function_default_parameter_at_end should not trigger for isolated parameter.

[Supereg]

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Feature or Enhancement Proposal

Swift 6 introduced a new notation for inheriting the actor isolation from the call site (see SE-0420). The special parameter isolated is typically placed as the first argument of a method with the default value #isolation.

This violates the function_default_parameter_at_end rule and I think such cases should receive an exemption from the rule.
The current implementation, only considers closures as special cases.

// warning: Function Default Parameter at End Violation: Prefer to locate parameters with defaults toward the end of the parameter list (function_default_parameter_at_end)
func foo(isolation: isolated (any Actor)? = #isolation, bar: String) {
    print("foo \(bar)")
}

Looking at the original proposal (see SE-0313), isolated parameter can occur at any position. Checking for the isolated attribute and a default value #isolation should be enough to detect isolation inheritance.

[SimplyDanny]

This should be hidden behind a new option which is off by default.

[Supereg]

This should be hidden behind a new option which is off by default.

So the idea would be to add something like a ignore_isolation_inheritance_parameter configuration option for the function_default_parameter_at_end rule that is disabled by default?

[SimplyDanny]

This should be hidden behind a new option which is off by default.

So the idea would be to add something like a ignore_isolation_inheritance_parameter configuration option for the function_default_parameter_at_end rule that is disabled by default?

Yes, that'd be the idea. For the option name, we might prefer the plural ignore_isolation_inheritance_parameters. That's currently inconsistent throughout the configurations. Plural feels more natural though.