[generics] Type parameter inference in generic struct literals

[to...@sourcegraph.com]

Hello all,

Could type parameters be omitted when they could be inferred in struct literals? 

Here's a scenario that doesn't work today (https://go2goplay.golang.org/p/Jt5OGfLePuu)

package main

import (

"fmt"

)

type BinaryTree(type T) struct {

Value       T

Left, Right *BinaryTree(T)

}

func main() {

n := int(42)

tree := BinaryTree{

Value: n,

Left:  {Value: n - 1},

Right: {Value: n + 1},

}

fmt.Println(tree)

}

Instead we must be explicit at every struct literal instantiation which quickly becomes quite cluttered (https://go2goplay.golang.org/p/vi6GM4AxyV_r):

package main

import (

"fmt"

)

type BinaryTree(type T) struct {

Value       T

Left, Right *BinaryTree(T)

}

func main() {

n := int(42)

tree := BinaryTree(int) {

Value: n,

Left:  &BinaryTree(int){Value: n - 1},

Right: &BinaryTree(int){Value: n + 1},

}

fmt.Println(tree)

}

[Ian Lance Taylor]

On Wed, Jun 17, 2020 at 9:35 AM tomas via golang-nuts
<golan...@googlegroups.com> wrote:
>
> Could type parameters be omitted when they could be inferred in struct literals?

https://go.googlesource.com/proposal/+/refs/heads/master/design/go2draft-type-parameters.md#type-inference-for-composite-literals

Ian