macroSwizzle.lean:4:7-4:23: error: failed to synthesize
  HAdd Bool String ?m

Hint: Additional diagnostic information may be available using the `set_option diagnostics true` command.
macroSwizzle.lean:6:7-6:10: error: Application type mismatch: The argument
  "x"
has type
  String
but is expected to have type
  Nat
in the application
  Nat.succ "x"
sorry.succ : Nat