[clang] [clang][nullability] allow _Nonnull etc on nullable class types (PR #82705)

[Dmitri Gribenko via cfe-commits]

================
@@ -96,8 +146,16 @@ void AssignAndInitNonNullFromFn() {
   void *_Nonnull nonnull;
   nonnull = ReturnNullable(); // expected-warning{{implicit conversion from nullable pointer 'void * _Nullable' to non-nullable pointer type 'void * _Nonnull'}}
   nonnull = {ReturnNullable()}; // expected-warning{{implicit conversion from nullable pointer 'void * _Nullable' to non-nullable pointer type 'void * _Nonnull'}}
-
   TakeNonnull(ReturnNullable()); //expected-warning{{implicit conversion from nullable pointer 'void * _Nullable' to non-nullable pointer type 'void * _Nonnull}}
+
+  SmartPtr _Nonnull s(ReturnSmartNullable()); // expected-warning{{implicit conversion from nullable pointer 'SmartPtr _Nullable' to non-nullable pointer type 'SmartPtr _Nonnull'}}
+  SmartPtr _Nonnull s2{ReturnSmartNullable()}; // expected-warning{{implicit conversion from nullable pointer 'SmartPtr _Nullable' to non-nullable pointer type 'SmartPtr _Nonnull'}}
+  SmartPtr _Nonnull s3 = {ReturnSmartNullable()}; // expected-warning{{implicit conversion from nullable pointer 'SmartPtr _Nullable' to non-nullable pointer type 'SmartPtr _Nonnull'}}
+  SmartPtr _Nonnull s4 = ReturnSmartNullable(); // expected-warning{{implicit conversion from nullable pointer 'SmartPtr _Nullable' to non-nullable pointer type 'SmartPtr _Nonnull'}}
+  SmartPtr _Nonnull s_nonnull;
+  s_nonnull = ReturnSmartNullable(); // expected-warning{{implicit conversion from nullable pointer 'SmartPtr _Nullable' to non-nullable pointer type 'SmartPtr _Nonnull'}}
+  s_nonnull = {ReturnSmartNullable()};
+  TakeSmartNonnull(ReturnSmartNullable()); //expected-warning{{implicit conversion from nullable pointer 'SmartPtr _Nullable' to non-nullable pointer type 'SmartPtr _Nonnull}}
----------------
gribozavr wrote:

```suggestion
  TakeSmartNonnull(ReturnSmartNullable()); // expected-warning{{implicit conversion from nullable pointer 'SmartPtr _Nullable' to non-nullable pointer type 'SmartPtr _Nonnull'}}
```

https://github.com/llvm/llvm-project/pull/82705