(RUST)cannot infer type for type parameter X

Question

I am learning to make functions with generic types but I have been stuck for a few hours with this error that says cannot infer type for type parameter 'X' It is assumed that in my Impl I have already defined the types that X and Y will have.

pub struct Generate<X,Y>{
    pub data_type:X,
    pub data_config:Y
}

impl<X,Y> Generate<X,Y>{
     pub fn new_bi()->Generate<u16,String>{
        Generate{
            data_type:10,
            data_config:String::from("Hello"),
        }
    }
    pub fn new_an()->Generate<String,u16>{
        Generate{
            data_type:String::from("Hello"),
            data_config:10
        }
    }
}

fn main(){
 let y = Generate::new_bi();// ERROR HERE
 let y: Generate<u16,String> = Generate::new_bi();//I tried this but it didn't work
}

Answer 1

You can make specific implementations depending on the types:

pub struct Generate<X,Y>{
    pub data_type:X,
    pub data_config:Y
}

impl Generate<u16,String>{
     pub fn new_bi()->Generate<u16,String>{
        Generate{
            data_type:10,
            data_config:String::from("Hello"),
        }
    }
}

impl Generate<String,u16>{
    pub fn new_an()->Generate<String,u16>{
        Generate{
            data_type:String::from("Hello"),
            data_config:10
        }
    }
}

fn main(){
 let y = Generate::new_bi();// ERROR HERE
 let y: Generate<u16,String> = Generate::new_bi();//I tried this but it didn't work
 let x = Generate::new_an();
}

Playground