Any vs. any Sendable discrepancies are marked as errors for uses of inout properties

[jmschonfeld]

Description

When calling a function with an inout property, if the type of the value provided mismatches due to Sendable conformances (even if the provided variable is @preconcurrency the mismatch is diagnosed as an error even in Swift 5 mode.

Reproduction

@preconcurrency var d = Dictionary<String, any Sendable>()
func foo(_: inout Dictionary<String, Any>) {}
foo(&d) // Inout argument could be set to a value with a type other than '[String : any Sendable]'; use a value declared as type 'Dictionary<String, Any>' instead

Expected behavior

I'd expect this to be a warning in Swift 5 mode for clients not opting into strict concurrency checking

Environment

Tested with a reason Swift 6.1 development snapshot

Additional information

No response