I don't know what you are doing, here, but…
func some() string {
foo := struct{ Key string, Value int }{}
// some code
// compie error: Can't use foo.Key (type string) as int
acceptInt(foo.Key)
// compile error: mismatched types string and int
if foo.Key == foo.Value {
}
// compile error: Can't use foo.Value (type int) as string
return foo.Value
}
perfectly type safe.
On Wed, Jun 22, 2016 at 6:21 AM, <andrew.mez...@gmail.com> wrote:
> >> The issue is, that a "KeyValuePair<K, V>" (no matter if you implemented
> it via generics or like you mention via interfaces) is a fundamentally
> useless type and generics encourage people to add useless types. A
> "KeyValuePair<K, V>" is a "struct { Key K, Value V }", plain and simple.
> It's not an interface and it's not a generic type, it's simply a struct.
>
> I not agree with you only because with generics this pattern is always
> type safe.
>
> Eg.
>
> type Foo<K, V> struct {
>
> key K
> val V
> }
> func accepInt(i int) {
> }
> func some() string {
> foo := &Foo<string, int>()
> // some code
>
> // Compile error: `key` is not `int`
> acceptInt(foo.key)
>
> // Compile error: `key` (int) cannot be compared with `string`
> if foo.key == foo.val {
> }
>
> // Compile error: `key` is not `string`
> return foo.val
> }
> func baz(foo Foo<K, V>) bool {
> // Compile error: `key` (K) cannot be compared with `V`
> return foo.key == foo.val
> }
>
>
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