eagerUnfoldingIssue.lean:6:2-6:17: error(lean.synthInstanceFailed): failed to synthesize instance of type class
  MonadLog (StateM Nat)

Hint: Type class instance resolution failures can be inspected with the `set_option trace.Meta.synthInstance true` command.
eagerUnfoldingIssue.lean:12:2-12:17: error(lean.synthInstanceFailed): failed to synthesize instance of type class
  MonadLog (StateM Nat)

Hint: Type class instance resolution failures can be inspected with the `set_option trace.Meta.synthInstance true` command.