. // double check here that given keypath is appropriate for it.
if (memberLocator) { if (isKeyPathDynamicMemberLookup(memberLocator)) {
auto path = memberLocator->getPath(); auto path = memberLocator->getPath();
if (!path.empty() && path.back().isKeyPathDynamicMember()) { auto *keyPath = path.back().getKeyPath();
auto *keyPath = path.back().getKeyPath(); if (auto *storage = dyn_cast<AbstractStorageDecl>(decl)) {
if (auto *storage = dyn_cast<AbstractStorageDecl>(decl)) { // If this is an attempt to access read-only member via
// If this is an attempt to access read-only member via // writable key path, let's fail this choice early.
// writable key path, let's fail this choice early. if (isReadOnlyKeyPathComponent(storage) &&
if (isReadOnlyKeyPathComponent(storage) && keyPath == getASTContext().getWritableKeyPathDecl()) {
keyPath == getASTContext().getWritableKeyPathDecl()) { result.addUnviable(
result.addUnviable( candidate,
candidate, MemberLookupResult::UR_WritableKeyPathOnReadOnlyMember);
MemberLookupResult::UR_WritableKeyPathOnReadOnlyMember); return;
return;
}
} }
} }
} }

3
test/attr/attr_dynamic_member_lookup.swift
View File

@@ -601,6 +601,9 @@ struct WithTrailingClosure {
func keypath_with_trailing_closure_subscript(_ ty: inout SubscriptLens<WithTrailingClosure>) { func keypath_with_trailing_closure_subscript(_ ty: inout SubscriptLens<WithTrailingClosure>) {
_ = ty[0] { 42 } // expected-error {{subscript index of type '() -> Int' in a key path must be Hashable}} _ = ty[0] { 42 } // expected-error {{subscript index of type '() -> Int' in a key path must be Hashable}}
_ = ty[0] { 42 } = 0 // FIXME(diagnostics): Once keypath related diagnostics are using fixes, "ambiguous" error would disappear
// expected-error@-1 {{subscript index of type '() -> Int' in a key path must be Hashable}}
// expected-error@-2 {{type of expression is ambiguous without more context}}
_ = ty[] { 42 } // expected-error {{subscript index of type '() -> Int' in a key path must be Hashable}} _ = ty[] { 42 } // expected-error {{subscript index of type '() -> Int' in a key path must be Hashable}}
_ = ty[] { 42 } = 0 // expected-error {{subscript index of type '() -> Int' in a key path must be Hashable}} _ = ty[] { 42 } = 0 // expected-error {{subscript index of type '() -> Int' in a key path must be Hashable}}
} }