Why would this take 410ms to type-check?

[dnadoba (David Nadoba)]

Operator overload resolution is known to be expensive.:

Boolean comparison causes extremely slow compilation

== is one of the operators with the most overloads in the standard library (over 70 overloads!), and currently the type checker is not very good at filtering out choices that won't work with the given argument types, so it ends up trying way too many of them even when it has enough information to narrow the choices down. Operator type checking performance is something we're actively working to improve.

The compiler is unable to type-check this expression in reasonable time... String [edit] addition with an Int in the mix (solved)

Hello, I've heard of the error "The compiler is unable to type-check this expression in reasonable time; try breaking up the expression into distinct sub-expressions" before, but never seen it myself. I was surprised to find it with this, seemingly simple code: public struct HikVisionCamera: Codable { var localIPAddress: String var username: String var password: String var channel: Int func srcURL() -> String { return "http://" + username + ":" + password + "@" + localIPAddress + "/I…

You can find more examples in the forums.

You can workaround this by splitting up the expression into multiple expression e.g. by using temporary variables.