Improving F# Error Handling: Introducing FaultReport

This article critiques the shortcomings of F#'s Result type in error handling, highlighting inconsistencies in error types and the problems stemming from using strings as error types. The author proposes FaultReport as an alternative, using an IFault interface to standardize error types and a Report<'Pass', 'Fail> type to represent operation outcomes, where 'Fail must implement IFault. This ensures consistent and type-safe error handling, avoiding the inconveniences of string-based errors. FaultReport further provides Report.generalize for upcasting and a FailAs active pattern for downcasting, facilitating handling of diverse error types. While replacing FSharp.Core's Result is a significant undertaking, the author argues that FaultReport's design offers a valuable improvement to F#'s error handling.