==== tests/cases/conformance/types/typeRelationships/bestCommonType/bestCommonTypeOfConditionalExpressions2.ts (8 errors) ====
    // conditional expressions return the best common type of the branches plus contextual type (using the first candidate if multiple BCTs exist)
    // these are errors
    
    class Base { foo: string; }
    class Derived extends Base { bar: string; }
    class Derived2 extends Base { baz: string; }
    var base: Base;
    var derived: Derived;
    var derived2: Derived2;
    
    var r2 = true ? 1 : '';
             ~~~~~~~~~~~~~
!!! No best common type exists between 'number' and 'string'.
    var r9 = true ? derived : derived2;
             ~~~~~~~~~~~~~~~~~~~~~~~~~
!!! No best common type exists between 'Derived' and 'Derived2'.
    
    function foo<T, U>(t: T, u: U) {
        return true ? t : u;
               ~~~~~~~~~~~~
!!! No best common type exists between 'T' and 'U'.
    }
    
    function foo2<T extends U, U>(t: T, u: U) { // Error for referencing own type parameter
                  ~~~~~~~~~~~
!!! Constraint of a type parameter cannot reference any type parameter from the same type parameter list.
        return true ? t : u; // Ok because BCT(T, U) = U
               ~~~~~~~~~~~~
!!! No best common type exists between 'T' and 'U'.
    }
    
    function foo3<T extends U, U extends V, V>(t: T, u: U) {
                  ~~~~~~~~~~~
!!! Constraint of a type parameter cannot reference any type parameter from the same type parameter list.
                               ~~~~~~~~~~~
!!! Constraint of a type parameter cannot reference any type parameter from the same type parameter list.
        return true ? t : u;
               ~~~~~~~~~~~~
!!! No best common type exists between 'T' and 'U'.
    }