Introduction

A little command-line utility to add variance to interfaces in a .NET assembly.

This is especially useful for F# since it can't define variance yet.

Example

Given an assembly Target.dll with

namespace Coco

type IVariant<'OutR, 'InA> =
    abstract GetSomething: unit -> 'OutR
    abstract SetSomething: 'InA -> unit
    abstract GetSetSomething: 'InA -> 'OutR

You can make IVariant covariant in OutR and contravariant in InR by running:

VariantInterfaces.exe Target.dll Coco.IVariant`2/+OutR/-InA

This overwrites the original DLL.

Binaries

Available on Nuget.