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[CodeCompletion] Use Self type in extension for generic substitution when doing implicit member lookup on protocol type #75648

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Merged
merged 1 commit into from
Aug 2, 2024
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[CodeCompletion] Use Self type in extension for generic substitution when doing implicit member lookup on protocol type #75648

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29 changes: 29 additions & 0 deletions lib/IDE/CompletionLookup.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -720,6 +720,35 @@ Type CompletionLookup::getTypeOfMember(const ValueDecl *VD, Type ExprType) {
if (MaybeNominalType->hasUnboundGenericType())
return T;

// If we are doing implicit member lookup on a protocol and we have found
// a declaration in an extension, use the extension's `Self` type for the
// generic substitution.
// Eg in the following, the `Self` type returned by `qux` is
// `MyGeneric<Int>`, not `MyProto` because of the `Self` type restriction.
// ```
// protocol MyProto {}
// struct MyGeneric<T>: MyProto {}
// extension MyProto where Self == MyGeneric<Int> {
// static func qux() -> Self { .init() }
// }
// func takeMyProto(_: any MyProto) {}
// func test() {
// takeMyProto(.#^COMPLETE^#)
// }
// ```
if (MaybeNominalType->isExistentialType()) {
Type SelfType;
if (auto ED = dyn_cast<ExtensionDecl>(VD->getDeclContext())) {
SelfType = ED->getGenericSignature()->getConcreteType(
ED->getSelfInterfaceType());
}
if (SelfType) {
MaybeNominalType = SelfType;
} else {
return T;
}
}

// For everything else, substitute in the base type.
auto Subs = MaybeNominalType->getMemberSubstitutionMap(VD);

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2 changes: 1 addition & 1 deletion test/IDE/complete_from_stdlib.swift
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Expand Up @@ -28,7 +28,7 @@ func protocolExtCollection1b(_ a: Collection) {
}

// FIXME(https://github.com/apple/swift/issues/65696): We should not be showing this because (1) it cannot be accessed on the existential (2) we don't have the syntax and features to represent the projected type sig anyway.
// PRIVATE_NOMINAL_MEMBERS_2B-DAG: map({#(transform): (any Collection.Element) throws(Error) -> T##(any Collection.Element) throws(Error) -> T#})[' throws'][#[T]#]{{; name=.+}}
// PRIVATE_NOMINAL_MEMBERS_2B-DAG: map({#(transform): (Collection.Element) throws(Error) -> T##(Collection.Element) throws(Error) -> T#})[' throws'][#[T]#]{{; name=.+}}
// NEGATIVE_PRIVATE_NOMINAL_MEMBERS_2B-NOT: Decl{{.*}}: index({#before: any Comparable#})

func protocolExtCollection2<C : Collection where C.Index : BidirectionalIndex>(_ a: C) {
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2 changes: 1 addition & 1 deletion test/IDE/complete_rdar129024996.swift
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Expand Up @@ -46,4 +46,4 @@ extension P where Self == B<A> {
func bar() {}
// COMPLETE: Begin completions, 2 items
// COMPLETE-DAG: Decl[StaticMethod]/Super/TypeRelation[Convertible]: foo()[#S#]; name=foo()
// COMPLETE-DAG: Decl[StaticMethod]/Super/Flair[ExprSpecific]/TypeRelation[Convertible]: qux()[#any Q#]; name=qux()
// COMPLETE-DAG: Decl[StaticMethod]/Super/TypeRelation[Convertible]: qux()[#B<S>#]; name=qux()
10 changes: 5 additions & 5 deletions test/IDE/complete_value_expr.swift
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Expand Up @@ -1523,8 +1523,8 @@ func testUnusableProtExt(_ x: PWithT) {
x.#^PROTOCOL_EXT_UNUSABLE_EXISTENTIAL^#
}
// FIXME(https://github.com/apple/swift/issues/65696): We should not be showing these because (1) they cannot be accessed on the existential (2) we don't have the syntax and features to represent the projected type sigs anyway.
// PROTOCOL_EXT_UNUSABLE_EXISTENTIAL: Decl[InstanceMethod]/CurrNominal: foo({#(x): any PWithT.T#})[#any PWithT.T#]{{; name=.+}}
// PROTOCOL_EXT_UNUSABLE_EXISTENTIAL: Decl[InstanceMethod]/CurrNominal: bar({#(x): any PWithT.T#})[#any PWithT.T#]{{; name=.+}}
// PROTOCOL_EXT_UNUSABLE_EXISTENTIAL: Decl[InstanceMethod]/CurrNominal: foo({#(x): PWithT.T#})[#PWithT.T#]{{; name=.+}}
// PROTOCOL_EXT_UNUSABLE_EXISTENTIAL: Decl[InstanceMethod]/CurrNominal: bar({#(x): PWithT.T#})[#PWithT.T#]{{; name=.+}}

protocol dedupP {
associatedtype T
Expand Down Expand Up @@ -1559,10 +1559,10 @@ func testDeDuped(_ x: dedupS) {
func testDeDuped2(_ x: dedupP) {
x#^PROTOCOL_EXT_DEDUP_2^#
// PROTOCOL_EXT_DEDUP_2: Begin completions, 5 items
// PROTOCOL_EXT_DEDUP_2-DAG: Decl[InstanceMethod]/CurrNominal: .foo()[#any dedupP.T#]; name=foo()
// PROTOCOL_EXT_DEDUP_2-DAG: Decl[InstanceVar]/CurrNominal: .bar[#any dedupP.T#]; name=bar
// PROTOCOL_EXT_DEDUP_2-DAG: Decl[InstanceMethod]/CurrNominal: .foo()[#dedupP.T#]; name=foo()
// PROTOCOL_EXT_DEDUP_2-DAG: Decl[InstanceVar]/CurrNominal: .bar[#dedupP.T#]; name=bar
// FIXME(https://github.com/apple/swift/issues/65696): We should not be showing this because (1) it cannot be accessed on the existential (2) we don't have the syntax and features to represent the projected type sig anyway.
// PROTOCOL_EXT_DEDUP_2-DAG: Decl[Subscript]/CurrNominal: [{#(x): any dedupP.T#}][#any dedupP.T#]; name=[:]
// PROTOCOL_EXT_DEDUP_2-DAG: Decl[Subscript]/CurrNominal: [{#(x): dedupP.T#}][#dedupP.T#]; name=[:]
// PROTOCOL_EXT_DEDUP_2-DAG: Keyword[self]/CurrNominal: .self[#any dedupP#]; name=self
}
func testDeDuped3<T : dedupP where T.T == Int>(_ x: T) {
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