Merge pull request #77210 from slavapestov/fix-rdar135445004

Parse: Save and restore InFreestandingMacroArgument when delayed parsing

Author: slavapestov

include/swift/AST/DeclContext.h

@@ -798,6 +798,10 @@ class IterableDeclContext {
   /// while skipping the body of this context.
   unsigned HasNestedClassDeclarations : 1;
 
+  /// Whether we were inside a freestanding macro argument when we were parsed.
+  /// We must restore this when delayed parsing the body.
+  unsigned InFreestandingMacroArgument : 1;
+
   template<class A, class B, class C>
   friend struct ::llvm::CastInfo;
 
@@ -814,6 +818,7 @@ class IterableDeclContext {
     AddedParsedMembers = 0;
     HasOperatorDeclarations = 0;
     HasNestedClassDeclarations = 0;
+    InFreestandingMacroArgument = 0;
   }
 
   /// Determine the kind of iterable context we have.
@@ -841,6 +846,15 @@ class IterableDeclContext {
     HasNestedClassDeclarations = 1;
   }
 
+  bool inFreestandingMacroArgument() const {
+    return InFreestandingMacroArgument;
+  }
+
+  void setInFreestandingMacroArgument() {
+    assert(hasUnparsedMembers());
+    InFreestandingMacroArgument = 1;
+  }
+
   /// Retrieve the current set of members in this context.
   ///
   /// NOTE: This operation is an alias of \c getCurrentMembers() that is considered

lib/Parse/ParseDecl.cpp

@@ -7031,15 +7031,17 @@ bool Parser::parseMemberDeclList(SourceLoc &LBLoc, SourceLoc &RBLoc,
   llvm::SaveAndRestore<std::optional<StableHasher>> T(CurrentTokenHash,
                                                       std::nullopt);
 
-  bool HasOperatorDeclarations;
-  bool HasNestedClassDeclarations;
+  bool HasOperatorDeclarations = false;
+  bool HasNestedClassDeclarations = false;
 
   if (canDelayMemberDeclParsing(HasOperatorDeclarations,
                                 HasNestedClassDeclarations)) {
     if (HasOperatorDeclarations)
       IDC->setMaybeHasOperatorDeclarations();
     if (HasNestedClassDeclarations)
       IDC->setMaybeHasNestedClassDeclarations();
+    if (InFreestandingMacroArgument)
+      IDC->setInFreestandingMacroArgument();
 
     if (delayParsingDeclList(LBLoc, RBLoc, IDC))
       return true;

lib/Parse/ParseRequests.cpp

@@ -75,6 +75,8 @@ ParseMembersRequest::evaluate(Evaluator &evaluator,
   // Lexer diagnostics have been emitted during skipping, so we disable lexer's
   // diagnostic engine here.
   Parser parser(bufferID, *sf, /*No Lexer Diags*/nullptr, nullptr, nullptr);
+  parser.InFreestandingMacroArgument = idc->inFreestandingMacroArgument();
+
   auto declsAndHash = parser.parseDeclListDelayed(idc);
   FingerprintAndMembers fingerprintAndMembers = {declsAndHash.second,
                                                  declsAndHash.first};

test/Macros/delayed_parsing.swift

@@ -0,0 +1,20 @@
+// REQUIRES: swift_swift_parser
+//
+// RUN: %empty-directory(%t)
+// RUN: %host-build-swift -swift-version 5 -parse-as-library -emit-library -o %t/%target-library-name(MacroDefinition) -module-name=MacroDefinition %S/Inputs/syntax_macro_definitions.swift -g -no-toolchain-stdlib-rpath
+
+// Type check testing
+// RUN: %target-swift-frontend -emit-module -emit-module-path %t/delayed_parsing.swiftmodule -experimental-skip-non-inlinable-function-bodies-without-types -swift-version 5 -parse-as-library -load-plugin-library %t/%target-library-name(MacroDefinition) %s
+
+@freestanding(declaration)
+macro freestandingWithClosure<T>(_ value: T, body: (T) -> T) = #externalMacro(module: "MacroDefinition", type: "EmptyDeclarationMacro")
+
+#freestandingWithClosure(0) { (x: Int) in
+  struct LocalStruct {
+    func opaqueReturn() -> some Any {
+      return 3
+    }
+  }
+
+  return x
+}