Extend :meta to allow saving extra information.
deprecate functions inf() and nan()
Avoid unstable return type.
Merge pull request #8779 from maleadt/pr_meta

Extend :meta to allow saving extra information.
rm obsolete commented-out code
fix #8785, compiler confusion when `call` is not a function
Merge branch 'master' of github.com:JuliaLang/julia
Merge pull request #8776 from JuliaLang/jb/infnan

deprecate functions `inf` and `nan`
remove `evaluate` function for functor types