Nullable compont generates recursive type

The GitHub API spec contains the following component:

"auto-merge": {
  "title": "Auto merge",
  "description": "The status of auto merging a pull request.",
  "type": "object",
  "properties": {
    "enabled_by": {
      "$ref": "#/components/schemas/simple-user"
    },
    "merge_method": {
      "type": "string",
      "description": "The merge method to use.",
      "enum": [
        "merge",
        "squash",
        "rebase"
      ]
    },
    "commit_title": {
      "type": "string",
      "description": "Title for the merge commit message."
    },
    "commit_message": {
      "type": "string",
      "description": "Commit message for the merge commit."
    }
  },
  "required": [
    "enabled_by",
    "merge_method",
    "commit_title",
    "commit_message"
  ],
  "nullable": true
}

When set as nullable: true this component generates duplicate structs, one of which is recursive:

#[doc = "The status of auto merging a pull request."]
#[derive(Clone, Debug, Deserialize, Serialize)]
pub struct AutoMerge(pub Option<AutoMerge>);

#[doc = "The status of auto merging a pull request."]
#[derive(Clone, Debug, Deserialize, Serialize)]
pub struct AutoMerge {
    #[doc = "Commit message for the merge commit."]
    pub commit_message: String,
    #[doc = "Title for the merge commit message."]
    pub commit_title: String,
    pub enabled_by: SimpleUser,
    #[doc = "The merge method to use."]
    pub merge_method: AutoMergeMergeMethod,
}

I haven't tracked down where this occurring, but it looks like:

• nullable triggers two structs to be created, one inner struct containing the fields and one newtype wrapper.
• If the component contains a title property, it does not get checked for uniqueness against the wrapper type, and does not have the Inner suffix added

As a test, if the component is changed to:

"auto-merge": {
  "title": "Auto merge test",
  ...
  "nullable": true
}

then it generates:

pub struct AutoMerge(pub Option<AutoMergeTest>);

and removing the tile property generates:

pub struct AutoMerge(pub Option<AutoMergeInner>);

Start by tracing how nullable components are handled during Rust type generation, focusing on wrapper and inner-type naming and uniqueness checks. Use the GitHub API auto-merge component from the issue as a reproduction; it is done when nullable components generate distinct wrapper and inner structs without recursive duplicate definitions.