F# – Referential equality for tuples, discriminated unions and records

By default, tuples, discriminated unions and records have what is known as structural equality – i.e. if two instances of these types have the same set of values then they are considered equal, just like value types – despite being reference types:

Tuples

image

Discriminated Unions

image

Records

image

To facilitate this form of equality, the F# compiler automatically overrides Object.Equals and Object.GetHashCode methods for you. However, there may be times when you want to use referential equality with these types, in which case you just need to add the ReferenceEquality attribute to your type:

image

 

Learn to build Production-Ready Serverless applications

Want to learn how to build Serverless applications and follow best practices? Subscribe to my newsletter and join over 5,000 AWS & Serverless enthusiasts who have signed up already.

1 thought on “F# – Referential equality for tuples, discriminated unions and records”

  1. Pingback: Contrasting F# and Elm’s record types | theburningmonk.com

Leave a Comment

Your email address will not be published. Required fields are marked *