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merged 1 commit into from
May 26, 2022
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Sema: Simplify logic for building extension generic signature #41820

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118 changes: 31 additions & 87 deletions lib/Sema/TypeCheckGeneric.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -468,23 +468,19 @@ void TypeChecker::checkReferencedGenericParams(GenericContext *dc) {
/// Generic types
///

/// Form the interface type of an extension from the raw type and the
/// extension's list of generic parameters.
static Type formExtensionInterfaceType(
ExtensionDecl *ext, Type type,
const GenericParamList *genericParams,
SmallVectorImpl<Requirement> &sameTypeReqs,
bool &mustInferRequirements) {
/// Collect additional requirements into \p sameTypeReqs.
static void collectAdditionalExtensionRequirements(
Type type, SmallVectorImpl<Requirement> &sameTypeReqs) {
if (type->is<ErrorType>())
return type;
return;

// Find the nominal type declaration and its parent type.
if (type->is<ProtocolCompositionType>())
type = type->getCanonicalType();

// A parameterized protocol type is not a nominal. Unwrap it to get
// the underlying nominal, and record a same-type requirement for
// the primary associated type.
// the primary associated types.
if (auto *paramProtoTy = type->getAs<ParameterizedProtocolType>()) {
auto *protoTy = paramProtoTy->getBaseType();
type = protoTy;
Expand All @@ -497,15 +493,9 @@ static Type formExtensionInterfaceType(
Type parentType = type->getNominalParent();
GenericTypeDecl *genericDecl = type->getAnyGeneric();

// Reconstruct the parent, if there is one.
// Visit the parent type, if there is one.
if (parentType) {
// Build the nested extension type.
auto parentGenericParams = genericDecl->getGenericParams()
? genericParams->getOuterParameters()
: genericParams;
parentType =
formExtensionInterfaceType(ext, parentType, parentGenericParams,
sameTypeReqs, mustInferRequirements);
collectAdditionalExtensionRequirements(parentType, sameTypeReqs);
}

// Find the nominal type.
Expand All @@ -516,59 +506,26 @@ static Type formExtensionInterfaceType(
nominal = type->getNominalOrBoundGenericNominal();
}

// Form the result.
Type resultType;
SmallVector<Type, 2> genericArgs;
if (!nominal->isGeneric() || isa<ProtocolDecl>(nominal)) {
resultType = NominalType::get(nominal, parentType,
nominal->getASTContext());
} else if (genericParams) {
auto currentBoundType = type->getAs<BoundGenericType>();

// Form the bound generic type with the type parameters provided.
unsigned gpIndex = 0;
for (auto gp : *genericParams) {
SWIFT_DEFER { ++gpIndex; };

// If we have a bound generic type, add same-type requirements for each of
// its generic arguments.
if (auto currentBoundType = type->getAs<BoundGenericType>()) {
auto *genericParams = currentBoundType->getDecl()->getGenericParams();
for (unsigned gpIndex : indices(genericParams->getParams())) {
auto *gp = genericParams->getParams()[gpIndex];
auto gpType = gp->getDeclaredInterfaceType();
genericArgs.push_back(gpType);

if (currentBoundType) {
sameTypeReqs.emplace_back(RequirementKind::SameType, gpType,
currentBoundType->getGenericArgs()[gpIndex]);
}
sameTypeReqs.emplace_back(RequirementKind::SameType, gpType,
currentBoundType->getGenericArgs()[gpIndex]);
}

resultType = BoundGenericType::get(nominal, parentType, genericArgs);
}

// If we have a typealias, try to form type sugar.
// If we have a passthrough typealias, add the requirements from its
// generic signature.
if (typealias && TypeChecker::isPassThroughTypealias(
typealias, typealias->getUnderlyingType(), nominal)) {
auto typealiasSig = typealias->getGenericSignature();
SubstitutionMap subMap;
if (typealiasSig) {
subMap = typealiasSig->getIdentitySubstitutionMap();

mustInferRequirements = true;
}

resultType = TypeAliasType::get(typealias, parentType, subMap, resultType);
for (auto req : typealias->getGenericSignature().getRequirements())
sameTypeReqs.push_back(req);
}


return resultType;
}

/// Retrieve the generic parameter depth of the extended type.
static unsigned getExtendedTypeGenericDepth(ExtensionDecl *ext) {
auto nominal = ext->getSelfNominalTypeDecl();
if (!nominal) return static_cast<unsigned>(-1);

auto sig = nominal->getGenericSignatureOfContext();
if (!sig) return static_cast<unsigned>(-1);

return sig.getGenericParams().back()->getDepth();
}

GenericSignature
Expand Down Expand Up @@ -605,7 +562,7 @@ GenericSignatureRequest::evaluate(Evaluator &evaluator,
}

bool allowConcreteGenericParams = false;
const auto *genericParams = GC->getGenericParams();
auto *genericParams = GC->getGenericParams();
const auto *where = GC->getTrailingWhereClause();

if (genericParams) {
Expand Down Expand Up @@ -650,10 +607,12 @@ GenericSignatureRequest::evaluate(Evaluator &evaluator,
return GC->getParentForLookup()->getGenericSignatureOfContext();
}

auto parentSig = GC->getParentForLookup()->getGenericSignatureOfContext();
GenericSignature parentSig;
SmallVector<TypeLoc, 2> inferenceSources;
SmallVector<Requirement, 2> sameTypeReqs;
if (auto VD = dyn_cast_or_null<ValueDecl>(GC->getAsDecl())) {
parentSig = GC->getParentForLookup()->getGenericSignatureOfContext();

auto func = dyn_cast<AbstractFunctionDecl>(VD);
auto subscr = dyn_cast<SubscriptDecl>(VD);

Expand Down Expand Up @@ -708,38 +667,23 @@ GenericSignatureRequest::evaluate(Evaluator &evaluator,
}
}
} else if (auto *ext = dyn_cast<ExtensionDecl>(GC)) {
// Form the interface type of the extension so we can use it as an inference
// source.
//
// FIXME: Push this into the "get interface type" request.
bool mustInferRequirements = false;
Type extInterfaceType =
formExtensionInterfaceType(ext, ext->getExtendedType(),
genericParams, sameTypeReqs,
mustInferRequirements);

auto cannotReuseNominalSignature = [&]() -> bool {
const auto finalDepth = genericParams->getParams().back()->getDepth();
return mustInferRequirements
|| !sameTypeReqs.empty()
|| ext->getTrailingWhereClause()
|| (getExtendedTypeGenericDepth(ext) != finalDepth);
};
parentSig = ext->getExtendedNominal()->getGenericSignatureOfContext();
genericParams = nullptr;

collectAdditionalExtensionRequirements(ext->getExtendedType(), sameTypeReqs);

// Re-use the signature of the type being extended by default.
if (!cannotReuseNominalSignature()) {
return ext->getSelfNominalTypeDecl()->getGenericSignatureOfContext();
// Re-use the signature of the type being extended by default.
if (sameTypeReqs.empty() && !ext->getTrailingWhereClause()) {
return parentSig;
}

// Allow parameters to be equated with concrete types.
allowConcreteGenericParams = true;

inferenceSources.emplace_back(nullptr, extInterfaceType);
}

auto request = InferredGenericSignatureRequest{
parentSig.getPointer(),
GC->getGenericParams(), WhereClauseOwner(GC),
genericParams, WhereClauseOwner(GC),
sameTypeReqs, inferenceSources,
allowConcreteGenericParams};
auto sig = evaluateOrDefault(ctx.evaluator, request,
Expand Down
3 changes: 3 additions & 0 deletions test/Generics/conditional_conformances.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -49,6 +49,7 @@ struct RedundantSame<T: P1> {}
// CHECK-LABEL: ExtensionDecl line={{.*}} base=RedundantSame
// CHECK-NEXT: (normal_conformance type=RedundantSame<T> protocol=P2)
extension RedundantSame: P2 where T: P1 {}
// expected-warning@-1 {{redundant conformance constraint 'T' : 'P1'}}

struct RedundantSuper<T: P4> {}
// CHECK-LABEL: ExtensionDecl line={{.*}} base=RedundantSuper
Expand Down Expand Up @@ -334,6 +335,8 @@ struct RedundancyOrderDependenceGood<T: P1, U> {}
// CHECK-NEXT: (normal_conformance type=RedundancyOrderDependenceGood<T, U> protocol=P2
// CHECK-NEXT: same_type: T U)
extension RedundancyOrderDependenceGood: P2 where U: P1, T == U {}
// expected-warning@-1 {{redundant conformance constraint 'U' : 'P1'}}

struct RedundancyOrderDependenceBad<T, U: P1> {}
// CHECK-LABEL: ExtensionDecl line={{.*}} base=RedundancyOrderDependenceBad
// CHECK-LABEL: ExtensionDecl line={{.*}} base=RedundancyOrderDependenceBad
Expand Down
13 changes: 9 additions & 4 deletions test/SourceKit/DocSupport/doc_swift_module.swift.response
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Original file line number Diff line number Diff line change
Expand Up @@ -1301,7 +1301,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
{
key.kind: source.lang.swift.ref.generic_type_param,
key.name: "Self",
key.usr: "s:4cake4ProtPAASi7ElementRtzrlE4Selfxmfp",
key.usr: "s:4cake4ProtP4Selfxmfp",
key.offset: 1595,
key.length: 4
},
Expand Down Expand Up @@ -1649,7 +1649,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
{
key.kind: source.lang.swift.ref.generic_type_param,
key.name: "Wrapped",
key.usr: "s:4cake2S3VA2A2P6RzrlE7Wrappedxmfp",
key.usr: "s:4cake2S3V7Wrappedxmfp",
key.offset: 2041,
key.length: 7
},
Expand Down Expand Up @@ -2557,7 +2557,7 @@ func shouldPrintAnyAsKeyword(x x: Any)
],
key.offset: 1574,
key.length: 63,
key.fully_annotated_decl: "<decl.extension.protocol><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.protocol usr=\"s:4cake4ProtP\">Prot</ref.protocol></decl.name> <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:4cake4ProtPAASi7ElementRtzrlE4Selfxmfp\">Self</ref.generic_type_param>.<ref.associatedtype usr=\"s:4cake4ProtP7ElementQa\">Element</ref.associatedtype> == <ref.struct usr=\"s:Si\">Int</ref.struct></decl.generic_type_requirement></decl.extension.protocol>",
key.fully_annotated_decl: "<decl.extension.protocol><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.protocol usr=\"s:4cake4ProtP\">Prot</ref.protocol></decl.name> <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:4cake4ProtP4Selfxmfp\">Self</ref.generic_type_param>.<ref.associatedtype usr=\"s:4cake4ProtP7ElementQa\">Element</ref.associatedtype> == <ref.struct usr=\"s:Si\">Int</ref.struct></decl.generic_type_requirement></decl.extension.protocol>",
key.extends: {
key.kind: source.lang.swift.ref.protocol,
key.name: "Prot",
Expand Down Expand Up @@ -2758,14 +2758,19 @@ func shouldPrintAnyAsKeyword(x x: Any)
},
{
key.kind: source.lang.swift.decl.extension.struct,
key.generic_params: [
{
key.name: "Wrapped"
}
],
key.generic_requirements: [
{
key.description: "Wrapped : P6"
}
],
key.offset: 2022,
key.length: 80,
key.fully_annotated_decl: "<syntaxtype.keyword>extension</syntaxtype.keyword> <ref.struct usr=\"s:4cake2S3V\">S3</ref.struct> <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:4cake2S3VA2A2P6RzrlE7Wrappedxmfp\">Wrapped</ref.generic_type_param> : <ref.protocol usr=\"s:4cake2P6P\">P6</ref.protocol></decl.generic_type_requirement>",
key.fully_annotated_decl: "<syntaxtype.keyword>extension</syntaxtype.keyword> <ref.struct usr=\"s:4cake2S3V\">S3</ref.struct> <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:4cake2S3V7Wrappedxmfp\">Wrapped</ref.generic_type_param> : <ref.protocol usr=\"s:4cake2P6P\">P6</ref.protocol></decl.generic_type_requirement>",
key.extends: {
key.kind: source.lang.swift.ref.struct,
key.name: "S3",
Expand Down
16 changes: 12 additions & 4 deletions test/SourceKit/DocSupport/doc_swift_module1.swift.response
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Original file line number Diff line number Diff line change
Expand Up @@ -569,7 +569,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
{
key.kind: source.lang.swift.ref.generic_type_param,
key.name: "Self",
key.usr: "s:5cake12P2PA2A2P3RzrlE4Selfxmfp",
key.usr: "s:5cake12P2P4Selfxmfp",
key.offset: 670,
key.length: 4
},
Expand Down Expand Up @@ -671,7 +671,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
{
key.kind: source.lang.swift.ref.generic_type_param,
key.name: "Key",
key.usr: "s:SD4KeysV5cake1AC2P1RzrlE3Keyxmfp",
key.usr: "s:SD3Keyxmfp",
key.offset: 836,
key.length: 3
},
Expand Down Expand Up @@ -1038,7 +1038,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
],
key.offset: 651,
key.length: 64,
key.fully_annotated_decl: "<decl.extension.protocol><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.protocol usr=\"s:5cake12P2P\">P2</ref.protocol></decl.name> <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:5cake12P2PA2A2P3RzrlE4Selfxmfp\">Self</ref.generic_type_param> : <ref.protocol usr=\"s:5cake12P3P\">P3</ref.protocol></decl.generic_type_requirement></decl.extension.protocol>",
key.fully_annotated_decl: "<decl.extension.protocol><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.protocol usr=\"s:5cake12P2P\">P2</ref.protocol></decl.name> <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:5cake12P2P4Selfxmfp\">Self</ref.generic_type_param> : <ref.protocol usr=\"s:5cake12P3P\">P3</ref.protocol></decl.generic_type_requirement></decl.extension.protocol>",
key.extends: {
key.kind: source.lang.swift.ref.protocol,
key.name: "P2",
Expand Down Expand Up @@ -1110,6 +1110,14 @@ extension Dictionary.Keys where Key : cake1.P1 {
},
{
key.kind: source.lang.swift.decl.extension.struct,
key.generic_params: [
{
key.name: "Key"
},
{
key.name: "Value"
}
],
key.generic_requirements: [
{
key.description: "Key : Hashable"
Expand All @@ -1120,7 +1128,7 @@ extension Dictionary.Keys where Key : cake1.P1 {
],
key.offset: 804,
key.length: 66,
key.fully_annotated_decl: "<decl.extension.struct><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.struct usr=\"s:SD\">Dictionary</ref.struct>.<ref.struct usr=\"s:SD4KeysV\">Keys</ref.struct></decl.name> <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:SD4KeysV5cake1AC2P1RzrlE3Keyxmfp\">Key</ref.generic_type_param> : <ref.protocol usr=\"s:5cake12P1P\">P1</ref.protocol></decl.generic_type_requirement></decl.extension.struct>",
key.fully_annotated_decl: "<decl.extension.struct><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.struct usr=\"s:SD\">Dictionary</ref.struct>.<ref.struct usr=\"s:SD4KeysV\">Keys</ref.struct></decl.name> <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:SD3Keyxmfp\">Key</ref.generic_type_param> : <ref.protocol usr=\"s:5cake12P1P\">P1</ref.protocol></decl.generic_type_requirement></decl.extension.struct>",
key.extends: {
key.kind: source.lang.swift.ref.struct,
key.name: "Keys",
Expand Down
17 changes: 11 additions & 6 deletions test/SourceKit/DocSupport/doc_swift_module_class_extension.swift.response
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Original file line number Diff line number Diff line change
Expand Up @@ -129,7 +129,7 @@ extension P8 where Self.T : module_with_class_extension.E {
{
key.kind: source.lang.swift.ref.generic_type_param,
key.name: "T",
key.usr: "s:27module_with_class_extension1CCA2A1DCRbzlE1Txmfp",
key.usr: "s:27module_with_class_extension1CC1Txmfp",
key.offset: 130,
key.length: 1
},
Expand Down Expand Up @@ -344,7 +344,7 @@ extension P8 where Self.T : module_with_class_extension.E {
{
key.kind: source.lang.swift.ref.generic_type_param,
key.name: "Self",
key.usr: "s:27module_with_class_extension2P8PA2A1DC1TRczrlE4Selfxmfp",
key.usr: "s:27module_with_class_extension2P8P4Selfxmfp",
key.offset: 480,
key.length: 4
},
Expand Down Expand Up @@ -397,7 +397,7 @@ extension P8 where Self.T : module_with_class_extension.E {
{
key.kind: source.lang.swift.ref.generic_type_param,
key.name: "Self",
key.usr: "s:27module_with_class_extension2P8PA2A1EC1TRczrlE4Selfxmfp",
key.usr: "s:27module_with_class_extension2P8P4Selfxmfp",
key.offset: 559,
key.length: 4
},
Expand Down Expand Up @@ -470,14 +470,19 @@ extension P8 where Self.T : module_with_class_extension.E {
},
{
key.kind: source.lang.swift.decl.extension.class,
key.generic_params: [
{
key.name: "T"
}
],
key.generic_requirements: [
{
key.description: "T : D"
}
],
key.offset: 112,
key.length: 87,
key.fully_annotated_decl: "<decl.extension.class><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.class usr=\"s:27module_with_class_extension1CC\">C</ref.class></decl.name> <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:27module_with_class_extension1CCA2A1DCRbzlE1Txmfp\">T</ref.generic_type_param> : <ref.class usr=\"s:27module_with_class_extension1DC\">D</ref.class></decl.generic_type_requirement></decl.extension.class>",
key.fully_annotated_decl: "<decl.extension.class><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.class usr=\"s:27module_with_class_extension1CC\">C</ref.class></decl.name> <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:27module_with_class_extension1CC1Txmfp\">T</ref.generic_type_param> : <ref.class usr=\"s:27module_with_class_extension1DC\">D</ref.class></decl.generic_type_requirement></decl.extension.class>",
key.extends: {
key.kind: source.lang.swift.ref.class,
key.name: "C",
Expand Down Expand Up @@ -630,7 +635,7 @@ extension P8 where Self.T : module_with_class_extension.E {
],
key.offset: 461,
key.length: 77,
key.fully_annotated_decl: "<decl.extension.protocol><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.protocol usr=\"s:27module_with_class_extension2P8P\">P8</ref.protocol></decl.name> <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:27module_with_class_extension2P8PA2A1DC1TRczrlE4Selfxmfp\">Self</ref.generic_type_param>.<ref.associatedtype usr=\"s:27module_with_class_extension2P8P1TQa\">T</ref.associatedtype> : <ref.class usr=\"s:27module_with_class_extension1DC\">D</ref.class></decl.generic_type_requirement></decl.extension.protocol>",
key.fully_annotated_decl: "<decl.extension.protocol><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.protocol usr=\"s:27module_with_class_extension2P8P\">P8</ref.protocol></decl.name> <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:27module_with_class_extension2P8P4Selfxmfp\">Self</ref.generic_type_param>.<ref.associatedtype usr=\"s:27module_with_class_extension2P8P1TQa\">T</ref.associatedtype> : <ref.class usr=\"s:27module_with_class_extension1DC\">D</ref.class></decl.generic_type_requirement></decl.extension.protocol>",
key.extends: {
key.kind: source.lang.swift.ref.protocol,
key.name: "P8",
Expand All @@ -656,7 +661,7 @@ extension P8 where Self.T : module_with_class_extension.E {
],
key.offset: 540,
key.length: 77,
key.fully_annotated_decl: "<decl.extension.protocol><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.protocol usr=\"s:27module_with_class_extension2P8P\">P8</ref.protocol></decl.name> <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:27module_with_class_extension2P8PA2A1EC1TRczrlE4Selfxmfp\">Self</ref.generic_type_param>.<ref.associatedtype usr=\"s:27module_with_class_extension2P8P1TQa\">T</ref.associatedtype> : <ref.class usr=\"s:27module_with_class_extension1EC\">E</ref.class></decl.generic_type_requirement></decl.extension.protocol>",
key.fully_annotated_decl: "<decl.extension.protocol><syntaxtype.keyword>extension</syntaxtype.keyword> <decl.name><ref.protocol usr=\"s:27module_with_class_extension2P8P\">P8</ref.protocol></decl.name> <syntaxtype.keyword>where</syntaxtype.keyword> <decl.generic_type_requirement><ref.generic_type_param usr=\"s:27module_with_class_extension2P8P4Selfxmfp\">Self</ref.generic_type_param>.<ref.associatedtype usr=\"s:27module_with_class_extension2P8P1TQa\">T</ref.associatedtype> : <ref.class usr=\"s:27module_with_class_extension1EC\">E</ref.class></decl.generic_type_requirement></decl.extension.protocol>",
key.extends: {
key.kind: source.lang.swift.ref.protocol,
key.name: "P8",
Expand Down
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