narrowingUnionToNeverAssigment.ts(8,15): error TS2322: Type '"c" | "d"' is not assignable to type 'never'.
  Type '"c"' is not assignable to type 'never'.


==== narrowingUnionToNeverAssigment.ts (1 errors) ====
    type Variants = "a" | "b" | "c" | "d";
    
    
    function fx1(x: Variants) {
        if (x === "a" || x === "b") {        
        }
        else {
            const y: never = x;
                  ~
!!! error TS2322: Type '"c" | "d"' is not assignable to type 'never'.
!!! error TS2322:   Type '"c"' is not assignable to type 'never'.
        }
    }
    