`Into` with `ToString` and `Vec<ToString>`

1

Hi,

I'm trying to convert a ToString or Vec<ToString> argument to an Enum, but I'm stuck on implementing the From trait, as there is a conflicting implementation, which seems logical to me as T covers both X and Vec<Y>:

fn main() {
    test("a");
    test("b".to_string());
    test(vec!["c"]);
    test(vec!["d".to_string()]);
}

fn test<T>(value: T) where T: Into<TestEnum> {
    let value = value.into();
}

enum TestEnum {
    String(String),
    Vec(Vec<String>),
}

impl<T> From<T> for TestEnum where T: ToString {
    fn from(value: T) -> Self {
        TestEnum::String(value.to_string())
    }
}

impl<T> From<Vec<T>> for TestEnum where T: ToString {
    fn from(value: Vec<T>) -> Self {
        TestEnum::Vec(value.iter().map(|value| value.to_string()).collect())
    }
}

The error:

error[E0119]: conflicting implementations of trait `std::convert::From<std::vec::Vec<_>>` for type `TestEnum`:
  --> src/main.rs:23:1
   |
17 | impl<T> From<T> for TestEnum where T: ToString {
   | ---------------------------------------------- first implementation here
...
23 | impl<T> From<Vec<T>> for TestEnum where T: ToString {
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `TestEnum`
   |
   = note: upstream crates may add a new impl of trait `std::fmt::Display` for type `std::vec::Vec<_>` in future versions

How can I implement this?

Kind regards,
Raymond

2

Sorry, you can't have both From impls.

3

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