a.ts(9,11): error TS2322: Type 'string | number' is not assignable to type 'never'.
  Type 'string' is not assignable to type 'never'.
a.ts(13,9): error TS7022: 'v' implicitly has type 'any' because it does not have a type annotation and is referenced directly or indirectly in its own initializer.
a.ts(14,14): error TS7023: 'h' implicitly has return type 'any' because it does not have a return type annotation and is referenced directly or indirectly in one of its return expressions.
a.ts(16,15): error TS2322: Type 'any' is not assignable to type 'never'.
