private void registerTypeNullability(@NotNull PsiType type, boolean isNullable) {
        if (isNullable(type)) {
            // If this type is already nullable:
            //   - don't try to make it nullable twice
            //   - or don't try to make it not-null because nullable is stronger than not-null
            return;
        }

        if (isNotNull(type) && !isNullable) {
            // Don't try to make the type not-null twice
            return;
        }

        PsiType unwrappedType = unwrap(type);

        if (isNullable) {
            myNullableTypes.add(unwrappedType);
            myNotNullTypes.remove(unwrappedType);
        } else {
            myNotNullTypes.add(unwrappedType);
        }

        numAnnotationsAdded++;
    }
private void registerTypeNullability(@NotNull PsiType type, boolean isNullable)