Merge pull request swiftlang#34088 from slavapestov/constraint-solver-fixes-for-astscope

Fixes for expression type checking with parse-time name lookup disabled

Author: slavapestov

include/swift/AST/ASTTypeIDZone.def

@@ -17,6 +17,8 @@
 
 SWIFT_TYPEID(ActorIsolation)
 SWIFT_TYPEID(AncestryFlags)
+SWIFT_TYPEID(BodyInitKind)
+SWIFT_TYPEID(BodyInitKindAndExpr)
 SWIFT_TYPEID(CtorInitializerKind)
 SWIFT_TYPEID(FunctionBuilderBodyPreCheck)
 SWIFT_TYPEID(GenericSignature)
@@ -35,6 +37,7 @@ SWIFT_TYPEID(TypePair)
 SWIFT_TYPEID(TypeWitnessAndDecl)
 SWIFT_TYPEID(Witness)
 SWIFT_TYPEID_NAMED(AbstractFunctionDecl *, AbstractFunctionDecl)
+SWIFT_TYPEID_NAMED(ApplyExpr *, ApplyExpr)
 SWIFT_TYPEID_NAMED(ClosureExpr *, ClosureExpr)
 SWIFT_TYPEID_NAMED(CodeCompletionCallbacksFactory *,
                    CodeCompletionCallbacksFactory)

include/swift/AST/ASTTypeIDs.h

@@ -24,6 +24,9 @@ namespace swift {
 
 class AbstractFunctionDecl;
 class ActorIsolation;
+class ApplyExpr;
+enum class BodyInitKind;
+struct BodyInitKindAndExpr;
 class BraceStmt;
 class ClosureExpr;
 class CodeCompletionCallbacksFactory;

include/swift/AST/Decl.h

@@ -451,14 +451,7 @@ class alignas(1 << DeclAlignInBits) Decl {
                         /// Whether we have computed the above.
                         IsTransparentComputed : 1);
 
-  SWIFT_INLINE_BITFIELD(ConstructorDecl, AbstractFunctionDecl, 3+1+1,
-    /// The body initialization kind (+1), or zero if not yet computed.
-    ///
-    /// This value is cached but is not serialized, because it is a property
-    /// of the definition of the constructor that is useful only to semantic
-    /// analysis and SIL generation.
-    ComputedBodyInitKind : 3,
-
+  SWIFT_INLINE_BITFIELD(ConstructorDecl, AbstractFunctionDecl, 1+1,
     /// Whether this constructor can fail, by building an Optional type.
     Failable : 1,
 
@@ -6770,6 +6763,37 @@ enum class CtorInitializerKind {
   Factory
 };
 
+/// Specifies the kind of initialization call performed within the body
+/// of the constructor, e.g., self.init or super.init.
+enum class BodyInitKind {
+  /// There are no calls to self.init or super.init.
+  None,
+  /// There is a call to self.init, which delegates to another (peer)
+  /// initializer.
+  Delegating,
+  /// There is a call to super.init, which chains to a superclass initializer.
+  Chained,
+  /// There are no calls to self.init or super.init explicitly in the body of
+  /// the constructor, but a 'super.init' call will be implicitly added
+  /// by semantic analysis.
+  ImplicitChained
+};
+
+struct BodyInitKindAndExpr {
+  BodyInitKind initKind;
+  ApplyExpr *initExpr;
+
+  BodyInitKindAndExpr() : initKind(BodyInitKind::None), initExpr(nullptr) {}
+
+  BodyInitKindAndExpr(BodyInitKind initKind, ApplyExpr *initExpr)
+      : initKind(initKind), initExpr(initExpr) {}
+
+  friend bool operator==(BodyInitKindAndExpr lhs, BodyInitKindAndExpr rhs) {
+    return (lhs.initKind == rhs.initKind &&
+            lhs.initExpr == rhs.initExpr);
+  }
+};
+
 /// ConstructorDecl - Declares a constructor for a type.  For example:
 ///
 /// \code
@@ -6818,38 +6842,11 @@ class ConstructorDecl : public AbstractFunctionDecl {
 
   ParamDecl **getImplicitSelfDeclStorage() { return &SelfDecl; }
 
-  /// Specifies the kind of initialization call performed within the body
-  /// of the constructor, e.g., self.init or super.init.
-  enum class BodyInitKind {
-    /// There are no calls to self.init or super.init.
-    None,
-    /// There is a call to self.init, which delegates to another (peer)
-    /// initializer.
-    Delegating,
-    /// There is a call to super.init, which chains to a superclass initializer.
-    Chained,
-    /// There are no calls to self.init or super.init explicitly in the body of
-    /// the constructor, but a 'super.init' call will be implicitly added
-    /// by semantic analysis.
-    ImplicitChained
-  };
-
   /// Determine whether the body of this constructor contains any delegating
   /// or superclass initializations (\c self.init or \c super.init,
   /// respectively) within its body.
-  ///
-  /// \param diags If non-null, this check will ensure that the constructor
-  /// body is consistent in its use of delegation vs. chaining and emit any
-  /// diagnostics through the given diagnostic engine.
-  ///
-  /// \param init If non-null and there is an explicit \c self.init or
-  /// \c super.init within the body, will be set to point at that
-  /// initializer.
-  BodyInitKind getDelegatingOrChainedInitKind(DiagnosticEngine *diags,
-                                              ApplyExpr **init = nullptr) const;
-  void clearCachedDelegatingOrChainedInitKind() {
-    Bits.ConstructorDecl.ComputedBodyInitKind = 0;
-  }
+  BodyInitKindAndExpr getDelegatingOrChainedInitKind() const;
+  void clearCachedDelegatingOrChainedInitKind();
 
   /// Whether this constructor is required.
   bool isRequired() const {

include/swift/AST/Evaluator.h

@@ -322,6 +322,13 @@ class Evaluator {
     cache.insert({AnyRequest(request), std::move(output)});
   }
 
+  /// Do not introduce new callers of this function.
+  template<typename Request,
+           typename std::enable_if<!Request::hasExternalCache>::type* = nullptr>
+  void clearCachedOutput(const Request &request) {
+    cache.erase(AnyRequest(request));
+  }
+
   /// Clear the cache stored within this evaluator.
   ///
   /// Note that this does not clear the caches of requests that use external

include/swift/AST/Expr.h

@@ -5793,6 +5793,7 @@ Expr *packSingleArgument(
 
 void simple_display(llvm::raw_ostream &out, const ClosureExpr *CE);
 void simple_display(llvm::raw_ostream &out, const DefaultArgumentExpr *expr);
+void simple_display(llvm::raw_ostream &out, const Expr *expr);
 
 SourceLoc extractNearestSourceLoc(const DefaultArgumentExpr *expr);
 

include/swift/AST/NameLookup.h

@@ -684,6 +684,14 @@ class ASTScope {
   static void unqualifiedLookup(SourceFile *, SourceLoc,
                                 namelookup::AbstractASTScopeDeclConsumer &);
 
+  /// Lookup that only finds local declarations and does not trigger
+  /// interface type computation.
+  static void lookupLocalDecls(SourceFile *, DeclName, SourceLoc,
+                               SmallVectorImpl<ValueDecl *> &);
+
+  /// Returns the result if there is exactly one, nullptr otherwise.
+  static ValueDecl *lookupSingleLocalDecl(SourceFile *, DeclName, SourceLoc);
+
   /// Entry point to record the visible statement labels from the given
   /// point.
   ///

include/swift/AST/TypeCheckRequests.h

@@ -211,6 +211,29 @@ class InitKindRequest :
   CtorInitializerKind
   evaluate(Evaluator &evaluator, ConstructorDecl *decl) const;
 
+public:
+// Caching.
+  bool isCached() const { return true; }
+};
+
+void simple_display(llvm::raw_ostream &out, BodyInitKind initKind);
+void simple_display(llvm::raw_ostream &out, BodyInitKindAndExpr initKindAndExpr);
+
+/// Computes the kind of initializer call (self.init or super.init) performed
+/// in the body of a \c ConstructorDecl
+class BodyInitKindRequest :
+    public SimpleRequest<BodyInitKindRequest,
+                         BodyInitKindAndExpr(ConstructorDecl *),
+                         RequestFlags::Cached> {
+public:
+  using SimpleRequest::SimpleRequest;
+
+private:
+  friend SimpleRequest;
+
+  // Evaluation.
+  BodyInitKindAndExpr evaluate(Evaluator &evaluator, ConstructorDecl *decl) const;
+
 public:
   // Caching.
   bool isCached() const { return true; }

include/swift/AST/TypeCheckerTypeIDZone.def

@@ -121,6 +121,9 @@ SWIFT_REQUEST(TypeChecker, InheritsSuperclassInitializersRequest,
               bool(ClassDecl *), SeparatelyCached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, InitKindRequest,
               CtorInitializerKind(ConstructorDecl *), Cached, NoLocationInfo)
+SWIFT_REQUEST(TypeChecker, BodyInitKindRequest,
+              BodyInitKindAndExpr(ConstructorDecl *), Cached,
+              NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, InterfaceTypeRequest,
               Type(ValueDecl *), SeparatelyCached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, IsAccessorTransparentRequest, bool(AccessorDecl *),

lib/AST/Decl.cpp

@@ -5463,8 +5463,8 @@ bool VarDecl::isSettable(const DeclContext *UseDC,
     // If this is a convenience initializer (i.e. one that calls
     // self.init), then let properties are never mutable in it.  They are
     // only mutable in designated initializers.
-    if (CD->getDelegatingOrChainedInitKind(nullptr) ==
-        ConstructorDecl::BodyInitKind::Delegating)
+    auto initKindAndExpr = CD->getDelegatingOrChainedInitKind();
+    if (initKindAndExpr.initKind == BodyInitKind::Delegating)
       return false;
 
     return true;
@@ -7522,7 +7522,6 @@ ConstructorDecl::ConstructorDecl(DeclName Name, SourceLoc ConstructorLoc,
   if (BodyParams)
     setParameters(BodyParams);
 
-  Bits.ConstructorDecl.ComputedBodyInitKind = 0;
   Bits.ConstructorDecl.HasStubImplementation = 0;
   Bits.ConstructorDecl.Failable = Failable;
 
@@ -7750,169 +7749,17 @@ CtorInitializerKind ConstructorDecl::getInitKind() const {
     CtorInitializerKind::Designated);
 }
 
-ConstructorDecl::BodyInitKind
-ConstructorDecl::getDelegatingOrChainedInitKind(DiagnosticEngine *diags,
-                                                ApplyExpr **init) const {
+BodyInitKindAndExpr
+ConstructorDecl::getDelegatingOrChainedInitKind() const {
+  return evaluateOrDefault(getASTContext().evaluator,
+    BodyInitKindRequest{const_cast<ConstructorDecl *>(this)},
+    BodyInitKindAndExpr());
   assert(hasBody() && "Constructor does not have a definition");
+}
 
-  if (init)
-    *init = nullptr;
-
-  // If we already computed the result, return it.
-  if (Bits.ConstructorDecl.ComputedBodyInitKind) {
-    auto Kind = static_cast<BodyInitKind>(
-        Bits.ConstructorDecl.ComputedBodyInitKind - 1);
-    assert((Kind == BodyInitKind::None || !init) &&
-           "can't return cached result with the init expr");
-    return Kind;
-  }
-
-
-  struct FindReferenceToInitializer : ASTWalker {
-    const ConstructorDecl *Decl;
-    BodyInitKind Kind = BodyInitKind::None;
-    ApplyExpr *InitExpr = nullptr;
-    DiagnosticEngine *Diags;
-
-    FindReferenceToInitializer(const ConstructorDecl *decl,
-                               DiagnosticEngine *diags)
-        : Decl(decl), Diags(diags) { }
-
-    bool walkToDeclPre(class Decl *D) override {
-      // Don't walk into further nominal decls.
-      return !isa<NominalTypeDecl>(D);
-    }
-    
-    std::pair<bool, Expr*> walkToExprPre(Expr *E) override {
-      // Don't walk into closures.
-      if (isa<ClosureExpr>(E))
-        return { false, E };
-      
-      // Look for calls of a constructor on self or super.
-      auto apply = dyn_cast<ApplyExpr>(E);
-      if (!apply)
-        return { true, E };
-
-      auto Callee = apply->getSemanticFn();
-      
-      Expr *arg;
-
-      if (isa<OtherConstructorDeclRefExpr>(Callee)) {
-        arg = apply->getArg();
-      } else if (auto *CRE = dyn_cast<ConstructorRefCallExpr>(Callee)) {
-        arg = CRE->getArg();
-      } else if (auto *dotExpr = dyn_cast<UnresolvedDotExpr>(Callee)) {
-        if (dotExpr->getName().getBaseName() != DeclBaseName::createConstructor())
-          return { true, E };
-
-        arg = dotExpr->getBase();
-      } else {
-        // Not a constructor call.
-        return { true, E };
-      }
-
-      // Look for a base of 'self' or 'super'.
-      BodyInitKind myKind;
-      if (arg->isSuperExpr())
-        myKind = BodyInitKind::Chained;
-      else if (arg->isSelfExprOf(Decl, /*sameBase*/true))
-        myKind = BodyInitKind::Delegating;
-      else {
-        // We're constructing something else.
-        return { true, E };
-      }
-      
-      if (Kind == BodyInitKind::None) {
-        Kind = myKind;
-
-        // If we're not emitting diagnostics, we're done.
-        if (!Diags)
-          return { false, nullptr };
-
-        InitExpr = apply;
-        return { true, E };
-      }
-
-      assert(Diags && "Failed to abort traversal early");
-
-      // If the kind changed, complain.
-      if (Kind != myKind) {
-        // The kind changed. Complain.
-        Diags->diagnose(E->getLoc(), diag::init_delegates_and_chains);
-        Diags->diagnose(InitExpr->getLoc(), diag::init_delegation_or_chain,
-                        Kind == BodyInitKind::Chained);
-      }
-
-      return { true, E };
-    }
-  };
-  
-  FindReferenceToInitializer finder(this, diags);
-  getBody()->walk(finder);
-
-  // get the kind out of the finder.
-  auto Kind = finder.Kind;
-
-  auto *NTD = getDeclContext()->getSelfNominalTypeDecl();
-
-  // Protocol extension and enum initializers are always delegating.
-  if (Kind == BodyInitKind::None) {
-    if (isa<ProtocolDecl>(NTD) || isa<EnumDecl>(NTD)) {
-      Kind = BodyInitKind::Delegating;
-    }
-  }
-
-  // Struct initializers that cannot see the layout of the struct type are
-  // always delegating. This occurs if the struct type is not fixed layout,
-  // and the constructor is either inlinable or defined in another module.
-  if (Kind == BodyInitKind::None && isa<StructDecl>(NTD)) {
-    // Note: This is specifically not using isFormallyResilient. We relax this
-    // rule for structs in non-resilient modules so that they can have inlinable
-    // constructors, as long as those constructors don't reference private
-    // declarations.
-    if (NTD->isResilient() &&
-        getResilienceExpansion() == ResilienceExpansion::Minimal) {
-      Kind = BodyInitKind::Delegating;
-
-    } else if (isa<ExtensionDecl>(getDeclContext())) {
-      const ModuleDecl *containingModule = getParentModule();
-      // Prior to Swift 5, cross-module initializers were permitted to be
-      // non-delegating. However, if the struct isn't fixed-layout, we have to
-      // be delegating because, well, we don't know the layout.
-      // A dynamic replacement is permitted to be non-delegating.
-      if (NTD->isResilient() ||
-          (containingModule->getASTContext().isSwiftVersionAtLeast(5) &&
-           !getAttrs().getAttribute<DynamicReplacementAttr>())) {
-        if (containingModule != NTD->getParentModule())
-          Kind = BodyInitKind::Delegating;
-      }
-    }
-  }
-
-  // If we didn't find any delegating or chained initializers, check whether
-  // the initializer was explicitly marked 'convenience'.
-  if (Kind == BodyInitKind::None && getAttrs().hasAttribute<ConvenienceAttr>())
-    Kind = BodyInitKind::Delegating;
-
-  // If we still don't know, check whether we have a class with a superclass: it
-  // gets an implicit chained initializer.
-  if (Kind == BodyInitKind::None) {
-    if (auto classDecl = getDeclContext()->getSelfClassDecl()) {
-      if (classDecl->hasSuperclass())
-        Kind = BodyInitKind::ImplicitChained;
-    }
-  }
-
-  // Cache the result if it is trustworthy.
-  if (diags) {
-    auto *mutableThis = const_cast<ConstructorDecl *>(this);
-    mutableThis->Bits.ConstructorDecl.ComputedBodyInitKind =
-        static_cast<unsigned>(Kind) + 1;
-    if (init)
-      *init = finder.InitExpr;
-  }
-
-  return Kind;
+void ConstructorDecl::clearCachedDelegatingOrChainedInitKind() {
+  getASTContext().evaluator.clearCachedOutput(
+    BodyInitKindRequest{const_cast<ConstructorDecl *>(this)});
 }
 
 SourceRange DestructorDecl::getSourceRange() const {