Struct variant don't deserialize from sequence with #[serde(untagged)]

[Baptistemontan]

I'm currently messing around with serde creating my own binary format, and I encode the type of the data, but I don't encode fields names for struct like type, so a struct is treated as a sequence. encoding the type allows me to implement Deserializer::deserialize_any as I can peek the tag and call the appropriate function.

It worked well until I tried with an enum with the #[serde(untagged)] attribute. I kind of lose my sanity trying to understand what was wrong, until I checked the expanded #[derive(Deserialize)] macro. Struct variant Visitor only implement Visitor::visit_map.

Is there a reason why struct variant don't implement Visitor::visit_seq like normal struct does when the #[serde(untagged)] is present ?

[Mingun]

My PR #2465 fixes exactly that problem

[Baptistemontan]

Thanks! I tried searching any related Issue but did not search through the PR. I kind of fixed the problem by looking throught the auto implemntation and found that the Field enum deserialized from the key of the map can be deserialized with a u64 representing the field index, so I now deserialize struct like types with a custom MapAccess that gives a u64 as a key, and just increment it. It feels a bit like a redneck solutions but everything seams to work fine.