Go Generics Laboratory

Design decisions

• Start from constraints.
• Keep APIs readable.
• Favor narrow, meaningful type sets.

~ and aliases

• ~int supports type MyInt int
• avoids forcing cast-heavy call sites.

Return types

• func F[S ~[]T, T any](...) S preserves typed slices.
• helps ergonomic libraries with named collection types.

Practical checklist

• explicit order of first-seen items
• deterministic handling of empty inputs
• predictable behavior when key function is missing