Merge pull request swiftlang#76705 from slavapestov/existential-parameterized-composition

Allow existential parameterized compositions: `any P<A> & Q`

Author: slavapestov

lib/AST/ASTDemangler.cpp

@@ -767,65 +767,88 @@ Type ASTBuilder::createExistentialMetatypeType(
 Type ASTBuilder::createConstrainedExistentialType(
     Type base, ArrayRef<BuiltRequirement> constraints,
     ArrayRef<BuiltInverseRequirement> inverseRequirements) {
-  Type constrainedBase;
-
-  if (auto baseTy = base->getAs<ProtocolType>()) {
-    auto baseDecl = baseTy->getDecl();
-    llvm::SmallDenseMap<Identifier, Type> cmap;
-    for (const auto &req : constraints) {
-      switch (req.getKind()) {
-      case RequirementKind::SameShape:
-        llvm_unreachable("Same-shape requirement not supported here");
-      case RequirementKind::Conformance:
-      case RequirementKind::Superclass:
-      case RequirementKind::Layout:
-        continue;
+  llvm::SmallDenseMap<Identifier, Type> primaryAssociatedTypes;
+  llvm::SmallDenseSet<Identifier> claimed;
+
+  for (const auto &req : constraints) {
+    switch (req.getKind()) {
+    case RequirementKind::SameShape:
+    case RequirementKind::Conformance:
+    case RequirementKind::Superclass:
+    case RequirementKind::Layout:
+      break;
 
-      case RequirementKind::SameType:
-        if (auto *DMT = req.getFirstType()->getAs<DependentMemberType>())
-          cmap[DMT->getName()] = req.getSecondType();
+    case RequirementKind::SameType: {
+      if (auto *memberTy = req.getFirstType()->getAs<DependentMemberType>()) {
+        if (memberTy->getBase()->is<GenericTypeParamType>()) {
+          // This is the only case we understand so far.
+          primaryAssociatedTypes[memberTy->getName()] = req.getSecondType();
+          continue;
+        }
       }
+      break;
+    }
     }
+
+    // If we end here, we didn't recognize this requirement.
+    return Type();
+  }
+
+  auto maybeFormParameterizedProtocolType = [&](ProtocolType *protoTy) -> Type {
+    auto *proto = protoTy->getDecl();
+
     llvm::SmallVector<Type, 4> args;
-    for (auto *assocTy : baseDecl->getPrimaryAssociatedTypes()) {
-      auto argTy = cmap.find(assocTy->getName());
-      if (argTy == cmap.end()) {
-        return Type();
-      }
-      args.push_back(argTy->getSecond());
+    for (auto *assocTy : proto->getPrimaryAssociatedTypes()) {
+      auto found = primaryAssociatedTypes.find(assocTy->getName());
+      if (found == primaryAssociatedTypes.end())
+        return protoTy;
+      args.push_back(found->second);
+      claimed.insert(found->first);
     }
 
     // We may not have any arguments because the constrained existential is a
     // plain protocol with an inverse requirement.
-    if (args.empty()) {
-      constrainedBase =
-          ProtocolType::get(baseDecl, baseTy, base->getASTContext());
-    } else {
-      constrainedBase =
-          ParameterizedProtocolType::get(base->getASTContext(), baseTy, args);
-    }
-  } else if (base->isAny()) {
-    // The only other case should be that we got an empty PCT, which is equal to
-    // the Any type. The other constraints should have been encoded in the
-    // existential's generic signature (and arrive as BuiltInverseRequirement).
-    constrainedBase = base;
+    if (args.empty())
+      return protoTy;
+
+    return ParameterizedProtocolType::get(Ctx, protoTy, args);
+  };
+
+  SmallVector<Type, 2> members;
+  bool hasExplicitAnyObject = false;
+  InvertibleProtocolSet inverses;
+
+  // We're given either a single protocol type, or a composition of protocol
+  // types. Transform each protocol type to add arguments, if necessary.
+  if (auto protoTy = base->getAs<ProtocolType>()) {
+    members.push_back(maybeFormParameterizedProtocolType(protoTy));
   } else {
-    return Type();
+    auto compositionTy = base->castTo<ProtocolCompositionType>();
+    hasExplicitAnyObject = compositionTy->hasExplicitAnyObject();
+    ASSERT(compositionTy->getInverses().empty());
+
+    for (auto member : compositionTy->getMembers()) {
+      if (auto *protoTy = member->getAs<ProtocolType>()) {
+        members.push_back(maybeFormParameterizedProtocolType(protoTy));
+        continue;
+      }
+      ASSERT(member->getClassOrBoundGenericClass());
+      members.push_back(member);
+    }
   }
 
-  assert(constrainedBase);
+  // Make sure that all arguments were actually used.
+  ASSERT(claimed.size() == primaryAssociatedTypes.size());
 
   // Handle inverse requirements.
   if (!inverseRequirements.empty()) {
-    InvertibleProtocolSet inverseSet;
     for (const auto &inverseReq : inverseRequirements) {
-      inverseSet.insert(inverseReq.getKind());
+      inverses.insert(inverseReq.getKind());
     }
-    constrainedBase = ProtocolCompositionType::get(
-        Ctx, { constrainedBase }, inverseSet, /*hasExplicitAnyObject=*/false);
   }
 
-  return ExistentialType::get(constrainedBase);
+  return ExistentialType::get(ProtocolCompositionType::get(
+      Ctx, members, inverses, hasExplicitAnyObject));
 }
 
 Type ASTBuilder::createSymbolicExtendedExistentialType(NodePointer shapeNode,

lib/Sema/TypeCheckType.cpp

@@ -6002,11 +6002,7 @@ TypeResolver::resolveCompositionType(CompositionTypeRepr *repr,
       continue;
     }
 
-    // FIXME: Support compositions involving parameterized protocol types,
-    // like 'any Collection<String> & Sendable', etc.
-    if (ty->is<ParameterizedProtocolType>() &&
-        !options.isConstraintImplicitExistential() &&
-        options.getContext() != TypeResolverContext::ExistentialConstraint) {
+    if (ty->is<ParameterizedProtocolType>()) {
       checkMember(tyR->getStartLoc(), ty);
       Members.push_back(ty);
       continue;

test/Constraints/parameterized_existential_composition.swift

@@ -0,0 +1,61 @@
+// RUN: %target-typecheck-verify-swift -disable-availability-checking
+
+func f1(_ s: any Sequence<Int> & Hashable) -> any Sequence<Int> {
+  return s
+}
+
+func f2(_ s: any Sequence<Int> & Hashable) -> any Hashable {
+  return s
+}
+
+func f3(_ s: any Sequence<Int> & Hashable) -> any Sequence {
+  return s
+}
+
+func f4(_ s: any Sequence<Int> & Hashable) -> any Sequence & Hashable {
+  return s
+}
+
+func f5(_ s: any Sequence<Int> & Hashable) -> any Sequence<Int> & Equatable {
+  return s
+}
+
+func f6(_ s: any Sequence<Int> & Hashable) -> any Sequence<String> & Hashable {
+  return s // expected-error {{cannot convert return expression of type 'Int' to return type 'String'}}
+}
+
+func f7(_ s: any Sequence<Int> & Hashable) -> any Sequence<String> {
+  return s // expected-error {{cannot convert return expression of type 'Int' to return type 'String'}}
+}
+
+func f8(_ s: any Collection<Int> & Hashable) -> any Sequence<Int> & Hashable {
+  return s
+}
+
+// https://github.com/swiftlang/swift/issues/71012
+
+protocol A<T> {
+  associatedtype T
+}
+protocol B {}
+typealias C = A & B
+typealias D<T> = A<T> & B
+
+struct Foo: C {
+  typealias T = Int
+}
+
+struct Bar<Value> { // expected-note {{arguments to generic parameter 'Value' ('any C' (aka 'any A & B') and 'any A<Int> & B') are expected to be equal}}
+  let value: Value
+}
+
+struct Baz<U> {
+  let bar: Bar<any D<U>>
+}
+
+func run() {
+  let foo: any C = Foo()
+  let bar = Bar(value: foo)
+  _ = Baz<Int>(bar: bar)
+  // expected-error@-1 {{cannot convert value of type 'Bar<any C>' (aka 'Bar<any A & B>') to expected argument type 'Bar<any A<Int> & B>'}}
+}

test/DebugInfo/parameterized_existential_composition.swift

@@ -0,0 +1,36 @@
+// RUN: %target-swift-frontend -emit-ir %s -g -target %target-swift-5.9-abi-triple
+
+public protocol P<A, B> {
+  associatedtype A
+  associatedtype B
+}
+
+public protocol Q<C> {
+  associatedtype C
+}
+
+public protocol R {}
+
+public class C<T: Equatable> {}
+
+public func foo(_ a: any P<Int, Float> & R) {}
+public func foo(_ a: any P<Int, Float> & Q<String>) {}
+public func foo(_ a: any P<Int, Float> & Q<String> & R) {}
+public func foo(_ a: any P<Int, Float> & Q<String> & R & C<Bool>) {}
+public func foo(_ a: any P<Int, Float> & Q<String> & R & AnyObject) {}
+
+public func foo(_ a: any (P<Int, Float> & R).Type) {}
+public func foo(_ a: any (P<Int, Float> & Q<String>).Type) {}
+public func foo(_ a: any (P<Int, Float> & Q<String> & R).Type) {}
+public func foo(_ a: any (P<Int, Float> & Q<String> & R & C<Bool>).Type) {}
+public func foo(_ a: any (P<Int, Float> & Q<String> & R & AnyObject).Type) {}
+
+public func foo(_ a: (any P<Int, Float> & R).Type) {}
+public func foo(_ a: (any P<Int, Float> & Q<String>).Type) {}
+public func foo(_ a: (any P<Int, Float> & Q<String> & R).Type) {}
+public func foo(_ a: (any P<Int, Float> & Q<String> & R & C<Bool>).Type) {}
+public func foo(_ a: (any P<Int, Float> & Q<String> & R & AnyObject).Type) {}
+
+public struct Foo<each T, U> {
+  public var a1: (repeat any P<each T, U> & R)
+}

test/SILGen/parameterized_existential_composition.swift

@@ -0,0 +1,40 @@
+// RUN: %target-swift-emit-silgen -disable-availability-checking %s | %FileCheck %s
+
+protocol P<A> {
+  associatedtype A
+}
+
+protocol Q<B> {
+  associatedtype B
+}
+
+// All of these should have unique mangling.
+func overload(_: any P<Int> & Q<String>) {}
+func overload(_: any P<Float> & Q<String>) {}
+func overload(_: any P & Q<String>) {}
+func overload(_: any P<Int> & Q<Bool>) {}
+func overload(_: any P<Float> & Q<Bool>) {}
+func overload(_: any P & Q<Bool>) {}
+func overload(_: any P<Int> & Q) {}
+func overload(_: any P<Float> & Q) {}
+func overload(_: any P & Q) {}
+func overload(_: any P<Int>) {}
+func overload(_: any P<Float>) {}
+func overload(_: any P) {}
+func overload(_: any Q<Bool>) {}
+func overload(_: any Q) {}
+
+// CHECK-LABEL: sil hidden [ossa] @$s37parameterized_existential_composition8overloadyyAA1P_AA1QpSi1AAaCPRts_SS1BAaDPRtsXPF : $@convention(thin) (@in_guaranteed any P<Int> & Q<String>) -> () {
+// CHECK-LABEL: sil hidden [ossa] @$s37parameterized_existential_composition8overloadyyAA1P_AA1QpSf1AAaCPRts_SS1BAaDPRtsXPF : $@convention(thin) (@in_guaranteed any P<Float> & Q<String>) -> () {
+// CHECK-LABEL: sil hidden [ossa] @$s37parameterized_existential_composition8overloadyyAA1P_AA1QpSS1BAaDPRts_XPF : $@convention(thin) (@in_guaranteed any P & Q<String>) -> () {
+// CHECK-LABEL: sil hidden [ossa] @$s37parameterized_existential_composition8overloadyyAA1P_AA1QpSi1AAaCPRts_Sb1BAaDPRtsXPF : $@convention(thin) (@in_guaranteed any P<Int> & Q<Bool>) -> () {
+// CHECK-LABEL: sil hidden [ossa] @$s37parameterized_existential_composition8overloadyyAA1P_AA1QpSf1AAaCPRts_Sb1BAaDPRtsXPF : $@convention(thin) (@in_guaranteed any P<Float> & Q<Bool>) -> () {
+// CHECK-LABEL: sil hidden [ossa] @$s37parameterized_existential_composition8overloadyyAA1P_AA1QpSb1BAaDPRts_XPF : $@convention(thin) (@in_guaranteed any P & Q<Bool>) -> () {
+// CHECK-LABEL: sil hidden [ossa] @$s37parameterized_existential_composition8overloadyyAA1P_AA1QpSi1AAaCPRts_XPF : $@convention(thin) (@in_guaranteed any P<Int> & Q) -> () {
+// CHECK-LABEL: sil hidden [ossa] @$s37parameterized_existential_composition8overloadyyAA1P_AA1QpSf1AAaCPRts_XPF : $@convention(thin) (@in_guaranteed any P<Float> & Q) -> () {
+// CHECK-LABEL: sil hidden [ossa] @$s37parameterized_existential_composition8overloadyyAA1P_AA1QpF : $@convention(thin) (@in_guaranteed any P & Q) -> () {
+// CHECK-LABEL: sil hidden [ossa] @$s37parameterized_existential_composition8overloadyyAA1P_pSi1AAaCPRts_XPF : $@convention(thin) (@in_guaranteed any P<Int>) -> () {
+// CHECK-LABEL: sil hidden [ossa] @$s37parameterized_existential_composition8overloadyyAA1P_pSf1AAaCPRts_XPF : $@convention(thin) (@in_guaranteed any P<Float>) -> () {
+// CHECK-LABEL: sil hidden [ossa] @$s37parameterized_existential_composition8overloadyyAA1P_pF : $@convention(thin) (@in_guaranteed any P) -> () {
+// CHECK-LABEL: sil hidden [ossa] @$s37parameterized_existential_composition8overloadyyAA1Q_pSb1BAaCPRts_XPF : $@convention(thin) (@in_guaranteed any Q<Bool>) -> () {
+// CHECK-LABEL: sil hidden [ossa] @$s37parameterized_existential_composition8overloadyyAA1Q_pF : $@convention(thin) (@in_guaranteed any Q) -> () {

test/decl/protocol/existential_member_access/basic.swift

@@ -506,8 +506,6 @@ do {
     func invariant11() -> Struct<${type}>.InnerGeneric<Void>
     // https://github.com/apple/swift/issues/61934
     func invariant12() -> any Sequence<${type}>
-    // FIXME
-    // expected-error@+1 {{non-protocol, non-class type 'Sequence<${type}>' cannot be used within a protocol-constrained type}}
     func invariant13() -> any P & Sequence<${type}>
     func invariant14() -> (any Sequence<${type}>).Type
     func invariant15() -> any (P & Class<${type}>).Type

test/type/parameterized_existential.swift

@@ -82,16 +82,6 @@ func typeExpr() {
   _ = (any Sequence<Int>).self
 }
 
-/// Not supported as a protocol composition term for now
-
-protocol SomeProto {}
-
-func protocolCompositionNotSupported1(_: SomeProto & Sequence<Int>) {}
-// expected-error@-1 {{non-protocol, non-class type 'Sequence<Int>' cannot be used within a protocol-constrained type}}
-
-func protocolCompositionNotSupported2(_: any SomeProto & Sequence<Int>) {}
-// expected-error@-1 {{non-protocol, non-class type 'Sequence<Int>' cannot be used within a protocol-constrained type}}
-
 func increment(_ n : any Collection<Float>) {
   for value in n {
       _ = value + 1