tests/cases/conformance/types/union/unionTypeEquivalence.ts(5,5): error TS2403: Subsequent variable declarations must have the same type.  Variable 'x' must be of type 'C', but here has type 'C | D'.


==== tests/cases/conformance/types/union/unionTypeEquivalence.ts (1 errors) ====
    // A | B is equivalent to A if B is a subtype of A
    class C { }
    class D extends C { foo() { } }
    var x: C;
    var x : C | D;
        ~
!!! error TS2403: Subsequent variable declarations must have the same type.  Variable 'x' must be of type 'C', but here has type 'C | D'.
    
    // A | B is equivalent to B | A.
    var y: string | number;
    var y : number | string;
    
    // AB | C is equivalent to A | BC, where AB is A | B and BC is B | C.
    var z : string | number | boolean;
    var z : (string | number) | boolean;
    var z : string | (number | boolean);
    var AB : string | number;
    var BC : number | boolean;
    var z1: typeof AB | boolean;
    var z1: string | typeof BC;