Confusing error from @lens _.[:a]

julia> @lens _[:a]
(@lens _[:a])

julia> @lens _.[:a]
ERROR: TypeError: in Type, in parameter, expected Type, got Expr
Stacktrace:
 [1] top-level scope at REPL[36]:1

julia> @macroexpand @lens _.[:a]
:(Setfield.compose(Setfield.PropertyLens{$(QuoteNode(:([:a])))}()))

Note the . before [:a].

Was the @lens _.[:a] a typo or did you expect any particular semantics?

Sorry, I should've clarified that it was about error handling. I think it would be nice to throw an error inside the macro.

(We probably can add some meaning to it after Julia adds getindex broadcasting.)

I think we simply need to check if property is a Symbol:

Setfield.jl/src/sugar.jl

Line 72 in 854fb3d

lens = :(PropertyLens{$(QuoteNode(property))}())

We also need to allow String. I just mark it as good first issue (although maybe I'll do it at some point).

Yeah, I already had kind of a bad feeling when I wrote Symbol. Good idea to label this first issue.

#98