If you see the error "Enum case 'someCase' not found in type 'someEnumType'", add ! to 'someEnumTypeVar'.

// Error
switch someEnumTypeVar {
case .someCase:
    <#code#>
default:
    <#code#>
}

// Fixed
switch someEnumTypeVar! {
case .someCase:
    <#code#>
default:
    <#code#>
}