FsCheck not registering a static method that takes Arbitrary<TType> in C# about fscheck HOT 7 CLOSED

Which version?On 25 Aug 2023, at 04:44, Bennie Copeland ***@***.***> wrote: When using FsCheck in a C# project, I wanted to register the Maybe type from CSharpFunctionalExtensions. I followed the F# example code for creating a Box<> type, but when it came to registering the generator and shrinker, FsCheck is ignoring the static method. I receive an exception "No instances found on type Maybe. Check that the type is public and has public static members with the right signature. using FsCheck; namespace FooBar; public class Foo<TBar> { public Foo(TBar bar) { Bar = bar; } public TBar Bar { get; } } public class FooGenerator<TBar> { public static Gen<Foo<TBar>> Generator(Arbitrary<TBar> contents) { return contents.Generator.Select(v => new Foo<TBar>(v)); } public static Func<Foo<TBar>, IEnumerable<Foo<TBar>>> Shrinker(Arbitrary<TBar> contents) { return foo => contents.Shrinker(foo.Bar).Select(v => new Foo<TBar>(v)); } } public static class MyGenerators { public static Arbitrary<Foo<TBar>> ArbitraryFoo<TBar>(Arbitrary<TBar> contents) { return Arb.From( FooGenerator<TBar>.Generator(contents), FooGenerator<TBar>.Shrinker(contents) ); } } public class MyPropertyAttribute : PropertyAttribute { public MyPropertyAttribute() { Arbitrary = new[] { typeof(MyGenerators) }; } } public class MyTests { [MyProperty] public void FooTest(Foo<string> foo) // throws exception { } } If I change the generator registration to remove the Arbitrary<TBar> and move it inside the method block, it works. public static class MyGenerators { public static Arbitrary<Foo<TBar>> ArbitraryFoo<TBar>() { var contents = Arb.From<TBar>(); return Arb.From( FooGenerator<TBar>.Generator(contents), FooGenerator<TBar>.Shrinker(contents) ); } } —Reply to this email directly, view it on GitHub, or unsubscribe.You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

Arbitrary methods with Arbitrary arguments are only supported in 3.x if I remember correctly.On 25 Aug 2023, at 09:18, Bennie Copeland ***@***.***> wrote: Dotnet Core 7 XUnit test project with FsCheck and FsCheck.Xunit at version 2.16.6 —Reply to this email directly, view it on GitHub, or unsubscribe.You are receiving this because you commented.Message ID: ***@***.***>