On this official Google page about canonical links it says:
Can rel="canonical" be a redirect?
Yes, you can specify a URL that redirects as a canonical URL. Google will then process the redirect as usual and try to index it.
There is no mention that this might dilute the impact of the canonical link. However, Google has made clear elsewhere that 301 redirects do dilute PageRank - roughly as much as a link dilutes PageRank. Is that relevant here? I'm assuming the answer is "no" but I wanted to confirm.
Relevant but not duplicate: Does Rel=Canonical Pass PR from Links or Just Fix Dup Content.