Function signature as string

[John Chapman]

Is there any way to get a string representing a function's exact 
signature as declared in the source? I can generate it myself 
using reflection but it might not be 100% verbatim so wanted to 
know if there's anything built in?

   foreach (m; __traits(allMembers, T)) {
     alias member = __traits(getMember, T, m);
     string signature = // Call some function to get "member"'s 
signature as a string
   }