Merge pull request #72528 from slavapestov/cherry-picks-6.0

[6.0] Cherry pick name lookup fixes

Author: slavapestov

CHANGELOG.md

@@ -4,6 +4,38 @@
 > This is in reverse chronological order, so newer entries are added to the top.
 
 ## Swift 6.0
+
+* Swift 5.10 missed a semantic check from [SE-0309][]. In type context, a reference to a
+  protocol `P` that has associated types or `Self` requirements should use
+  the `any` keyword, but this was not enforced in nested generic argument positions.
+  This is now an error as required by the proposal:
+
+  ```swift
+  protocol P { associatedtype A }
+  struct Outer<T> { struct Inner<U> { } }
+  let x = Outer<P>.Inner<P>()  // error
+  ```
+  To correct the error, add `any` where appropriate, for example
+  `Outer<any P>.Inner<any P>`.
+
+* Swift 5.10 accepted certain invalid opaque return types from [SE-0346][].
+  If a generic argument of a constrained opaque return type did not
+  satisfy the requirements on the primary associated type, the generic
+  argument was silently ignored and type checking would proceed as if it
+  weren't stated. This now results in a diagnostic:
+
+  ```swift
+  protocol P<A> { associatedtype A: Sequence }
+  struct G<A: Sequence>: P {}
+
+  func f() -> some P<Int> { return G<Array<Int>>() }  // error
+  ```
+
+  The return type above should be written as `some P<Array<Int>>` to match
+  the return statement. The old broken behavior in this situation can also
+  be restored, by removing the erroneous constraint and using the more general
+  upper bound `some P`.
+
 * [SE-0408][]:
   A `for`-`in` loop statement can now accept a pack expansion expression,
   enabling iteration over the elements of its respective value pack. This form

include/swift/AST/ASTScope.h

@@ -482,45 +482,33 @@ class Portion : public ASTAllocated<ASTScopeImpl> {
 
   virtual NullablePtr<ASTScopeImpl>
   insertionPointForDeferredExpansion(IterableTypeScope *) const = 0;
-  };
-
-  // For the whole Decl scope of a GenericType or an Extension
-  class GenericTypeOrExtensionWholePortion final : public Portion {
-  public:
-    GenericTypeOrExtensionWholePortion() : Portion("Decl") {}
-    virtual ~GenericTypeOrExtensionWholePortion() {}
-
-    // Just for TypeAlias
-    ASTScopeImpl *expandScope(GenericTypeOrExtensionScope *,
-                              ScopeCreator &) const override;
+};
 
-    SourceRange getChildlessSourceRangeOf(const GenericTypeOrExtensionScope *,
-                                          bool omitAssertions) const override;
+// For the whole Decl scope of a GenericType or an Extension
+class GenericTypeOrExtensionWholePortion final : public Portion {
+public:
+  GenericTypeOrExtensionWholePortion() : Portion("Decl") {}
+  virtual ~GenericTypeOrExtensionWholePortion() {}
 
-    NullablePtr<const ASTScopeImpl>
-    getLookupLimitFor(const GenericTypeOrExtensionScope *) const override;
+  // Just for TypeAlias
+  ASTScopeImpl *expandScope(GenericTypeOrExtensionScope *,
+                            ScopeCreator &) const override;
 
-    NullablePtr<ASTScopeImpl>
-    insertionPointForDeferredExpansion(IterableTypeScope *) const override;
-  };
+  SourceRange getChildlessSourceRangeOf(const GenericTypeOrExtensionScope *,
+                                        bool omitAssertions) const override;
 
-  /// GenericTypeOrExtension = GenericType or Extension
-  class GenericTypeOrExtensionWhereOrBodyPortion : public Portion {
-  public:
-    GenericTypeOrExtensionWhereOrBodyPortion(const char *n) : Portion(n) {}
-    virtual ~GenericTypeOrExtensionWhereOrBodyPortion() {}
+  NullablePtr<const ASTScopeImpl>
+  getLookupLimitFor(const GenericTypeOrExtensionScope *) const override;
 
-    bool lookupMembersOf(const GenericTypeOrExtensionScope *scope,
-                         ASTScopeImpl::DeclConsumer consumer) const override;
+  NullablePtr<ASTScopeImpl>
+  insertionPointForDeferredExpansion(IterableTypeScope *) const override;
 };
 
 /// Behavior specific to representing the trailing where clause of a
 /// GenericTypeDecl or ExtensionDecl scope.
-class GenericTypeOrExtensionWherePortion final
-    : public GenericTypeOrExtensionWhereOrBodyPortion {
+class GenericTypeOrExtensionWherePortion final : public Portion {
 public:
-  GenericTypeOrExtensionWherePortion()
-      : GenericTypeOrExtensionWhereOrBodyPortion("Where") {}
+  GenericTypeOrExtensionWherePortion() : Portion("Where") {}
 
   bool lookupMembersOf(const GenericTypeOrExtensionScope *scope,
                        ASTScopeImpl::DeclConsumer consumer) const override;
@@ -537,11 +525,12 @@ class GenericTypeOrExtensionWherePortion final
 
 /// Behavior specific to representing the Body of a NominalTypeDecl or
 /// ExtensionDecl scope
-class IterableTypeBodyPortion final
-    : public GenericTypeOrExtensionWhereOrBodyPortion {
+class IterableTypeBodyPortion final : public Portion {
 public:
-  IterableTypeBodyPortion()
-      : GenericTypeOrExtensionWhereOrBodyPortion("Body") {}
+  IterableTypeBodyPortion() : Portion("Body") {}
+
+  bool lookupMembersOf(const GenericTypeOrExtensionScope *scope,
+                       ASTScopeImpl::DeclConsumer consumer) const override;
 
   ASTScopeImpl *expandScope(GenericTypeOrExtensionScope *,
                             ScopeCreator &) const override;

include/swift/AST/Decl.h

@@ -32,7 +32,6 @@
 #include "swift/AST/IfConfigClause.h"
 #include "swift/AST/Import.h"
 #include "swift/AST/Initializer.h"
-#include "swift/AST/InverseMarking.h"
 #include "swift/AST/LayoutConstraint.h"
 #include "swift/AST/LifetimeAnnotation.h"
 #include "swift/AST/ReferenceCounting.h"
@@ -96,7 +95,6 @@ namespace swift {
   class NamedPattern;
   class EnumCaseDecl;
   class EnumElementDecl;
-  struct InverseMarking;
   class ParameterList;
   class ParameterTypeFlags;
   class Pattern;
@@ -600,7 +598,7 @@ class alignas(1 << DeclAlignInBits) Decl : public ASTAllocated<Decl> {
     IsComputingSemanticMembers : 1
   );
 
-  SWIFT_INLINE_BITFIELD_FULL(ProtocolDecl, NominalTypeDecl, 1+1+1+1+1+1+1+1+1+1+1+1+1+8,
+  SWIFT_INLINE_BITFIELD_FULL(ProtocolDecl, NominalTypeDecl, 1+1+1+1+1+1+1+1+1+1+1+1+1+1+8,
     /// Whether the \c RequiresClass bit is valid.
     RequiresClassValid : 1,
 
@@ -627,6 +625,9 @@ class alignas(1 << DeclAlignInBits) Decl : public ASTAllocated<Decl> {
     /// Whether we've computed the inherited protocols list yet.
     InheritedProtocolsValid : 1,
 
+    /// Whether we have computed a requirement signature.
+    HasRequirementSignature : 1,
+
     /// Whether we have a lazy-loaded requirement signature.
     HasLazyRequirementSignature : 1,
 
@@ -5124,15 +5125,11 @@ class ProtocolDecl final : public NominalTypeDecl {
     /// The superclass decl and a bit to indicate whether the
     /// superclass was computed yet or not.
     llvm::PointerIntPair<ClassDecl *, 1, bool> SuperclassDecl;
-
-    /// The superclass type and a bit to indicate whether the
-    /// superclass was computed yet or not.
-    llvm::PointerIntPair<Type, 1, bool> SuperclassType;
   } LazySemanticInfo;
 
   /// The generic signature representing exactly the new requirements introduced
   /// by this protocol.
-  std::optional<RequirementSignature> RequirementSig;
+  RequirementSignature RequirementSig;
 
   /// Returns the cached result of \c requiresClass or \c None if it hasn't yet
   /// been computed.
@@ -5219,16 +5216,10 @@ class ProtocolDecl final : public NominalTypeDecl {
   /// Determine whether this protocol has a superclass.
   bool hasSuperclass() const { return (bool)getSuperclassDecl(); }
 
-  /// Retrieve the superclass of this protocol, or null if there is no superclass.
-  Type getSuperclass() const;
-
   /// Retrieve the ClassDecl for the superclass of this protocol, or null if there
   /// is no superclass.
   ClassDecl *getSuperclassDecl() const;
 
-  /// Set the superclass of this protocol.
-  void setSuperclass(Type superclass);
-
   /// Retrieve the set of AssociatedTypeDecl members of this protocol; this
   /// saves loading the set of members in cases where there's no possibility of
   /// a protocol having nested types (ObjC protocols).
@@ -5447,7 +5438,7 @@ class ProtocolDecl final : public NominalTypeDecl {
 
   /// Has the requirement signature been computed yet?
   bool isRequirementSignatureComputed() const {
-    return RequirementSig.has_value();
+    return Bits.ProtocolDecl.HasRequirementSignature;
   }
 
   void setRequirementSignature(RequirementSignature requirementSig);

include/swift/AST/InverseMarking.h

@@ -247,6 +247,9 @@ enum class UnqualifiedLookupFlags {
   MacroLookup            = 1 << 7,
   /// This lookup should only return modules
   ModuleLookup           = 1 << 8,
+  /// This lookup should discard 'Self' requirements in protocol extension
+  /// 'where' clauses.
+  DisregardSelfBounds    = 1 << 9
 };
 
 using UnqualifiedLookupOptions = OptionSet<UnqualifiedLookupFlags>;

include/swift/AST/NameLookup.h

@@ -113,7 +113,7 @@ class InheritedTypeRequest
 /// Request the superclass type for the given class.
 class SuperclassTypeRequest
     : public SimpleRequest<
-          SuperclassTypeRequest, Type(NominalTypeDecl *, TypeResolutionStage),
+          SuperclassTypeRequest, Type(ClassDecl *, TypeResolutionStage),
           RequestFlags::SeparatelyCached | RequestFlags::DependencySink> {
 public:
   using SimpleRequest::SimpleRequest;
@@ -123,7 +123,7 @@ class SuperclassTypeRequest
 
   // Evaluation.
   Type
-  evaluate(Evaluator &evaluator, NominalTypeDecl *classDecl,
+  evaluate(Evaluator &evaluator, ClassDecl *classDecl,
            TypeResolutionStage stage) const;
 
 public:

include/swift/AST/TypeCheckRequests.h

@@ -137,10 +137,6 @@ class alignas(1 << TypeReprAlignInBits) TypeRepr
   /// Is this type representation a protocol?
   bool isProtocolOrProtocolComposition(DeclContext *dc);
 
-  /// Is this `~<target>` representation.
-  bool isInverseOf(InvertibleProtocolKind target,
-                   DeclContext *dc);
-
   /// Is this type representation known to be invalid?
   bool isInvalid() const { return Bits.TypeRepr.Invalid; }
 

include/swift/AST/TypeRepr.h

@@ -29,7 +29,6 @@
 #include "swift/AST/GenericEnvironment.h"
 #include "swift/AST/GenericParamList.h"
 #include "swift/AST/GenericSignature.h"
-#include "swift/AST/InverseMarking.h"
 #include "swift/AST/MacroDefinition.h"
 #include "swift/AST/Module.h"
 #include "swift/AST/NameLookup.h"
@@ -7767,7 +7766,9 @@ static void getSyntacticInheritanceClause(const ProtocolDecl *proto,
                                           llvm::SmallVectorImpl<InheritedEntry> &Results) {
   auto &ctx = proto->getASTContext();
 
-  if (auto superclassTy = proto->getSuperclass()) {
+  auto genericSig = proto->getGenericSignature();
+  if (auto superclassTy = genericSig->getSuperclassBound(
+        proto->getSelfInterfaceType())) {
     Results.emplace_back(TypeLoc::withoutLoc(superclassTy),
                          /*isUnchecked=*/false,
                          /*isRetroactive=*/false,

lib/AST/ASTPrinter.cpp

@@ -274,22 +274,24 @@ bool Portion::lookupMembersOf(const GenericTypeOrExtensionScope *,
   return false;
 }
 
-bool GenericTypeOrExtensionWhereOrBodyPortion::lookupMembersOf(
+bool GenericTypeOrExtensionWherePortion::lookupMembersOf(
     const GenericTypeOrExtensionScope *scope,
     ASTScopeImpl::DeclConsumer consumer) const {
   if (scope->getCorrespondingNominalTypeDecl().isNull())
     return false;
+
+  if (!scope->areMembersVisibleFromWhereClause())
+    return false;
+
   return consumer.lookInMembers(scope->getGenericContext());
 }
 
-bool GenericTypeOrExtensionWherePortion::lookupMembersOf(
+bool IterableTypeBodyPortion::lookupMembersOf(
     const GenericTypeOrExtensionScope *scope,
     ASTScopeImpl::DeclConsumer consumer) const {
-  if (!scope->areMembersVisibleFromWhereClause())
+  if (scope->getCorrespondingNominalTypeDecl().isNull())
     return false;
-
-  return GenericTypeOrExtensionWhereOrBodyPortion::lookupMembersOf(
-    scope, consumer);
+  return consumer.lookInMembers(scope->getGenericContext());
 }
 
 bool GenericTypeOrExtensionScope::areMembersVisibleFromWhereClause() const {