CNUL_ResharperNullabilityAnnotationsCanBeConvertedToCSharpSyntax.md

CNUL: Resharper nullability annotation(s) can be converted to C# syntax

Cause

A member or parameter contains Resharper nullability annotations, while the project is configured to enable C# nullable reference types.

Rule description

Nullable reference types are a new language feature in C# v8. It supersedes the nullability annotations that were introduced by Resharper. This rule offers to convert existing code that uses the Resharper attribute to the new C# syntax.

How to fix violations

Run the associated code fixer by selecting "Convert to C# syntax". It is recommended to run on entire document, project or solution (if memory allows). Remember to uninstall the ResharperCodeContractNullability package after all your code has been converted.

When to suppress warnings

There is no technical reason to suppress this warning.

Example of a violation

Description

The type C defines members and parameters that are decorated with Resharper annotations.

Code

using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using JetBrains.Annotations;

namespace N
{
    public class C
    {
        [CanBeNull]
        [ItemNotNull]
        private readonly List<string> _f = new List<string>();

        [CanBeNull]
        [ItemNotNull]
        public ICollection<string> P => _f?.AsReadOnly();

        [NotNull]
        [ItemNotNull]
        public Lazy<string> M([NotNull] [ItemNotNull] Task<string> p)
        {
            _f?.Add(p.Result);
            return new Lazy<string>(() => p.Result);
        }
    }
}

Example of how to fix

Description

All annotated members and parameters of the type C are now converted.

Code

using System;
using System.Collections.Generic;
using System.Threading.Tasks;

namespace N
{
    public class C
    {
        private readonly List<string>? _f = new List<string>();

        public ICollection<string>? P => _f?.AsReadOnly();

        public Lazy<string> M(Task<string> p)
        {
            _f?.Add(p.Result);
            return new Lazy<string>(() => p.Result);
        }
    }
}

Related rules

RNUL: Member is missing nullability annotation

RINUL: Member is missing item nullability annotation