Code inspection: Value tuple 'GetHashCode()' ignores some elements

This inspection reports GetHashCode() calls on value tuples with more than 8 components. For such tuples, the value tuple hash code is calculated from only the last 8 components, so the first component or components don't contribute to the result. Use a hash-code calculation that includes every value explicitly.

Example

                using System;
                public sealed class OrderKey(
                    int customerId,
                    int regionId,
                    int year,
                    int month,
                    int day,
                    int productId,
                    int channelId,
                    int campaignId,
                    int version)
                {
                    public override int GetHashCode()
                    {
                        return (customerId, regionId, year, month,
                            day, productId, channelId,
                            campaignId, version).GetHashCode();
                    }
                }
            

                using System;
                public sealed class OrderKey(
                    int customerId,
                    int regionId,
                    int year,
                    int month,
                    int day,
                    int productId,
                    int channelId,
                    int campaignId,
                    int version)
                {
                    public override int GetHashCode()
                    {
                        var hashCode = new HashCode();
                        hashCode.Add(customerId);
                        hashCode.Add(regionId);
                        hashCode.Add(year);
                        hashCode.Add(month);
                        hashCode.Add(day);
                        hashCode.Add(productId);
                        hashCode.Add(channelId);
                        hashCode.Add(campaignId);
                        hashCode.Add(version);
                        return hashCode.ToHashCode();
                    }
                }
            

How to fix

This inspection doesn't have a dedicated quick-fix. Replace the tuple-based hash code with an explicit HashCode calculation that includes every component.

13 July 2026