Code inspection: Declaration nullability inferred (type member is inferred to be nullable)

This inspection reports a method, property, indexer, or operator whose return value is inferred to be nullable. This usually means the member directly returns null on some paths, or yields nullable items in iterator or async-return scenarios. Adding [CanBeNull] makes that behavior explicit to callers and analysis tools.

Example

In this case, the method can return null. The quick-fix suggests annotating the method with the [CanBeNull] attribute.

                public class Settings
                {
                    public string FindName(bool exists)
                    {
                        return exists ? "Default" : null;
                    }
                }
            

                using JetBrains.Annotations;

                public class Settings
                {
                    [CanBeNull]
                    public string FindName(bool exists)
                    {
                        return exists ? "Default" : null;
                    }
                }
            

Quick-fix

Annotate the member with the inferred nullability attribute, usually [CanBeNull]. For iterators and async methods returning container-like values, the quick-fix can use [ItemCanBeNull].

28 March 2026