Conjure-generated client does not properly serialize nested aliases in PLAIN context

Generate a Conjure client using the following definition:

types:
  definitions:
    default-package: com.palantir.product
    objects:
      AliasOne:
        alias: string
      AliasTwo:
        alias: optional<AliasOne>
      AliasThree:
        alias: AliasTwo

services:
  EteService:
    name: Ete Service
    package: com.palantir.product
    base-path: /base

    endpoints:
      aliasThree:
        http: GET /aliasThree
        args:
          queryParamName:
            param-type: query
            type: AliasThree
        returns: AliasThree

Make the following client call:

eteService.aliasThree(AliasThree.of(AliasTwo.of(Optional.empty()))

Expected

Calls the endpoint with no query parameters (because serialized equivalent is Optional.empty())

Actual

Calls the endpoint with a query parameter that consists of the literal string Optional.empty

The same issue exists for non-optional calls:

eteService.aliasThree(
                AliasThree.of(AliasTwo.of(Optional.of(AliasOne.of("hello"))))

Expected

Query parameter value is hello

Actual

Query parameter value is Optional[hello]

Based on this, it appears that PLAIN serialization does not properly work for alias types nested in optionals.

Generate the client from the provided Conjure definition and reproduce the aliasThree calls in the generated client. Start at the PLAIN serialization path used for the query parameter; done means Optional.empty produces no parameter and the nested value produces hello rather than Optional[hello].