Rule Request: [no_number_literal_calculation]

New Issue Checklist

• Updated SwiftLint to the latest version
• I searched for existing GitHub issues

New rule request

I run into code like the below a few times

let secondsInOneDay = 60 * 60 * 24

Since this kind of code can slow the type inference, the calculation should be done beforehand and only the answer should be used.

let secondsInOneDay = 86400

This rule should calculate the expression and replace it when running swiftlint fix.

Note
Since (I believe) this rule would be a subset of no_magic_numbers, it might be better if this was a configuration of no_magic_numbers rather than a separate rule.

1. Why should this rule be added?

This can help users detect type inference-heavy codes and rewrite them easily.

2. Provide several examples of what would and wouldn't trigger violations.

Triggering:

let secondsInOneDay = 60 * 60 * 24
let n = 4
let secondsInNDays = 60 * 60 * 24 * n

Non triggering:

let secondsInOneDay = 86400
let n = 4
let secondsInNDays = 86400 * n

3. Should the rule be configurable, if so what parameters should be configurable?
   No
4. Should the rule be opt-in or enabled by default? Why?
   Personally I would love to have this rule by default but I think some people prefer 60 * 60 * 24 as their choice of coding style so this rule should be opt-in.

Start by reviewing the existing no_magic_numbers rule and how swiftlint fix handles rule violations. Clarify whether this should be a separate opt-in rule or a no_magic_numbers configuration, then define completion around folding constant arithmetic such as 60 * 60 * 24 while leaving expressions involving variables unchanged.