Description
There is some similar logic in promoting string to double type in TypeCoercion and AnsiTypeCoercion.
We can change the function Abs/UnaryMinus/UnaryPositive to extend
ImplicitCastInputTypes so that string will implicitly cast to Double type in the rule `ImplicitTypeCasts`. We don't have to repeat the logic in rule `PromoteStrings` or `PromoteStringLiterals`