ASTScope: Remove "re-expansion" mechanism

include/swift/AST/ASTScope.h

@@ -146,9 +146,6 @@ class ASTScopeImpl {
 
   bool wasExpanded = false;
 
-  /// For use-before-def, ASTAncestor scopes may be added to a BraceStmt.
-  unsigned astAncestorScopeCount = 0;
-
   /// Can clear storedChildren, so must remember this
   bool haveAddedCleanup = false;
 
@@ -192,26 +189,10 @@ class ASTScopeImpl {
 
   const Children &getChildren() const { return storedChildren; }
 
-  /// Get ride of descendants and remove them from scopedNodes so the scopes
-  /// can be recreated. Needed because typechecking inserts a return statment
-  /// into initializers.
-  void disownDescendants(ScopeCreator &);
-
-public: // for addReusedBodyScopes
+public:
   void addChild(ASTScopeImpl *child, ASTContext &);
-  std::vector<ASTScopeImpl *> rescueASTAncestorScopesForReuseFromMe();
-
-  /// When reexpanding, do we always create a new body?
-  virtual NullablePtr<ASTScopeImpl> getParentOfASTAncestorScopesToBeRescued();
-  std::vector<ASTScopeImpl *>
-  rescueASTAncestorScopesForReuseFromMeOrDescendants();
-  void replaceASTAncestorScopes(ArrayRef<ASTScopeImpl *>);
-
-private:
-  void removeChildren();
 
 private:
-  void emancipate() { parent = nullptr; }
   NullablePtr<ASTScopeImpl> getPriorSibling() const;
 
 public:
@@ -278,12 +259,6 @@ class ASTScopeImpl {
 private:
   void clearCachedSourceRangesOfMeAndAncestors();
 
-public:
-  /// Since source ranges are cached but depend on child ranges,
-  /// when descendants are added, my and my ancestor ranges must be
-  /// recalculated.
-  void ensureSourceRangesAreCorrectWhenAddingDescendants(function_ref<void()>);
-
 public: // public for debugging
   /// Returns source range of this node alone, without factoring in any
   /// children.
@@ -349,23 +324,11 @@ class ASTScopeImpl {
   /// fact, above and beyond adding Decls to the SourceFile.
   ASTScopeImpl *expandAndBeCurrent(ScopeCreator &);
 
-  unsigned getASTAncestorScopeCount() const { return astAncestorScopeCount; }
   bool getWasExpanded() const { return wasExpanded; }
 
 protected:
-  void resetASTAncestorScopeCount() { astAncestorScopeCount = 0; }
-  void increaseASTAncestorScopeCount(unsigned c) { astAncestorScopeCount += c; }
   void setWasExpanded() { wasExpanded = true; }
   virtual ASTScopeImpl *expandSpecifically(ScopeCreator &) = 0;
-  virtual void beCurrent();
-  virtual bool doesExpansionOnlyAddNewDeclsAtEnd() const;
-
-public:
-  bool isExpansionNeeded(const ScopeCreator &) const;
-
-protected:
-  bool isCurrent() const;
-  virtual bool isCurrentIfWasExpanded() const;
 
 private:
   /// Compare the pre-expasion range with the post-expansion range and return
@@ -382,13 +345,6 @@ class ASTScopeImpl {
   virtual SourceRange sourceRangeForDeferredExpansion() const;
 
 public:
-  // Some nodes (VarDecls and Accessors) are created directly from
-  // pattern scope code and should neither be deferred nor should
-  // contribute to widenSourceRangeForIgnoredASTNode.
-  // Closures and captures are also created directly but are
-  // screened out because they are expressions.
-  static bool isHandledSpeciallyByPatterns(const ASTNode n);
-
   virtual NullablePtr<AbstractStorageDecl>
   getEnclosingAbstractStorageDecl() const;
 
@@ -530,12 +486,6 @@ class ASTSourceFileScope final : public ASTScopeImpl {
   ScopeCreator *const scopeCreator;
   ASTScopeImpl *insertionPoint;
 
-  /// The number of \c Decls in the \c SourceFile that were already seen.
-  /// Since parsing can be interleaved with type-checking, on every
-  /// lookup, look at creating scopes for any \c Decls beyond this number.
-  /// TODO: Unify with numberOfChildrenWhenLastExpanded
-  size_t numberOfDeclsAlreadySeen = 0;
-
   ASTSourceFileScope(SourceFile *SF, ScopeCreator *scopeCreator);
 
   std::string getClassName() const override;
@@ -560,9 +510,6 @@ class ASTSourceFileScope final : public ASTScopeImpl {
 
 protected:
   ASTScopeImpl *expandSpecifically(ScopeCreator &scopeCreator) override;
-  bool isCurrentIfWasExpanded() const override;
-  void beCurrent() override;
-  bool doesExpansionOnlyAddNewDeclsAtEnd() const override;
 
   ScopeCreator &getScopeCreator() override;
 
@@ -609,8 +556,6 @@ class Portion {
   virtual const Decl *
   getReferrentOfScope(const GenericTypeOrExtensionScope *s) const;
 
-  virtual void beCurrent(IterableTypeScope *) const = 0;
-  virtual bool isCurrentIfWasExpanded(const IterableTypeScope *) const = 0;
   virtual NullablePtr<ASTScopeImpl>
   insertionPointForDeferredExpansion(IterableTypeScope *) const = 0;
   virtual SourceRange
@@ -636,19 +581,6 @@ class Portion {
     const Decl *
     getReferrentOfScope(const GenericTypeOrExtensionScope *s) const override;
 
-    /// Make whole portion lazy to avoid circularity in lookup of generic
-    /// parameters of extensions. When \c bindExtension is called, it needs to
-    /// unqualifed-lookup the type being extended. That causes an \c
-    /// ExtensionScope
-    /// (\c GenericTypeOrExtensionWholePortion) to be built.
-    /// The building process needs the generic parameters, but that results in a
-    /// request for the extended nominal type of the \c ExtensionDecl, which is
-    /// an endless recursion. Although we only need to make \c ExtensionScope
-    /// lazy, might as well do it for all \c IterableTypeScopes.
-
-    void beCurrent(IterableTypeScope *) const override;
-    bool isCurrentIfWasExpanded(const IterableTypeScope *) const override;
-
     NullablePtr<ASTScopeImpl>
     insertionPointForDeferredExpansion(IterableTypeScope *) const override;
     SourceRange
@@ -682,9 +614,6 @@ class GenericTypeOrExtensionWherePortion final
   SourceRange getChildlessSourceRangeOf(const GenericTypeOrExtensionScope *,
                                         bool omitAssertions) const override;
 
-  void beCurrent(IterableTypeScope *) const override;
-  bool isCurrentIfWasExpanded(const IterableTypeScope *) const override;
-
   NullablePtr<ASTScopeImpl>
   insertionPointForDeferredExpansion(IterableTypeScope *) const override;
   SourceRange
@@ -704,8 +633,6 @@ class IterableTypeBodyPortion final
   SourceRange getChildlessSourceRangeOf(const GenericTypeOrExtensionScope *,
                                         bool omitAssertions) const override;
 
-  void beCurrent(IterableTypeScope *) const override;
-  bool isCurrentIfWasExpanded(const IterableTypeScope *) const override;
   NullablePtr<ASTScopeImpl>
   insertionPointForDeferredExpansion(IterableTypeScope *) const override;
   SourceRange
@@ -796,11 +723,6 @@ class GenericTypeScope : public GenericTypeOrExtensionScope {
 };
 
 class IterableTypeScope : public GenericTypeScope {
-  /// Because of \c parseDelayedDecl members can get added after the tree is
-  /// constructed, and they can be out of order. Detect this happening by
-  /// remembering the member count.
-  unsigned memberCount = 0;
-
 public:
   IterableTypeScope(const Portion *p) : GenericTypeScope(p) {}
   virtual ~IterableTypeScope() {}
@@ -810,15 +732,7 @@ class IterableTypeScope : public GenericTypeScope {
   bool doesDeclHaveABody() const override;
   void expandBody(ScopeCreator &) override;
 
-protected:
-  void beCurrent() override;
-  bool isCurrentIfWasExpanded() const override;
-
 public:
-  void makeWholeCurrent();
-  bool isWholeCurrent() const;
-  void makeBodyCurrent();
-  bool isBodyCurrent() const;
   NullablePtr<ASTScopeImpl> insertionPointForDeferredExpansion() override;
   SourceRange sourceRangeForDeferredExpansion() const override;
 
@@ -1019,18 +933,11 @@ class AbstractFunctionBodyScope : public ASTScopeImpl {
 public:
   AbstractFunctionDecl *const decl;
 
-  /// \c Parser::parseAbstractFunctionBodyDelayed can call \c
-  /// AbstractFunctionDecl::setBody after the tree has been constructed. So if
-  /// this changes, have to rebuild body.
-  NullablePtr<BraceStmt> bodyWhenLastExpanded;
-
   AbstractFunctionBodyScope(AbstractFunctionDecl *e) : decl(e) {}
   virtual ~AbstractFunctionBodyScope() {}
 
 protected:
   ASTScopeImpl *expandSpecifically(ScopeCreator &scopeCreator) override;
-  void beCurrent() override;
-  bool isCurrentIfWasExpanded() const override;
 
 private:
   void expandAScopeThatDoesNotCreateANewInsertionPoint(ScopeCreator &);
@@ -1045,8 +952,6 @@ class AbstractFunctionBodyScope : public ASTScopeImpl {
   virtual NullablePtr<Decl> getDeclIfAny() const override { return decl; }
   Decl *getDecl() const { return decl; }
 
-  NullablePtr<ASTScopeImpl> getParentOfASTAncestorScopesToBeRescued() override;
-
 protected:
   bool lookupLocalsOrMembers(DeclConsumer) const override;
 
@@ -1173,9 +1078,6 @@ class AbstractPatternEntryScope : public ASTScopeImpl {
 };
 
 class PatternEntryDeclScope final : public AbstractPatternEntryScope {
-  const Expr *initWhenLastExpanded;
-  unsigned varCountWhenLastExpanded = 0;
-
 public:
   PatternEntryDeclScope(PatternBindingDecl *pbDecl, unsigned entryIndex,
                         DeclVisibilityKind vis)
@@ -1184,8 +1086,6 @@ class PatternEntryDeclScope final : public AbstractPatternEntryScope {
 
 protected:
   ASTScopeImpl *expandSpecifically(ScopeCreator &scopeCreator) override;
-  void beCurrent() override;
-  bool isCurrentIfWasExpanded() const override;
 
 private:
   AnnotatedInsertionPoint
@@ -1354,20 +1254,16 @@ class ClosureParametersScope final : public ASTScopeImpl {
 class TopLevelCodeScope final : public ASTScopeImpl {
 public:
   TopLevelCodeDecl *const decl;
-  BraceStmt *bodyWhenLastExpanded;
 
   TopLevelCodeScope(TopLevelCodeDecl *e) : decl(e) {}
   virtual ~TopLevelCodeScope() {}
 
 protected:
   ASTScopeImpl *expandSpecifically(ScopeCreator &scopeCreator) override;
-  void beCurrent() override;
-  bool isCurrentIfWasExpanded() const override;
 
 private:
   AnnotatedInsertionPoint
   expandAScopeThatCreatesANewInsertionPoint(ScopeCreator &);
-  std::vector<ASTScopeImpl *> rescueBodyScopesToReuse();
 
 public:
   std::string getClassName() const override;
@@ -1379,8 +1275,6 @@ class TopLevelCodeScope final : public ASTScopeImpl {
   virtual NullablePtr<Decl> getDeclIfAny() const override { return decl; }
   Decl *getDecl() const { return decl; }
   NullablePtr<const void> getReferrent() const override;
-
-  NullablePtr<ASTScopeImpl> getParentOfASTAncestorScopesToBeRescued() override;
 };
 
 /// The \c _@specialize attribute.

include/swift/AST/Decl.h

@@ -1948,8 +1948,6 @@ class PatternBindingEntry {
   CaptureInfo getCaptureInfo() const { return Captures; }
   void setCaptureInfo(CaptureInfo captures) { Captures = captures; }
 
-  unsigned getNumBoundVariables() const;
-
 private:
   SourceLoc getLastAccessorEndLoc() const;
 };

include/swift/AST/DeclContext.h

@@ -712,13 +712,6 @@ class IterableDeclContext {
   /// member loading, as a key when doing lookup in this IDC.
   serialization::DeclID SerialID;
 
-  /// Because \c parseDelayedDecl and lazy member adding can add members *after*
-  /// an \c ASTScope tree is created, there must be some way for the tree to
-  /// detect when a member has been added. A bit would suffice,
-  /// but would be more fragile, The scope code could count the members each
-  /// time, but I think it's a better trade to just keep a count here.
-  unsigned MemberCount : 29;
-
   /// Whether we have already added the parsed members into the context.
   unsigned AddedParsedMembers : 1;
 
@@ -741,7 +734,6 @@ class IterableDeclContext {
 public:
   IterableDeclContext(IterableDeclContextKind kind)
     : LastDeclAndKind(nullptr, kind) {
-    MemberCount = 0;
     AddedParsedMembers = 0;
     HasOperatorDeclarations = 0;
     HasNestedClassDeclarations = 0;
@@ -794,9 +786,6 @@ class IterableDeclContext {
   /// is inserted immediately after the hint.
   void addMember(Decl *member, Decl *hint = nullptr);
 
-  /// See \c MemberCount
-  unsigned getMemberCount() const;
-
   /// Check whether there are lazily-loaded members.
   bool hasLazyMembers() const {
     return FirstDeclAndLazyMembers.getInt();

include/swift/Basic/LangOptions.h

@@ -251,9 +251,6 @@ namespace swift {
     /// Someday, ASTScopeLookup will supplant lookup in the parser
     bool DisableParserLookup = false;
 
-    /// Should  we stress ASTScope-based resolution for debugging?
-    bool StressASTScopeLookup = false;
-
     /// Whether to enable the new operator decl and precedencegroup lookup
     /// behavior. This is a staging flag, and will be removed in the future.
     bool EnableNewOperatorLookup = false;

include/swift/Option/FrontendOptions.td

@@ -157,9 +157,6 @@ def disable_target_os_checking :
 def crosscheck_unqualified_lookup : Flag<["-"], "crosscheck-unqualified-lookup">,
   HelpText<"Compare legacy DeclContext- to ASTScope-based unqualified name lookup (for debugging)">;
 
-def stress_astscope_lookup : Flag<["-"], "stress-astscope-lookup">,
-  HelpText<"Stress ASTScope-based unqualified name lookup (for testing)">;
-
 def use_clang_function_types : Flag<["-"], "use-clang-function-types">,
   HelpText<"Use stored Clang function types for computing canonical types.">;