==== tests/cases/conformance/types/typeRelationships/assignmentCompatibility/typeParameterAssignability3.ts (4 errors) ====
    // type parameters are not assignable to one another unless directly or indirectly constrained to one another
    
    class Foo { foo: string; }
    
    function foo<T extends Foo, U extends Foo>(t: T, u: U) {
        var a: T;
        var b: U;
        t = a; // ok
        a = t; // ok
    
        b = u; // ok
        u = b; // ok
    
        t = u; // error
        ~
!!! error TS2323: Type 'U' is not assignable to type 'T'.
        u = t; // error
        ~
!!! error TS2323: Type 'T' is not assignable to type 'U'.
    }
    
    class C<T extends Foo, U extends Foo> {
        t: T;
        u: U;
        r = () => {
            this.t = this.u; // error
            ~~~~~~
!!! error TS2323: Type 'U' is not assignable to type 'T'.
            this.u = this.t; // error
            ~~~~~~
!!! error TS2323: Type 'T' is not assignable to type 'U'.
        }
    }