Merge pull request #14292 from rudkx/iuo-update-type-check-decl-for-optional-result-differences

IUO: Update decl checking for result type optionality differences.

Author: rudkx

lib/Sema/TypeCheckDecl.cpp

@@ -4373,6 +4373,13 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
 
     validateAttributes(TC, SD);
 
+    auto *TyR = SD->getElementTypeLoc().getTypeRepr();
+    if (TyR && TyR->getKind() == TypeReprKind::ImplicitlyUnwrappedOptional) {
+      auto &C = SD->getASTContext();
+      SD->getAttrs().add(
+          new (C) ImplicitlyUnwrappedOptionalAttr(/* implicit= */ true));
+    }
+
     if (!checkOverrides(TC, SD)) {
       // If a subscript has an override attribute but does not override
       // anything, complain.
@@ -4415,13 +4422,6 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
       synthesizeSetterForMutableAddressedStorage(SD, TC);
     }
 
-    auto *TyR = SD->getElementTypeLoc().getTypeRepr();
-    if (TyR && TyR->getKind() == TypeReprKind::ImplicitlyUnwrappedOptional) {
-      auto &C = SD->getASTContext();
-      SD->getAttrs().add(
-          new (C) ImplicitlyUnwrappedOptionalAttr(/* implicit= */ true));
-    }
-
     TC.checkDeclAttributes(SD);
   }
 
@@ -5746,7 +5746,11 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
 
       TypeRepr *TR = resultTL.getTypeRepr();
 
-      if (resultOTK == OTK_Optional || treatIUOResultAsError) {
+      bool resultIsPlainOptional = resultOTK == OTK_Optional;
+      if (member->getAttrs().hasAttribute<ImplicitlyUnwrappedOptionalAttr>())
+        resultIsPlainOptional = false;
+
+      if (resultIsPlainOptional || treatIUOResultAsError) {
         if (parentResultTy->getAnyOptionalObjectType())
           return;
         emittedError = true;
@@ -6119,7 +6123,13 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
         auto canDeclTy = declTy->getCanonicalType(genericSig);
         auto canParentDeclTy = parentDeclTy->getCanonicalType(genericSig);
 
-        if (canDeclTy == canParentDeclTy) {
+        auto declIUOAttr =
+            decl->getAttrs().hasAttribute<ImplicitlyUnwrappedOptionalAttr>();
+        auto parentDeclIUOAttr =
+            parentDecl->getAttrs()
+                .hasAttribute<ImplicitlyUnwrappedOptionalAttr>();
+
+        if (declIUOAttr == parentDeclIUOAttr && canDeclTy == canParentDeclTy) {
           matches.push_back({parentDecl, true, parentDeclTy});
           hadExactMatch = true;
           continue;
@@ -6321,8 +6331,13 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
         (attempt == OverrideCheckingAttempt::MismatchedOptional ||
          attempt == OverrideCheckingAttempt::BaseNameWithMismatchedOptional);
 
+    auto declIUOAttr =
+        decl->getAttrs().hasAttribute<ImplicitlyUnwrappedOptionalAttr>();
+    auto matchDeclIUOAttr =
+        matchDecl->getAttrs().hasAttribute<ImplicitlyUnwrappedOptionalAttr>();
+
     // If this is an exact type match, we're successful!
-    if (declTy->isEqual(matchType)) {
+    if (declIUOAttr == matchDeclIUOAttr && declTy->isEqual(matchType)) {
       // Nothing to do.
 
     } else if (method) {