B.foo "hello" : String × String
[Meta.synthInstance] ❌️ Add String
  [Meta.synthInstance] no instances for Add String
    [Meta.synthInstance.instances] #[]
  [Meta.synthInstance] result <not-available>
[Meta.synthInstance] ❌️ Add Bool
  [Meta.synthInstance] no instances for Add Bool
    [Meta.synthInstance.instances] #[]
  [Meta.synthInstance] result <not-available>