JuliaLang/julia — pull request #8883 by ninjin (2014-11-03 07:04:30+00:00)
Title: WIP: Type promotion for keys and values for Dict merge

@wlbksy was puzzled by the current behaviour in #8877. This PR does not affect `merge!`, but makes `merge` promote the key and value types if necessary for the returned dictionary. Tests included.

Until I find a better way than what you see below to access the type parameters, this PR is to be considered work in progress. I do feel slightly ashamed that my Julia/Google-fu has failed me when looking for a better solution.

ktype{K,_}(d::Associative{K,_}) = K
vtype{_,V}(d::Associative{_,V}) = V