generics: how to repeat type in parameters

[Sathish VJ]

How can I repeat the same generics type in the parameters?  I'm getting a "does not match inferred type" error for the code below.

func Print[T Worker](a T, b T) {

fmt.Println(a.Work() + b.Work())

}

func main() {

        c1 := coder{}

        t1 := tester{}

        Print(c1, t1)

}

Compiler Error: type tester of t1 does not match inferred type coder for T

If I flip the parameters that I pass, then the error is now for the second one.  

        Print(c1, t1)

Compiler Error: type coder of c1 does not match inferred type tester for T)

Play link: https://go2goplay.golang.org/p/z6YsFbZSdRg

[Brian Candler]

"coder" and "tester" are two different defined types, but function Print is defined to take two arguments of the same type.

Even though they implement the same interface, they are not the same type.  I'd say you want to interfaces *instead* of generics:

https://go2goplay.golang.org/p/rPU46HWvZJu

[Brian Candler]

Alternatively, your function can be generic over two different types:

https://go2goplay.golang.org/p/WVVZM-Q_P3t

In this trivial example though, I still think interface values are what you want.  There's not much difference in safety, except you could get passed nil interface values.

[Sathish VJ]

Makes sense.  Thank you Brian.