[ASTScopeCreation] Teach ASTScope to find the enclosing type context for

synthesized member macro expansion buffers.

Author: hborla

lib/AST/ASTScopeCreation.cpp

@@ -248,7 +248,28 @@ ASTSourceFileScope::ASTSourceFileScope(SourceFile *SF,
                                        ScopeCreator *scopeCreator)
     : SF(SF), scopeCreator(scopeCreator) {
   if (auto enclosingSF = SF->getEnclosingSourceFile()) {
-    SourceLoc parentLoc = SF->getMacroExpansion().getStartLoc();
+    SourceLoc parentLoc;
+    auto macroRole = SF->getFulfilledMacroRole();
+    auto expansion = SF->getMacroExpansion();
+
+    // Determine the parent source location based on the macro role.
+    switch (*macroRole) {
+    case MacroRole::Expression:
+    case MacroRole::FreestandingDeclaration:
+    case MacroRole::Accessor:
+    case MacroRole::MemberAttribute:
+      parentLoc = expansion.getStartLoc();
+      break;
+    case MacroRole::SynthesizedMembers: {
+      // For synthesized member macros, take the end loc of the
+      // enclosing declaration (before the closing brace), because
+      // the macro expansion is inside this scope.
+      auto *decl = expansion.getAsDeclContext()->getAsDecl();
+      parentLoc = decl->getEndLoc();
+      break;
+    }
+    }
+
     if (auto parentScope = findStartingScopeForLookup(enclosingSF, parentLoc)) {
       parentAndWasExpanded.setPointer(const_cast<ASTScopeImpl *>(parentScope));
     }

lib/Sema/TypeCheckMacros.cpp

@@ -1251,7 +1251,6 @@ bool swift::expandSynthesizedMembers(CustomAttr *attr, MacroDecl *macro,
       extension->addMember(member);
     }
 
-    TypeChecker::typeCheckDecl(member);
     synthesizedMembers = true;
   }
 

test/Macros/Inputs/syntax_macro_definitions.swift

@@ -355,12 +355,12 @@ public struct AddMembers: MemberDeclarationMacro {
   ) throws -> [DeclSyntax] {
     let storageStruct: StructDeclSyntax =
       """
-      struct Nested {}
+      struct Storage {}
       """
 
     let storageVariable: VariableDeclSyntax =
       """
-      var value: Int = 0
+      var storage = Storage()
       """
 
     let instanceMethod: FunctionDeclSyntax =

test/Macros/macro_expand_synthesized_members.swift

@@ -14,15 +14,13 @@
 @addMembers
 struct S {
   func useSynthesized() {
-    print(s.value)
-    print(S.Nested())
-    s.method()
+    print(type(of: storage))
+    method()
   }
 }
 
 let s = S()
 
-// CHECK: 0
-// CHECK: Nested
+// CHECK: Storage
 // CHECK: synthesized method
 s.useSynthesized()