Confusing compiler error "Value of optional type 'T?' must be unwrapped to a value of type 'T'" when comparing optional with non-optional

[nickasd]

Description

When comparing an optional with a non-optional with == where the type doesn't conform to Equatable, the compiler shows a confusing error Value of optional type 'T?' must be unwrapped to a value of type 'T'.

Reproduction

class MyClass<T: RawRepresentable> where T.RawValue == String {
    
    func asd(a: T?) {
        let b = a!
        print(a == b) // compiler error: Value of optional type 'T?' must be unwrapped to a value of type 'T'
    }
    
}

Expected behavior

The compiler should show the error

Operator function '==' requires that 'T' conform to 'Equatable'

which correctly appears when removing the constraint where T.RawValue == String.

Environment

swift-driver version: 1.90.11.1 Apple Swift version 5.10 (swiftlang-5.10.0.13 clang-1500.3.9.4)
Target: arm64-apple-macosx14.0

Additional information

No response