The bifcl parser doesn't understand compound types very well

[ckreibich]

builtin-func.y has a couple of TODOs that have been around for a long time. For example, the type rule has this comment:

// TODO: Migrate all other compound types to this rule. Once the BiF language
// can parse all regular Zeek types, we can throw out the unnecessary
// boilerplate typedefs for addr_set, string_set, etc.

For example, this means that a BiF can return a type alias that's a vector of foo, but the function cannot itself return vector of foo.

[timwoj]

Maybe related: zeek/zeek#1472