(See the following code repository for a working example: https://github.com/frenchy64/typed-cljc-bug)
When cljc reader conditionals (#? and #?@) are used in the ns form of a cljc file, check-ns returns :ok, but does not actually check the namespace.
The following error message is displayed, complaining of a lacking NS form:
Bump tools.namespace to 0.2.11.
Fix is to update tools.namespace https://github.com/clojure/tools.namespace/blob/master/CHANGES.md#version-0211-on-19-jun-2015