Errors in Liveview: Parse error ... expected attribute name

I’m stumped. I have a LiveView form tied to a Changeset (rather than a schema) like so:

~H"""
  <.form as={:form} for={@changeset} :let={f} phx-change="validate" phx-submit="save">
    <.input field={f[:email]} />
  </.form>
"""

I can see errors collecting into my changeset on validate. What’s the best pattern for showing an error from the changeset? I see reference to phx-feedback-for and an <.error> helper, but something like this:

<div phx-feedback-for={:email}>
  <.input field={f[:email]} />
  <.error :for={msg <- @changeset.errors}><%%= msg %></.error>
</div>

leaves me with an Parse error ... expected attribute name.

Thank you in advance.