Merge pull request #63431 from DougGregor/accessor-macro-implicit-cycle

Author: DougGregor

lib/Sema/TypeCheckStorage.cpp

@@ -280,6 +280,27 @@ StoredPropertiesAndMissingMembersRequest::evaluate(Evaluator &evaluator,
   return decl->getASTContext().AllocateCopy(results);
 }
 
+/// Check whether the pattern may have storage.
+///
+/// This query is careful not to trigger accessor macro expansion, which
+/// creates a cycle. It conservatively assumes that all accessor macros
+/// produce computed properties, which is... incorrect.
+static bool mayHaveStorage(Pattern *pattern) {
+  // Check whether there are any accessor macros.
+  bool hasAccessorMacros = false;
+  pattern->forEachVariable([&](VarDecl *VD) {
+    VD->forEachAttachedMacro(MacroRole::Accessor,
+      [&](CustomAttr *customAttr, MacroDecl *macro) {
+        hasAccessorMacros = true;
+      });
+  });
+
+  if (hasAccessorMacros)
+    return false;
+
+  return pattern->hasStorage();
+}
+
 /// Validate the \c entryNumber'th entry in \c binding.
 const PatternBindingEntry *PatternBindingEntryRequest::evaluate(
     Evaluator &eval, PatternBindingDecl *binding, unsigned entryNumber,
@@ -380,7 +401,7 @@ const PatternBindingEntry *PatternBindingEntryRequest::evaluate(
   // default-initializable. If so, do it.
   if (!pbe.isInitialized() &&
       binding->isDefaultInitializable(entryNumber) &&
-      pattern->hasStorage()) {
+      mayHaveStorage(pattern)) {
     if (auto defaultInit = TypeChecker::buildDefaultInitializer(patternType)) {
       // If we got a default initializer, install it and re-type-check it
       // to make sure it is properly coerced to the pattern type.

test/Macros/accessor_macros.swift

@@ -53,7 +53,7 @@ struct MyStruct {
   // CHECK-DUMP: }
 
   @myPropertyWrapper
-  var birthDate: Date? = nil
+  var birthDate: Date?
   // CHECK-DUMP: @__swiftmacro_15accessor_macros8MyStructV9birthDateAA0F0VSgvp17myPropertyWrapperfMa_.swift 
   // CHECK-DUMP: get {
   // CHECK-DUMP:   _birthDate.wrappedValue