TypeEquality 0.3.0

.NET Standard 2.0 .NET Framework 4.6.1
NuGet\Install-Package TypeEquality -Version 0.3.0
This command is intended to be used within the Package Manager Console in Visual Studio, as it uses the NuGet module's version of Install-Package.
dotnet add package TypeEquality --version 0.3.0
<PackageReference Include="TypeEquality" Version="0.3.0" />
For projects that support PackageReference, copy this XML node into the project file to reference the package.
paket add TypeEquality --version 0.3.0
#r "nuget: TypeEquality, 0.3.0"
#r directive can be used in F# Interactive, C# scripting and .NET Interactive. Copy this into the interactive tool or source code of the script to reference the package.
// Install TypeEquality as a Cake Addin
#addin nuget:?package=TypeEquality&version=0.3.0

// Install TypeEquality as a Cake Tool
#tool nuget:?package=TypeEquality&version=0.3.0


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Type equalities for F#

This library contains type equalities (Teqs) for F#. These equalities allow us to create type-safe abstractions by allowing us to encode Generalised Algebraic Data Types (GADTs), as found in languages like Haskell.


To use Teqs in your projects, you'll want to reference the main TypeEquality project. The project is available as a nuget package - https://www.nuget.org/packages/TypeEquality.
This project provides a type Teq<'a,'b> of proofs that 'a and 'b are the same type. By including these in the declaration of a generic discriminated union, you can constrain the types each case applies to, encoding a GADT. An example of this may be found in the Example folder.

For more advanced usage, TypeEquality also allows you to reason about Teqs using the functions in the Teq and Teq.Cong (congruence) modules.

The library has some unit tests in the Test/TypeEquality.Test.fsproj project.


We welcome new contributors! We'll happily receive PRs for bug fixes or small changes. If you're contemplating something larger please get in touch first by opening a GitHub Issue describing the problem and how you propose to solve it.


Copyright 2018 G-Research

Licensed under the Apache License, Version 2.0 (the "License"); you may not use these files except in compliance with the License. You may obtain a copy of the License at


Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

Product Versions
.NET net5.0 net5.0-windows net6.0 net6.0-android net6.0-ios net6.0-maccatalyst net6.0-macos net6.0-tvos net6.0-windows
.NET Core netcoreapp2.0 netcoreapp2.1 netcoreapp2.2 netcoreapp3.0 netcoreapp3.1
.NET Standard netstandard2.0 netstandard2.1
.NET Framework net461 net462 net463 net47 net471 net472 net48
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NuGet packages (2)

Showing the top 2 NuGet packages that depend on TypeEquality:

Package Downloads

Heterogeneous collections for F#. Using heterogeneous collections, it's possible to act on arbitrary sum and product types in a generic way.


A lightweight parser combinator library for F#.

GitHub repositories

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Version Downloads Last updated
0.3.0 1,178 1/14/2020
0.2.4 479 10/7/2019
0.2.3 457 10/5/2019
0.2.2 370 9/28/2019
0.2.1 848 1/9/2019
0.2.0 496 1/2/2019
0.0.1 497 11/7/2018