You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: 393_serde_errors.rs
    path of file: ./repos/ron/tests
    
    the code of the file until where you have to start completion: use ron::error::{Error, Position, SpannedError};

#[derive(Debug, serde::Deserialize, PartialEq)]
#[serde(deny_unknown_fields)]
enum TestEnum {
    StructVariant { a: bool, b: char, c: i32 },
    NewtypeVariant(TestStruct),
}

#[derive(Debug, serde::Deserialize, PartialEq)]
#[serde(tag = "type")]
enum TestEnumInternal {
    StructVariant { a: bool },
}

#[derive(Debug, serde::Deserialize, PartialEq)]
#[serde(tag = "type"
    
fn test_adjacently_tagged_enum() {
    // Note: TestEnumAdjacent makes sense here since we are now treating
    //        the enum as a struct

    assert_eq!(
        ron::from_str::<TestEnumAdjacent>("(type: StructVariant, content: (d: 4))"),
        Err(SpannedError {
            code: Error::MissingStructField {
                field: "a",
                outer: Some(String::from("TestEnumAdjacent")),
            },
            position: Position { line: 1, col: 37 },
        })
    );
}