Another slightly strange enum cast future.  If the enum declaration is
moved to the global scope or if the string type is used directly
(vs. as a type parameter), things work fine.
Merge pull request #245 from sungeunchoi/cast-enum-in-fn-future

Another slightly strange enum cast future.

bug: Unable to resolve return type for cast between enum and string if enum declared in function and string passed in as type parameter

If the enum declaration is moved to the global scope or if the string type is used directly
(vs. as a type parameter), things work fine.