TypeScript strange downcast rules

InJava.java

// ==== Basic Elements

class Elem {
    public String id;
}

class NamedElem extends Elem {
    public String name;
} 

interface Printer<E extends Elem> {
    public void print(E e);
}

class PrintNamed implements Printer<NamedElem> {
    public void print(NamedElem e) {
        System.out.println(e);
    }
}

public class Main {
    public static void main(String[] args) {
        Elem ebase = new Elem();
        NamedElem namedelem = new NamedElem();
                
        PrintNamed named = new PrintNamed();
        named.print(namedelem);
        
        Printer<NamedElem> n2 = named;
        n2.print(namedelem);
        
        // Unlike TS, Java says
        // error: incompatible types: Printer<NamedElem> cannot be converted to Printer<Elem>
        Printer<Elem> n3 = n2;
        n3.print(namedelem);
    }
}

InTypeScript.ts

// ==== Basic Elements

type Elem = { id: string };
type NamedElem = Elem & { name: string };
// Any NamedElem is an Elem


// ==== Printers

interface Printer<E extends Elem = Elem> {
    print(e: E): void;
}

class PrintBase implements Printer<Elem> {
    print(e: Elem): void {
        console.log(e);
    }
}

class PrintNamed implements Printer<NamedElem> {
    print(e: NamedElem) {
        console.log(e);
    }
}


// ==== Go

const base = new PrintBase();
base.print({ id: "Basic elem" });

const named = new PrintNamed();
named.print({ id: "Named element", name: "COUCOU" });
// named.print({ id: "Not named but error" }); // error

const notSoNamed: Printer<Elem> = named;
notSoNamed.print({ id: "same printer but now accepts without name" });