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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;
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