Probably needs a small addition to rfc/new small rfc, so behaviour is documented.

@kerams will it make possible to intersect generic and non-generic restrictions? E.g.

let test (env: 'T & #IDisposable & #ILogger<'T>) =
    ()

Yes, but unless I am misunderstanding something, your constraints are not satisfiable. 'T cannot be an ILogger of itself.

This appears to be doable:

let test (env: 't & #seq<'u> & #Collections.IEnumerable) =
    ()

test [ [ 1 ] ]

'T cannot be an ILogger of itself.

I think it can, the whole Generic Maths feature is build atop of 'T when 'T :> INumber<'T>
https://learn.microsoft.com/en-us/dotnet/standard/generics/math

@Lanayx, you're right. I don't quite understand how, but this works:

let test (env: 't & #System.Numerics.INumber<'t> & #IEquatable<'t>) =
    ()

let test2 (env: 't when 't :> #System.Numerics.INumber<'t> and 't :> IEquatable<'t>) =
    ()

test 1
test2 1

@Lanayx, you're right. I don't quite understand how, but this works:

let test (env: 't & #System.Numerics.INumber<'t> & #IEquatable<'t>) =
    ()

let test2 (env: 't when 't :> #System.Numerics.INumber<'t> and 't :> IEquatable<'t>) =
    ()

test 1
test2 1

Yeah, that's pretty much due to changes we introduced for static abstracts in interfaces. At least I believe so.

That's great! In that case it will subsume the old syntax (which I didn't like anyway), e.g. instead of

let test (env: 'T when INumber<'T>) =
    ()

we'll be able to write

let test (env: 'T & #INumber<'T>) =
    ()

Why do you think constraints are not solvable? It's just an interface like for example INumber'TSelf which works via implementing an interface of itself.