reflect: Overflow methods should be on Type #60427
Description
See these four methods on reflect.Value:
- https://pkg.go.dev/reflect#Value.OverflowComplex
- https://pkg.go.dev/reflect#Value.OverflowFloat
- https://pkg.go.dev/reflect#Value.OverflowInt
- https://pkg.go.dev/reflect#Value.OverflowUint
For example, looking at OverflowInt's godoc:
OverflowInt reports whether the int64 x cannot be represented by v's type. It panics if v's Kind is not Int, Int8, Int16, Int32, or Int64.
None of that needs a value, in my opinion - a type would suffice. The implementation seems to confirm that - only the "kind" and "type" are used, not the actual value.
So I think the methods should be added to Type, with the same signature.
I noticed this because quite a few projects have code like reflect.Zero(typ).OverflowInt(x), when in fact it could just be typ.OverflowInt(x), saving the creation of a new value. For example, in encoding/json: https://cs.opensource.google/go/go/+/refs/tags/go1.20.4:src/encoding/json/decode.go;l=799
As for users who have a reflect.Value rather than a reflect.Type, they could also replace val.OverflowInt(x) with val.Type().OverflowInt(x), and we could consider deprecating the Value methods in favor of the Type methods after a few Go releases. I don't personally see a point in keeping eight methods around; .Type() isn't enough characters to warrant a shortcut, and in my experience, most reflect users will need to get the reflect.Type for other reasons.