CODEWITHSUNDEEP
genericsf#type-inference
LA.27
LA.27

Reputation: 2248

F#: Function parameter defaults to obj in class

I created a simple function:

let myGenericFunc abc = printfn "%A" abc

Its type is: 

'a -> unit

Then I want to make it a member of a class:

type MyClass() =
    member x.Func = myGenericFunc

However, type of "Func" is now

obj -> unit

Moreover: If I make the parameter explicit, everything is ok again:

type MyClass() =
    // Func : 'a -> unit
    member x.Func y = myGenericFunc y

The question is: what happens ?!

Upvotes: 3

Views: 75

Answers (1)

Leaf Garland
Leaf Garland

Reputation: 3697

Your first x.Func is defining a property, not a method and because properties cannot be generic it has to use a concrete type for 'a.

When you define x.Func y you are creating a method and that can be generic.

Upvotes: 7

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