Remove support for looking up names in nested expansions.

Author: rxwei

include/swift/AST/Decl.h

@@ -8476,7 +8476,6 @@ class MacroExpansionDecl : public Decl {
   ArgumentList *getArgs() const { return ArgList; }
   void setArgs(ArgumentList *args) { ArgList = args; }
   ArrayRef<ASTNode> getRewritten() const;
-  ArrayRef<ASTNode> getFlattenedExpansion() const;
   ConcreteDeclRef getMacroRef() const { return macroRef; }
   void setMacroRef(ConcreteDeclRef ref) { macroRef = ref; }
 

include/swift/AST/TypeCheckRequests.h

@@ -3828,23 +3828,6 @@ class ExpandMacroExpansionDeclRequest
   bool isCached() const { return true; }
 };
 
-class RecursivelyExpandMacroExpansionDeclRequest
-    : public SimpleRequest<RecursivelyExpandMacroExpansionDeclRequest,
-                           ArrayRef<ASTNode>(MacroExpansionDecl *),
-                           RequestFlags::Cached> {
-public:
-  using SimpleRequest::SimpleRequest;
-
-private:
-  friend SimpleRequest;
-
-  ArrayRef<ASTNode>
-  evaluate(Evaluator &evaluator, MacroExpansionDecl *med) const;
-
-public:
-  bool isCached() const { return true; }
-};
-
 /// Expand all accessor macros attached to the given declaration.
 ///
 /// Produces the set of macro expansion buffer IDs.

include/swift/AST/TypeCheckerTypeIDZone.def

@@ -431,9 +431,6 @@ SWIFT_REQUEST(TypeChecker, ExternalMacroDefinitionRequest,
 SWIFT_REQUEST(TypeChecker, ExpandMacroExpansionDeclRequest,
               ArrayRef<ASTNode> (MacroExpansionDecl *),
               Cached, NoLocationInfo)
-SWIFT_REQUEST(TypeChecker, RecursivelyExpandMacroExpansionDeclRequest,
-              ArrayRef<ASTNode> (MacroExpansionDecl *),
-              Cached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, ExpandMemberAttributeMacros,
               ArrayRef<unsigned>(Decl *),
               Cached, NoLocationInfo)

lib/AST/Decl.cpp

@@ -10010,13 +10010,6 @@ ArrayRef<ASTNode> MacroExpansionDecl::getRewritten() const {
       ExpandMacroExpansionDeclRequest{mutableThis}, {});
 }
 
-ArrayRef<ASTNode> MacroExpansionDecl::getFlattenedExpansion() const {
-  auto mutableThis = const_cast<MacroExpansionDecl *>(this);
-  return evaluateOrDefault(
-      getASTContext().evaluator,
-      RecursivelyExpandMacroExpansionDeclRequest{mutableThis}, {});
-}
-
 NominalTypeDecl *
 ValueDecl::getRuntimeDiscoverableAttrTypeDecl(CustomAttr *attr) const {
   auto &ctx = getASTContext();

lib/AST/Module.cpp

@@ -3812,9 +3812,9 @@ void FileUnit::getExpandedTopLevelDecls(SmallVectorImpl<Decl*> &results) const {
   getTopLevelDecls(nonExpandedDecls);
   for (auto *decl : nonExpandedDecls) {
     if (auto *med = dyn_cast<MacroExpansionDecl>(decl)) {
-      for (auto node : med->getFlattenedExpansion())
-        if (auto *decl = node.dyn_cast<Decl *>())
-          results.push_back(decl);
+      med->visitAuxiliaryDecls([&](Decl *decl) {
+        results.push_back(decl);
+      });
     } else {
       results.push_back(decl);
     }

lib/AST/NameLookup.cpp

@@ -1514,9 +1514,9 @@ populateLookupTableEntryFromMacroExpansions(ASTContext &ctx,
                                             DeclName name,
                                             NominalTypeDecl *dc) {
   auto expandAndPopulate = [&](MacroExpansionDecl *med) {
-    for (auto node : med->getFlattenedExpansion())
-      if (auto *decl = node.dyn_cast<Decl *>())
-        table.addMember(decl);
+    med->visitAuxiliaryDecls([&](Decl *decl) {
+      table.addMember(decl);
+    });
   };
 
   for (auto *member : dc->getCurrentMembersWithoutLoading()) {

lib/Sema/TypeCheckDecl.cpp

@@ -2840,9 +2840,9 @@ static ArrayRef<Decl *> evaluateMembersRequest(
     }
 
     if (auto *med = dyn_cast<MacroExpansionDecl>(member)) {
-      for (auto node : med->getFlattenedExpansion())
-        if (auto *decl = node.dyn_cast<Decl *>())
-          result.push_back(decl);
+      med->visitAuxiliaryDecls([&](Decl *decl) {
+        result.push_back(decl);
+      });
       continue;
     }
 

lib/Sema/TypeCheckDeclPrimary.cpp

@@ -3785,36 +3785,3 @@ ExpandMacroExpansionDeclRequest::evaluate(Evaluator &evaluator,
   assert(roles.contains(MacroRole::Declaration));
   return expandFreestandingMacro(MED);
 }
-
-static void collectMacroExpansions(ASTNode node,
-                                   SmallVectorImpl<ASTNode> &result) {
-  if (auto *expr = node.dyn_cast<Expr *>()) {
-    if (auto *mee = dyn_cast<MacroExpansionExpr>(expr)) {
-      if (!mee->getRewritten()) {
-        if (auto *med = mee->getSubstituteDecl()) {
-          med->visitAuxiliaryDecls([&](Decl *decl) {
-            collectMacroExpansions(decl, result);
-          });
-          return;
-        }
-      }
-    }
-  } else if (auto *decl = node.dyn_cast<Decl *>()) {
-    if (auto *med = dyn_cast<MacroExpansionDecl>(decl)) {
-      med->visitAuxiliaryDecls([&](Decl *decl) {
-        collectMacroExpansions(decl, result);
-      });
-      return;
-    }
-  }
-  result.push_back(node);
-}
-
-ArrayRef<ASTNode>
-RecursivelyExpandMacroExpansionDeclRequest::evaluate(
-    Evaluator &evaluator, MacroExpansionDecl *med) const {
-  SmallVector<ASTNode, 4> result;
-  for (auto node : med->getRewritten())
-    collectMacroExpansions(node, result);
-  return med->getASTContext().AllocateCopy(result);
-}

test/Macros/Inputs/syntax_macro_definitions.swift

@@ -1029,29 +1029,3 @@ public struct DefineStructWithUnqualifiedLookupMacro: DeclarationMacro {
     """]
   }
 }
-
-public struct NestedDeclarationsMacro: DeclarationMacro {
-  public static func expansion(
-    of node: some FreestandingMacroExpansionSyntax,
-    in context: some MacroExpansionContext
-  ) throws -> [DeclSyntax] {
-    return [
-    """
-
-    #bitwidthNumberedStructs("Nested")
-    """,
-    """
-
-    @NewType<Int>
-    public struct MyNewType {}
-    """,
-    // FIXME: Request cycle
-    // """
-    //
-    // struct NestedStruct {
-    //   #bitwidthNumberedStructs("NestedStructMember")
-    // }
-    // """
-    ]
-  }
-}

test/Macros/macro_expand_freestanding.swift

@@ -19,9 +19,6 @@
 // Test non-arbitrary names
 @freestanding(declaration, names: named(A), named(B), named(foo), named(addOne))
 macro defineDeclsWithKnownNames() = #externalMacro(module: "MacroDefinition", type: "DefineDeclsWithKnownNamesMacro")
-// Test nested expansions
-@freestanding(declaration, names: arbitrary)
-macro nestedDeclarations() = #externalMacro(module: "MacroDefinition", type: "NestedDeclarationsMacro")
 // Test expanding to an attached macro.
 @attached(
   member,
@@ -60,7 +57,6 @@ func testFreestandingMacroExpansion() {
   struct Foo2 {
     #bitwidthNumberedStructs("MyIntTwo", blah: false)
     #defineDeclsWithKnownNames()
-    #nestedDeclarations()
   }
   // CHECK: MyIntTwo8
   print(Foo2.MyIntTwo8.self)
@@ -78,12 +74,6 @@ func testFreestandingMacroExpansion() {
   print(Foo2().foo)
   // CHECK: 2
   print(Foo2().addOne(1))
-  // CHECK: Nested8
-  print(Foo2.Nested8.self)
-  // CHECK: Int
-  print(Foo2.MyNewType.RawValue.self)
-  // CHECK: NestedStruct.NestedStructMember8
-  // print(Foo2.NestedStruct.NestedStructMember8.self)
 
   #if TEST_DIAGNOSTICS
   struct Foo3 {